TY  - JOUR
AU  - Ilić, Dejan
AU  - Janković, Novica
AU  - Čantrak, Đorđe
AU  - Savić, Ljubomir
PY  - 2024
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6994
AB  - In this paper are presented desing, testing and numerical analysis for two manufactured control valve trims. Valve trim is consisted of cage or dick stack, plug, stem and seat. Size from app. 15.88 mm (0.625 in) up to 101.6 mm (4 in) is suitable for 3D metal and plastic print, what is presented in this paper. Selective laser melting 3D metal printing is applied on the disc presented in this paper. Even better material properties from rest of the valve parts could be obtained. This is of great importance for valve retrofitting. In this paper is presented, also, new developed channel geometry, what is followed by various fluid flow phenomena. Measurement results for second prototype manufactured by 3D printing using plastics are presented in details. Here is shown, in short, procedure for determination of KV values of the test valves according to the EN 60534-2-3, Industrial-process control valves - Part 2-3: Flow capacity - Test procedures. In addition, some aspects of CFD calculations are presented.
PB  - VINČA Institute of Nuclear Sciences
T2  - Thermal Science
T1  - Experimental and numerical research of the flow inside the control valves trim
EP  - 587
IS  - 1B
SP  - 579
VL  - 28
DO  - 10.2298/TSCI230405157I
ER  - 

@article{
author = "Ilić, Dejan and Janković, Novica and Čantrak, Đorđe and Savić, Ljubomir",
year = "2024",
abstract = "In this paper are presented desing, testing and numerical analysis for two manufactured control valve trims. Valve trim is consisted of cage or dick stack, plug, stem and seat. Size from app. 15.88 mm (0.625 in) up to 101.6 mm (4 in) is suitable for 3D metal and plastic print, what is presented in this paper. Selective laser melting 3D metal printing is applied on the disc presented in this paper. Even better material properties from rest of the valve parts could be obtained. This is of great importance for valve retrofitting. In this paper is presented, also, new developed channel geometry, what is followed by various fluid flow phenomena. Measurement results for second prototype manufactured by 3D printing using plastics are presented in details. Here is shown, in short, procedure for determination of KV values of the test valves according to the EN 60534-2-3, Industrial-process control valves - Part 2-3: Flow capacity - Test procedures. In addition, some aspects of CFD calculations are presented.",
publisher = "VINČA Institute of Nuclear Sciences",
journal = "Thermal Science",
title = "Experimental and numerical research of the flow inside the control valves trim",
pages = "587-579",
number = "1B",
volume = "28",
doi = "10.2298/TSCI230405157I"
}

Ilić, D., Janković, N., Čantrak, Đ.,& Savić, L.. (2024). Experimental and numerical research of the flow inside the control valves trim. in Thermal Science
VINČA Institute of Nuclear Sciences., 28(1B), 579-587.
https://doi.org/10.2298/TSCI230405157I

Ilić D, Janković N, Čantrak Đ, Savić L. Experimental and numerical research of the flow inside the control valves trim. in Thermal Science. 2024;28(1B):579-587.
doi:10.2298/TSCI230405157I .

Ilić, Dejan, Janković, Novica, Čantrak, Đorđe, Savić, Ljubomir, "Experimental and numerical research of the flow inside the control valves trim" in Thermal Science, 28, no. 1B (2024):579-587,
https://doi.org/10.2298/TSCI230405157I . .

TY  - CONF
AU  - Ilić, Jelena
AU  - Medojević, Ivana
AU  - Janković, Novica
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7171
AB  - In the last decades, the field of fluid dynamics has evolved significantly thanks to the
development of experimental and measurement techniques (hot wire, LDA, PTV, PIV), as well as
the increasing computational capabilities and the improvement of available software and
methods, such as CFD. All these techniques generate enormous volumes of data. Extracting
valuable and useful information from them is often a time-consuming task, that could be aided by
Deep Learning (DL). Herein, some of the many possible applications of DL, in particular the
YOLO algorithm, in the practice of PIV, are considered and suggested.
T1  - DEEP LEARNING IN PIV APPLICATIONS
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7171
ER  - 

@conference{
author = "Ilić, Jelena and Medojević, Ivana and Janković, Novica",
year = "2023",
abstract = "In the last decades, the field of fluid dynamics has evolved significantly thanks to the
development of experimental and measurement techniques (hot wire, LDA, PTV, PIV), as well as
the increasing computational capabilities and the improvement of available software and
methods, such as CFD. All these techniques generate enormous volumes of data. Extracting
valuable and useful information from them is often a time-consuming task, that could be aided by
Deep Learning (DL). Herein, some of the many possible applications of DL, in particular the
YOLO algorithm, in the practice of PIV, are considered and suggested.",
title = "DEEP LEARNING IN PIV APPLICATIONS",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7171"
}

Ilić, J., Medojević, I.,& Janković, N.. (2023). DEEP LEARNING IN PIV APPLICATIONS. .
https://hdl.handle.net/21.15107/rcub_machinery_7171

Ilić J, Medojević I, Janković N. DEEP LEARNING IN PIV APPLICATIONS. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_7171 .

Ilić, Jelena, Medojević, Ivana, Janković, Novica, "DEEP LEARNING IN PIV APPLICATIONS" (2023),
https://hdl.handle.net/21.15107/rcub_machinery_7171 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
AU  - Lečić, Lazar
PY  - 2023
UR  - http://www.ssm.kg.ac.rs/congress_2023/papers/
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6911
UR  - http://www.ssm.kg.ac.rs/congress_2023/wp-content/uploads/upload/ICSSM2023_Book_of_Proceedings.pdf
AB  - Turbulent swirling flow is characterized by significant vortex fluctuations, intensive diffusion processes and energy cascade transfer from larger to smaller vortices over a continuous spectrum of wave numbers. The dissipation of the kinetic energy of turbulence occurs in the smallest vortices, because in these areas, both the velocity gradients and the deformation velocities are the largest. In this paper is analyzed turbulent swirling flow in pipe, generated by the axial fan impellers for three various blade angles (22°, 26° and 30°). Vorticity, enstrophy and lambda 2 values are calculated in order to study the structure of the generated turbulent swirling flows. Axial fan impeller operates in the region of lower flow rates, and it is shown that blade angle doesn’t influence much on the integral flow parameters, as well as on the enstrophy distribution. It is, also, shown that the dissipation of the kinetic energy of turbulence is associated with the vorticity fluctuations, i.e. with turbulent fluctuating enstrophy. All these distributions are obtained by use of the high speed particle image velocimetry data and provided velocity fields. Enstrophy is directly related to the kinetic energy, i.e. it corresponds to dissipation effects in this flow. It has maximum in small vortices, i.e. in shear layer, that surrounds vortex core region, where the process of turbulence kinetic energy dissipation occurs.
PB  - Српско друштво за механику
C3  - 9th International Congress of the Serbian Society of Mechanics July 5-7, 2023, Vrnjačka Banja, Serbia
T1  - Enstrophy Study of the Turbulent Swirling Flow in Pipe
SP  - 84
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6911
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan and Lečić, Lazar",
year = "2023",
abstract = "Turbulent swirling flow is characterized by significant vortex fluctuations, intensive diffusion processes and energy cascade transfer from larger to smaller vortices over a continuous spectrum of wave numbers. The dissipation of the kinetic energy of turbulence occurs in the smallest vortices, because in these areas, both the velocity gradients and the deformation velocities are the largest. In this paper is analyzed turbulent swirling flow in pipe, generated by the axial fan impellers for three various blade angles (22°, 26° and 30°). Vorticity, enstrophy and lambda 2 values are calculated in order to study the structure of the generated turbulent swirling flows. Axial fan impeller operates in the region of lower flow rates, and it is shown that blade angle doesn’t influence much on the integral flow parameters, as well as on the enstrophy distribution. It is, also, shown that the dissipation of the kinetic energy of turbulence is associated with the vorticity fluctuations, i.e. with turbulent fluctuating enstrophy. All these distributions are obtained by use of the high speed particle image velocimetry data and provided velocity fields. Enstrophy is directly related to the kinetic energy, i.e. it corresponds to dissipation effects in this flow. It has maximum in small vortices, i.e. in shear layer, that surrounds vortex core region, where the process of turbulence kinetic energy dissipation occurs.",
publisher = "Српско друштво за механику",
journal = "9th International Congress of the Serbian Society of Mechanics July 5-7, 2023, Vrnjačka Banja, Serbia",
title = "Enstrophy Study of the Turbulent Swirling Flow in Pipe",
pages = "84",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6911"
}

Čantrak, Đ., Janković, N., Ilić, D.,& Lečić, L.. (2023). Enstrophy Study of the Turbulent Swirling Flow in Pipe. in 9th International Congress of the Serbian Society of Mechanics July 5-7, 2023, Vrnjačka Banja, Serbia
Српско друштво за механику., 84.
https://hdl.handle.net/21.15107/rcub_machinery_6911

Čantrak Đ, Janković N, Ilić D, Lečić L. Enstrophy Study of the Turbulent Swirling Flow in Pipe. in 9th International Congress of the Serbian Society of Mechanics July 5-7, 2023, Vrnjačka Banja, Serbia. 2023;:84.
https://hdl.handle.net/21.15107/rcub_machinery_6911 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, Lečić, Lazar, "Enstrophy Study of the Turbulent Swirling Flow in Pipe" in 9th International Congress of the Serbian Society of Mechanics July 5-7, 2023, Vrnjačka Banja, Serbia (2023):84,
https://hdl.handle.net/21.15107/rcub_machinery_6911 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
AU  - Nedeljković, Miloš
PY  - 2022
UR  - https://www.iahr.org/library/infor?pid=21378
UR  - https://cmswebonline.com/iahr2022/epro/html/06-08-039-1817.xml
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5573
AB  - Turbulent swirling flow occupies attention of numerous researchers worldwide. In this paper are presented experimental results of the research of the self induced pre-swirl by the centrifugal impeller. Circumferential velocity was measured in two cross-sections by use of the one-component laser Doppler velocimetry (LDV) system. Flow visualization at the pump inlet, as well as at the pump outlet, was conducted by using the high speed camera Photron Fastcam SA1.1 and the LED light for illumination. Air bubbles were used for flow illumination, and silver coated particles for LDV measurements. Pump characteristics (head, volume flow rate and power) are, also, measured in the tested duty point. Pre-swirl is visualized, while almost developed uniform turbulent flow is documented at the pump casing outlet. By using LDV it was possible to identify almost solid body circumferential velocity profile at the pump inlet, only 0.5D upstream, where D is pipe inner diameter. So, the influence of the impeller suction is obvious. In paper is, also discussed statistics of the generated turbulence.
C3  - 39th IAHR World Congress, Proceedings, Ed.: Miguel Ortega-Sánchez, No. 06-08-039-1817, June 19-24th, Granada, Spain
T1  - LDV Investigation of the Self Induced Pre-Swirl and Flow Visualization at the Centrifugal Pump Inlet and Outlet
EP  - 5270
SP  - 5264
DO  - 10.3850/IAHR-39WC2521711920221817
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan and Nedeljković, Miloš",
year = "2022",
abstract = "Turbulent swirling flow occupies attention of numerous researchers worldwide. In this paper are presented experimental results of the research of the self induced pre-swirl by the centrifugal impeller. Circumferential velocity was measured in two cross-sections by use of the one-component laser Doppler velocimetry (LDV) system. Flow visualization at the pump inlet, as well as at the pump outlet, was conducted by using the high speed camera Photron Fastcam SA1.1 and the LED light for illumination. Air bubbles were used for flow illumination, and silver coated particles for LDV measurements. Pump characteristics (head, volume flow rate and power) are, also, measured in the tested duty point. Pre-swirl is visualized, while almost developed uniform turbulent flow is documented at the pump casing outlet. By using LDV it was possible to identify almost solid body circumferential velocity profile at the pump inlet, only 0.5D upstream, where D is pipe inner diameter. So, the influence of the impeller suction is obvious. In paper is, also discussed statistics of the generated turbulence.",
journal = "39th IAHR World Congress, Proceedings, Ed.: Miguel Ortega-Sánchez, No. 06-08-039-1817, June 19-24th, Granada, Spain",
title = "LDV Investigation of the Self Induced Pre-Swirl and Flow Visualization at the Centrifugal Pump Inlet and Outlet",
pages = "5270-5264",
doi = "10.3850/IAHR-39WC2521711920221817"
}

Čantrak, Đ., Janković, N., Ilić, D.,& Nedeljković, M.. (2022). LDV Investigation of the Self Induced Pre-Swirl and Flow Visualization at the Centrifugal Pump Inlet and Outlet. in 39th IAHR World Congress, Proceedings, Ed.: Miguel Ortega-Sánchez, No. 06-08-039-1817, June 19-24th, Granada, Spain, 5264-5270.
https://doi.org/10.3850/IAHR-39WC2521711920221817

Čantrak Đ, Janković N, Ilić D, Nedeljković M. LDV Investigation of the Self Induced Pre-Swirl and Flow Visualization at the Centrifugal Pump Inlet and Outlet. in 39th IAHR World Congress, Proceedings, Ed.: Miguel Ortega-Sánchez, No. 06-08-039-1817, June 19-24th, Granada, Spain. 2022;:5264-5270.
doi:10.3850/IAHR-39WC2521711920221817 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, Nedeljković, Miloš, "LDV Investigation of the Self Induced Pre-Swirl and Flow Visualization at the Centrifugal Pump Inlet and Outlet" in 39th IAHR World Congress, Proceedings, Ed.: Miguel Ortega-Sánchez, No. 06-08-039-1817, June 19-24th, Granada, Spain (2022):5264-5270,
https://doi.org/10.3850/IAHR-39WC2521711920221817 . .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Savić, Ljubomir
AU  - Janković, Novica
AU  - Ilić, Dejan
PY  - 2022
UR  - https://ieep-2022.drustvo-termicara.com/book
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6049
AB  - Control valves have numerous applications like in natural gas control and transport (as anti surge and recycle valves, hot/cold bypass valves, throttling valves, degasser flow/level control valves), natural gas treatment for dehydration and desulphuring (TEG injection, flashing drum pressure control, amine pump recirculation control valves), LNG processing (gas/steam to vent valves, blowdown and depressing valves), refineries and petrochemical (charge pump recycle valves, blowdown control valves, emergency vent valves, amine pump recycle valves), ethylene plants (feed-pump recycle valve, blowdown and gas to vent/flare valves, steam conditioning and desuperheating, compressor recycle) and etc. Valve trim is consisted of cage or dick stack, plug, stem and seat. Size from app. 15.88 mm (0.625 in) up to 101.6 mm (4 in) is suitable for 3D metal print, what is presented in this paper. Selective laser melting 3D metal printing is applied on the disc presented in this paper. Even better material properties from rest of the valve parts could be obtained. This is of great importance for valve retrofitting. In this paper is presented, also new developed channel geometry, what is followed by various fluid flow phenomena. Here is shown, in short, procedure for determination of KV-Values of the test valves according to the EN 60534-2-3, Industrial-process control valves - Part 2-3: Flow capacity - Test procedures. Some aspects of CFD calculations will be presented, also.
C3  - Full Papers Proceedings of International Conference "IEEP 2022", November 08-09, 2022, Faculty of Mechanical Engineering of the University of Belgrade, Belgrade, Serbia
T1  - CONTROL VALVES TRIM DESIGN, RETROFITTING AND TESTING
EP  - 259
SP  - 253
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6049
ER  - 

@conference{
author = "Čantrak, Đorđe and Savić, Ljubomir and Janković, Novica and Ilić, Dejan",
year = "2022",
abstract = "Control valves have numerous applications like in natural gas control and transport (as anti surge and recycle valves, hot/cold bypass valves, throttling valves, degasser flow/level control valves), natural gas treatment for dehydration and desulphuring (TEG injection, flashing drum pressure control, amine pump recirculation control valves), LNG processing (gas/steam to vent valves, blowdown and depressing valves), refineries and petrochemical (charge pump recycle valves, blowdown control valves, emergency vent valves, amine pump recycle valves), ethylene plants (feed-pump recycle valve, blowdown and gas to vent/flare valves, steam conditioning and desuperheating, compressor recycle) and etc. Valve trim is consisted of cage or dick stack, plug, stem and seat. Size from app. 15.88 mm (0.625 in) up to 101.6 mm (4 in) is suitable for 3D metal print, what is presented in this paper. Selective laser melting 3D metal printing is applied on the disc presented in this paper. Even better material properties from rest of the valve parts could be obtained. This is of great importance for valve retrofitting. In this paper is presented, also new developed channel geometry, what is followed by various fluid flow phenomena. Here is shown, in short, procedure for determination of KV-Values of the test valves according to the EN 60534-2-3, Industrial-process control valves - Part 2-3: Flow capacity - Test procedures. Some aspects of CFD calculations will be presented, also.",
journal = "Full Papers Proceedings of International Conference "IEEP 2022", November 08-09, 2022, Faculty of Mechanical Engineering of the University of Belgrade, Belgrade, Serbia",
title = "CONTROL VALVES TRIM DESIGN, RETROFITTING AND TESTING",
pages = "259-253",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6049"
}

Čantrak, Đ., Savić, L., Janković, N.,& Ilić, D.. (2022). CONTROL VALVES TRIM DESIGN, RETROFITTING AND TESTING. in Full Papers Proceedings of International Conference "IEEP 2022", November 08-09, 2022, Faculty of Mechanical Engineering of the University of Belgrade, Belgrade, Serbia, 253-259.
https://hdl.handle.net/21.15107/rcub_machinery_6049

Čantrak Đ, Savić L, Janković N, Ilić D. CONTROL VALVES TRIM DESIGN, RETROFITTING AND TESTING. in Full Papers Proceedings of International Conference "IEEP 2022", November 08-09, 2022, Faculty of Mechanical Engineering of the University of Belgrade, Belgrade, Serbia. 2022;:253-259.
https://hdl.handle.net/21.15107/rcub_machinery_6049 .

Čantrak, Đorđe, Savić, Ljubomir, Janković, Novica, Ilić, Dejan, "CONTROL VALVES TRIM DESIGN, RETROFITTING AND TESTING" in Full Papers Proceedings of International Conference "IEEP 2022", November 08-09, 2022, Faculty of Mechanical Engineering of the University of Belgrade, Belgrade, Serbia (2022):253-259,
https://hdl.handle.net/21.15107/rcub_machinery_6049 .

TY  - CONF
AU  - Janković, Novica
AU  - Čantrak, Đorđe
AU  - Kokotović, Branko
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6821
PB  - Belgrade : Mining Institute
C3  - 8th Balkan Mining Congress : Proceedings, September 28-30, Belgrade 2022.
T1  - Reconstruction of Centrifugal Pump Impeller
EP  - 383
SP  - 377
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6821
ER  - 

@conference{
author = "Janković, Novica and Čantrak, Đorđe and Kokotović, Branko",
year = "2022",
publisher = "Belgrade : Mining Institute",
journal = "8th Balkan Mining Congress : Proceedings, September 28-30, Belgrade 2022.",
title = "Reconstruction of Centrifugal Pump Impeller",
pages = "383-377",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6821"
}

Janković, N., Čantrak, Đ.,& Kokotović, B.. (2022). Reconstruction of Centrifugal Pump Impeller. in 8th Balkan Mining Congress : Proceedings, September 28-30, Belgrade 2022.
Belgrade : Mining Institute., 377-383.
https://hdl.handle.net/21.15107/rcub_machinery_6821

Janković N, Čantrak Đ, Kokotović B. Reconstruction of Centrifugal Pump Impeller. in 8th Balkan Mining Congress : Proceedings, September 28-30, Belgrade 2022.. 2022;:377-383.
https://hdl.handle.net/21.15107/rcub_machinery_6821 .

Janković, Novica, Čantrak, Đorđe, Kokotović, Branko, "Reconstruction of Centrifugal Pump Impeller" in 8th Balkan Mining Congress : Proceedings, September 28-30, Belgrade 2022. (2022):377-383,
https://hdl.handle.net/21.15107/rcub_machinery_6821 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6844
C3  - 1st International Conference on Mathematical Modelling in Mechanics and Engineering, Booklet of Abstracts, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, 8-10 September 2022
T1  - Enstrophy in Turbulent Swirling Flow in Pipe
SP  - 72
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6844
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan",
year = "2022",
journal = "1st International Conference on Mathematical Modelling in Mechanics and Engineering, Booklet of Abstracts, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, 8-10 September 2022",
title = "Enstrophy in Turbulent Swirling Flow in Pipe",
pages = "72",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6844"
}

Čantrak, Đ., Janković, N.,& Ilić, D.. (2022). Enstrophy in Turbulent Swirling Flow in Pipe. in 1st International Conference on Mathematical Modelling in Mechanics and Engineering, Booklet of Abstracts, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, 8-10 September 2022, 72.
https://hdl.handle.net/21.15107/rcub_machinery_6844

Čantrak Đ, Janković N, Ilić D. Enstrophy in Turbulent Swirling Flow in Pipe. in 1st International Conference on Mathematical Modelling in Mechanics and Engineering, Booklet of Abstracts, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, 8-10 September 2022. 2022;:72.
https://hdl.handle.net/21.15107/rcub_machinery_6844 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, "Enstrophy in Turbulent Swirling Flow in Pipe" in 1st International Conference on Mathematical Modelling in Mechanics and Engineering, Booklet of Abstracts, Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, 8-10 September 2022 (2022):72,
https://hdl.handle.net/21.15107/rcub_machinery_6844 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6812
C3  - Светски дан метрологије, „Метрологија у дигиталној ери“, 20. мај 2022., Машински факултет у Београду
T1  - Савремене мерне технике у Лабораторији за турбуленцију и мерење брзине струјања флуида
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6812
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan",
year = "2022",
journal = "Светски дан метрологије, „Метрологија у дигиталној ери“, 20. мај 2022., Машински факултет у Београду",
title = "Савремене мерне технике у Лабораторији за турбуленцију и мерење брзине струјања флуида",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6812"
}

Čantrak, Đ., Janković, N.,& Ilić, D.. (2022). Савремене мерне технике у Лабораторији за турбуленцију и мерење брзине струјања флуида. in Светски дан метрологије, „Метрологија у дигиталној ери“, 20. мај 2022., Машински факултет у Београду.
https://hdl.handle.net/21.15107/rcub_machinery_6812

Čantrak Đ, Janković N, Ilić D. Савремене мерне технике у Лабораторији за турбуленцију и мерење брзине струјања флуида. in Светски дан метрологије, „Метрологија у дигиталној ери“, 20. мај 2022., Машински факултет у Београду. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_6812 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, "Савремене мерне технике у Лабораторији за турбуленцију и мерење брзине струјања флуида" in Светски дан метрологије, „Метрологија у дигиталној ери“, 20. мај 2022., Машински факултет у Београду (2022),
https://hdl.handle.net/21.15107/rcub_machinery_6812 .

TY  - JOUR
AU  - Čantrak, Đorđe
AU  - Janković, Novica
PY  - 2022
UR  - https://journals.sagepub.com/doi/10.1177/16878132221130563
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6338
AB  - Investigation of the turbulent swirl flow in the piping system is one of the most complex investigations in the field of energetics and turbulence. Axial fans in a pipe, without guide vanes, are widely used in practice and the problem of their duty point and energy efficiency is still extensively discussed. Analysis of the interaction between axial fans energy and construction parameters is one of the main topics in defining the fans energy efficiency potential. On one side, there is a three-dimensional velocity field in the wall-bounded flow with regions of great turbulence intensity. On the other side, there is a complex blade geometry, which generates the turbulent swirl flow. This paper presents research on the turbulent swirl flow, Rankine type, in an axially restricted system, using high-speed stereo particle image velocimetry (HSS PIV). Axial fan impeller, with outer diameter 0.399 m and nine twisted blades is the flow generator. The Reynolds number Re = 176,529 is achieved in the pipe. Reynolds stresses, statistical moments of higher order, and invariant maps are calculated based on the three component velocity fields. Here, intensive changes of all statistical parameters occur in radial and axial direction. In the flow region, four flow regions can be identified. Interaction of all these four flow regions produces extremely complex turbulent swirl flow, which is generated behind the axial fans. Determined invariant maps reveal turbulence structure. It is shown that the state of turbulence on the pipe axis is three-component isotropic, which is contrary to the case of axially unrestricted turbulent swirl flows. In the rest of the space, in the region up to r/R = 0.52, the states of turbulence occur in the area in between the boundaries which designate axis-symmetric turbulence (contraction) and axis-symmetric turbulence (expansion), in the vicinity of the state of three-component isotropic turbulence.
PB  - SAGE JOURNALS
T2  - Advances in Mechanical Engineering
T1  - High Speed Stereo PIV Investigation of the Turbuelnce Structure of the Axially Restricted Turbulent Swirl Flow behind the Axial Fan in Pipe
VL  - 14
DO  - 10.1177/16878132221130563
ER  - 

@article{
author = "Čantrak, Đorđe and Janković, Novica",
year = "2022",
abstract = "Investigation of the turbulent swirl flow in the piping system is one of the most complex investigations in the field of energetics and turbulence. Axial fans in a pipe, without guide vanes, are widely used in practice and the problem of their duty point and energy efficiency is still extensively discussed. Analysis of the interaction between axial fans energy and construction parameters is one of the main topics in defining the fans energy efficiency potential. On one side, there is a three-dimensional velocity field in the wall-bounded flow with regions of great turbulence intensity. On the other side, there is a complex blade geometry, which generates the turbulent swirl flow. This paper presents research on the turbulent swirl flow, Rankine type, in an axially restricted system, using high-speed stereo particle image velocimetry (HSS PIV). Axial fan impeller, with outer diameter 0.399 m and nine twisted blades is the flow generator. The Reynolds number Re = 176,529 is achieved in the pipe. Reynolds stresses, statistical moments of higher order, and invariant maps are calculated based on the three component velocity fields. Here, intensive changes of all statistical parameters occur in radial and axial direction. In the flow region, four flow regions can be identified. Interaction of all these four flow regions produces extremely complex turbulent swirl flow, which is generated behind the axial fans. Determined invariant maps reveal turbulence structure. It is shown that the state of turbulence on the pipe axis is three-component isotropic, which is contrary to the case of axially unrestricted turbulent swirl flows. In the rest of the space, in the region up to r/R = 0.52, the states of turbulence occur in the area in between the boundaries which designate axis-symmetric turbulence (contraction) and axis-symmetric turbulence (expansion), in the vicinity of the state of three-component isotropic turbulence.",
publisher = "SAGE JOURNALS",
journal = "Advances in Mechanical Engineering",
title = "High Speed Stereo PIV Investigation of the Turbuelnce Structure of the Axially Restricted Turbulent Swirl Flow behind the Axial Fan in Pipe",
volume = "14",
doi = "10.1177/16878132221130563"
}

Čantrak, Đ.,& Janković, N.. (2022). High Speed Stereo PIV Investigation of the Turbuelnce Structure of the Axially Restricted Turbulent Swirl Flow behind the Axial Fan in Pipe. in Advances in Mechanical Engineering
SAGE JOURNALS., 14.
https://doi.org/10.1177/16878132221130563

Čantrak Đ, Janković N. High Speed Stereo PIV Investigation of the Turbuelnce Structure of the Axially Restricted Turbulent Swirl Flow behind the Axial Fan in Pipe. in Advances in Mechanical Engineering. 2022;14.
doi:10.1177/16878132221130563 .

Čantrak, Đorđe, Janković, Novica, "High Speed Stereo PIV Investigation of the Turbuelnce Structure of the Axially Restricted Turbulent Swirl Flow behind the Axial Fan in Pipe" in Advances in Mechanical Engineering, 14 (2022),
https://doi.org/10.1177/16878132221130563 . .

TY  - JOUR
AU  - Čantrak, Đorđe
AU  - Janković, Novica
PY  - 2022
UR  - https://www.mdpi.com/1996-1073/15/15/5417
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6336
AB  - Turbulent swirl flow, which exists in numerous turbomachinery systems, is the focus of
this paper. It consumes a significant amount of energy, so it is a subject of investigation for many
researchers. It is even more present in ventilation systems, as numerous axial fans are still installed without guide vanes. The experimental investigation of the turbulent swirl flow behind an axial fan in a pipe, installed in a test rig with a free inlet and ducted outlet, as defined in the international standard ISO 5801, is presented in this paper. Moreover, in this paper, the axially restricted case is studied. A designed axial fan generates a Rankine vortex with a complex structure, and research on the vortex turbulence structure and dynamics is presented. On the basis of the HSS PIV (high-speed stereo particle image velocimetry), measurement results are calculated using invariant maps. All states of turbulence anisotropy are thoroughly analyzed by applying the invariant theory on HSS PIV results. Vortex dynamics is observed on the basis of the total velocity minima positions and their repetitions. Both methods are correlated, and important conclusions regarding vortex behavior are deduced.
PB  - MDPI
T2  - Energies
T1  - Turbulence Structure and Dynamics Investigation of Turbulent Swirl Flow in Pipe Using High-Speed Stereo PIV Data
VL  - 15
DO  - 10.3390/en15155417
ER  - 

@article{
author = "Čantrak, Đorđe and Janković, Novica",
year = "2022",
abstract = "Turbulent swirl flow, which exists in numerous turbomachinery systems, is the focus of
this paper. It consumes a significant amount of energy, so it is a subject of investigation for many
researchers. It is even more present in ventilation systems, as numerous axial fans are still installed without guide vanes. The experimental investigation of the turbulent swirl flow behind an axial fan in a pipe, installed in a test rig with a free inlet and ducted outlet, as defined in the international standard ISO 5801, is presented in this paper. Moreover, in this paper, the axially restricted case is studied. A designed axial fan generates a Rankine vortex with a complex structure, and research on the vortex turbulence structure and dynamics is presented. On the basis of the HSS PIV (high-speed stereo particle image velocimetry), measurement results are calculated using invariant maps. All states of turbulence anisotropy are thoroughly analyzed by applying the invariant theory on HSS PIV results. Vortex dynamics is observed on the basis of the total velocity minima positions and their repetitions. Both methods are correlated, and important conclusions regarding vortex behavior are deduced.",
publisher = "MDPI",
journal = "Energies",
title = "Turbulence Structure and Dynamics Investigation of Turbulent Swirl Flow in Pipe Using High-Speed Stereo PIV Data",
volume = "15",
doi = "10.3390/en15155417"
}

Čantrak, Đ.,& Janković, N.. (2022). Turbulence Structure and Dynamics Investigation of Turbulent Swirl Flow in Pipe Using High-Speed Stereo PIV Data. in Energies
MDPI., 15.
https://doi.org/10.3390/en15155417

Čantrak Đ, Janković N. Turbulence Structure and Dynamics Investigation of Turbulent Swirl Flow in Pipe Using High-Speed Stereo PIV Data. in Energies. 2022;15.
doi:10.3390/en15155417 .

Čantrak, Đorđe, Janković, Novica, "Turbulence Structure and Dynamics Investigation of Turbulent Swirl Flow in Pipe Using High-Speed Stereo PIV Data" in Energies, 15 (2022),
https://doi.org/10.3390/en15155417 . .

TY  - CONF
AU  - Raković, Milan
AU  - Lečić, Lazar
AU  - Ćoćić, Aleksandar
AU  - Janković, Novica
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6276
C3  - Full Paper Proceedings International Conference IEEP2022
T1  - Experimental Аnd Numerical Investigation of Ball Valve Characteristics
SP  - 252
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6276
ER  - 

@conference{
author = "Raković, Milan and Lečić, Lazar and Ćoćić, Aleksandar and Janković, Novica",
year = "2022",
journal = "Full Paper Proceedings International Conference IEEP2022",
title = "Experimental Аnd Numerical Investigation of Ball Valve Characteristics",
pages = "252",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6276"
}

Raković, M., Lečić, L., Ćoćić, A.,& Janković, N.. (2022). Experimental Аnd Numerical Investigation of Ball Valve Characteristics. in Full Paper Proceedings International Conference IEEP2022, 252.
https://hdl.handle.net/21.15107/rcub_machinery_6276

Raković M, Lečić L, Ćoćić A, Janković N. Experimental Аnd Numerical Investigation of Ball Valve Characteristics. in Full Paper Proceedings International Conference IEEP2022. 2022;:252.
https://hdl.handle.net/21.15107/rcub_machinery_6276 .

Raković, Milan, Lečić, Lazar, Ćoćić, Aleksandar, Janković, Novica, "Experimental Аnd Numerical Investigation of Ball Valve Characteristics" in Full Paper Proceedings International Conference IEEP2022 (2022):252,
https://hdl.handle.net/21.15107/rcub_machinery_6276 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6843
C3  - 19th International Symposium on Flow Visualization, ISFV 19, Shanghai, China, Sept. 14-16, Session 10: Industrial Flow, Sept. 15th
T1  - Stereo PIV and Flow Visualizations in the Turbulent Swirl Flow Investigation of the Rankine Type in the Pipe behind the Axial Fan
EP  - 209
SP  - 201
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6843
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica",
year = "2021",
journal = "19th International Symposium on Flow Visualization, ISFV 19, Shanghai, China, Sept. 14-16, Session 10: Industrial Flow, Sept. 15th",
title = "Stereo PIV and Flow Visualizations in the Turbulent Swirl Flow Investigation of the Rankine Type in the Pipe behind the Axial Fan",
pages = "209-201",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6843"
}

Čantrak, Đ.,& Janković, N.. (2021). Stereo PIV and Flow Visualizations in the Turbulent Swirl Flow Investigation of the Rankine Type in the Pipe behind the Axial Fan. in 19th International Symposium on Flow Visualization, ISFV 19, Shanghai, China, Sept. 14-16, Session 10: Industrial Flow, Sept. 15th, 201-209.
https://hdl.handle.net/21.15107/rcub_machinery_6843

Čantrak Đ, Janković N. Stereo PIV and Flow Visualizations in the Turbulent Swirl Flow Investigation of the Rankine Type in the Pipe behind the Axial Fan. in 19th International Symposium on Flow Visualization, ISFV 19, Shanghai, China, Sept. 14-16, Session 10: Industrial Flow, Sept. 15th. 2021;:201-209.
https://hdl.handle.net/21.15107/rcub_machinery_6843 .

Čantrak, Đorđe, Janković, Novica, "Stereo PIV and Flow Visualizations in the Turbulent Swirl Flow Investigation of the Rankine Type in the Pipe behind the Axial Fan" in 19th International Symposium on Flow Visualization, ISFV 19, Shanghai, China, Sept. 14-16, Session 10: Industrial Flow, Sept. 15th (2021):201-209,
https://hdl.handle.net/21.15107/rcub_machinery_6843 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Nedeljković, Miloš
PY  - 2021
UR  - https://onlinelibrary.wiley.com/doi/10.1002/pamm.202000051
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6351
AB  - Kolmogorov has formulated his two hypotheses of similarity in 1941 considering local-isotropic turbulence, and later has
refined his theory [1, 2]. In this paper are discussed three turbulent swirl flows generated by the three various axial fan types
in-built in the pipe. The spectral characteristics of the generated turbulent swirl flows are determined on the basis on the LDA
(laser Doppler anemometry) experimental data for the circumferential velocity. In the inertial subranges these curves have the
same tangent and obey the “- 5/3” Kolmogorov law. It is shown that in the generated turbulent swirl flows occur eddies of
various scales, encompassing very wide spectra of wave numbers, i.e. frequencies.
PB  - WILEY
C3  - Proceedings in Applied Mathematics and Mechanics (PAMM)
T1  - Turbulent Swirl Flow Analysis by Kolmogorov’s Similarity Hypotheses
VL  - 20
DO  - 10.1002/pamm.202000051
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Nedeljković, Miloš",
year = "2021",
abstract = "Kolmogorov has formulated his two hypotheses of similarity in 1941 considering local-isotropic turbulence, and later has
refined his theory [1, 2]. In this paper are discussed three turbulent swirl flows generated by the three various axial fan types
in-built in the pipe. The spectral characteristics of the generated turbulent swirl flows are determined on the basis on the LDA
(laser Doppler anemometry) experimental data for the circumferential velocity. In the inertial subranges these curves have the
same tangent and obey the “- 5/3” Kolmogorov law. It is shown that in the generated turbulent swirl flows occur eddies of
various scales, encompassing very wide spectra of wave numbers, i.e. frequencies.",
publisher = "WILEY",
journal = "Proceedings in Applied Mathematics and Mechanics (PAMM)",
title = "Turbulent Swirl Flow Analysis by Kolmogorov’s Similarity Hypotheses",
volume = "20",
doi = "10.1002/pamm.202000051"
}

Čantrak, Đ., Janković, N.,& Nedeljković, M.. (2021). Turbulent Swirl Flow Analysis by Kolmogorov’s Similarity Hypotheses. in Proceedings in Applied Mathematics and Mechanics (PAMM)
WILEY., 20.
https://doi.org/10.1002/pamm.202000051

Čantrak Đ, Janković N, Nedeljković M. Turbulent Swirl Flow Analysis by Kolmogorov’s Similarity Hypotheses. in Proceedings in Applied Mathematics and Mechanics (PAMM). 2021;20.
doi:10.1002/pamm.202000051 .

Čantrak, Đorđe, Janković, Novica, Nedeljković, Miloš, "Turbulent Swirl Flow Analysis by Kolmogorov’s Similarity Hypotheses" in Proceedings in Applied Mathematics and Mechanics (PAMM), 20 (2021),
https://doi.org/10.1002/pamm.202000051 . .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Nedeljković, Miloš
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6842
C3  - 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM, Section S10: Turbulence and reactive flows, Uni. Kassel, March 15-19, Book of Abstracts
T1  - Kolmogorov's similarity hypothesis application in research of the turbulent swirl flows in pipe generated by the various axial fan geometries
EP  - 360
SP  - 359
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6842
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Nedeljković, Miloš",
year = "2021",
journal = "91st Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM, Section S10: Turbulence and reactive flows, Uni. Kassel, March 15-19, Book of Abstracts",
title = "Kolmogorov's similarity hypothesis application in research of the turbulent swirl flows in pipe generated by the various axial fan geometries",
pages = "360-359",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6842"
}

Čantrak, Đ., Janković, N.,& Nedeljković, M.. (2021). Kolmogorov's similarity hypothesis application in research of the turbulent swirl flows in pipe generated by the various axial fan geometries. in 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM, Section S10: Turbulence and reactive flows, Uni. Kassel, March 15-19, Book of Abstracts, 359-360.
https://hdl.handle.net/21.15107/rcub_machinery_6842

Čantrak Đ, Janković N, Nedeljković M. Kolmogorov's similarity hypothesis application in research of the turbulent swirl flows in pipe generated by the various axial fan geometries. in 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM, Section S10: Turbulence and reactive flows, Uni. Kassel, March 15-19, Book of Abstracts. 2021;:359-360.
https://hdl.handle.net/21.15107/rcub_machinery_6842 .

Čantrak, Đorđe, Janković, Novica, Nedeljković, Miloš, "Kolmogorov's similarity hypothesis application in research of the turbulent swirl flows in pipe generated by the various axial fan geometries" in 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics, GAMM, Section S10: Turbulence and reactive flows, Uni. Kassel, March 15-19, Book of Abstracts (2021):359-360,
https://hdl.handle.net/21.15107/rcub_machinery_6842 .

TY  - CONF
AU  - Janković, Novica
AU  - Nedeljković, Miloš
AU  - Atanasijević, P.
AU  - Čantrak, Đorđe
AU  - Ilić, Dejan
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6826
PB  - Београд : Грађевински факултет
C3  - Зборник радова 19. научног саветовања Српског друштва за хидрауличка истраживања и Српског друштва за хидрологију, Београд, 18-19. октобар 2021
T1  - Показно-образовна инсталација за испитивање пумпи у лабораторији и преко интернета
EP  - 46
SP  - 45
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6826
ER  - 

@conference{
author = "Janković, Novica and Nedeljković, Miloš and Atanasijević, P. and Čantrak, Đorđe and Ilić, Dejan",
year = "2021",
publisher = "Београд : Грађевински факултет",
journal = "Зборник радова 19. научног саветовања Српског друштва за хидрауличка истраживања и Српског друштва за хидрологију, Београд, 18-19. октобар 2021",
title = "Показно-образовна инсталација за испитивање пумпи у лабораторији и преко интернета",
pages = "46-45",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6826"
}

Janković, N., Nedeljković, M., Atanasijević, P., Čantrak, Đ.,& Ilić, D.. (2021). Показно-образовна инсталација за испитивање пумпи у лабораторији и преко интернета. in Зборник радова 19. научног саветовања Српског друштва за хидрауличка истраживања и Српског друштва за хидрологију, Београд, 18-19. октобар 2021
Београд : Грађевински факултет., 45-46.
https://hdl.handle.net/21.15107/rcub_machinery_6826

Janković N, Nedeljković M, Atanasijević P, Čantrak Đ, Ilić D. Показно-образовна инсталација за испитивање пумпи у лабораторији и преко интернета. in Зборник радова 19. научног саветовања Српског друштва за хидрауличка истраживања и Српског друштва за хидрологију, Београд, 18-19. октобар 2021. 2021;:45-46.
https://hdl.handle.net/21.15107/rcub_machinery_6826 .

Janković, Novica, Nedeljković, Miloš, Atanasijević, P., Čantrak, Đorđe, Ilić, Dejan, "Показно-образовна инсталација за испитивање пумпи у лабораторији и преко интернета" in Зборник радова 19. научног саветовања Српског друштва за хидрауличка истраживања и Српског друштва за хидрологију, Београд, 18-19. октобар 2021 (2021):45-46,
https://hdl.handle.net/21.15107/rcub_machinery_6826 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Lečić, Milan
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6820
PB  - Belgrade : Serbian Society of Mechanics
C3  - The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence
T1  - Forced Vortex in Turbulent Swirling Flow
EP  - 516
SP  - 509
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6820
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Lečić, Milan",
year = "2021",
publisher = "Belgrade : Serbian Society of Mechanics",
journal = "The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence",
title = "Forced Vortex in Turbulent Swirling Flow",
pages = "516-509",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6820"
}

Čantrak, Đ., Janković, N.,& Lečić, M.. (2021). Forced Vortex in Turbulent Swirling Flow. in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence
Belgrade : Serbian Society of Mechanics., 509-516.
https://hdl.handle.net/21.15107/rcub_machinery_6820

Čantrak Đ, Janković N, Lečić M. Forced Vortex in Turbulent Swirling Flow. in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence. 2021;:509-516.
https://hdl.handle.net/21.15107/rcub_machinery_6820 .

Čantrak, Đorđe, Janković, Novica, Lečić, Milan, "Forced Vortex in Turbulent Swirling Flow" in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence (2021):509-516,
https://hdl.handle.net/21.15107/rcub_machinery_6820 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3682
AB  - In this paper is analyzed turbulent swirling flow generated by axial fans. Three cases will be presented. The first one is the axial fan impeller in-built in the pipe 27.74D long, where D = 0.4 m is pipe inner diameter. The second case is study of the turbulent swirling flow in the free jet generated by the axial fan impeller with casing. The third case is conical diffuser with the inlet diameter D = 0.4 m and total divergence angle of 8.6°, studied in the test chamber followed by the flow meter. Axial fan, even in the case of the same impeller geometry, had various duty points in all these installations. All regimes were adjusted by the continuous fan rotation speed regulation, as well as with the impeller blade angles. Only in the case of the installation with diffuser, additional regulating valve and booster fan were sometimes applied. In all these cases was used laser Doppler anemometry (LDA), one- and three-component systems. All generated flows are extremely turbulent and in the case of the pipe and diffuser occur reverse flows in the central flow region. In the paper will be discussed calculated integral values, such as average circulation or swirl number. Time-averaged circumferential velocity profiles revealed Rankine vortex type in pipe, while in the diffuser is generated, with the different type of impeller, solid body profile. Turbulence levels and their distributions are analyzed. In addition, statistical moments of the higher order, like skewness and flatness factors are discussed.
PB  - Springer
C3  - Lecture Notes in Networks and Systems
T1  - LDA Experimental Research of Turbulent Swirling Flow Behind the Axial Fans in Pipe, Jet and Diffuser
EP  - 202
SP  - 184
VL  - 153
DO  - 10.1007/978-3-030-58362-0_12
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan",
year = "2021",
abstract = "In this paper is analyzed turbulent swirling flow generated by axial fans. Three cases will be presented. The first one is the axial fan impeller in-built in the pipe 27.74D long, where D = 0.4 m is pipe inner diameter. The second case is study of the turbulent swirling flow in the free jet generated by the axial fan impeller with casing. The third case is conical diffuser with the inlet diameter D = 0.4 m and total divergence angle of 8.6°, studied in the test chamber followed by the flow meter. Axial fan, even in the case of the same impeller geometry, had various duty points in all these installations. All regimes were adjusted by the continuous fan rotation speed regulation, as well as with the impeller blade angles. Only in the case of the installation with diffuser, additional regulating valve and booster fan were sometimes applied. In all these cases was used laser Doppler anemometry (LDA), one- and three-component systems. All generated flows are extremely turbulent and in the case of the pipe and diffuser occur reverse flows in the central flow region. In the paper will be discussed calculated integral values, such as average circulation or swirl number. Time-averaged circumferential velocity profiles revealed Rankine vortex type in pipe, while in the diffuser is generated, with the different type of impeller, solid body profile. Turbulence levels and their distributions are analyzed. In addition, statistical moments of the higher order, like skewness and flatness factors are discussed.",
publisher = "Springer",
journal = "Lecture Notes in Networks and Systems",
title = "LDA Experimental Research of Turbulent Swirling Flow Behind the Axial Fans in Pipe, Jet and Diffuser",
pages = "202-184",
volume = "153",
doi = "10.1007/978-3-030-58362-0_12"
}

Čantrak, Đ., Janković, N.,& Ilić, D.. (2021). LDA Experimental Research of Turbulent Swirling Flow Behind the Axial Fans in Pipe, Jet and Diffuser. in Lecture Notes in Networks and Systems
Springer., 153, 184-202.
https://doi.org/10.1007/978-3-030-58362-0_12

Čantrak Đ, Janković N, Ilić D. LDA Experimental Research of Turbulent Swirling Flow Behind the Axial Fans in Pipe, Jet and Diffuser. in Lecture Notes in Networks and Systems. 2021;153:184-202.
doi:10.1007/978-3-030-58362-0_12 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, "LDA Experimental Research of Turbulent Swirling Flow Behind the Axial Fans in Pipe, Jet and Diffuser" in Lecture Notes in Networks and Systems, 153 (2021):184-202,
https://doi.org/10.1007/978-3-030-58362-0_12 . .

TY  - CONF
AU  - Nikolić, Mateja
AU  - Mrsević, Dejan
AU  - Ristić, Leposava
AU  - Čantrak, Đorđe
AU  - Janković, Novica
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3582
AB  - There is a potential for increasing energy efficiency, as well as financial cost-effectiveness of modern water distribution networks, irrigation systems, wastewater treatment plants and intense water usage industries in general, by incorporating micro-hydro turbines in certain points of the system where excess pressure is traditionally dissipated via pressure relief valves. Induction motors used as generators coupled to pumps used as turbines are widely spread in these applications, due to their low cost, robustness, and relatively simple operation, either connected to grid or in island mode of operation. The paper presents analytical and model-based considerations of an induction machine in micro-hydropower system through various operating regimes.
PB  - IEEE, New York
C3  - Proceedings of The 2021 6th International Symposium on Environment - Friendly Energies and Applicati
T1  - Induction Machine Driven Pump Applied as Turbine in Micro-hydro Power Plants
DO  - 10.1109/EFEA49713.2021.9406236
ER  - 

@conference{
author = "Nikolić, Mateja and Mrsević, Dejan and Ristić, Leposava and Čantrak, Đorđe and Janković, Novica",
year = "2021",
abstract = "There is a potential for increasing energy efficiency, as well as financial cost-effectiveness of modern water distribution networks, irrigation systems, wastewater treatment plants and intense water usage industries in general, by incorporating micro-hydro turbines in certain points of the system where excess pressure is traditionally dissipated via pressure relief valves. Induction motors used as generators coupled to pumps used as turbines are widely spread in these applications, due to their low cost, robustness, and relatively simple operation, either connected to grid or in island mode of operation. The paper presents analytical and model-based considerations of an induction machine in micro-hydropower system through various operating regimes.",
publisher = "IEEE, New York",
journal = "Proceedings of The 2021 6th International Symposium on Environment - Friendly Energies and Applicati",
title = "Induction Machine Driven Pump Applied as Turbine in Micro-hydro Power Plants",
doi = "10.1109/EFEA49713.2021.9406236"
}

Nikolić, M., Mrsević, D., Ristić, L., Čantrak, Đ.,& Janković, N.. (2021). Induction Machine Driven Pump Applied as Turbine in Micro-hydro Power Plants. in Proceedings of The 2021 6th International Symposium on Environment - Friendly Energies and Applicati
IEEE, New York..
https://doi.org/10.1109/EFEA49713.2021.9406236

Nikolić M, Mrsević D, Ristić L, Čantrak Đ, Janković N. Induction Machine Driven Pump Applied as Turbine in Micro-hydro Power Plants. in Proceedings of The 2021 6th International Symposium on Environment - Friendly Energies and Applicati. 2021;.
doi:10.1109/EFEA49713.2021.9406236 .

Nikolić, Mateja, Mrsević, Dejan, Ristić, Leposava, Čantrak, Đorđe, Janković, Novica, "Induction Machine Driven Pump Applied as Turbine in Micro-hydro Power Plants" in Proceedings of The 2021 6th International Symposium on Environment - Friendly Energies and Applicati (2021),
https://doi.org/10.1109/EFEA49713.2021.9406236 . .

TY  - CONF
AU  - Ocokoljić, Goran
AU  - Janković, Novica
AU  - Samardžić, Marija
AU  - Svorcan, Jelena
AU  - Čantrak, Đorđe
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4256
AB  - Water cavitation tunnel T-33, which exists in the Experimental Aerodynamics Laboratory of the Military Technical Institute, in Belgrade, since 1952 is presented in this paper. It is a continuous close-loop water tunnel. Pump has 91 kW DC power supply. It is refurbished and has a new test section with dimensions 450 mm x 500 mm. Measurements have been performed by use of one-component laser Doppler velocimetry (LDV). In this paper are presented axial velocity profiles in the measuring section for three various axial pump rotation speeds. In some cases is checked also vertical velocity component.
PB  - International Association for Hydro-Environment Engineering and Research (IAHR)
C3  - Abstract Book - 6th IAHR Europe Congress
T1  - Water cavitation tunnel characterisation by LDV
EP  - 849
SP  - 848
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4256
ER  - 

@conference{
author = "Ocokoljić, Goran and Janković, Novica and Samardžić, Marija and Svorcan, Jelena and Čantrak, Đorđe",
year = "2021",
abstract = "Water cavitation tunnel T-33, which exists in the Experimental Aerodynamics Laboratory of the Military Technical Institute, in Belgrade, since 1952 is presented in this paper. It is a continuous close-loop water tunnel. Pump has 91 kW DC power supply. It is refurbished and has a new test section with dimensions 450 mm x 500 mm. Measurements have been performed by use of one-component laser Doppler velocimetry (LDV). In this paper are presented axial velocity profiles in the measuring section for three various axial pump rotation speeds. In some cases is checked also vertical velocity component.",
publisher = "International Association for Hydro-Environment Engineering and Research (IAHR)",
journal = "Abstract Book - 6th IAHR Europe Congress",
title = "Water cavitation tunnel characterisation by LDV",
pages = "849-848",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4256"
}

Ocokoljić, G., Janković, N., Samardžić, M., Svorcan, J.,& Čantrak, Đ.. (2021). Water cavitation tunnel characterisation by LDV. in Abstract Book - 6th IAHR Europe Congress
International Association for Hydro-Environment Engineering and Research (IAHR)., 848-849.
https://hdl.handle.net/21.15107/rcub_machinery_4256

Ocokoljić G, Janković N, Samardžić M, Svorcan J, Čantrak Đ. Water cavitation tunnel characterisation by LDV. in Abstract Book - 6th IAHR Europe Congress. 2021;:848-849.
https://hdl.handle.net/21.15107/rcub_machinery_4256 .

Ocokoljić, Goran, Janković, Novica, Samardžić, Marija, Svorcan, Jelena, Čantrak, Đorđe, "Water cavitation tunnel characterisation by LDV" in Abstract Book - 6th IAHR Europe Congress (2021):848-849,
https://hdl.handle.net/21.15107/rcub_machinery_4256 .

TY  - CONF
AU  - Savić, Ljubomir
AU  - Janković, Novica
AU  - Čantrak, Đorđe
AU  - Ilić, Dejan
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5575
AB  - The paper investigates the sizing methodology for control valve regulative element (per international standard ISA-75.01.01), produced by additive manufacturing.
The overall objective is to develop a design of the valve controlling/ regulating element. This design should be the most suitable for the selective laser melting (SLM) 3D metal printing process – “design for manufacturing” ensuring the best techno-commercial balance for bringing the product successfully to the market. 
The 3D Metal Print technology, additive manufacturing in general, has reached the level of maturity which enables wide utilisation within different industries - processing industry/ control valve technology is the subject of the investigation. 
The complex shapes and geometries are the field where the additive manufacturing brings the real advantage, however not only in this segment. The physical properties of the obtained manufactured parts, combined with standard heat treatments, overcoming the values of forged parts. This fact enables much broader market space for product utilisation, especially within high pressure and erosion aggressive environment. 
The goals of the paper are to tackle the following: 

	Developing the flow capacity and pressure reduction tool, i.e. calculator for the valve regulating element after the ISA-75.01.01 standard.
	Design and production of the prototype. The finalized, piece is to be in the Nickel alloy steel, ∅25.4 x ∅67 x 38 mm. This prototype is already manufactured. 
It is of interest to study the turbulent flow parameters calculated in the ISA-75.01.01 standard.
In addition to the presented research, it is planned to perform the evaluation of the used SLM technology capabilities, i.e. tolerances of channel dimensions and geometry, remaining of powder in channels and other traces of clogging. This will be based on the following:
	Experimental evaluation of the prototype flow capacity. This test will be performed by the third-party certified laboratory. Negotiations are in progress.
	Numerical simulation of the channel flow and calculation of the flow capacity (Cv) of regulative element. Obtained experimental results will be the boundary conditions for the planned numerical simulation. Preliminary numerical simulation results are presented in this paper.
PB  - Srpsko društvo za Mehaniku
C3  - The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence, Eds.: Kojić M. and Filipović N.
T1  - Sizing Valve Regulating Element
EP  - 556
SP  - 551
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5575
ER  - 

@conference{
author = "Savić, Ljubomir and Janković, Novica and Čantrak, Đorđe and Ilić, Dejan",
year = "2021",
abstract = "The paper investigates the sizing methodology for control valve regulative element (per international standard ISA-75.01.01), produced by additive manufacturing.
The overall objective is to develop a design of the valve controlling/ regulating element. This design should be the most suitable for the selective laser melting (SLM) 3D metal printing process – “design for manufacturing” ensuring the best techno-commercial balance for bringing the product successfully to the market. 
The 3D Metal Print technology, additive manufacturing in general, has reached the level of maturity which enables wide utilisation within different industries - processing industry/ control valve technology is the subject of the investigation. 
The complex shapes and geometries are the field where the additive manufacturing brings the real advantage, however not only in this segment. The physical properties of the obtained manufactured parts, combined with standard heat treatments, overcoming the values of forged parts. This fact enables much broader market space for product utilisation, especially within high pressure and erosion aggressive environment. 
The goals of the paper are to tackle the following: 

	Developing the flow capacity and pressure reduction tool, i.e. calculator for the valve regulating element after the ISA-75.01.01 standard.
	Design and production of the prototype. The finalized, piece is to be in the Nickel alloy steel, ∅25.4 x ∅67 x 38 mm. This prototype is already manufactured. 
It is of interest to study the turbulent flow parameters calculated in the ISA-75.01.01 standard.
In addition to the presented research, it is planned to perform the evaluation of the used SLM technology capabilities, i.e. tolerances of channel dimensions and geometry, remaining of powder in channels and other traces of clogging. This will be based on the following:
	Experimental evaluation of the prototype flow capacity. This test will be performed by the third-party certified laboratory. Negotiations are in progress.
	Numerical simulation of the channel flow and calculation of the flow capacity (Cv) of regulative element. Obtained experimental results will be the boundary conditions for the planned numerical simulation. Preliminary numerical simulation results are presented in this paper.",
publisher = "Srpsko društvo za Mehaniku",
journal = "The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence, Eds.: Kojić M. and Filipović N.",
title = "Sizing Valve Regulating Element",
pages = "556-551",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5575"
}

Savić, L., Janković, N., Čantrak, Đ.,& Ilić, D.. (2021). Sizing Valve Regulating Element. in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence, Eds.: Kojić M. and Filipović N.
Srpsko društvo za Mehaniku., 551-556.
https://hdl.handle.net/21.15107/rcub_machinery_5575

Savić L, Janković N, Čantrak Đ, Ilić D. Sizing Valve Regulating Element. in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence, Eds.: Kojić M. and Filipović N.. 2021;:551-556.
https://hdl.handle.net/21.15107/rcub_machinery_5575 .

Savić, Ljubomir, Janković, Novica, Čantrak, Đorđe, Ilić, Dejan, "Sizing Valve Regulating Element" in The 8th International Congress of Serbian Society of Mechanics, Kragujevac, Serbia, June 28-30 2021., Proceedings, Minisymposium M2: Turbulence, Eds.: Kojić M. and Filipović N. (2021):551-556,
https://hdl.handle.net/21.15107/rcub_machinery_5575 .

TY  - CONF
AU  - Bojović, Dušan
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Nedeljković, Miloš
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6343
AB  - In this paper is presented the Fast Response Aerodynamic Probe (FRAP), for measurements of the nonstationary fluid flow, widely present in the energy systems. Multihole probes are well known in experimental fluid mechanics. This is, on the contrary to the optical velocity measurement techniques, intrusive anemometry and pressure measuring device. It is, recently, updated with fast response sensors, which enable good sampling rate, necessary for turbulence study. 
Calibrations, aerodynamic, as well as dynamic one, and working principles of the FRAP probe are introduced. Probe design and implemented sensors are presented and described in numerous details.
Design of the test rig for necessary pitch-yaw aerodynamic calibration is developed and it is planned to achieve automated calibration procedure.
Results of the dynamic/acoustic calibration reveal fast probes response, up to 10 kHz.In addition, results of the first aerodynamic calibration for one velocity are presented and discussed. Obtained map of the calibration angles is provided, as well as diagrams of two out of five measured pressures. Determined velocity is, also, presented and analyzed error.
PB  - Српско друштво за механику
C3  - The 8th International Congress of Serbian Society of Mechanics
T1  - Five Hole Fast Response Probe for Measurements of 3D Velocity and Pressure Fields
SP  - 557
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6343
ER  - 

@conference{
author = "Bojović, Dušan and Čantrak, Đorđe and Janković, Novica and Nedeljković, Miloš",
year = "2021",
abstract = "In this paper is presented the Fast Response Aerodynamic Probe (FRAP), for measurements of the nonstationary fluid flow, widely present in the energy systems. Multihole probes are well known in experimental fluid mechanics. This is, on the contrary to the optical velocity measurement techniques, intrusive anemometry and pressure measuring device. It is, recently, updated with fast response sensors, which enable good sampling rate, necessary for turbulence study. 
Calibrations, aerodynamic, as well as dynamic one, and working principles of the FRAP probe are introduced. Probe design and implemented sensors are presented and described in numerous details.
Design of the test rig for necessary pitch-yaw aerodynamic calibration is developed and it is planned to achieve automated calibration procedure.
Results of the dynamic/acoustic calibration reveal fast probes response, up to 10 kHz.In addition, results of the first aerodynamic calibration for one velocity are presented and discussed. Obtained map of the calibration angles is provided, as well as diagrams of two out of five measured pressures. Determined velocity is, also, presented and analyzed error.",
publisher = "Српско друштво за механику",
journal = "The 8th International Congress of Serbian Society of Mechanics",
title = "Five Hole Fast Response Probe for Measurements of 3D Velocity and Pressure Fields",
pages = "557",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6343"
}

Bojović, D., Čantrak, Đ., Janković, N.,& Nedeljković, M.. (2021). Five Hole Fast Response Probe for Measurements of 3D Velocity and Pressure Fields. in The 8th International Congress of Serbian Society of Mechanics
Српско друштво за механику., 557.
https://hdl.handle.net/21.15107/rcub_machinery_6343

Bojović D, Čantrak Đ, Janković N, Nedeljković M. Five Hole Fast Response Probe for Measurements of 3D Velocity and Pressure Fields. in The 8th International Congress of Serbian Society of Mechanics. 2021;:557.
https://hdl.handle.net/21.15107/rcub_machinery_6343 .

Bojović, Dušan, Čantrak, Đorđe, Janković, Novica, Nedeljković, Miloš, "Five Hole Fast Response Probe for Measurements of 3D Velocity and Pressure Fields" in The 8th International Congress of Serbian Society of Mechanics (2021):557,
https://hdl.handle.net/21.15107/rcub_machinery_6343 .

TY  - JOUR
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Nedeljković, Miloš
PY  - 2021
UR  - https://onlinelibrary.wiley.com/doi/10.1002/pamm.202100177
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6352
AB  - Kolmogorov has formulated his two hypotheses of similarity in 1941 considering local-isotropic turbulence, and later has
refined his theory [1, 2]. In this paper are discussed three turbulent swirl flows generated by the three various axial fan types
in-built in the pipe. The spectral characteristics of the generated turbulent swirl flows are determined on the basis on the LDA
(laser Doppler anemometry) experimental data for the circumferential velocity. In the inertial subranges these curves have the
same tangent and obey the “- 5/3” Kolmogorov law. It is shown that in the generated turbulent swirl flows occur eddies of
various scales, encompassing very wide spectra of wave numbers, i.e. frequencies.
PB  - WILEY
T2  - Proceedings in Applied Mathematics and Mechanics (PAMM)
T1  - Kolmogorov's Similarity Hypotheses Application in Research of the Turbulent Swirl Flows in Pipe Generated by the Various Axial Fan Geometries
VL  - 21
DO  - 10.1002/pamm.202100177
ER  - 

@article{
author = "Čantrak, Đorđe and Janković, Novica and Nedeljković, Miloš",
year = "2021",
abstract = "Kolmogorov has formulated his two hypotheses of similarity in 1941 considering local-isotropic turbulence, and later has
refined his theory [1, 2]. In this paper are discussed three turbulent swirl flows generated by the three various axial fan types
in-built in the pipe. The spectral characteristics of the generated turbulent swirl flows are determined on the basis on the LDA
(laser Doppler anemometry) experimental data for the circumferential velocity. In the inertial subranges these curves have the
same tangent and obey the “- 5/3” Kolmogorov law. It is shown that in the generated turbulent swirl flows occur eddies of
various scales, encompassing very wide spectra of wave numbers, i.e. frequencies.",
publisher = "WILEY",
journal = "Proceedings in Applied Mathematics and Mechanics (PAMM)",
title = "Kolmogorov's Similarity Hypotheses Application in Research of the Turbulent Swirl Flows in Pipe Generated by the Various Axial Fan Geometries",
volume = "21",
doi = "10.1002/pamm.202100177"
}

Čantrak, Đ., Janković, N.,& Nedeljković, M.. (2021). Kolmogorov's Similarity Hypotheses Application in Research of the Turbulent Swirl Flows in Pipe Generated by the Various Axial Fan Geometries. in Proceedings in Applied Mathematics and Mechanics (PAMM)
WILEY., 21.
https://doi.org/10.1002/pamm.202100177

Čantrak Đ, Janković N, Nedeljković M. Kolmogorov's Similarity Hypotheses Application in Research of the Turbulent Swirl Flows in Pipe Generated by the Various Axial Fan Geometries. in Proceedings in Applied Mathematics and Mechanics (PAMM). 2021;21.
doi:10.1002/pamm.202100177 .

Čantrak, Đorđe, Janković, Novica, Nedeljković, Miloš, "Kolmogorov's Similarity Hypotheses Application in Research of the Turbulent Swirl Flows in Pipe Generated by the Various Axial Fan Geometries" in Proceedings in Applied Mathematics and Mechanics (PAMM), 21 (2021),
https://doi.org/10.1002/pamm.202100177 . .

TY  - THES
AU  - Janković, Novica
PY  - 2020
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=8006
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:23393/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=27898889
UR  - https://nardus.mpn.gov.rs/handle/123456789/18158
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/76
AB  - U okviru disertacije se istražuje struktura turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora. Generisano turbulentno strujanje je trodimenziono, nehomogeno i anizotropno. Primenjeni su složeni eksperimentalni, numerički i teorijski pristupi. Eksperimentalna instalacija je u radu detaljno opisana, kao i kvantifikacija merne nesigurnosti trokomponentnog sistema za Laser Dopler anemometriju (LDA). LDA sistem je, pri simultanom merenju tri komponente brzine, zahtevao precizna podešavanja merne zapremine u granicama prečnika do 100 μm. Ostvareno je precizno pomeranje ove zapremine duž mlaza. Poseban izazov je predstavljala numerička obrada dobijenih, u vremenu nejednako raspoređenih, mernih rezultata. Teorijskim razmatranjima, u okviru disertacije, bačeno je novo svetlo na klasične zapise Navije-Stoksovih i Rejnoldsovih jednačina u polarno-cilindričnim koordinatama. Detaljno su razmatrane empirijske radijalnoaksijalne raspodele ukupne, aksijalne, radijalne i obimske brzine, izmerene za dve brzine obrtanja ventilatora i tri ugla lopatica. Na ovaj način je bilo moguće istražiti uticaj Rejnoldsovog broja, kao i geometrijskih karakteristika ventilatora, tj. ugla lopatica, na karakter dejstva vihora na turbulenciju i evoluciju nivoa turbulencije, kako u samom mernom preseku, tako i u nizstrujnom razvoju mlaza. Analiza generisanja turbulencije i produkcije pojedinih Rejnoldsovih napona ukazala je na bitne karakteristike turbulentnog prenosa u slobodnom vihornom mlazu. Uočeno je da promena znaka gradijenta brzine ne izaziva uvek i promenu znaka pripadajuće komponente tenzora turbulentnog napona. U domenima strujnog polja u kojima se to dešava, mehanizam turbulentnog prenosa je nelokalnog karaktera, prisutna je negradijentna turbulentna difuzija i javlja se negativna produkcija kinetičke energije turbulencije. Izložena je diskusija o uticaju vihora na strukturu turbulencije i mehanizam turbulentnog prenosa. Analiza je ukazala na složena međudejstva osrednjenih i fluktuacionih polja u vihornom mlazu. Zaključeno je da generisanje energije fluktuacionog kretanja ne nastaje na osnovu kinetičke energije osrednjenog kretanja, već naprotiv. Smer prenošenja energije se menja, tako da osrednjeno kretanje „crpi” kinetičku energiju fluktuacionog kretanja, štoodgovara složenim strukturalnim svojstvima turbulencije. Zato su eksperimentalna istraživanja bila usmerena na merenje i analizu statističkih momenata višeg reda, i to ovde do šestog reda...
AB  - The dissertation deals with the structure of the turbulent swirl flow in an axial fan jet. The generated turbulent flow is three-dimensional, inhomogeneous and anisotropic. Complex experimental, numerical and theoretical approaches were applied. The experimental setup is described in detail, as well as the quantification of the measurement uncertainty of a three-component Laser Doppler Anemometry (LDA) system. The LDA system, while measuring the three velocity components simultaneously, requires precise adjustments of the measuring volume up to 100 μm in diameter. A precise displacement of this volume along the jet was achieved. A particular challenge was the numerical processing of the obtained unequally spaced data. Theoretical considerations, in the framework of the dissertation, have brought new light on classical notations of Navier-Stokes and Reynolds equations in polar-cylindrical coordinates. The empirical radial-axial distributions of total, axial, radial, and circumferential velocities measured for two fan speeds and three vanes angles are thoroughly analyzed. In this way, it was possible to investigate the influence of the Reynolds number as well as the geometric characteristics of the fan, i.e. angles of the blades, on the character of the swirl influence on turbulence and the evolution of the turbulence level, both in the measuring cross section and in the downstream development of the jet. An analysis of the generation of turbulence and the production of individual Reynolds stresses indicated the essential characteristics of turbulent transfer in a free swirl jet. It has been observed that a change in the sign of the velocity gradient does not always cause a change in the sign of the corresponding component of the turbulent stress tensor. In the fluid flow domains where this occurs, the turbulent transfer mechanism has nonlocal character, non-gradient turbulent diffusion and negative production of turbulence kinetic energy occur. Discussion of the effect of the swirl on the turbulence structure and the mechanism of turbulent transfer is presented. The analysis indicated the complex interactions of averaged and fluctuating fields in a swirl flow. It is concluded that the generation of fluctuating motion energy does not occur on the basis of kinetic energy of averaged motion, but on the contrary. The direction of energy transfer changes so that theaveraged motion "draws" the kinetic energy of the fluctuating motion, which corresponds to the complex structural properties of the turbulence. That is why experimental research has focused on measuring and analyzing higher order statistical moments, up to the sixth order here...
PB  - Univerzitet u Beogradu, Mašinski fakultet
T1  - Eksperimentalna i teorijska istraživanja strukture turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora
T1  - Experimental and theoretical research of the structure of turbulent swirl flow in axial fan jet
UR  - https://hdl.handle.net/21.15107/rcub_nardus_18158
ER  - 

@phdthesis{
author = "Janković, Novica",
year = "2020",
abstract = "U okviru disertacije se istražuje struktura turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora. Generisano turbulentno strujanje je trodimenziono, nehomogeno i anizotropno. Primenjeni su složeni eksperimentalni, numerički i teorijski pristupi. Eksperimentalna instalacija je u radu detaljno opisana, kao i kvantifikacija merne nesigurnosti trokomponentnog sistema za Laser Dopler anemometriju (LDA). LDA sistem je, pri simultanom merenju tri komponente brzine, zahtevao precizna podešavanja merne zapremine u granicama prečnika do 100 μm. Ostvareno je precizno pomeranje ove zapremine duž mlaza. Poseban izazov je predstavljala numerička obrada dobijenih, u vremenu nejednako raspoređenih, mernih rezultata. Teorijskim razmatranjima, u okviru disertacije, bačeno je novo svetlo na klasične zapise Navije-Stoksovih i Rejnoldsovih jednačina u polarno-cilindričnim koordinatama. Detaljno su razmatrane empirijske radijalnoaksijalne raspodele ukupne, aksijalne, radijalne i obimske brzine, izmerene za dve brzine obrtanja ventilatora i tri ugla lopatica. Na ovaj način je bilo moguće istražiti uticaj Rejnoldsovog broja, kao i geometrijskih karakteristika ventilatora, tj. ugla lopatica, na karakter dejstva vihora na turbulenciju i evoluciju nivoa turbulencije, kako u samom mernom preseku, tako i u nizstrujnom razvoju mlaza. Analiza generisanja turbulencije i produkcije pojedinih Rejnoldsovih napona ukazala je na bitne karakteristike turbulentnog prenosa u slobodnom vihornom mlazu. Uočeno je da promena znaka gradijenta brzine ne izaziva uvek i promenu znaka pripadajuće komponente tenzora turbulentnog napona. U domenima strujnog polja u kojima se to dešava, mehanizam turbulentnog prenosa je nelokalnog karaktera, prisutna je negradijentna turbulentna difuzija i javlja se negativna produkcija kinetičke energije turbulencije. Izložena je diskusija o uticaju vihora na strukturu turbulencije i mehanizam turbulentnog prenosa. Analiza je ukazala na složena međudejstva osrednjenih i fluktuacionih polja u vihornom mlazu. Zaključeno je da generisanje energije fluktuacionog kretanja ne nastaje na osnovu kinetičke energije osrednjenog kretanja, već naprotiv. Smer prenošenja energije se menja, tako da osrednjeno kretanje „crpi” kinetičku energiju fluktuacionog kretanja, štoodgovara složenim strukturalnim svojstvima turbulencije. Zato su eksperimentalna istraživanja bila usmerena na merenje i analizu statističkih momenata višeg reda, i to ovde do šestog reda..., The dissertation deals with the structure of the turbulent swirl flow in an axial fan jet. The generated turbulent flow is three-dimensional, inhomogeneous and anisotropic. Complex experimental, numerical and theoretical approaches were applied. The experimental setup is described in detail, as well as the quantification of the measurement uncertainty of a three-component Laser Doppler Anemometry (LDA) system. The LDA system, while measuring the three velocity components simultaneously, requires precise adjustments of the measuring volume up to 100 μm in diameter. A precise displacement of this volume along the jet was achieved. A particular challenge was the numerical processing of the obtained unequally spaced data. Theoretical considerations, in the framework of the dissertation, have brought new light on classical notations of Navier-Stokes and Reynolds equations in polar-cylindrical coordinates. The empirical radial-axial distributions of total, axial, radial, and circumferential velocities measured for two fan speeds and three vanes angles are thoroughly analyzed. In this way, it was possible to investigate the influence of the Reynolds number as well as the geometric characteristics of the fan, i.e. angles of the blades, on the character of the swirl influence on turbulence and the evolution of the turbulence level, both in the measuring cross section and in the downstream development of the jet. An analysis of the generation of turbulence and the production of individual Reynolds stresses indicated the essential characteristics of turbulent transfer in a free swirl jet. It has been observed that a change in the sign of the velocity gradient does not always cause a change in the sign of the corresponding component of the turbulent stress tensor. In the fluid flow domains where this occurs, the turbulent transfer mechanism has nonlocal character, non-gradient turbulent diffusion and negative production of turbulence kinetic energy occur. Discussion of the effect of the swirl on the turbulence structure and the mechanism of turbulent transfer is presented. The analysis indicated the complex interactions of averaged and fluctuating fields in a swirl flow. It is concluded that the generation of fluctuating motion energy does not occur on the basis of kinetic energy of averaged motion, but on the contrary. The direction of energy transfer changes so that theaveraged motion "draws" the kinetic energy of the fluctuating motion, which corresponds to the complex structural properties of the turbulence. That is why experimental research has focused on measuring and analyzing higher order statistical moments, up to the sixth order here...",
publisher = "Univerzitet u Beogradu, Mašinski fakultet",
title = "Eksperimentalna i teorijska istraživanja strukture turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora, Experimental and theoretical research of the structure of turbulent swirl flow in axial fan jet",
url = "https://hdl.handle.net/21.15107/rcub_nardus_18158"
}

Janković, N.. (2020). Eksperimentalna i teorijska istraživanja strukture turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora. 
Univerzitet u Beogradu, Mašinski fakultet..
https://hdl.handle.net/21.15107/rcub_nardus_18158

Janković N. Eksperimentalna i teorijska istraživanja strukture turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora. 2020;.
https://hdl.handle.net/21.15107/rcub_nardus_18158 .

Janković, Novica, "Eksperimentalna i teorijska istraživanja strukture turbulentnog vihornog strujanja u mlazu aksijalnog ventilatora" (2020),
https://hdl.handle.net/21.15107/rcub_nardus_18158 .

TY  - CONF
AU  - Čantrak, Đorđe
AU  - Janković, Novica
AU  - Ilić, Dejan
AU  - Nedeljković, Miloš
PY  - 2020
UR  - https://www.iahr.org/video/collection/38?page=3
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5267
AB  - In this paper is presented educational hydraulic pump test rig which has numerous applications. Some of them are: testing centrifugal pump after international standard ISO 9906:2012 (Rotodynamic pumps — Hydraulic performance acceptance tests — Grades 1, 2 and 3), calibration of the Venturi flow meter after international standard ISO 8316:1987 (Measurement of liquid flow in closed conduits — Method by collection of the liquid in a volumetric tank), energy efficiency issues like comparison of energy saving by adjusting the same flow rate by valve, using by-pass or by pump speed, determination of pump duty points, work in two pumps series mode, observation through the transparent walls of the cavitation and turbulent swirl phenomena, and etc (Nedeljković et al., Čantrak et al., 2019). Some experimentally obtained results are presented and discussed in this paper.
C3  - Book of Abstracts, 6th IAHR Europe Congress – Hydro Environment Research and Bioengineering, paper 62131228719, Feb. 15-18, 2021, Warsaw, Poland Special Session KS6: Measurement techniques and demonstration test rigs in hydraulic research
T1  - Educational Centrifugal Pump Test Rig
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5267
ER  - 

@conference{
author = "Čantrak, Đorđe and Janković, Novica and Ilić, Dejan and Nedeljković, Miloš",
year = "2020",
abstract = "In this paper is presented educational hydraulic pump test rig which has numerous applications. Some of them are: testing centrifugal pump after international standard ISO 9906:2012 (Rotodynamic pumps — Hydraulic performance acceptance tests — Grades 1, 2 and 3), calibration of the Venturi flow meter after international standard ISO 8316:1987 (Measurement of liquid flow in closed conduits — Method by collection of the liquid in a volumetric tank), energy efficiency issues like comparison of energy saving by adjusting the same flow rate by valve, using by-pass or by pump speed, determination of pump duty points, work in two pumps series mode, observation through the transparent walls of the cavitation and turbulent swirl phenomena, and etc (Nedeljković et al., Čantrak et al., 2019). Some experimentally obtained results are presented and discussed in this paper.",
journal = "Book of Abstracts, 6th IAHR Europe Congress – Hydro Environment Research and Bioengineering, paper 62131228719, Feb. 15-18, 2021, Warsaw, Poland Special Session KS6: Measurement techniques and demonstration test rigs in hydraulic research",
title = "Educational Centrifugal Pump Test Rig",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5267"
}

Čantrak, Đ., Janković, N., Ilić, D.,& Nedeljković, M.. (2020). Educational Centrifugal Pump Test Rig. in Book of Abstracts, 6th IAHR Europe Congress – Hydro Environment Research and Bioengineering, paper 62131228719, Feb. 15-18, 2021, Warsaw, Poland Special Session KS6: Measurement techniques and demonstration test rigs in hydraulic research.
https://hdl.handle.net/21.15107/rcub_machinery_5267

Čantrak Đ, Janković N, Ilić D, Nedeljković M. Educational Centrifugal Pump Test Rig. in Book of Abstracts, 6th IAHR Europe Congress – Hydro Environment Research and Bioengineering, paper 62131228719, Feb. 15-18, 2021, Warsaw, Poland Special Session KS6: Measurement techniques and demonstration test rigs in hydraulic research. 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_5267 .

Čantrak, Đorđe, Janković, Novica, Ilić, Dejan, Nedeljković, Miloš, "Educational Centrifugal Pump Test Rig" in Book of Abstracts, 6th IAHR Europe Congress – Hydro Environment Research and Bioengineering, paper 62131228719, Feb. 15-18, 2021, Warsaw, Poland Special Session KS6: Measurement techniques and demonstration test rigs in hydraulic research (2020),
https://hdl.handle.net/21.15107/rcub_machinery_5267 .

TY  - CONF
AU  - Janković, Novica
AU  - Jeremić, Đorđe
AU  - Čantrak, Đorđe
AU  - Ilić, Dejan
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5261
AB  - Existing wind tunnel in the Laboratory for Hydraulic machinery and energy systems, Faculty of Mechanical Engineering, University of Belgrade, is redesigned, by adding axial fan regulated by the inverter at the tunnel inlet and flow straightener in the pipe before the carefully profiled Witoshinsky nozzle. Various anemometers could be calibrated in the axisymmetric uniform jet after the nozzle with inner diameter of 145 mm. In this paper are presented experimental results of the flow uniformity and turbulence levels, as well as skewness and flatness distributions for various flow regimes in the wind tunnel measurement section by one-component laser Doppler anemometry (LDA) along the horizontal radius in 27 points. Time-averaged axial velocity profiles have been obtained for twenty Reynolds numbers in the interval Re = 1780 to 148869, determined for point on the jet axis r/R =0. Uniform velocity profiles are obtained in the jet core region, i.e. up to r/R = 0,9 for all Reynolds numbers except the lowest one. Turbulence levels have been also reported for all these cases and achieved turbulence levels were below 2% in the free jet core region for almost all measuring points and regimes, what follows standard ISO 17713-1 requirements. Achieved validation was high. Sampling rate varied and in most of the cases was in average 250-400 Hz. Thermal fog seeding was applied at the calibration tunnel inlet, i.e. at the axial fan suction side.
C3  - Proceedings, 9th International Scientific Conference on Defensive Technologies, OTEH 2020, Belgrade, Serbia, 15-16 October 2020., Session Quality, Standardization, Metrology, Maintenance and Exploitation, 6 pages, paper no. 013.
T1  - Flow Uniformity and Turbulence Level Measurements by LDA in the Wind Tunnel for Anemometers Calibration
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5261
ER  - 

@conference{
author = "Janković, Novica and Jeremić, Đorđe and Čantrak, Đorđe and Ilić, Dejan",
year = "2020",
abstract = "Existing wind tunnel in the Laboratory for Hydraulic machinery and energy systems, Faculty of Mechanical Engineering, University of Belgrade, is redesigned, by adding axial fan regulated by the inverter at the tunnel inlet and flow straightener in the pipe before the carefully profiled Witoshinsky nozzle. Various anemometers could be calibrated in the axisymmetric uniform jet after the nozzle with inner diameter of 145 mm. In this paper are presented experimental results of the flow uniformity and turbulence levels, as well as skewness and flatness distributions for various flow regimes in the wind tunnel measurement section by one-component laser Doppler anemometry (LDA) along the horizontal radius in 27 points. Time-averaged axial velocity profiles have been obtained for twenty Reynolds numbers in the interval Re = 1780 to 148869, determined for point on the jet axis r/R =0. Uniform velocity profiles are obtained in the jet core region, i.e. up to r/R = 0,9 for all Reynolds numbers except the lowest one. Turbulence levels have been also reported for all these cases and achieved turbulence levels were below 2% in the free jet core region for almost all measuring points and regimes, what follows standard ISO 17713-1 requirements. Achieved validation was high. Sampling rate varied and in most of the cases was in average 250-400 Hz. Thermal fog seeding was applied at the calibration tunnel inlet, i.e. at the axial fan suction side.",
journal = "Proceedings, 9th International Scientific Conference on Defensive Technologies, OTEH 2020, Belgrade, Serbia, 15-16 October 2020., Session Quality, Standardization, Metrology, Maintenance and Exploitation, 6 pages, paper no. 013.",
title = "Flow Uniformity and Turbulence Level Measurements by LDA in the Wind Tunnel for Anemometers Calibration",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5261"
}

Janković, N., Jeremić, Đ., Čantrak, Đ.,& Ilić, D.. (2020). Flow Uniformity and Turbulence Level Measurements by LDA in the Wind Tunnel for Anemometers Calibration. in Proceedings, 9th International Scientific Conference on Defensive Technologies, OTEH 2020, Belgrade, Serbia, 15-16 October 2020., Session Quality, Standardization, Metrology, Maintenance and Exploitation, 6 pages, paper no. 013..
https://hdl.handle.net/21.15107/rcub_machinery_5261

Janković N, Jeremić Đ, Čantrak Đ, Ilić D. Flow Uniformity and Turbulence Level Measurements by LDA in the Wind Tunnel for Anemometers Calibration. in Proceedings, 9th International Scientific Conference on Defensive Technologies, OTEH 2020, Belgrade, Serbia, 15-16 October 2020., Session Quality, Standardization, Metrology, Maintenance and Exploitation, 6 pages, paper no. 013.. 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_5261 .

Janković, Novica, Jeremić, Đorđe, Čantrak, Đorđe, Ilić, Dejan, "Flow Uniformity and Turbulence Level Measurements by LDA in the Wind Tunnel for Anemometers Calibration" in Proceedings, 9th International Scientific Conference on Defensive Technologies, OTEH 2020, Belgrade, Serbia, 15-16 October 2020., Session Quality, Standardization, Metrology, Maintenance and Exploitation, 6 pages, paper no. 013. (2020),
https://hdl.handle.net/21.15107/rcub_machinery_5261 .