TY  - CONF
AU  - Rajić, Milena
AU  - Živković, Dragoljub
AU  - Banić, Milan
AU  - Mančić, Marko
AU  - Mitrović, Nenad
AU  - Milošević, Miloš
PY  - 2021-07
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7697
AB  - The aim of the paper is to investigate the transient regime of hot water boiler numerically and experimentally. In the regime of starting up, as the most critical one, measurements were done on the boiler critical element. The operating characteristics as well as safe and reliable operation conditions of hot water boilers are limited by thermal stresses that occur in their structure. The greatest thermal stresses occur in transient operating regimes such as starting-up, changing operation mode or sudden shutdown, resulting in uneven heating or cooling of boiler elements. Large temperature gradients cause high thermal stresses that are especially critical
in elements with thick walls. As thermal stresses may limit the heating and cooling rates of temperature changes, boiler structure is exposed to variable temperature and stress field. The largest absolute value of thermal stresses occurs at the inner surface, where direct measurements are not possible to take, since the inner surface is in direct contact with hot water under high pressure. This was the reason to measure the temperature of boiler structure inside the boiler, on tube plate, as one of the critical part of the boiler. In this paper the experimental results of temperature measurement of tube plate were presented, during the regime of starting-up. Numerical model done by FEM was verified by experimental results. The performed analysis showed that the tube plate of the first reversing chamber, the boiler element with the thickest wall, is exposed to the highest thermal stresses. This part of the boiler is exposed to temperatures
t>500 ℃ and it is exposed to creep. In conditions of creep, continuous accumulation of plastic deformations occurs at a rate that depends on the level of stress, temperature and material characteristics.
PB  - Innovation Center of Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2021
T1  - EXPERIMENTAL AND NUMERICAL ANALYSIS OF HOT WATER BOILER IN START UP REGIME
SP  - 30
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7697
ER  - 

@conference{
author = "Rajić, Milena and Živković, Dragoljub and Banić, Milan and Mančić, Marko and Mitrović, Nenad and Milošević, Miloš",
year = "2021-07",
abstract = "The aim of the paper is to investigate the transient regime of hot water boiler numerically and experimentally. In the regime of starting up, as the most critical one, measurements were done on the boiler critical element. The operating characteristics as well as safe and reliable operation conditions of hot water boilers are limited by thermal stresses that occur in their structure. The greatest thermal stresses occur in transient operating regimes such as starting-up, changing operation mode or sudden shutdown, resulting in uneven heating or cooling of boiler elements. Large temperature gradients cause high thermal stresses that are especially critical
in elements with thick walls. As thermal stresses may limit the heating and cooling rates of temperature changes, boiler structure is exposed to variable temperature and stress field. The largest absolute value of thermal stresses occurs at the inner surface, where direct measurements are not possible to take, since the inner surface is in direct contact with hot water under high pressure. This was the reason to measure the temperature of boiler structure inside the boiler, on tube plate, as one of the critical part of the boiler. In this paper the experimental results of temperature measurement of tube plate were presented, during the regime of starting-up. Numerical model done by FEM was verified by experimental results. The performed analysis showed that the tube plate of the first reversing chamber, the boiler element with the thickest wall, is exposed to the highest thermal stresses. This part of the boiler is exposed to temperatures
t>500 ℃ and it is exposed to creep. In conditions of creep, continuous accumulation of plastic deformations occurs at a rate that depends on the level of stress, temperature and material characteristics.",
publisher = "Innovation Center of Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2021",
title = "EXPERIMENTAL AND NUMERICAL ANALYSIS OF HOT WATER BOILER IN START UP REGIME",
pages = "30",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7697"
}

Rajić, M., Živković, D., Banić, M., Mančić, M., Mitrović, N.,& Milošević, M.. (2021-07). EXPERIMENTAL AND NUMERICAL ANALYSIS OF HOT WATER BOILER IN START UP REGIME. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2021
Innovation Center of Faculty of Mechanical Engineering., 30.
https://hdl.handle.net/21.15107/rcub_machinery_7697

Rajić M, Živković D, Banić M, Mančić M, Mitrović N, Milošević M. EXPERIMENTAL AND NUMERICAL ANALYSIS OF HOT WATER BOILER IN START UP REGIME. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2021. 2021;:30.
https://hdl.handle.net/21.15107/rcub_machinery_7697 .

Rajić, Milena, Živković, Dragoljub, Banić, Milan, Mančić, Marko, Mitrović, Nenad, Milošević, Miloš, "EXPERIMENTAL AND NUMERICAL ANALYSIS OF HOT WATER BOILER IN START UP REGIME" in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2021 (2021-07):30,
https://hdl.handle.net/21.15107/rcub_machinery_7697 .

TY  - CONF
AU  - Rajić, Milena
AU  - Živković, Dragoljub
AU  - Banić, Milan
AU  - Mančić, Marko
AU  - Milošević, Miloš
AU  - Maneski, Taško
AU  - Mitrović, Nenad
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7695
AB  - Hot water boilers, especially boilers with fire tube where the combustion takes place, are widely used in process industry. Elements of the boiler are exposed to high pressures and temperatures during boiler operation. Exploitation experience indicates constant and permanent breakdowns occurring as a result of accidental states of individual boiler elements. Studies done before in this field indicate certain critical boiler elements that may have influence on the reliability and safety of the entire unit. In order to avoid this state, certain investigation should be made that would examine the influence of different regimes on the boiler structure. Lack of available data concerning the temperature as well as stress-strain field in boiler elements led us to perform such kind of experiment. This paper presents results of numerical analysis performed on the modelled
boiler. Validation of the numerical model was performed based on experimental results obtained using 3D Digital Image Correlation analysis. This paper analyses critical elements of the hot water boiler by experimental data obtained from its model and improved numerical model in order to analyze constrains and loads the model is exposed to and to have fully-covered stress-strain field obtained from experimental data.
PB  - Innovation Center of Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2020
T1  - 3D DIGITAL IMAGE CORRELATION ANALYSIS OF THE MODELLED BOILER ELEMENT
SP  - 15
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7695
ER  - 

@conference{
author = "Rajić, Milena and Živković, Dragoljub and Banić, Milan and Mančić, Marko and Milošević, Miloš and Maneski, Taško and Mitrović, Nenad",
year = "2020",
abstract = "Hot water boilers, especially boilers with fire tube where the combustion takes place, are widely used in process industry. Elements of the boiler are exposed to high pressures and temperatures during boiler operation. Exploitation experience indicates constant and permanent breakdowns occurring as a result of accidental states of individual boiler elements. Studies done before in this field indicate certain critical boiler elements that may have influence on the reliability and safety of the entire unit. In order to avoid this state, certain investigation should be made that would examine the influence of different regimes on the boiler structure. Lack of available data concerning the temperature as well as stress-strain field in boiler elements led us to perform such kind of experiment. This paper presents results of numerical analysis performed on the modelled
boiler. Validation of the numerical model was performed based on experimental results obtained using 3D Digital Image Correlation analysis. This paper analyses critical elements of the hot water boiler by experimental data obtained from its model and improved numerical model in order to analyze constrains and loads the model is exposed to and to have fully-covered stress-strain field obtained from experimental data.",
publisher = "Innovation Center of Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2020",
title = "3D DIGITAL IMAGE CORRELATION ANALYSIS OF THE MODELLED BOILER ELEMENT",
pages = "15",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7695"
}

Rajić, M., Živković, D., Banić, M., Mančić, M., Milošević, M., Maneski, T.,& Mitrović, N.. (2020). 3D DIGITAL IMAGE CORRELATION ANALYSIS OF THE MODELLED BOILER ELEMENT. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2020
Innovation Center of Faculty of Mechanical Engineering., 15.
https://hdl.handle.net/21.15107/rcub_machinery_7695

Rajić M, Živković D, Banić M, Mančić M, Milošević M, Maneski T, Mitrović N. 3D DIGITAL IMAGE CORRELATION ANALYSIS OF THE MODELLED BOILER ELEMENT. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2020. 2020;:15.
https://hdl.handle.net/21.15107/rcub_machinery_7695 .

Rajić, Milena, Živković, Dragoljub, Banić, Milan, Mančić, Marko, Milošević, Miloš, Maneski, Taško, Mitrović, Nenad, "3D DIGITAL IMAGE CORRELATION ANALYSIS OF THE MODELLED BOILER ELEMENT" in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2020 (2020):15,
https://hdl.handle.net/21.15107/rcub_machinery_7695 .

TY  - JOUR
AU  - Stojanović, Andrijana
AU  - Stevanović, Vladimir
AU  - Petrović, Milan M.
AU  - Živković, Dragoljub
AU  - Stanković, Branislav
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4532
AB  - In this paper three-dimensional numerical simulation of the atmospheric saturated 
pool boiling was performed. The applied modelling and numerical methods enable 
full representation of the two-phase mixture behaviour on the heating surface with 
the inclusion of the swell level prediction. The three-dimensional investigation presented
here was performed in order to take into account a convective heat transfer 
on the heated surface, as well as spatial effects of the vapour generation and a twophase
flow such as phase dispersion within the two-phase mixture. The results are 
presented for a short period of time after the initiation of the heat supply and vapor 
generation on the heating surface. The replenishment of the heating surface with 
water and partial surface wetting for lower heat fluxes is shown. The influence of 
the density of nucleation sites and the bubble residence time on the wall on the pool 
boiling dynamics is discussed. Also, the influence of the heat flux intensity on the 
pool boiling dynamics is investigated. The applied numerical and modelling method 
showed  robustness by allowing stable calculations for wide ranges of applied modelling
boiling parameters.
PB  - Univerzitet u Nišu - Tehnološki fakultet, Leskovac
T2  - Savremene tehnologije – Advanced Technologies
T1  - Numerical study of heat transfer during nucleate pool boiling
EP  - 80
IS  - 1
SP  - 73
VL  - 5
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4532
ER  - 

@article{
author = "Stojanović, Andrijana and Stevanović, Vladimir and Petrović, Milan M. and Živković, Dragoljub and Stanković, Branislav",
year = "2016",
abstract = "In this paper three-dimensional numerical simulation of the atmospheric saturated 
pool boiling was performed. The applied modelling and numerical methods enable 
full representation of the two-phase mixture behaviour on the heating surface with 
the inclusion of the swell level prediction. The three-dimensional investigation presented
here was performed in order to take into account a convective heat transfer 
on the heated surface, as well as spatial effects of the vapour generation and a twophase
flow such as phase dispersion within the two-phase mixture. The results are 
presented for a short period of time after the initiation of the heat supply and vapor 
generation on the heating surface. The replenishment of the heating surface with 
water and partial surface wetting for lower heat fluxes is shown. The influence of 
the density of nucleation sites and the bubble residence time on the wall on the pool 
boiling dynamics is discussed. Also, the influence of the heat flux intensity on the 
pool boiling dynamics is investigated. The applied numerical and modelling method 
showed  robustness by allowing stable calculations for wide ranges of applied modelling
boiling parameters.",
publisher = "Univerzitet u Nišu - Tehnološki fakultet, Leskovac",
journal = "Savremene tehnologije – Advanced Technologies",
title = "Numerical study of heat transfer during nucleate pool boiling",
pages = "80-73",
number = "1",
volume = "5",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4532"
}

Stojanović, A., Stevanović, V., Petrović, M. M., Živković, D.,& Stanković, B.. (2016). Numerical study of heat transfer during nucleate pool boiling. in Savremene tehnologije – Advanced Technologies
Univerzitet u Nišu - Tehnološki fakultet, Leskovac., 5(1), 73-80.
https://hdl.handle.net/21.15107/rcub_machinery_4532

Stojanović A, Stevanović V, Petrović MM, Živković D, Stanković B. Numerical study of heat transfer during nucleate pool boiling. in Savremene tehnologije – Advanced Technologies. 2016;5(1):73-80.
https://hdl.handle.net/21.15107/rcub_machinery_4532 .

Stojanović, Andrijana, Stevanović, Vladimir, Petrović, Milan M., Živković, Dragoljub, Stanković, Branislav, "Numerical study of heat transfer during nucleate pool boiling" in Savremene tehnologije – Advanced Technologies, 5, no. 1 (2016):73-80,
https://hdl.handle.net/21.15107/rcub_machinery_4532 .

TY  - JOUR
AU  - Stojanović, Andrijana
AU  - Stevanović, Vladimir
AU  - Petrović, Milan M.
AU  - Živković, Dragoljub
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2290
AB  - Multi-dimensional numerical simulation of the atmospheric saturated pool boiling is performed. The applied modelling and numerical methods enable a full representation of the liquid and vapour two-phase mixture behaviour on the heated surface, with included prediction of the swell level and heated wall temperature field. In this way the integral behaviour of nucleate pool boiling is simulated. The micro conditions of bubble generation at the heated wall surface are modelled by the bubble nucleation site density, the liquid wetting contact angle and the bubble grow time. The bubble nucleation sites are randomly located within zones of equal size, where the number of zones equals the nucleation site density. The conjugate heat transfer from the heated wall to the liquid is taken into account in wetted heated wall areas around bubble nucleation sites. The boiling curve relation between the heat flux and the heated wall surface temperature in excess of the saturation temperature is predicted for the pool boiling conditions reported in the literature and a good agreement is achieved with experimentally measured data. The influence of the nucleation site density on the boiling curve characteristic is confirmed. In addition, the influence of the heat flux intensity on the spatial effects of vapour generation and two-phase flow are shown, such as the increase of the swell level position and the reduced wetting of the heated wall surface by the heat flux increase.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Numerical investigation of nucleate pool boiling heat transfer
EP  - S1312
SP  - S1301
VL  - 20
DO  - 10.2298/TSCI160404276S
ER  - 

@article{
author = "Stojanović, Andrijana and Stevanović, Vladimir and Petrović, Milan M. and Živković, Dragoljub",
year = "2016",
abstract = "Multi-dimensional numerical simulation of the atmospheric saturated pool boiling is performed. The applied modelling and numerical methods enable a full representation of the liquid and vapour two-phase mixture behaviour on the heated surface, with included prediction of the swell level and heated wall temperature field. In this way the integral behaviour of nucleate pool boiling is simulated. The micro conditions of bubble generation at the heated wall surface are modelled by the bubble nucleation site density, the liquid wetting contact angle and the bubble grow time. The bubble nucleation sites are randomly located within zones of equal size, where the number of zones equals the nucleation site density. The conjugate heat transfer from the heated wall to the liquid is taken into account in wetted heated wall areas around bubble nucleation sites. The boiling curve relation between the heat flux and the heated wall surface temperature in excess of the saturation temperature is predicted for the pool boiling conditions reported in the literature and a good agreement is achieved with experimentally measured data. The influence of the nucleation site density on the boiling curve characteristic is confirmed. In addition, the influence of the heat flux intensity on the spatial effects of vapour generation and two-phase flow are shown, such as the increase of the swell level position and the reduced wetting of the heated wall surface by the heat flux increase.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Numerical investigation of nucleate pool boiling heat transfer",
pages = "S1312-S1301",
volume = "20",
doi = "10.2298/TSCI160404276S"
}

Stojanović, A., Stevanović, V., Petrović, M. M.,& Živković, D.. (2016). Numerical investigation of nucleate pool boiling heat transfer. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 20, S1301-S1312.
https://doi.org/10.2298/TSCI160404276S

Stojanović A, Stevanović V, Petrović MM, Živković D. Numerical investigation of nucleate pool boiling heat transfer. in Thermal Science. 2016;20:S1301-S1312.
doi:10.2298/TSCI160404276S .

Stojanović, Andrijana, Stevanović, Vladimir, Petrović, Milan M., Živković, Dragoljub, "Numerical investigation of nucleate pool boiling heat transfer" in Thermal Science, 20 (2016):S1301-S1312,
https://doi.org/10.2298/TSCI160404276S . .

TY  - JOUR
AU  - Stojanović, Andrijana
AU  - Stevanović, Vladimir
AU  - Petrović, Milan M.
AU  - Živković, Dragoljub
AU  - Stanković, Branislav
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2259
AB  - U ovom radu je izvršena trodimenzionalna numerička simulacija atmosferskog, zasićenog ključanja u velikoj zapremini. Primenjeni matematički model i numerička metoda omogućavaju potpuni prikaz ponašanja dvofazne mešavine na grejnoj površini kao i predviđanje slobodnog nivoa tečnosti. Ovde prikazano trodimenzionalno istraživanje je sprovedeno kako bi se uzela u obzir konvektivna razmena toplote na grejnoj površini kao i prostorni efekti generacije pare i dvofaznog toka, kao što su disprzija faza u dvofaznoj mešavini. Predstavljeni su rezultati simulacije nakon kratkog vremenskog perioda od početka zagrevanja i formiranja mehurova na grejnoj površini. Prikazani su popunjenost grejne površine vodom i parcijalna okvašenost površine za niže vrednosti toplotnog fluksa. Diskutovan je uticaj gustine nukleacije i vremena zadržavanja mehurova na grejnom zidu na dinamiku ključanja. Takođe je proučen uticaj intenziteta toplotnog fluksa na dinamiku ključanja u velikoj zapremini. Primenjeni numerički metod i matematički model je pokazao ispravnost, omogućavajući stabilan proračun za širok opseg primenjenih parametara pri modeliranju.
AB  - In this paper three-dimensional numerical simulation of the atmospheric saturated pool boiling was performed. The applied modelling and numerical methods enable full representation of the two-phase mixture behaviour on the heating surface with the inclusion of the swell level prediction. The three-dimensional investigation presented here was performed in order to take into account a convective heat transfer on the heated surface, as well as spatial effects of the vapour generation and a two phase flow such as phase dispersion within the two-phase mixture. The results are presented for a short period of time after the initiation of the heat supply and vapor generation on the heating surface. The replenishment of the heating surface with water and partial surface wetting for lower heat fluxes is shown. The influence of the density of nucleation sites and the bubble residence time on the wall on the pool boiling dynamics is discussed. Also, the influence of the heat flux intensity on the pool boiling dynamics is investigated. The applied numerical and modelling method showed robustness by allowing stable calculations for wide ranges of applied modelling boiling parameters.
PB  - Univerzitet u Nišu - Tehnološki fakultet, Leskovac
T2  - Advanced Technologies
T1  - Numeričko proučavanje procesa razmene toplote pri ključanju u velikoj zapremini
T1  - Numerical study of heat transfer during nucleate pool boiling
EP  - 80
IS  - 1
SP  - 73
VL  - 5
DO  - 10.5937/savteh1601073S
ER  - 

@article{
author = "Stojanović, Andrijana and Stevanović, Vladimir and Petrović, Milan M. and Živković, Dragoljub and Stanković, Branislav",
year = "2016",
abstract = "U ovom radu je izvršena trodimenzionalna numerička simulacija atmosferskog, zasićenog ključanja u velikoj zapremini. Primenjeni matematički model i numerička metoda omogućavaju potpuni prikaz ponašanja dvofazne mešavine na grejnoj površini kao i predviđanje slobodnog nivoa tečnosti. Ovde prikazano trodimenzionalno istraživanje je sprovedeno kako bi se uzela u obzir konvektivna razmena toplote na grejnoj površini kao i prostorni efekti generacije pare i dvofaznog toka, kao što su disprzija faza u dvofaznoj mešavini. Predstavljeni su rezultati simulacije nakon kratkog vremenskog perioda od početka zagrevanja i formiranja mehurova na grejnoj površini. Prikazani su popunjenost grejne površine vodom i parcijalna okvašenost površine za niže vrednosti toplotnog fluksa. Diskutovan je uticaj gustine nukleacije i vremena zadržavanja mehurova na grejnom zidu na dinamiku ključanja. Takođe je proučen uticaj intenziteta toplotnog fluksa na dinamiku ključanja u velikoj zapremini. Primenjeni numerički metod i matematički model je pokazao ispravnost, omogućavajući stabilan proračun za širok opseg primenjenih parametara pri modeliranju., In this paper three-dimensional numerical simulation of the atmospheric saturated pool boiling was performed. The applied modelling and numerical methods enable full representation of the two-phase mixture behaviour on the heating surface with the inclusion of the swell level prediction. The three-dimensional investigation presented here was performed in order to take into account a convective heat transfer on the heated surface, as well as spatial effects of the vapour generation and a two phase flow such as phase dispersion within the two-phase mixture. The results are presented for a short period of time after the initiation of the heat supply and vapor generation on the heating surface. The replenishment of the heating surface with water and partial surface wetting for lower heat fluxes is shown. The influence of the density of nucleation sites and the bubble residence time on the wall on the pool boiling dynamics is discussed. Also, the influence of the heat flux intensity on the pool boiling dynamics is investigated. The applied numerical and modelling method showed robustness by allowing stable calculations for wide ranges of applied modelling boiling parameters.",
publisher = "Univerzitet u Nišu - Tehnološki fakultet, Leskovac",
journal = "Advanced Technologies",
title = "Numeričko proučavanje procesa razmene toplote pri ključanju u velikoj zapremini, Numerical study of heat transfer during nucleate pool boiling",
pages = "80-73",
number = "1",
volume = "5",
doi = "10.5937/savteh1601073S"
}

Stojanović, A., Stevanović, V., Petrović, M. M., Živković, D.,& Stanković, B.. (2016). Numeričko proučavanje procesa razmene toplote pri ključanju u velikoj zapremini. in Advanced Technologies
Univerzitet u Nišu - Tehnološki fakultet, Leskovac., 5(1), 73-80.
https://doi.org/10.5937/savteh1601073S

Stojanović A, Stevanović V, Petrović MM, Živković D, Stanković B. Numeričko proučavanje procesa razmene toplote pri ključanju u velikoj zapremini. in Advanced Technologies. 2016;5(1):73-80.
doi:10.5937/savteh1601073S .

Stojanović, Andrijana, Stevanović, Vladimir, Petrović, Milan M., Živković, Dragoljub, Stanković, Branislav, "Numeričko proučavanje procesa razmene toplote pri ključanju u velikoj zapremini" in Advanced Technologies, 5, no. 1 (2016):73-80,
https://doi.org/10.5937/savteh1601073S . .