Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans
Апстракт
To investigate air flow in longitudinally ventilated traffic tunnels, a scaled model of a typical road-traffic tunnel with an appropriate ventilation system based on axial ducted fans, is designed and built in the Lab. The focus of this paper is the airflow in a bi-directional traffic, two-lane tunnel. At the scale ratio of approx. 1:20, at 20.52 m length it represents approximate to 400 m of a real-scale tunnel. The model consists of two parallel tunnel tubes, where the main tunnel (with a hydraulic diameter of D-h1 approximate to 0.4 m has the geometry of a scaled road traffic-tunnel. The second tunnel (D-h2 approximate to 0.16 m) has a smaller size and is circular in cross-section, used only to simulate airflow towards an evacuation tunnel tube. Thus the two tunnels are connected by the evacuation passages, equipped with adjustable escape doors. By a combination of experimental and numerical work, the air flow-field and the performance of the ventilation system are investigated. The... velocity field and its turbulence properties exiting the fans were determined experimentally using hot-wire anemometry. These data were further processed to be used in the tunnel flow computations by CFD. The efficiency of momentum transfer (eta(i), Kempf factor) of the longitudinal tunnel ventilation is determined. The effect that the imposed boundary conditions and the level of their detail, have within a CFD computation of tunnel airflow, with respect to accuracy, velocity distribution and computed eta(i), Finally a traffic-loaded (traffic "jam'') case of flow is studied through experiment and CFD. The difficulty in assessing the required thrust of the plant in traffic-jam tunnel conditions is discussed, and the ventilation efficiency is estimated. Based on later results, the two limiting shapes of axial velocity distribution with respect to height above the road, in this type of tunnel and traffic, are estimated. The last result can be used as a realistic boundary condition (as inlet b.c. and/or initial condition) for numerical studies of flow and fire scenarios in such tunnels with the traffic load critical for design.
Кључне речи:
ventilation flows / turbulence / tunnels / numerical boundary conditions / CFD / axial ducted fansИзвор:
Theoretical and Applied Mechanics, 2018, 45, 2, 151-165Издавач:
- Srpsko društvo za mehaniku, Beograd
Финансирање / пројекти:
- Примена савремених мерних и прорачунских техника за изучавање струјних параметара вентилационих система на моделу енергетски изузетно ефикасног (пасивног) објекта (RS-MESTD-Technological Development (TD or TR)-35046)
- MESTD, Serbia
- Ministry of Science, Montenegro
- University of Belgrade, Faculty of Mechanical Engineering
- University of Montenegro, Faculty of Mechanical Engineering
DOI: 10.2298/TAM171201010S
ISSN: 1450-5584
WoS: 000455467700003
Scopus: 2-s2.0-85063056183
Колекције
Институција/група
Mašinski fakultetTY - JOUR AU - Sekularac, Milan AU - Janković, Novica PY - 2018 UR - https://machinery.mas.bg.ac.rs/handle/123456789/2861 AB - To investigate air flow in longitudinally ventilated traffic tunnels, a scaled model of a typical road-traffic tunnel with an appropriate ventilation system based on axial ducted fans, is designed and built in the Lab. The focus of this paper is the airflow in a bi-directional traffic, two-lane tunnel. At the scale ratio of approx. 1:20, at 20.52 m length it represents approximate to 400 m of a real-scale tunnel. The model consists of two parallel tunnel tubes, where the main tunnel (with a hydraulic diameter of D-h1 approximate to 0.4 m has the geometry of a scaled road traffic-tunnel. The second tunnel (D-h2 approximate to 0.16 m) has a smaller size and is circular in cross-section, used only to simulate airflow towards an evacuation tunnel tube. Thus the two tunnels are connected by the evacuation passages, equipped with adjustable escape doors. By a combination of experimental and numerical work, the air flow-field and the performance of the ventilation system are investigated. The velocity field and its turbulence properties exiting the fans were determined experimentally using hot-wire anemometry. These data were further processed to be used in the tunnel flow computations by CFD. The efficiency of momentum transfer (eta(i), Kempf factor) of the longitudinal tunnel ventilation is determined. The effect that the imposed boundary conditions and the level of their detail, have within a CFD computation of tunnel airflow, with respect to accuracy, velocity distribution and computed eta(i), Finally a traffic-loaded (traffic "jam'') case of flow is studied through experiment and CFD. The difficulty in assessing the required thrust of the plant in traffic-jam tunnel conditions is discussed, and the ventilation efficiency is estimated. Based on later results, the two limiting shapes of axial velocity distribution with respect to height above the road, in this type of tunnel and traffic, are estimated. The last result can be used as a realistic boundary condition (as inlet b.c. and/or initial condition) for numerical studies of flow and fire scenarios in such tunnels with the traffic load critical for design. PB - Srpsko društvo za mehaniku, Beograd T2 - Theoretical and Applied Mechanics T1 - Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans EP - 165 IS - 2 SP - 151 VL - 45 DO - 10.2298/TAM171201010S ER -
@article{ author = "Sekularac, Milan and Janković, Novica", year = "2018", abstract = "To investigate air flow in longitudinally ventilated traffic tunnels, a scaled model of a typical road-traffic tunnel with an appropriate ventilation system based on axial ducted fans, is designed and built in the Lab. The focus of this paper is the airflow in a bi-directional traffic, two-lane tunnel. At the scale ratio of approx. 1:20, at 20.52 m length it represents approximate to 400 m of a real-scale tunnel. The model consists of two parallel tunnel tubes, where the main tunnel (with a hydraulic diameter of D-h1 approximate to 0.4 m has the geometry of a scaled road traffic-tunnel. The second tunnel (D-h2 approximate to 0.16 m) has a smaller size and is circular in cross-section, used only to simulate airflow towards an evacuation tunnel tube. Thus the two tunnels are connected by the evacuation passages, equipped with adjustable escape doors. By a combination of experimental and numerical work, the air flow-field and the performance of the ventilation system are investigated. The velocity field and its turbulence properties exiting the fans were determined experimentally using hot-wire anemometry. These data were further processed to be used in the tunnel flow computations by CFD. The efficiency of momentum transfer (eta(i), Kempf factor) of the longitudinal tunnel ventilation is determined. The effect that the imposed boundary conditions and the level of their detail, have within a CFD computation of tunnel airflow, with respect to accuracy, velocity distribution and computed eta(i), Finally a traffic-loaded (traffic "jam'') case of flow is studied through experiment and CFD. The difficulty in assessing the required thrust of the plant in traffic-jam tunnel conditions is discussed, and the ventilation efficiency is estimated. Based on later results, the two limiting shapes of axial velocity distribution with respect to height above the road, in this type of tunnel and traffic, are estimated. The last result can be used as a realistic boundary condition (as inlet b.c. and/or initial condition) for numerical studies of flow and fire scenarios in such tunnels with the traffic load critical for design.", publisher = "Srpsko društvo za mehaniku, Beograd", journal = "Theoretical and Applied Mechanics", title = "Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans", pages = "165-151", number = "2", volume = "45", doi = "10.2298/TAM171201010S" }
Sekularac, M.,& Janković, N.. (2018). Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans. in Theoretical and Applied Mechanics Srpsko društvo za mehaniku, Beograd., 45(2), 151-165. https://doi.org/10.2298/TAM171201010S
Sekularac M, Janković N. Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans. in Theoretical and Applied Mechanics. 2018;45(2):151-165. doi:10.2298/TAM171201010S .
Sekularac, Milan, Janković, Novica, "Experimental and numerical analysis of flow field and ventilation performance in a traffic tunnel ventilated by axial fans" in Theoretical and Applied Mechanics, 45, no. 2 (2018):151-165, https://doi.org/10.2298/TAM171201010S . .