建筑热羽流影响下空气污染物跨楼层扩散特性
摘要：采用风洞实验和数值模拟，以单侧通风6层建筑为研究对象，考虑水平来流和太阳辐射引起的近壁面热羽流的耦合作用，探究了不同理查德森数Ri下建筑壁面热流运动、温度分布及污染物在竖直方向的跨楼层扩散传播特性。研究表明：当Ri≤5.64时，水平风力占主导，建筑2/3高度以下迎风面有明显的下行及向两侧的流动，1层释放的污染物对2层及以上楼层几乎没有影响，此时归一化净逃逸速度NEV*基本保持不变；当Ri>5.64时，壁面热浮升力作用不能被忽略，随着Ri的增大，NEV*明显增大，表明有更多污染物从1层室内扩散出来，沿迎风面向上运动的热流对高层室内产生影响，导致污染物跨楼层传播的风险增大。
关键词：风效应热羽流污染物扩散跨楼层传播净逃逸速度
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参考文献[1] NIU J,TUNG T C W.On-site quantification of re-entry ratio of ventilation exhausts in multi-family residential buildings and implications[J].Indoor air,2010,18(1):12- 26.
[2] LIU X P,NIU J L,KWOK K C S,et al.Investigation of indoor air pollutant dispersion and cross-contamination around a typical high-rise residential building:wind tunnel tests[J].Building and environment,2010,45(8):1769- 1778.
[3] AI Z T,MAK C M,NIU J L.Numerical investigation of wind-induced airflow and interunit dispersion characteristics in multistory residential buildings[J].Indoor air,2013,23(5):417- 429.
[4] ASHRAE.ASHRAE handbook:fundamentals[M].Atlanta:ASHRAE Inc.,2013:Chapter 24.
[5] LIU X P,NIU J L,PERINO M,et al.Numerical simulation of inter-flat air cross-contamination under the condition of single-sided natural ventilation[J].Journal of building performance simulation,2008,1(2):133- 147.
[6] WANG Y,ZHAO T T,CAO Z X,et al.The influence of indoor thermal conditions on ventilation flow and pollutant dispersion in downstream industrial workshop[J].Building and environment,2021,187:107400.
[7] MU D,GAO N P,ZHU T.CFD investigation on the effects of wind and thermal wall-flow on pollutant transmission in a high-rise building[J].Building and environment,2018,137:185- 197.
[8] FAN Y F,LI Y G,HANG J,et al.Natural convection flows along a 16-storey high-rise building[J].Building and environment,2016,107:215- 225.
[9] GAO N P,NIU J L,PERINO M,et al.The airborne transmission of infection between flats in high-rise residential buildings:particle simulation[J].Building and environment,2009,44 (2):402- 410.
[10] CACIOLO M,STABAT P,MARCHIO D.Numerical simulation of single-sided ventilation using RANS and LES and comparison with full-scale experiments[J].Building and environment,2012,50:202- 213.
[11] ZHANG Y,KWOK K C S,LIU X P,et al.Characteristics of air pollutant dispersion around a high-rise building[J].Environmental pollution,2015,204:280- 288.
[12] ZHUANG J W,DIAO Y F.Influences of radiation on the prediction of thermal environment in a transient buoyancy-driven natural ventilation classroom[J].Science and technology for the built environment,2020,26 (3):334- 348.
[13] SREBRIC J,VUKOVIC V,HE G Q,et al.CFD boundary conditions for contaminant dispersion,heat transfer and airflow simulations around human occupants in indoor environments[J].Building and environment,2008,43 (3):294- 303.
[14] LATEB M,MASSON C,STATHOPOULOS T,et al.Comparison of various types of k-ε models for pollutant emissions around a two-building configuration[J].Journal of wind engineering and industrial aerodynamics,2013,115:9- 21.
[15] HUANG X T,HUANG Y D,XU N,et al.Thermal effects on the dispersion of rooftop stack emission in the wake of a tall building within suburban areas by wind-tunnel experiments[J].Journal of wind engineering and industrial aerodynamics,2020,205:104295.
[16] TOMINAGA Y,STATHOPOULOS T.Turbulent Schmidt numbers for CFD analysis with various types of flow field[J].Atmospheric environment,2007,41(37):8091- 8099.
[17] YAKHOT V,ORSZAG S A.Renormalization group analysis of turbulence.I.Basic theory[J].Journal of scientific computing,1986,1:3- 11.
[18] FRANKE J,HELLSTEN A,SCHLUNZEN K H,et al.The COST 732 best practice guideline for CFD simulation of flows in the urban environment:a summary[J].International journal of environmental pollution,2011,44 (1/2/3/4):419- 427.
[19] BADY M,KATO S,HUANG H.Towards the application of indoor ventilation efficiency indices to evaluate the air quality of urban areas[J].Building and environment,2008,43(12):1991- 2004.
[20] CHAVEV M,HAJRA B,STATHOPOULOS T,et al.Assessment of near-field pollutant dispersion:effect of upstream buildings[J].Journal of wind engineering and industrial aerodynamics,2012,104/105/106:509- 515.
[21] CHAVEZ M,HAJRA B,STATHOPOULOS T,et al.Near-field pollutant dispersion in the built environment by CFD and wind tunnel simulations[J].Journal of wind engineering and industrial aerodynamics,2011,99(4):330- 339.
[22] YANG X,ZHANG Y,HANG J,et al.Integrated assessment of indoor and outdoor ventilation in street canyons with naturally-ventilated buildings by various ventilation indexes[J].Building and environment,2020,169(1):106528.
[23] LIM E,ITO S,SANDBERG M.New ventilation index for evaluating imperfect mixing conditions:analysis of net escape velocity based on RANS approach[J].Building and environment,2013,61:45- 56.
[24] HANG J,WANG Q,CHEN X Y,et al.City breathability in medium density urban-like geometries evaluated through the pollutant transport rate and the net escape velocity[J].Building and environment,2015,94:166- 182.
[2] LIU X P,NIU J L,KWOK K C S,et al.Investigation of indoor air pollutant dispersion and cross-contamination around a typical high-rise residential building:wind tunnel tests[J].Building and environment,2010,45(8):1769- 1778.
[3] AI Z T,MAK C M,NIU J L.Numerical investigation of wind-induced airflow and interunit dispersion characteristics in multistory residential buildings[J].Indoor air,2013,23(5):417- 429.
[4] ASHRAE.ASHRAE handbook:fundamentals[M].Atlanta:ASHRAE Inc.,2013:Chapter 24.
[5] LIU X P,NIU J L,PERINO M,et al.Numerical simulation of inter-flat air cross-contamination under the condition of single-sided natural ventilation[J].Journal of building performance simulation,2008,1(2):133- 147.
[6] WANG Y,ZHAO T T,CAO Z X,et al.The influence of indoor thermal conditions on ventilation flow and pollutant dispersion in downstream industrial workshop[J].Building and environment,2021,187:107400.
[7] MU D,GAO N P,ZHU T.CFD investigation on the effects of wind and thermal wall-flow on pollutant transmission in a high-rise building[J].Building and environment,2018,137:185- 197.
[8] FAN Y F,LI Y G,HANG J,et al.Natural convection flows along a 16-storey high-rise building[J].Building and environment,2016,107:215- 225.
[9] GAO N P,NIU J L,PERINO M,et al.The airborne transmission of infection between flats in high-rise residential buildings:particle simulation[J].Building and environment,2009,44 (2):402- 410.
[10] CACIOLO M,STABAT P,MARCHIO D.Numerical simulation of single-sided ventilation using RANS and LES and comparison with full-scale experiments[J].Building and environment,2012,50:202- 213.
[11] ZHANG Y,KWOK K C S,LIU X P,et al.Characteristics of air pollutant dispersion around a high-rise building[J].Environmental pollution,2015,204:280- 288.
[12] ZHUANG J W,DIAO Y F.Influences of radiation on the prediction of thermal environment in a transient buoyancy-driven natural ventilation classroom[J].Science and technology for the built environment,2020,26 (3):334- 348.
[13] SREBRIC J,VUKOVIC V,HE G Q,et al.CFD boundary conditions for contaminant dispersion,heat transfer and airflow simulations around human occupants in indoor environments[J].Building and environment,2008,43 (3):294- 303.
[14] LATEB M,MASSON C,STATHOPOULOS T,et al.Comparison of various types of k-ε models for pollutant emissions around a two-building configuration[J].Journal of wind engineering and industrial aerodynamics,2013,115:9- 21.
[15] HUANG X T,HUANG Y D,XU N,et al.Thermal effects on the dispersion of rooftop stack emission in the wake of a tall building within suburban areas by wind-tunnel experiments[J].Journal of wind engineering and industrial aerodynamics,2020,205:104295.
[16] TOMINAGA Y,STATHOPOULOS T.Turbulent Schmidt numbers for CFD analysis with various types of flow field[J].Atmospheric environment,2007,41(37):8091- 8099.
[17] YAKHOT V,ORSZAG S A.Renormalization group analysis of turbulence.I.Basic theory[J].Journal of scientific computing,1986,1:3- 11.
[18] FRANKE J,HELLSTEN A,SCHLUNZEN K H,et al.The COST 732 best practice guideline for CFD simulation of flows in the urban environment:a summary[J].International journal of environmental pollution,2011,44 (1/2/3/4):419- 427.
[19] BADY M,KATO S,HUANG H.Towards the application of indoor ventilation efficiency indices to evaluate the air quality of urban areas[J].Building and environment,2008,43(12):1991- 2004.
[20] CHAVEV M,HAJRA B,STATHOPOULOS T,et al.Assessment of near-field pollutant dispersion:effect of upstream buildings[J].Journal of wind engineering and industrial aerodynamics,2012,104/105/106:509- 515.
[21] CHAVEZ M,HAJRA B,STATHOPOULOS T,et al.Near-field pollutant dispersion in the built environment by CFD and wind tunnel simulations[J].Journal of wind engineering and industrial aerodynamics,2011,99(4):330- 339.
[22] YANG X,ZHANG Y,HANG J,et al.Integrated assessment of indoor and outdoor ventilation in street canyons with naturally-ventilated buildings by various ventilation indexes[J].Building and environment,2020,169(1):106528.
[23] LIM E,ITO S,SANDBERG M.New ventilation index for evaluating imperfect mixing conditions:analysis of net escape velocity based on RANS approach[J].Building and environment,2013,61:45- 56.
[24] HANG J,WANG Q,CHEN X Y,et al.City breathability in medium density urban-like geometries evaluated through the pollutant transport rate and the net escape velocity[J].Building and environment,2015,94:166- 182.
Diffusion characteristics of air pollutants across building floors under thermal plume effect
Abstract: Taking a 6-storey building with single-side ventilation as the research object, considering the coupling effect of horizontal flow and near-wall thermal plume caused by solar radiation, this study conducts the wind tunnel experiment and numerical simulation to investigate the heat flux movement on the building wall, the temperature distribution and the diffusion and transmission characteristics of pollutants across building floors in the vertical direction under different Ri. The results show that when Ri≤5.64, the horizontal wind is dominant, and there is obvious downwind and bilateral flow on the windward wall below 2/3 of the building height. The pollutants released from the first floor have almost no effect on the floors above the second floor, and the normalized net escape velocity NEV* remains basically unchanged. When Ri>5.64, the effect of wall thermal buoyancy cannot be ignored, and NEV* increases obviously with the increase of Ri, which indicates that more pollutants will diffuse from the first floor, and the heat flux moving upwind along the windward wall has an impact on the upper floors, resulting in increasing risk of pollutant cross-floor transmission.
Keywords: wind effect; thermal plume; pollutant diffusion; cross-floor transmission; net escape velocity;
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