This study conducted the numerical models validated by wind-tunnel experiments to investigate the issues of Re-independence of indoor airflow and pollutant dispersion within an isolated building.The window Reynolds nu...This study conducted the numerical models validated by wind-tunnel experiments to investigate the issues of Re-independence of indoor airflow and pollutant dispersion within an isolated building.The window Reynolds number(Re_(w))was specified to characterize the indoor flow and dispersion.The indicators of RRC(ratio of relative change)or DR(K_DR)(difference ratio of dimensionless concentration)<5%were applied to quantitatively determine the critical Rew for indoor flow and turbulent diffusion.The results show that the critical Re(Re_(crit)) value is position-dependent,and Re_(crit) at the most unfavorable position should be suggested as the optimal value within the whole areas of interest.Thus Re(H,orit)=27,000 is recommended for the outdoor flows;while Re_(w,crit)=15,000 is determined for the indoor flows due to the lower part below the window showing the most unfavorable.The suggested Re_(w,crit)(=15,000)for indoor airflow and cross ventilation is independence of the window size.Moreover,taking K_DR≤5% as the indicator,the suggested Re_(w,crit) for ensuring indoor pollutant diffusion enter the independence regime should also be 15,000,indicating that indoor passive diffusion is completely determined by the flow structures.The contours of dimensionless velocity(U/U_(0))and concentration(K)against the increasing Re(w) further confirmed this critical value.This study further reveals the Re-independence issues for indoor flow and dispersion to ensure the reliability of the data obtained by reduced-scale numerical or wind-tunnel models.展开更多
基金This work was supported by Shanghai Sailing Program(No.18YF1417600),Scientific and Innovative Action Plan of Shanghai(No.20dz 1204008)the National Natural Science Foundation of China(No.51536006).
文摘This study conducted the numerical models validated by wind-tunnel experiments to investigate the issues of Re-independence of indoor airflow and pollutant dispersion within an isolated building.The window Reynolds number(Re_(w))was specified to characterize the indoor flow and dispersion.The indicators of RRC(ratio of relative change)or DR(K_DR)(difference ratio of dimensionless concentration)<5%were applied to quantitatively determine the critical Rew for indoor flow and turbulent diffusion.The results show that the critical Re(Re_(crit)) value is position-dependent,and Re_(crit) at the most unfavorable position should be suggested as the optimal value within the whole areas of interest.Thus Re(H,orit)=27,000 is recommended for the outdoor flows;while Re_(w,crit)=15,000 is determined for the indoor flows due to the lower part below the window showing the most unfavorable.The suggested Re_(w,crit)(=15,000)for indoor airflow and cross ventilation is independence of the window size.Moreover,taking K_DR≤5% as the indicator,the suggested Re_(w,crit) for ensuring indoor pollutant diffusion enter the independence regime should also be 15,000,indicating that indoor passive diffusion is completely determined by the flow structures.The contours of dimensionless velocity(U/U_(0))and concentration(K)against the increasing Re(w) further confirmed this critical value.This study further reveals the Re-independence issues for indoor flow and dispersion to ensure the reliability of the data obtained by reduced-scale numerical or wind-tunnel models.
