热压自然通风房间的瞬态污染状况分析

Analysis on Transient Air Pollution in Buoyancy-Induced Naturally Ventilated Enclosures

热压自然通风向稳态发展的过程中室内空气污染状况必然会不断变化.在热压自然通风瞬态模型的基础上,给出了自然通风的污染物输送模型,理论分析了典型条件下通风房间内污染物浓度的瞬变过程,讨论了主要因素对室内瞬态污染物浓度的影响.研究表明,室内热空气层的污染物浓度和原有冷空气层的污染物浓度均是先升高后降低,且前者的最高值大于后者.增大热源浮升力通量或有效通风面积、减小房间面积或房间高度均可以加速室内污染物浓度的变化,但是增大热源浮升力通量或减小房间面积对污染物浓度的峰值没有影响,而增大有效通风面积或减小房间高度却会使污染物浓度峰值升高.

Indoor air pollution is influenced continuously by the airflow during the development of thermal natural ventilation to its steady state. The theoretical model of pollutant transport during natural ventilation is presented on the basic of the transient model of thermal natural ventilation to analyze the time evolution of indoor pollutant concentration and to explore the effects of main factors on the transient pollutant concentration during ventilation. The results indicate that the pollutant concentrations of the warm air layer and the original air layer both increase earlier and drop later. The maximal concentration of the warm air layer is shown to be greater than that of the original air layer. The variation of indoor pollutant concentration with time can be accelerated by increasing the source buoyancy flux or effective vent area, or decreasing the enclosure floor area or enclosure height. The increase of the source buoyancy flux or the decrease of the enclosure floor area would not affect the peak value of the transient pollutant concentration, which may be elevated by increasing of effective vent area or decreasing of the enclosure height.