自然置换通风对温暖房间内污染物的冲刷效应

Pollutant flushing by natural displacement ventilation in a warm room

针对室内初始温度高于室外温度房间的典型自然置换通风情形,在瞬态通风理论模型的基础上,给出了室内污染物守恒方程,并进行数值求解,分析了瞬态通风过程对室内污染物的冲刷效应.结果表明:通风过程中,室内原有热空气层和上部新形成的热空气层的污染物浓度均逐渐降低,且前者下降速度较快;室内初始温度较高时,热源浮升力通量较大,在有效通风面积较大或房间面积较小的条件下,室内原有热空气层和上部热空气层的污染物浓度均较低;房间高度仅影响室内上部新形成热空气层的污染物浓度,且高度越低,该空气层的污染物浓度衰减越快.

The mass conservation equations of air pollutant in a warm room are proposed based on an existing theoretical model on the transient natural displacement ventilation, and are then solved numerically to examine the pollutant flushing by natural displacement ventilation. The results indicate that air pollutant concentrations in the upper warm air layer and original warm air layer both decrease gradually, and the latter evolves faster than the former. Higher interior initial temperature, greater source buoyancy flux, larger effective vent area or smaller floor area help to decrease the pollutant concentrations both in the upper warm air layer and original warm air layer more effectively during the transient ventilation. The room height, however, is only relevant to the variation of pollutant concentration in the upper air layer. The lower the room is, the faster the pollutant concentration in the upper air layer decreases.