負壓空間之污染擴散研究

Abstract

本文在數值計算上使用有限體積法及紊流k-ε模式計算負壓區間的流場計算與污染擴散研究現象。本文分別研究於穩態計算下的排風管有無含有過濾材的負壓區間流場結構，並且分析在不同通風條件下的情形。以及研究負壓區間以暫態的滑移開門作用下，其原本流場受到作用而改變的情形。 結果顯示在通風條件為房間全封閉之不通風情況下，負壓情形較好，但污染累積程度極為嚴重。而在換氣率較佳的情形下，雖然保持負壓情況較為不佳，但區間內污染情形較低。由此可知通風對於防止污染擴散有較大的影響。 而滑移門開門作用使得負壓區間整體負壓環境難以維持，無法持續地維持區間內與外界保持一定壓差的狀態。如需改善則可增設緩衝室以減低污染外洩。

The research is primary to solve the flow field and pollution diffusivity of the negative pressure isolation rooms (NPIRs) by using finite volume method and standard k-ε turbulent model in numerical study. On the one hand this paper analyzes the steady state with or without filter belonging in wind tunnel in NPIRs and calculates these situations individually based on different ventilated boundary conditions. On the other hand, this paper analyzes the change of NPIRs flow field in each transient movement by sliding open door events. The result shows the case in closed ventilation boundary conditions with the negative pressure situation is better than normal ventilation boundary conditions but it also reveals pollution concentration heavily. Under the condition of the more air change rate (ACH) the lower pollution concentration, although it‘s hard to keep the negative pressure situation. The result shows us that pollution diffusivity is mainly influenced by the ventilation conditions. The transient study shows that negative pressure zone is hard to maintain while the door is opening. But it can be slow down by setting the baffle rooms.