潔淨室內污染物擴散分析

Abstract

本文是採用CFX4.2套裝軟體作數值模擬，探討潔淨室的流場佈，並模擬潔淨室發生污染氣體洩漏時，流場對污染氣體擴散的影響。本論文分三個階段進行，在第一階段是改變不同孔隙率的高架地板，造成潔淨隧道內流場、濃度場與紊流動量場變化模擬；第二階段是利用第一部份中，最佳組合的高架地板，則對HEPA (High efficiency particulater air filter)過濾器開啟個數進行研究；第三階段是進行回風區高度對潔淨隧道內流場與壓力場之影響；結果得知：離回風口越遠的高架地板，其孔隙率需增大；離回風口越近的高架地板，其孔隙率需縮小，以造成室內流場均勻。出風口成交錯排列比一般排列成一直線， 其通風效率更好。回風區高度對潔凈隧道內流場與濃度之影響很大；回風區面積至少比出風口面積大0.87倍以上，潔淨隧道總壓損才會低到一定值。

This research is studied the diffusion characteristics of airborne particles in clean room and analyzed numerically by the computer program CFX4.2. Building a clean room can be partitioned into three stages; In the first stage, the different permeability of the floors are employed to simulatethe flow field, diffusion field and the turbulent intensity field. Then based on the above optimal results, the number and the position of HEPA filters are determined in the second stage, In the last stage, the relation between the flow field, and pressure field can be obtained by changing the different height of Reture-Air plenum. The results show that in order to get uniform flow distribution, the permeability of the floor can be reduced if the floor nears the Returen-Air zone, and the permeability of the floor can be increased if the floor was removed to the Return-Air zone. The crossed filters are better than straight line in performance of ventilation. Finally the Return-Air area must be 0.87 times larger than Supply-Air area at least to obtain lower total-pressure-drop.