壁付け機械排煙口への空気混入率の予測式 : 二層ゾーンモデルにおける機械排煙口への空気混入の定式化(その3)

Abstract

A prediction model was proposed for air entrainment ratio into wall-equipped mechanical smoke vent under two-layer environment where upper part of room is occupied by hot smoke layer while lower part is occupied by air of normal temperature. This model consists of two parts similar to the prediction model for horizontal ceiling vent as described in preceding paper. The first is the case that lower air is directly entrained into vent opening when smoke layer thickness is small. The second is the case that air is entrained after mixing with upper smoke layer when smoke layer thickness is relatively large. Carrying out model scale experiments, three flow patterns (direct entrainment, visible critical condition for the onset of entrainment and mixing entrainment) were observed. Distributions of carbon dioxide concentration and temperature near wall-equipped vent opening were fairly similar to those for horizontal ceiling vent, which indicates that similar approximation with ceiling vent is reasonable. The accuracy of prediction model was verified against model-scale experiments for various aspect ratios of vent opening.