狭长受限空间火灾突变行为倾角效应的数值模拟

为了研究倾斜狭长空间火灾突变行为特性,基于CFD数值模拟方法研究了倾角为0°到30°范围内狭长受限空间(30 m×4 m×4 m)火灾特性参数(火焰形态和温度)的变化规律。结果发现:火焰高温区面积和火焰倾角等参数随倾角增加存在一个突变区域。当倾斜角度小于10°时,高温区面积、火焰与水平方向夹角以及纵向温度最大值位置等参数都基本维持不变;一旦超过10°,高温区面积明显增大,火焰与水平方向夹角明显减小,纵向温度最大值的位置也开始逐渐向火源上方移动。这表明倾斜壁面吸附作用会导致倾角过大的狭长空间火灾行为突变和后果剧增,这对于揭示火灾加速突变机理和指导狭长空间火灾安全设计有重要意义。

Numerical Simulation of Inclination Effect on Sudden-change of Fire Behaviors in Long-narrow Confined Space

To investigate fire sudden-change characteristics in inclined long-narrow space,the fire behaviors in a long-narrow confined space with dimensions of 30 m × 4 m × 4 m were simulated by CFD under various inclination angles from 0° to 30°. The results showed a transition region occurred with the increasing of inclination angle (θ). The high temperature area of flame and tilt angle from horizontal surface and the peak location of longitudinal temper-ature stayed almost the same value when θ < 10°;whereas,the high temperature area increased significantly,and the tilt angle dropped obviously when θ beyond 10°. Besides,the peak location of longitudinal fire temperature remark-ably moved upward. These results indicate the Coanda effect of inclined surface causes the sudden-change of fire be-havior in over-inclined long-narrow space and the sharp increase of disaster effect. The discovery is helpful to reveal the mechanism of fire acceleration and fire safety design in long-narrow constructions.