狭长通道内风幕挡烟效果的数值分析

研究利用风幕阻挡通道内烟气蔓延的可能性及其效果,结合一小型狭长通道,采用数值模拟计算方法进行了初步分析.重点考察了风幕前倾角、风幕出口风速和回风口位置三个主要因素对风幕在狭长通道内挡烟效果的影响.结果表明,适当增大风幕前倾角、逐渐提高出口风速、适当前移回风口位置均有助于加强风幕在狭长通道内的挡烟效果.而当火源功率较大而风幕出口风速过小时,将不能很好地阻挡烟气的蔓延.数值分析结果表明,综合考虑上述三种因素,就可以使用风幕有效地阻挡烟气在狭长通道内的蔓延.

Numerical simulation on screening by air curtain in long narrow channels

The present paper aims to introduce the authors' numerical simulations on finding possibility and efficiency to hold smoke back in the long-narrow channels by using an air screen. Actually, there exist three most important factors that influence the smoke control efficiency: i.e. the velocity of the wind, its onward obliquity of the outlet, and the relative position of the discharge vent at the floor level. In order to make clear the influence of the three factors, numerical simulations are done to simulate the smoke control efficiency by air curtain. The results of simulations have shown that the smoke control efficiency tends to be enhanced when the onward obliquity or the velocity of the outlet wind is increased. Besides, properly adjusted straight-forward movement of the discharge vent can also improve the smoke control ability of the air curtain. But when the fire size is relatively too large or the velocity of outlet wind was too small, the air curtain will fail to hold smoke back effectively. Finally, it can be drawn from the numerical simulations that the air curtain could hold smoke back effectively in the long-narrow channels when these three factors can be taken into consideration comprehensively.