长通道内烟气层水平蔓延阶段的质量卷吸速率实验研究

Experimental study on the entrainment mass flow rate across the smoke layer interface during horizontal spread in a long channel

根据卷吸机理不同,可将通道内烟气蔓延过程分为四个不同阶段.通过模拟尺寸实验,测量了烟气层温度、厚度以及典型截面处的烟气流动速度,确定了不同蔓延阶段的起止位置,并重点计算了火羽流撞击顶棚后的径向蔓延阶段以及随后向一维水平蔓延的过渡阶段烟气层分界面处的质量卷吸速率.通过对实验结果的分析,给出了这两个阶段烟气层卷吸速率的经验关系式.

Based on the different entrainment mechanisms, the smoke movement in a long channel can be divided into four stages. Small scale experiments were carried out with temperature, thickness and velocity of the smoke layer measured. The transitional states of the four stages were analyzed and determined. The entrainment mass flow rate across the smoke layer interface in the stage of radial spread after impinging onto the ceiling and in the transitional stage it gradually assumes one-dimensional horizontal spread was deduced. Combining the experimental results and theoretical analysis, an empirical formula for predicting the entrainment rate across the smoke layer interface was deduced.