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

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.