Abstract
A mathematical model is proposed to describe the spread rate of a smoke front under horizontal and inclined ceiling. The smoke flow is treated as two zone flow, and both the smoke and air layers are divided into smaller sections in the moving direction of smoke front. The heat loss to wall and the entrainment of ambient air are taken into consideration in this paper. The entrainment theory by Morton et al. is modified by assuming the entrainment rate of ambient air to be proportional to a sine of the inclined ceiling angle.
To substantiate the validity of this model, the calculated results by this model are compared with the results of the full scale and model experiments. The proposed model is valid to predict the smoke front movement under horizontal and inclined ceiling of up to 75 degrees of slope angle until the smoke front reaches the floor.
