Fire smoke flow rate variety in a long-narrow space with an irregularly shaped smoke barrier

The smoke barrier is an important facility to restrict the flow of fire smoke in long and narrow space. In recent years, researchers have proposed irregularly shaped smoke barrier to pursue a better smoke restriction effect. However, the irregularly shaped smoke barrier not only restricts the smoke flow, but also causes density jump, which importantly affects the smoke entrapment and smoke flow rate. In order to study the smoke control effect of irregularly shaped smoke barrier in long-narrow space, this paper uses numerical simulation methods to study the density jump phenomenon of smoke before and after crossing the smoke barrier with different shapes. The results show that the density jump phenomenon before the smoke barrier is weakened, and a new density jump phenomenon occurs after the smoke barrier. The I-shaped smoke barrier (general shape) causes the most obvious reduction in the amount of smoke entrained before the smoke barrier and the most obvious increase in the amount of smoke entrained after the smoke barrier. In the irregularly shaped smoke barrier discussed in this paper (L-shaped, inverted T-shaped, and inclined shaped), the inclined smoke barrier causes the total smoke entrainment volume to decrease most. From the perspective of reducing the amount of smoke generated, the inclined smoke barrier has the best smoke-blocking effect. Finally, through the analysis of upstream and downstream velocity vector fields, it is explained how the irregularly shaped smoke barrier reshapes the smoke flow field by changing the local shear and momentum-heat conversion mechanism. This study reveals the mechanism of the impact of irregularly shaped smoke barrier on smoke flow in a long and narrow space and provides theoretical support for optimizing the smoke control in long and narrow space.