Study On Smoke Flowing And Controlling In Subway Tunnel

Based on the current situation of research on smoke movement and control in the subway tunnel at broad and home, the methods of numerical simulation and spot experiments are used to study the smoke movement and control laws of Guangzhou subway tunnel.A three-dimensional mathematical and physical modle of subway tunnel fire smoke movement is established based on the general CFD compute program. According to the finite volume method, a k-ε model with buoyancy modification and SIMPLEST algorithm is used to study the smoke traits, smoke distribution and the critical velocity numerically by treating the fire as a volumetric heat source, and analyses the influence of tunnel section on the critical velocity and smoke distribution. The mutative relation curve of critical velocity and fire intensity is obtained. Towards to the subway tunnel with 1 or 2 cross-passages, the comprehensive ventilation and evacuation modes are gived, in which the most two complicated modes are simulated detailedly, and the optimal ventilation velocity are obtained.Combined with the fire checking experiments of Guangzhou metro company, the spot experiments of unartifical and mechanical smoke exhausting are studied. The satck-effecting of piston silo on the smoke movement and diffusion at the situation of unartifical smoke exhausting, and the longitudinal ventilation destroying the smoke layer at the situation of mechanical smoke exhausting are analyzed. At last, the spot experiments results of mechanical smoke exhausting and numerical simulation results are contrasted, so the results of the numerical simulation are validated.The results of numerical simulation and spot experiments show that the established mathematical and physical modes are reasonable and credible. The results not only provide the direct theory basised and instructions for the fire fighting and smoke exhausting design of subway tunnel, but also provide correlative reference for choosing of the smoke control and people evacuation modes in subway tunnel fire, and have important applied value to the future study of subway tunnel fire and ventilation.