Research of the Influence of Fire upon the Performance of the Exhaust Smoke Fan for the Subway Tunnel Ventilation System

The influence of fire smoke behavior upon exhaust fan performance was theoretically studied. The buoyancy effect and thermal resistance effect of fire smoke in the fire tunnel were systematically analyzed. The influence of the thermal resistance effect, chimney effect as well as the smoke flow behavior on the movement of tunnel fire smoke were comprehensively explored. Considering the underground tunnel ventilation network and the exhaust smoke fan as a whole, keeping in mind the factors such as the changing pattern of the smoke temperature, the density of the smoke flow, the mass flow, instead of the volume flow in the subway fire ventilation simulation, and the correction mechanism of exhaust fan performance influenced by smoke density fluctuations, a mathematical model of tunnel fire ventilation simulation was established and its numerical simulation method of tunnel fire smoke flow was provided. The study method and results will provide a scientific basis for the tunnel fire smoke management and decision making during fire emergency.