Study On Fire Smoke Flow Characteristics In Subway Tunnel

With the continuous and rapid economic growth in China, Subway has become one of the important means of transport among medium and large cities in China. Meanwhile, the subway fire accidents occur frequently, which has brought catastrophic losses to the society. Subway Interval Tunnel fires release large amounts of high-temperature toxic smoke in the condition of incomplete combustion. The toxic smoke would not only undermine the overall stability of the tunnel structure, but also be the main factor leading to death. Therefore, it is important to study Subway Interval Tunnel fire smoke flow characteristics and control it reasonably.This paper summarized the research experience and achievements of domestic and foreign tunnel fire smoke flow characteristics, and based on the project of Chongqing Scientific Committee of"Subway Tunnel fire smoke control? theoretical research"(CSTC2009BB6193) and the project of Chongqing Public security bureau scientific research of"Subway fire smoke flow and staff evacuation simulation", and choose a Subway Interval Tunnel which is in Chongqing as a prototype, establishing a reduced-scale Subway Interval Tunnel model experiment table with the length of 15m and the ratio of 1:10 according to Froude-number Model, then carry out fire tests. Contemporary combined with the numerical simulation software of FDS to set up primary size Subway Interval Tunnel model and make analog computation of the impact of the fire heat release rate on the Subway Interval Tunnel fire smoke spread characteristics. The main work and results of research were shown as follows:1) The shrunken size subway Tunnel model with the ratio of 1:10 consisting of interval tunnel and exhaust duct was installed according to Froude-number Model; and the test systems of temperature and velocity and fans of supply and return air were debugged.2) The relations between different fire powers and longitudinal air supply velocities and the length of the upstream smoke were researched in this paper, and the relations between different fire powers and longitudinal air supply velocities and the length of the upstream smoke were also deduced according to date fitting.3) Fitting and theoretical analyzing the critical air speeds at different fire heat release rates by means of numerical simulation and reduced-scale experiment, then by dimensionless comparing with theoretical value and full-scale experimental data, prediction formula about critical air speed and fire heat release rate can be obtained.In this paper, using the method of numerical simulation software of FDS combined with the similar model experiment. Subway Interval Tunnel fire smoke flow and control law can be studied, which provide a theoretical basis and technical support for ensuring the safe operation of subway and fire smoke control.