Simulation Of Fire Smoke Flow And Smoke Venting Research

As the development of urbanization, urban population increases rapidly which results in serious transportation problems. Besides, there is an increasing demand for transportation tools in the city. Subway, which is regarded as the"green transportation"for its safety, comfort, capacity, speed, punctuation, low power consumption, and low population, is more and more popular. Therefore, subway becomes a place with a rather high flow rate, especially in rush hours with a rather high density, but as the main connection with outside world, exits are airtight and with large stream of people. In case of fire, it not only spreads quickly, but accumulates intense smoke with high temperature. The smoke is hard to be removed, which would threat the safety of the passengers, staff and rescuers. According to the survey, the majority of injuries in the fire are due to the smoke poisoning and suffocation. Therefore, ventilation equipment plays a very importation role in the casualty's reduction and property loss.The researches of limited space fire are mainly experimental research and numerical simulation. Comparing with the previous one, numerical simulation is characterized by low investment, minor cycle and low repetitiveness. At present, the numerical simulation based on CFD is popular in the smoke flow research. This paper builds the numerical simulation of smoke flow by FLUENT software. The FLUENT can be used to calculate the liquid flow, heat and mass transfer, combustion and other chemical reaction, besides, it has mesh adapting and result processing functions.The flow of subway fire smoke is three- dimensional non-static turbulent flow. Based on the analysis of the causes of fire and fuel, this paper establishes a mathematical model to simulate the smoke flow in the subway station. The research object is a subway station in Tianjin. According to the real size of the subway station, the author establishes physical geometric model. The numerical simulation is built according to different ignition points, ignition source strengths and ventilation models. The temperature and density distributions in case of fire in a certain period are obtained. At last, the result processing is gained by tecplot. Studies show that when the mechanical smoke venting is used, the smoke temperature, and spreading speed can be reduced and this would contribute to the safe escape.