Research On Smoke Diffusion Of Smoldering Stage And Early Smoke Detection Of Fire In Train

As high speed, closed, narrow and high personnel density of train, the smoke will be spread rapidly throughout the train in short time, once fired, causing casualties and significant economic losses. Fire detection technology has been applied to the train fire hazard to prevent disaster. So it is great significant to research on motion characteristics of smoke in smoldering stages of a fire.The physical model and mathematic model of train have been established to simulate smoke concentration distribution of train. According to the simulation results of smoke concentration field and the principle of the detector arrangement, determine that the key location for the detection is the smoke side roof detection point and vent which distance 5m from smoke source location. The key position is selected to analyze the concentration change of typical position.Then, test-bed of smoke exploration is built in the 1:1 train model, according to action time and action threshold of key position, the change of smoke concentration is obtained indirectly. When detector action threshold is set at170db/m, the key positions will be alarms with in 1 minute. This shows that not only verifies the accuracy of CFD simulations, but also confirms the reasonableness of the detector setting.Last, According to smoke characteristics in a fire smoldering stage, Analyze characteristics smoke diffusion on different tobacco source location, different smoke volume, different ways of air supply, different air volumes, open or closed train door and air conditioning systems start or stop. When air conditioning system opened, the detector placed in vent duct near vent is appropriate, but once it is shut down, the detector should be placed on the detection point. In the economic condition, the detection point and vent are set detectors at the same time to alarm quickly and accurately.