Experimental study and numerical simulation of spread law for fire on tunnel

NIU Hui-yong(牛会永)^{1, 2}, QIAO Chen-lu(乔晨露)^{1, 2}, AN Jing-yu(安敬鱼)^{1, 2}, DENG Jun(邓军)¹

(1. School of Energy and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines
(Hunan University of Science and Technology), Xiangtan 411201, China)

Abstract:In order to research spread law and distribution law of temperature nearby fire sources on roadway in mine, according to combustion theory and other basic, the theory model of temperature attenuation was determined under unsteady heat-exchange between wind and roadway wall. The full-size roadway fire simulation experiments were carried out in Chongqing Research Institute of China Coal Technology & Engineering Group Corporation. The development processes of mine fire and flow pattern of high temperature gas were analyzed. Experimental roadway is seen as physical model, and through using CFD software, the processes of mine fire have been simulated on computer. The results show that, after fire occurs, if the wind speed is less than the minimum speed which can prevent smoke from rolling back, then the smaller wind speed can cause smoke to roll back easily. Hot plume will lead to secondary disasters in upwind side. Because of roadway wall, hot plume released from roadway fire zone has caused the occurrence of the ceiling jet, and the hot plume has been forced down. Whereas, owing to the higher temperature, buoyancy effect is more obvious. Therefore, smoke rises gradually along the roadway in the flow process, and the hierarchical interface appears wavy. Oxygen-enriched combustion and fuel-enriched combustion are the two kinds of combustion states of fire. The oxygen content of downwind side of fire is maintained at around 15% for oxygen-enriched combustion, and the oxygen content of downwind side of fire is maintained at around 2% for fuel-enriched combustion. Furthermore, fuel-enriched combustion can lead to secondary disasters easily.

Key words:fire on roadway; experiments of fire; numerical simulation