Simulation Study On Influence Of Wind Speed And Conditions Of Pile To Spontaneous Combustion And Wind Barrier Technology

Coal stockpiles to spontaneous combustion is a serious threat to the coal storage and transportation safety, and reduces the calorific value of the coal, for the effective prevention of coal spontaneous combustion of coal stockpiles, study on the influence factors, and put forward the preventing coal spontaneous combustion technology is very necessary. In this paper, numerical simulation model of spontaneous combustion process of the coal stockpiles piled on atmospheric environment is established. Influence law of coal stockpiles to spontaneous combustion by environmental factors and coal stockpiles self stacking factor is researched in the spontaneous combustion process. Numerical simulation of wind barrier preventing coal spontaneous heating is carried out. Windbreaks and coals studied distance, wind barrier height and other factors on their own coals spontaneous combustion is studied. Reasonable parameters and conditions of controlling the coal spontaneous heating are proposed when using wind barrier. It provides a theoretical basis for preventing coal stockpiles to spontaneous combustion. The main results are as follows:(1)Wind speed increases,wind pressure and wind speed of coal stockpiles surface increases relatively, when airflow velocity is small, the high temperature region in coal stockpiles appears near the windward side about 2m in distance to coal pile wall, the upper part of the coal pile distance is more than 2m. Further increase with wind speed, high temperature zone develop to middle and lower leeward side. When the wind speed was in the range of 0-1 m/s, wind speed increases is conducive to coal stockpiles temperature, when the wind speed of 0.1-0.5m/s, the most prone to spontaneous combustion coal pile temperature rise, It will becomes slow When the wind speed is larger than lm/s, while spontaneous combustion phenomenon won't appear basically when the wind speed is larger than 2m/s.(2)Coal stockpiles temperature rise slowly when porosity is 0.1-0.15.Porosity decreases in favor of preventing coal stockpiles to spontaneous combustion and heating. With the coal pile height reduction, coal pile internal temperature will rise, the speed becomes slow. Coals stockpiles smaller the angle, the longer the period of spontaneous combustion coal stockpiles, the lower the heating rate.Reduction of coal heap stacking height and angle can be used for preventing coal self combustion reactor.(3)Setting the wind barrier, coal stockpiles surface wind pressure, pressure difference decreased significantly and the distribution situation opposite without the wind barrier. Effect of coal stockpiles internal temperature by wind barrier is different because of environmental wind. There is not suitable range for wind speed usingwindbreaks. With the wind barrier height increasing, coal pile internal temperature rises to 343K time gradually increases, when the wind barrier height increases to 5m and continue increasing, windbreak height required to appear the tendency of decrease, coal stack height 6m, get the optimal height is 5m, and the coal pile distance should be 4m.Through the above study, we make clear the affecting factors of coal spontaneous and mechanism, environmental factors and its influence factors of coal pile to spontaneous combustion, and identify the best parameters and conditions of controlling the coal pile to spontaneous combustion. It provides a theoretical basis for preventing coal stockpiles to spontaneous combustion.