开区注氮采空区自燃温度场的数值模拟研究

为了研究开区注氮采空区遗煤自燃和被抑制的力学过程，用非均质多孔介质中的渗流连续性方程、气体弥散方程和综合传热方程的联立，建立了采空区注氮非定常数值模型．结合实例，用迎风格式有限元方法求解．给出了采空区的漏风流态、氮气流态，描绘了采空区自燃过程中氧、CO浓度和温度分布的变化过程．计算考虑了瓦斯涌出和工作面推进的影响．得到注氮条件下采空区高温区形状变窄；随着注氮量的提高，使自然发火期逐渐变长，直至不自燃．理论计算与实际情况吻合．

NUMERICAL SIMULATION OF TEMPERATURE FIELD WITH SPONTANEOUS COMBUSTION IN OPEN REGION NITROGEN INJECTION GOAF

To study the complicated mechanical process of spontaneous combustion of remnant coal in goafs under the conditions of open region nitrogen injection, based on seepage continuous equation, gas dispersion equation and integrated heat transfer equation, a non-steady numerical model of spontaneous combustion of coal in nitrogen injection goaf is established, and these equations are solved by windward finite element method. The spontaneous combustion process in goaf with different flux of nitrogen is computated, and the flow pattern of air leakage and the flow pattern of nitrogen are expressed by graphs, together with the variation of oxygen and carbon monoxide concentration and temperature distribution in goaf. Some influencing factors, such as gas effusion and the advance of working front are taken into account during computation. It is concluded that a high temperature zone usually appears at the inlet air side in goaf spontaneous combustion under open region nitrogen injection, but the shape turns to narrow. The spontaneous combustion period will become long with the increase of nitrogen injection quantity until spontaneous combustion stops. Theoretical simulation result and practical nitrogen injection conditions are in general agreement.