地面钻井抽采负压对采空区气体流场分布影响

Negative Pressure of Gas Drainage Well at Surface Affected to Distribution of Gas Flow Filed in Goaf

将采空区视为各向同性多孔介质,构建了采空区气体流场基本闭合方程组,利用FLUENT模拟软件对采空区内部气体流场进行模拟,分析了地面钻井不同抽采条件下的采空区内部气体浓度分布特征,以此研究地面钻井不同抽采负压对采空区气体流场的影响。研究发现地面钻井布置在采空区靠近回风巷20～70 m有利于抽采,且负压抽采可能给采空区带来自然发火的危险,但在采取一定的监控措施下,40～50 kPa的抽采负压是可取的。

Taking a goal as all directional same nature porous medium, a basic closed equation group of the gas flow field in the goal was established. The FLUENT simulation software was applied to simulate the gas flow field within the goaf, analyze the gas concentration dis- tribution features within the goal under the different gas drainage conditions of the surface drilling boreholes. A study was conducted on the different negative pressure of the surface drilling boreholes affected to the gas flow field in the goaf. The study found that the surface drill- ing boreholes located in the goaf with 20 - 70 m near the air returning gateway would be favorable to the gas drainage and the negative pressure of gas drainage may bring a spontaneous combustion danger to the goaf. But with the certain monitoring and control measures, the 40 -50 kPa negative pressure of gas drainage could be acceptable .