【摘要】 为进一步研究综放采空区的多场分布特征,以大兴矿N2-706工作面为例,构建"双三"模型,即优化三维"O"型圈采空区冒落非均质多孔介质数学模型及"U"型通风方式下的三维综放采空区物理模型,重点考虑了采空区垂直方向上的孔隙率变化,并实现了孔隙率的三维可视化。运用Fluent软件加载自定义UDF对采空区气体压力分布、漏风场及氧气、瓦斯分布情况进行了数值模拟,得出与实际情况相吻合的采空区气体压力分布、合理漏风量范围内的风流场分布,其中重点分析瓦斯体积分数分布规律。结果表明:考虑三维孔隙率的数值模拟结果收敛性更好,采空区瓦斯的积聚现象不仅出现在采空区顶部,在距底板20~25 m高度的位置就大量上浮,且呈现高体积分数瓦斯积聚分布的特征规律。更多还原

【Abstract】 The paper is to make an exploration of the multi-field distribution characteristic features in the goaf of a fully-mechanized working face. For this purpose,we have established a"Double Three"model by taking N2-706 working face of Daxing Mine as a case study sample. In brief,the model under study can be thought of a mathematical model of porous media for the goaf caving based on the optimized 3D "O"type circle,including a3 D physical model of fully-mechanized goaf under the U-shape ventilation trend. Based on the above mentioned 3D physical model,we have put our study focus on analyzing the porosity changes of the goaf in the vertical direction by going over a 3D visualization of the said porosity. At the same time,we have elaborated a model for the gas pressure distribution in order to scrutinize the air-leakage field,the oxygen distribution and the gas distribution in the goaf via a software Fluent with UDF. From what has been analyzed above,we have identified and determined that the leakage rate of the goaf is supposed to have a significant impact on the gas distribution in the goaf,which may lead to the necessity to find the reasonable distribution range for the research of the airflow field in the goaf. And,in turn,the above investigation results have finally enabled us to ascertain that the pressure distribution of the goaf and airflow field within the reasonable air-leakage range is likely to be coincided with the practical cases based on the results of the numerical simulation we have done above.Furthermore,we have emphatically analyzed the distribution regularity of the gas resource for the purpose to disclose the gas current regularity in the goaf. Thus,the aforementioned exploration results can be presented systematically in the following order: In contrast,while the numerical simulation results for finding the 3D porosity may have a better convergence in the gas accumulation type in the goaf. Moreover,not only the 3D porosity may exist at the top of goaf,but it may also float upwards in a number of ways with the width of accumulating zone being after 20-25 m from the base plate. In addition,the gas accumulation can be characteristic with the high volume fractions. In summary,it can be concluded that the above mentioned multi-field distribution characteristic features of the goaf may help us to disclose a new regularity of the gas distribution features.更多还原