采空区孔隙率非均质模型及其流场分布模拟  

Heterogeneous model of porosity in gobs and its airflow field distribution

作　　者：梁运涛[1,2] 张腾飞[3] 王树刚[3] 孙金鹏[3] 

机构地区：[1]浙江大学能源清洁利用国家重点实验室,浙江杭州310007 [2]煤炭科学研究总院沈阳研究院煤矿安全技术国家重点实验室,辽宁沈阳110016 [3]大连理工大学土木水利学院,辽宁大连116024

出　　处：《煤炭学报》2009年第9期1203-1207,共5页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)基金资助项目(2006CB202206);国家自然科学基金资助项目(50574049)

摘　　要：分析了现有采空区渗透率分块取值或仅按走向上连续分布取值计算方法的缺点,引用顶板岩层沉降理论,建立了垮落带介质孔隙率和渗透率的非均匀连续分布模型;并引入Brinkman-Forchheimer的扩展Darcy模型,采用多孔介质流体计算的单区域处理方法,建立了涵盖工作面与采空区统一流场的数学模型.U型采场模拟分析表明:距煤壁10 m以内,受支架和煤柱支撑作用,孔隙率较大为0.4左右,采空区深处岩层沉降明显,其深部边界处孔隙率已接近0.1,总体上采空区倾斜方向和工作面推进方向上孔隙率表现为二维分布规律;漏风风流沿工作面倾向在中间位置点之前即汇出,沿采空区深度方向上漏风强度逐渐减小,在距工作面约40 m时趋于一致,总体上漏风流场垂直于工作面煤壁的中心线呈现出非对称的分布规律.The disadvantage of existing gob porosity or permeability models was analyzed, which generally simplify porosity or permeability as discontinuous distributed or one-dimensional continuous parameter. Based on the theory of roof strata collapse, the distribution model of continuous and heterogeneous porosity and permeability was deduced. By incorporating the Brinkman-Forchheimer-extended-Darcy model especially for air flow in permeable gobs, and applying the stream function-vorticity approach of porous/fluid composite system, the mathematic model of seepage filed involve the mining face and the gob was established. The simulation of a ＂U＂ ventilation retreating longwall face shows that the porosity have a two dimension distribution rule both on the gob incline direction and face working direction. Within 10 m away from the coal mining face, the gob porosity reaches about 0. 4 due to the supporting of coal pillar and supports. For reason of roof strata collapse, the porosity decreases quickly along the gob direction, finally to about 0. 1 in the gob boundary. On the other hand, the leakage filed show an asymmetric airflow pattern perpendicular to the face centerline in the gob. The leakage airflow returns back in the front of the middle of the working face. Moreover, the leakage intensity reduces gradually along gob depth direction, and the intensity almost unchanged in the place of 40 m away from working face.

关 键 词：采空区 孔隙率 多孔介质 漏风 渗流场 

分 类 号：TD721[矿业工程—矿井通风与安全]