【作者】 王红刚；

【导师】 常心坦；

【作者基本信息】 西安科技大学 ， 安全技术及工程， 2009， 博士

【摘要】 采空区漏风是造成工作面上隅角瓦斯超限和采空区遗煤自燃的直接原因,因而摸清采空区在各种复杂生产边界条件下的漏风流场就显得尤为重要。由于采空区工作人员无法出入,通过现场检测手段准确获知其中各种物理量的分布规律是十分困难的,而实物相似模拟试验又需要大量的人力物力。因此,许多学者采用计算流体力学的方法,针对不同的采煤工作面,通过数值模拟试验研究其采空区的流场,取得了一定的成果。但是,不同的采空区边界条件差别很大,即使同一采空区,在不同时期其边界条件也不尽相同,这就使得对具体的采空区进行数值模拟试验的结果很难推广到其它采空区;另一方面,如果对各种不同采空区在不同边界条件下进行数值模拟,则需要耗费巨大的计算机资源。本文以偏微分方程理论为基础,通过对采空区渗流流场和瓦斯浓度场控制微分方程的分析,将线性叠加原理应用到采空区流场的数值计算中,简化了具有复杂边界条件和源项的流场问题的求解,减少了所需要的数值模拟试验次数和模拟时间,实现了采空区流场数值模拟领域从个性到共性、从特殊到一般、从具体到抽象的升华,为将来采空区流场在线实时分析奠定了理论基础,提供了技术保障。在研究的过程中,本文推导了叠加原理通用公式、采空区浓度场计算公式、采空区渗透率与瓦斯浓度之间的关系式以及工作面风量与采空区漏风量之间的关系式等一系列公式,这些公式分别在不同的方面简化了采空区流场问题的求解。在采空区渗透率分布形态方面,本文提出了采空区“自由堆积渗透率假设”,为采空区渗透率的分布确定了合理的边界条件,有利于更为准确地描述和研究采空区的渗透率分布。基于“自由堆积渗透率假设”的采空区氧化升温带分布可以在一定程度上对工作面快速推进时仍存在的零星自燃发火现象做出解释。这些公式和假设及其应用,构成了本论文的核心内容。针对现场应用,以陈家山416工作面2006年11月份的生产跟踪数据为基础,应用叠加原理及本文推导的相关公式,在不同抽放条件下对工作面和采空区的耦合流场进行了计算和分析,对416工作面所采取的采空区瓦斯综合治理措施的有效性做了验证。更多还原

【Abstract】 Air leakage in an exhausted gob is the most important inducement of two main hazards in a working face:gas overrun in the upper corner of working face and spontaneous combustion of abandoned coals in the gob, therefore it becomes especially significant to make clear the seeping field of a gob under different complex boundary conditions. In view of the impossibility for persons to get into a gob,it is very difficulty to obtain exactly the distribution of different physical variables by field measurement. Furthermore,not only does the practical similitude simulation need a lot of manpower and material resources,but also are its results difficulty to be verified,so nowadays many scholars have adopted a CFD method to numerically simulate the flow field of different gobs behind different working faces and have achieved some aims.In one hand,however,different gobs have different boundary conditions,even in the same gob various working periods also mean various boundary conditions;in other hand it will occupy plenty of computer resources to numerically simulate all kinds of boundary conditions in all kinds of gobs.Based on the relevant theory of PDEs and the analysis of controlling equations of the seeping field and gas concentration field in a gob, this paper introduced the linear superposition theory to the numerical calculation of gob flow field, and then simplified the determination of flow field with complex boundary conditions and sources and reduced the necessary numerical test as well as simulation time. In the area of numerical simulation of gob’s flow field,this method realized the transformation from individuality to commonness、from particularity to generalization、from embodiment to abstract,thus established the theory base of on-line analysis of gob’s flow field and provided technical supports.During the research,this paper deduced a series of formulas,such as the general formula of superposition theory、the calculation formula of gas concentration in gobs、relations between permeability and gas concentration in gobs as well as formulas connecting the airflow rate of working face and the air leakage of gobs,which simplified to some extent the flow field calculation of gobs in different ways respectively. As to the distribution styles of permeability,this paper put forward the hypothesis of“free falling permeability”,which equipped a reasonable boundary condition for the change of permeability in gobs and helpt to depict and research more exactly the distribution of gob’s permeability. The distribution of oxidization and heat accumulation zone, which is deduced from the hypothesis of“free falling permeability”, can explain to some extent the sporadic spontaneous combustion phenomenon of a gob after a rapid working face. These formulas and hypothesis themselves and their application composed the core elements of this paper.Based on the tracking data of 416# working face of Chen Jia-Shan mine in Nov.2006, this paper employed the superposition theory and relevant formulas deduced in the same paper to analyze and calculate the coupled flow field of the working face and its gob under different gas pumping conditions, and then proved that the integrated gas pumping measures equipped in 416# working face were rather effective.更多还原