矿井采空区漏风问题的迎风有限元求解技术及其应用

(1.西安科技大学 安全科学与工程学院,陕西 西安 710054; 2.西安科技大学 西部矿井开采与灾害防治教育重点实验室,陕西 西安 710054)

矿业工程; 采空区漏风; 煤自燃; 瓦斯; 迎风有限元

Technology for problems caused by gob air leakage in coal mine based on upwind finite element method and its application
WU Feng-liang1,2,LI Zhi-sheng1,2,CHANG Xin-tan1,2

(1.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi'an University of Science and Technology,Xi'an 710054,China)

mining engineering; gob air leakage; coal spontaneous combustion; gas; upwind finite element method

DOI: 10.13800/j.cnki.xakjdxxb.2019.0208

备注

为模拟矿井采空区漏风引起的煤自燃与瓦斯问题,建立了采空区“瓦斯-氧”对流扩散过程的迎风有限元统一求解模型。分析了基于伽辽金法的采空区流场有限元求解技术。给出了采空区“瓦斯-氧”对流扩散过程的统一模型,针对标准伽辽金有限元法求解统一模型时计算结果振荡的问题,采用迎风有限元方法得到模型的稳定解。基于三角形单元离散的采空区,给出了以所有节点的压力以及气体浓度为未知数的控制方程组。使用VC++开发了模拟软件,采用典型算例对软件的稳定性与实用性进行了验证,模拟结果表明:煤自燃耗氧导致采空区氧浓度降低,可爆瓦斯浓度范围5%~15%不再适用,采空区内具有瓦斯爆炸危险性覆盖的区域随遗煤耗氧与瓦斯涌出情况而动态变化; 开发的软件可以直接划定采空区内煤自燃三带及具有爆炸危险性的采空区区域。

In order to simulate the problems of coal mine methane and spontaneous combustion caused by air flowing through gob area,a general “methane-oxygen” migration model was established based on the upwind finite element method.The standard Galerkin finite element method for solving the gob flow field was analyzed.The general “methane-oxygen” migration model based on convection-diffusion model was put forward.Since an oscillation problem arises when standard Galerkin finite element method is used to solve convection-dominated problems,the upwind finite element method was adopted to treat the “methane-oxygen” transportation process with a stable results.The governing equations about nodal pressure were put forward based on the discretization with triangle element.A program developed in VC++ and ObjectARX for the general “methane-oxygen” migration mode was validated with representative case.Simulation results show that coal oxidation in spontaneous combustion leads to the decrease of oxygen concentration in gob,and the range of explosive methane concentration of 5%~15% is no longer applicable.The explosive gas zone in gob varies with oxygen consumption and methane emission.The developed program offers the function to directly delineate the zones prone to spontaneous combustion and methane explosion.