采空垮落区瓦斯非线性渗流-扩散模型及其求解

Numerical model of nonlinear flow-diffusion for gas mitigation in goaf and atmosphere

根据高强度快速推进条件下大空间采空垮落区瓦斯运移的特点,按照渗流力学理论,将采空区视为连续的渗流空间,瓦斯在采空区实际是机械弥散和分子扩散引起的散布过程,通风风流流动状态是由工作面湍流向采空区深部层流的过渡状态.运用质量守恒定律和非线性渗流方程,提出基于Fick扩散定律和Brinkman方程的瓦斯扩散-通风对流运移模型,综合考虑了流体压力梯度和动能作用,比较适合采空垮落区的风流运动和瓦斯对流扩散规律.通过数值求解,研究采煤工作面采空垮落区内瓦斯运移的作用机理.

According to the theory of seepage and mechanics and the characteristics of gas mitigation during the large area roof caving in goaf under the fast and high-duty mining activities, the goal was a continuous seepage spatial field, the transport mechanisms of the gas were dispersion, diffusion in fact, ventilation transits from turbulence in working face to laminar deep goaf. Based on the law of mass conservation and nonlinear seepage equation, a diffusion-ventilation model for gas mitigation in goaf, which considers the comprehensive contribution of flow pressure gradient and kinetic energy during the gas flow, was proposed based Fick＇ s law of diffusion and Brinkman equa- tion. This model is capable of describing the gas mitigation under the ventilation conditions during the large area roof caving in goaf. Based on numerical solution of the proposed model, the mechanism controlling the gas flow in goaf was clarified.