It is important to study the methane transport phenomenon in a longwall panel under descensional ventilation conditions. In this paper the gob area is divided into a number of nodes to represent the rectangular percol...It is important to study the methane transport phenomenon in a longwall panel under descensional ventilation conditions. In this paper the gob area is divided into a number of nodes to represent the rectangular percolating elements. The connections between nodes (elements) become branches,so that a network can be formed. Using the mechanics of porous media fluid flow, the mathematical model of air and gas flows has been established. Based on the existing ground pressure theories,the porosity of the inhomogeneous porous media in the gob can be given. In computer simulation it is considered that air pressure and temperature are functions of position ; air density, viscosity, and natural ventilation pressure are functions of temperature,pressure and methane concentration,and the resistance varies with air density and viscosity. Finally,the calculation results are given to show the differences between ascensional and descensional ventilation methods.展开更多
文摘It is important to study the methane transport phenomenon in a longwall panel under descensional ventilation conditions. In this paper the gob area is divided into a number of nodes to represent the rectangular percolating elements. The connections between nodes (elements) become branches,so that a network can be formed. Using the mechanics of porous media fluid flow, the mathematical model of air and gas flows has been established. Based on the existing ground pressure theories,the porosity of the inhomogeneous porous media in the gob can be given. In computer simulation it is considered that air pressure and temperature are functions of position ; air density, viscosity, and natural ventilation pressure are functions of temperature,pressure and methane concentration,and the resistance varies with air density and viscosity. Finally,the calculation results are given to show the differences between ascensional and descensional ventilation methods.
