Experimental Study Of Gas Permeability Of Tectonic Coal Under Negative Drainage Pressure

Gas permeability of coal is a significant physical parameter closely related to gas drainage and other projects. It is must to exert necessary negative drainage pressure on the drainage pipe and drill to achieve the gas drainage in the process of coal mining, and at present, the negative pressure regulation mostly from some experience. For the sake of uncover the regularity of coal gas permeability under the function of negative drainage pressure, the experimental study of tectonic coal gas permeability under different negative pressure is developed in this paper.Tectonic coal is so soft and crumbly and the raw coal sample is difficult to preparation, on coal sample production method we were attempted and improved many times, and we successfully developed a set of raw tectonic coal sample production method. We designed and modified the test device on the basis of the existing experimental equipment, and the machine can achieve the test of coal gas seepage under negative pressure. The calculation formula of Darcy’s law in the condition of negative pressure in outflow surface was deduced. The experiment of raw tectonic coal gas permeability under negative pressure and static and dynamic load condition were conducted respectively, the characteristics of gas permeability of coal sample under negative pressure was came out, and its mechanism were discussed. Numerical simulations were carried out under negative pressure conditions and gas permeability of coal by using COMSOL Multiphysics software, and further verified the correctness of the test results.