Study Of The Influence Of Ignition Energy And Initial Pressure On The Gas Explosion Characteristics

In the coal mine, on-site conditions are complex and many factors such as the ignition energy, the initial pressure, the initial temperature and so on have major influences on the gas explosion. According to these problems, the influences of ignition energy and initial pressure on the gas explosion characteristics were studieded comprehensivily in this paper with the methods of theoretical analysis, experimental study and numerical simulation.The theoretical analysis of gas explosion parameters, the influences of ignition energy and initial pressure on the gas explosion characteristics and explosion criteria were carried out in this paper. And by introducing van der Waals equation suitable for real gas derived the theoretical calculation of gas constant volume explosion pressure under high pressure.Experimental studies of gas explosion characteristics under different gas concentrations, different ignition energy and different initial pressures conditions were carried out using the developed experimental equipments, such as the DHN-200-type high-energy electrical energy generator, the ZL-1 type ignition controller and the test equipment for gas explosion characteristics under high initial pressure,.The experiments found that the relationship among the gas concentration and the maximum explosion pressure, the maximum pressure rise rate, the ignition delay time was different quadratic function.At the premise of lighting gas, with the ignition energy became higher, the maximum explosion pressure and the maximum pressure rise rate of the gas explosion became larger, the ignition delay time became shorter, and the explosive limit range became wider. And the relationship among the ignition energy and the above parameters was different exponential function. The more deviated from the optimal explosion concentration, the influences of ignition energy on the above parameters will be more evident.The influence of the initial pressure and ignition energy coupling on the gas upper explosive limit was obvious than the influence of simple one factor on the gas upper explosive limit. The influence of the initial pressure on the gas upper explosive limit was more obvious than the influence of the ignition energy on the gas upper explosive limit in the range of the initial pressure and the ignition energy in these experiments. The gas explosion limit exceeded the scope of the original 5% to 16% in the high pressure and high-energy ignition conditions. So, a concept of critical explosive limit was obtained, which provided a new basis for the effective prevention of gas explosion accidents and the accidents investigation in coal mine.Numerical simulations of gas explosion processes were carried out under the conditions of normal temperature and pressure, high ignition energies and high initial pressures. The flow field characteristics of the parameters in explosion processes were showed clearly. And the developments and changes of the explosion pressure, the flame temperature, the reaction rate and the other parameters were analyzed in the processes of different explosion conditions, and the corresponding variations were obtained.Some of the conclusions which this article got have important guiding significance on the amendments of the gas safety standards and the industry standards, the effective prevention of the gas explosion accidents and the accidents investigation in coal mine.