Study On The Power Propagation Characteristics Of Gas Explosion In The Pipe Network Of Diagonal Structure

In order to study the evolution law of overpressure,the propagation law of high temperature flame wave and the propagation law of toxic and harmful gases in the complex pipe network under different working conditions.Using the method of combining experimental research and numerical simulation,aiming at the ventilation pipe network model of the angleconnected structure,the propagation laws of gas explosion overpressure,high temperature and toxic and harmful gases at each monitoring point in the pipe network under different conditions are analyzed.The research results can provide theoretical support for reducing casualties and property losses in coal mine gas explosion disasters,emergency rescue and disaster relief.Firstly,the small-scale angle-connected structure pipe network experimental platform designed and built by ourselves is used to verify the wind flow propagation in the angleconnected pipe network.Through the experimental research on the influence of the steady-state characteristics of the wind flow in the corner ventilation pipe network under the conditions of different blocking rates,ventilation and obstacle positions,the theoretical and parameter basis for the numerical simulation is provided.The FLUENT software is used to establish a 1:1physical model of the pipe network with the angle-connected structure for numerical simulation.According to the comparison between the results obtained and the experiment,it is found that the two have the same trend.The research results effectively verify the feasibility of numerical simulation.The physical model of the angle-connected pipe network is established by using the FLUENT software,and the propagation of gas explosion in the angle-connected pipe network is simulated numerically under different ventilation conditions and barrier placement conditions.Based on the simulated data of 18 measuring points,the propagation characteristics of explosion shock wave overpressure and high temperature flame wave under different working conditions are analyzed.The results show that the gas explosion shock wave produces three local high-pressure areas during the propagation of the angle-connected pipe network.The high-temperature gas mainly propagates in the left and right passages,and the angle-connected branches are only slightly affected.The existence of the wind flow at the inlet of the pipe network makes the shock wave overpressure in the early stage of the explosion propagate through the same distance in a shorter time,with a larger peak value and stronger destructive power.The existence of the air flow at the inlet of the pipe network changes the propagation state of the high-temperature gas in the pipe network,and the heat accumulates in the oblique branch and the tail of the left passage,and the temperature peak is larger.The existence of wind flow at the inlet of the pipe network makes the cooling and depressurization effect in the later stage of the explosion better,and the time is shorter,but the wind speed has little effect on it.However,when the right passage is blocked,two airflow vortices are formed at the corner branch of the right passage and behind the obstacle when the high-speed airflow passes through.This makes the propagation of shock waves in the angle-connected ventilation pipe network more complicated due to the increase of turbulence intensity and the positive feedback of flame waves.And make the high temperature flame wave propagate in the oblique angle pipe network,and expand the distribution range of high temperature gas.It provides a reference for emergency rescue and disaster relief of gas explosion accidents under real ventilation scenarios.In terms of toxic and harmful gases,numerical simulations are carried out on the propagation of CO gas generated by high-concentration gas explosions in the angle-connected pipe network,and the influence of different ventilation conditions and barrier placement conditions on the propagation of CO toxic and harmful gases is analyzed.The results show that the higher the wind speed at the inlet of the pipe network,the lower the overall concentration distribution of CO in the corner-connected pipe network,and the faster the propagation speed in the left channel.In addition,the barrier condition of the right channel makes the CO gas hindered and spreads to the left channel through the oblique branch.The CO concentration in the oblique branch increases and the distribution range is wider.