Research On The Injury Model Of Methane And Coal Dust Coupled Explosion

With the increase of coal mining depth,coal mine methane control and coal dust reduction work are difficult,and the accompanying methane coal dust explosion problem becomes more and more serious.The importance of studying the injury of methane and coal dust coupled explosion has become increasingly prominent.In order to reduce coal mine explosion casualties and provide theoretical support for emergency rescue,the injury of methane and coal dust coupled explosion have been systematically studied by combining experimental research,numerical simulation and theoretical research.The injury rate model corresponding to shock wave over-pressure,CO gas and flame thermal radiation and comprehensive injury model have been established.The main conclusions are as follows:(1)The explosion experiments of different concentrations of methane and coal dust have been carried out in the self-built explosion experiment system.The experimental results show that in the explosion cavity,the higher the methane concentration is,the smaller the maximum explosion equivalent concentration of coal dust corresponding to the maximum pressure is.When the methane concentration is5%,the maximum explosive equivalent concentration of coal dust is about 300 g/m~3;when the methane concentration is 7%,the maximum explosive equivalent concentration of coal dust is about 100 g/m~3;when the methane concentration is increased to 9%and 11%,the explosion pressure without coal dust is the highest.When the coal dust concentration is less than(equal to)the maximum explosive equivalent concentration,the pressure and CO gas concentration in the explosion chamber gradually increase with the increase of coal dust concentration.On the contrary,when the coal dust concentration is greater than the maximum explosive equivalent concentration,the CO gas concentration increases significantly,while the pressure decreases gradually with the increase of coal dust concentration.(2)The experiment found the pressure propagation characteristics in the injury area of methane and coal dust coupled explosion are found.When the coal dust is less than(equal to)the maximum explosion equivalent concentration,the pressure decreases with the increase of distance,and the most serious area of pressure injury is at the explosion source.On the contrary,when the concentration of coal dust is greater than the maximum explosion equivalent concentration,the pressure increases at first and then decreases,and the most serious area of pressure injury is near the explosion source.(3)Through the methane and coal dust coupled explosion experiment,the propagation characteristics of CO gas in the methane and coal dust coupled explosion injury area are determined.When the coal dust is less than(equal to)the maximum explosion equivalent concentration,the concentration of CO gas increases at first and then decreases with the increase of distance,and the most serious area of CO gas injury is near the explosion source.When the concentration of coal dust is greater than the maximum explosion equivalent concentration,the concentration of CO gas decreases with the increase of distance.The area with the most serious injury caused by CO gas is at the explosion source.(4)The propagation characteristics of shock wave overpressure,temperature and CO gas in the methane and coal dust coupled explosion injury area have been simulated by Fluent software.The shock wave propagates in the pipe in the form of a plane wave during the explosion propagation,while the temperature and CO gas distribution front in the pipe evolve from a spherical shape to a side V shape,and finally to an oblique plane.When the methane concentration increases from 5%to11%,the peak shock wave pressure increases significantly;the temperature and CO gas distribution range increases,and the corresponding injury range increases.When the coal dust concentration increases from 0 to 200 g/m~3,the symmetry of the V-shaped distribution front of temperature and CO gas side decrease.The temperature and CO gas distribution show a sinking phenomenon,and the temperature and CO gas concentration at the bottom are higher than those at the top.(5)Based on the empirical formulas of different explosion characteristic parameters,the calculation formulas of shock wave overpressure,CO gas concentration and flame heat radiation of methane and coal dust coupled explosion are deduced.The area outer boundaries of death,serious injury and minor injury has been determined.With the increase of methane concentration and coal dust concentration,the increase of the outer boundary of the dead area is the smallest,and the increase of the outer boundary of the minor injury area is the largest.Based on the human injury rate model,the injury rate model corresponding to shock wave overpressure,CO gas and flame thermal radiation is established,and the injury rate attenuates in inverse"S"shape with the increase of distance.(6)According to the theory of probability and statistics,the explosion comprehensive injury rate model is constructed on the basis of the injury rate model of shock wave overpressure,CO gas and flame heat radiation.Combined with the distribution of workers in the roadway,the comprehensive explosion injury consequence model is established.Taking the explosion accident of Xinhua No.4Coal Mine in Pingdingshan,Henan Province as an example,the injury model has been verified,which shows the model is reliable.The research results provide a scientific basis for the rescue of coal mine methane and coal dust coupled explosion accidents and reduce disaster losses,and have important theoretical guiding significance and application value for improving the safety level of coal mines.There are 92 pictures,28 tables and 158 references in the paper.