Study On The Propagation Laws Of Gas And Coal Dust Explosion In Coal Mine

Supported by subject "Dynamics evolvement of gas and coal dust explosion and multiphase coupling effect" of "973 program", propagating laws of shock wave and flame produced by gas and coal dust explosion in mine laneway have been studied by experiment research, theory analysis and numerical simulation. And explosion accident in coal mine has been investigated according to these research production.The gas explosion, gas and coal dust explosion experiments are carried out in the experimental roadway which is the largest dimensions experimental roadway in Asia and the Pacific and one and only experimental roadway in China . And the analysis of the test data is as following: (1) With the increase of gas, the largest gas explosion absolute peak pressure is increased too, and the appeared location is near to the explosion source. Gas explosion flame propagation velocity is increase, and position with the most explosive flame speed is far to explosion source. (2) In the process of gas and coal dust explosion, the maximum peak pressure and the biggest explosion flame propagation speed are both appeared in the coal dust segment. Because gas capacity is small in the experiment, gas explosion in this process has two main roles: blowing coal dust and igniting coal dust explosion.(3) Gas explosion flame length is greater than the growth of gas and coal dust explosion in the process of gas explosion: Gas explosion flame length is 3-6 times than that of the original gas accumulation area in the process of gas explosion. But it is about 2 times in the gas and coal dust explosion. (4) Compared to gas explosion, the maximum explosion peak pressure and flame propagation speed are both increased significantly in gas and coal dust explosions.Based on the experimental data, the paper formulates the principle of promulgation deflagration in shock wave changing to detonation from gas and coal dust explosion in the gas explosion flame propagation and shock wave. With the analyze the hoist mechanism of deposited coal dust in the gas explosion, the paper also thinks that adhesive shear lift and turbulence effects both have an effect to particles and to lead to coal dust particles rising. Based on the two-phase's capacity average conservation equation, this paper establishes two-phase burning turbulence model, analyzes the principle of accelerating flame by turbulence, and carries out discussion of two-phase detonation of gas and solid based on the ZND model.Using flow simulation platform and on the base of gas and coal dust explosion propagation theoretical model, the coal mine gas and coal dust explosion propagation simulation system is established applying the calculation method of continuous phase and particles phase. Through analysis and comparison of simulation and experimental results, it is found that the simulation system is basically reach the precision of quantitative research process, it can be effectively simulated mine methane and coal dust explosion propagation process to providing a scientific basis for the investigation. With the system the developing process of coal gas deflagration changing to detonation pressure wave is simulated. Gas explosion promulgation process in the tunnel network in heading face is simulated and blast pressure mutation is found in the tunnel section and diverging mutations. The process of hoist deposited coal dust by gas explosion is simulated, and it is found that the deposited coal dust particle has the process of startup, acceleration and deceleration in hoist process.The special big gas explosion accidents of Jianxin coal mine and dust explosion of Dongfeng coal mine were analyzed with the studied propagation laws of gas and dust explosion and numerical simulation system.