28 / 2023-05-14 23:36:23

Numerical Study on the Dynamic Response of Gas Explosion in Coal Mine Tunnels Using LS DYNA-CESE Reaction Dynamics Model

Keywords: CESE solver; Methane deflagration; Shock wave overpressure; Tunnel with uneven walls; Structural response

In order to achieve the coupling analysis of gas deflagration reaction dynamics and tunnel structure, and to explore the influence of uneven coal tunnel surface on shock wave propagation and wall dynamic response, gas deflagration numerical models that approximate real tunnels and smooth walls tunnels have been established. By immersing the Boundary layer algorithm (IBM), the tunnel structure is coupled with the finite rate chemical model of the space-time conservation element CE/SE solver, the concentration changes of reactants and products in a short time during methane explosion are tracked, the different propagation and attenuation processes of shock waves in the two tunnel models, as well as the different dynamic responses of the two tunnel walls, are compared and analyzed.The research results show that methane gas with a total volume of nearly 3.39m³ is consumed after 1.2ms, and the mass fractions of CO and CO₂ generated by the reaction reach 4.7% and 12.1%, respectively; When the shock wave propagates in a straight tunnel, the overpressure in the smooth walls tunnel is symmetrically distributed, and the orange red high-pressure area in the approximate real tunnel model shifts towards the more obvious concave and convex coal tunnel on the right. In the approximate real tunnel model, the peak overpressure and shock wave propagation velocity of the bend tunnel are lower than those in the smooth walls tunnel model, the maximum difference in peak overpressure between the two reaches 81.91 kPa, and the maximum difference in time to reach the peak overpressure is 7.4 ms; The stress distribution on the approximate real tunnel wall is discontinuous, and the transition zone is serrated. The duration of high load is slightly lower than that of tunnels with smooth walls; The total displacement of the approximate real tunnel wall is usually lower than that of the smooth tunnel walls, and the maximum displacement of most measuring points is only 1/3-1/2 of the latter.