Influence of Wall Heat Effect on Gas Explosion and Its Propagation

The gas explosion process in pipes is often accompanied by an intense wall heat effect. A considerable part of the explosion energy is dissipated, and the process of gas explosion and its propagationis affected. In order to study the influence of wall heat effect on gas explosion and its propagation, numerical models of gas explosion in pipes with different adiabatic degrees were established by ANSYS/LS-DYNA. The propagation process of gas explosion in pipes under the influence of the wall heat effect was numerically simulated and analyzed, and the thermal stress and temperature distribution of pipes with different adiabatic degrees were studied. The results show that with a decrease in pipe insulation, the wall heat effect increases, the heat loss of gas explosion increases, and the overpressurizationof the shock wave, the explosion intensity, and the thermal stress of the pipe wall are significantly reduced. The results indicate that the wall heat effect can weaken the gas explosion and its propagation. At the same time, it is found that the influence of the wall heat effect on the initiation section is greater than that on other positions of the pipe. With the decrease in the heat effect of the pipe wall, the heat loss of the wall decreases, the temperature difference between the inner and outer wall surfaces expands, and the total energy released by the gas explosion increases. The released energy is used to heat and compress the unburned gas, resulting in a more intense explosion reaction and a substantial increase in the temperature of the explosive gas. Therefore, it can be seen that the wall heat effect has an important influence on the gas explosion and its propagation. The influence of wall adiabatic condition on gas explosion with a higher combustion level is greater than the influence on gas explosion with low combustion levels.