Effects of changes in pipe cross-section on the explosion-proof distance and the propagation characteristics of gas explosions

•Pipe cross-section has a distinct effect on gas explosion parameters.•Increasing equivalent pipe diameter decreases explosion overpressure and temperature.•Increasing equivalent pipe diameter can decrease the explosion-proof safety distance.•Increasing equivalent pipe diameter can strongly decrease the flameproof distance.

After establishing a pipe model with a length of 100 m, the propagation characteristics of gas deflagrations were simulated using AutoReaGas software for pipe cross-sectional areas of 0.04 m × 0.04 m, 0.08 m × 0.08 m, 0.12 m × 0.12 m and 0.16 m × 0.16 m. The results showed that the pipe cross-section had a distinct effect on the overpressure, density, temperature, gas velocity and combustion rate of gas explosions. Specifically, as the equivalent pipe diameter increased, the maximum overpressure, density, temperature, gas velocity and combustion rate at each gauge point decreased. As the equivalent pipe diameter increased, the flame arrival time at each gauge point was consequently delayed. In addition, the increase in the equivalent pipe diameter decreased the explosion-proof distance, as well as the dimensionless safety distance. In addition, increasing the equivalent pipe diameter can largely reduce the dimensionless flame-proof distance, thereby making mining workers immune to the threat of gas explosion shockwaves.