Numerical Simulation of Premixed Methane-air Flame Propagating Parameters in Square Tube with Different Solid Obstacles

Based on the basic conservation equations, k − ɛ turbulence model, Zimont premixed combustion model and SIMPLE algorithm, the premixed methane-air flame propagating velocity and its pressure were numerical simulated in a half open square tube with three forms of solid obstacles. Simulation results showed that: (1) At the same blockage ratio of 40%, the triangular prism obstacle was beneficial to the flame and airflow accelerating processes, and its propagating velocity and deflagration pressure induced by obstacle were slightly larger than cuboid and cylinder obstacles. (2) The obstacles revealed the block effect which led to the reduced trend of flame speed before the flame front has arrived at the different obstacles, and the flame propagating velocity was enhanced rapidly in the process of the interaction between the flame and obstacles, and then the speed began to decline. But, the flame propagating pressure was increased quickly before the premixed flame interacts with the different obstacles, and then the pressure began to decline. (3) The time of the maximum premixed flame peak-pressure stayed prior to the time of the maximum flame propagating velocity under three solid obstacles. The numerical simulation study can be acted as a qualitative analysis for premixed methane-air flame propagation in the half open tube, and can provide the theoretical basis and technical guidance for preventing and controlling the gas explosion induced by obstacles in coal mines.