Large Eddy Simulation of Premixed CH4/Air Deflagration in a Duct with Obstacles at Different Heights

In this work, the propagation of CH4/air deflagration flames in three semi-confined ducts with different obstacles was numerically investigated using large eddy simulation (LES). The shape of the premixed flame, flow field structure, and overpressure characteristics of the interaction between the flame and the obstacle are simulated accurately in three ducts with obstacles of different heights. The results show that the structure of the flame is changed by the presence of obstacles, and a change in the shape of the hemispherical conical brush appears, and a flame vortex is generated by the entrapment of unburned premixed gas on the left side of the obstacles. In the process of CH4/air deflagration, the existence of obstacles would lead to the change in combustion velocity and overpressure relief velocity and then have a certain influence on the peak of overpressure and the shape of the premixed flame.