Effects of grains shapes of porous media on combustion onset—A numerical simulation using Lattice Boltzmann method

Abstract The Lattice Boltzmann method is used to simulate the propane–air mixture combustion in a porous media with different grain shapes of triangular, elliptical, rectangular, and star. The effects of these shapes on the flow and temperature fields and the flame characteristics were investigated. In order to simulate the flow in the porous medium, the method of creating barriers against the flow is used. The black and white photos are transformed into the matrix of 0 and 1, written in the form of the lattice Boltzmann code for solving the momentum, energy, and concentration equations. The results show that the porous media made by grains with sharp corners provide the highest reverse flow. The porous media with grain shapes of rectangular and triangular provide the highest and least pressure drop, respectively. The length of the flame decreases by using the porous media and the star shape has the largest length of the flame, while the rectangular one has the smallest flame length. The shapes of flames obtained for the elliptical and triangular grains are very similar to each other, while, the shape of flame for the star grain is close to the non-porous medium case. In general, using the porous media increases the heat transfer rate from the walls and also creates the fluctuations in the heat transfer along the wall.