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In this paper the coupled lattice Boltzmann model is developed for simulation of multi-step combustion mechanism of a methane jet diffusion flame. The lattice Boltzmann scheme employs the double-distribution-function model, one distribution function for solving flow field and another for temperature and species concentration fields. The density and temperature fields are coupled through low Mach number flow field. The solution parameters such as species properties and rate of chemical reactions adjust in every time step according to temperature and concentration of species variations. Using combustion mechanisms instead of one step fast chemistry reaction and considering effect of temperature and species concentration on solution parameters are the main advantages of the developed model. For validation of the model, a four-step reduced mechanism with six species is used for simulation of combustion in a methane jet diffusion flame configuration. Agreement between the present results and experimental data confirms that this scheme is also an efficient numerical method for more detailed combustion simulations.

In this paper، the thermo-hydrodynamical analysis of incompressible flow in conjunction with cell-centered finite volume-lattice Boltzmann method (FV-LBM) was developed. To demonstrate the temperature field، the double distributions function (DDF) was used. A novel approach was applied in cell flux calculation by definition of biasing factors based on pressure and temperature. This treatment enlarges the domain stability and leads to faster convergence. A consistent open and solid boundary treatment of flow was also addressed. The unknown energy distribution at the boundary cells were decomposed into its equilibrium and non-equilibrium parts. Then، the non-equilibrium part was approximated with extrapolation of the non-equilibrium part of the populations at the neighboring nodes. Two test cases namely، thermo-hydrodynamic in a backward-facing step and around a circular cylinder inserted within the backward-facing step were carried out. The results were compared with the available solutions in the technical literature showing reasonable agreements.