Numerical Study Of Natural Gas Premixed Combustion In Porous Inert Media

Natural gas is being exploited and utilized rapidly for solving the serious environmental pollution problem due to the bad energy structure in our country. To develop the technique of natural gas combustion with higher efficiency and lower pollutants emission becomes very significant. The technique of natural gas combustion in porous inert media has many advantages, and becomes an important topic in combustion research field.Premixed combustion of natural gas in inert porous media is being numerical studied. The thesis computes the thermal and transport properties of gas species with molecular kinetics theory, including specific heat volume, viscosity, diffusion coefficient and conductivity.YIX method has many advantages when solving radiation transfer equations especially in nonhomogeneous media such as easy to use and high accuracy. The thesis solves RTE in porous inert media by YIX method and uses the result to simulate the premixed combustion in porous inert media.Because of the big temperature gradient near the flame zone, non-uniform grid is used and finite difference method is used to discretize the control equations and Fortran is used to write calculating code. During the calculation process, the thesis uses Newton method to solve nonlinear equations. Because this problem is an eigenvalue problem the thesis uses the method of fixing the temperature at one point to solve it.The results show that the radiation of solid and the heat exchange between gas and solid are two main factors impacting the combustion performance of porous inert media burners. Increased convectivecoefficient between gas and solid will enhance the heat transfer between gas and solid and decrease the temperature difference between them. If the extinction coefficient of porous medium were increased, then the radiation heat transfer ability of porous medium will decrease, which will make the heat transfer from reaction zone to both downstream and upstream reduced, so the temperature of reaction zone will be higher.