The Theoretical Investigation Of The Combustion Characteristics In Ring-like Porous Burner

Compared with the traditional combustion, porous medium combustion (PMC) technology has several advantages, such as high combustion efficiency, adjustable power range, widening flammability limits, and low pollutant emissions. Based on the wide application of furnace in industrial and the theory and experimental research about PMC, this article proposes a novel type of ring porous media burners, which is aim to overcome the problems in the production. In order to get the burning characteristics of gases in this burner, the paper investigated methane/air combustion characteristic in a ring-type burner by numerical simulating method.Firstly, the paper made a summary introduction on porous medium combustion technology and its application, especially about the theory and numerical simulation of PMC. Secondly, basing on laminar combustion basic equations, the porous media burning mathematical model is deduced by RVE and volume average method. The mass and heat transfer in porous media is controlled by the amended continuous equation, momentum equations and energy equations. Especially, the two different energy equations, single temperature and double temperature, are gained by the local thermal equilibrium condition about mixtures gas and porous medium.The methane/air gas combustion in porous medium ring burner is simulated by using stationary and non- stationary computations two-dimensional single temperature model, our research focus on combustion characteristics in different methane/air ratio, the velocity of flow and heat loss of internal and external wall of the burner in the novel porous burner. It is shown that the methane/air ratio is the key factor on temperature; the low methane/air ratio is more sensitive to fluid the velocity than the high methane/air ratio, heat loss of wall was not an important on the influence of temperature. At last, the combustion case of methane/air ratio 0.6, fluid the velocity 0.2m/s and the adiabatic wall of burner is simulated again by three-dimensional single temperature model. The simulated results between three-dimensional and two-dimensional is researched detailed, the comparisons results show that the two simulations results coincide very well.By our research, it is shown that the ring porous media burners have some advantages different from straight or rectangular porous media burners. Due to annular asymmetric structure, the temperature distribution of ring porous media burners is more uniform, and there are no unfavorable phenomenon such as the local high temperature and the hot spots. The simulation results for ring porous medium in this paper provides important theoretical basis for the development of new porous media burners.