Study on Combustion Characteristics of Premixed Methane-Oxygen in a Cylindrical Porous Media Combustor

A three-dimensional numerical and experimental study on methane-oxygen combustion has been conducted in a small scale porous-media cylindrical combustor which aims at extending the optimized controlling parameters for thermophotovoltaic power application. Different equivalence ratios, inlet velocities, porous-media porosities and wall thermal conductivities are simulated in the same configuration and the results show that porous-media improves the thermal characteristics of a combustor compared to the non-porous-media counterpart. There is about 350 K difference in peak wall temperature for the porous-media combustor over the non-porous-media combustor. The flame temperature first increases as porosity increases, and then slightly decreases as the porosity increases. At higher wall thermal conductivities, the effect of the change in porosity does not affect the mean temperature distribution on the combustor wall. Based on the findings, the porous-media combustor with equivalence ratio of 0.8, porosity of 0.5, inlet velocity of 0.35 m/s and wall thermal conductivity of 20 W/ (m2219;K) are identified as key combustion conditions that can produce uniform and stable wall temperature for an efficient combustion chamber for the thermophotovoltaic system. With the inherent constraint associated with small-scale combustion this study will provide a premise for developing and enhancing the performance of the combustor under the given constraints.