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Effects of foam structure on thermochemical characteristics of porous-filled solar reactor

Abstract:

The foam-structured reactor is one which has hitherto been regarded as of great potential for industrial applications in the field of solar thermochemistry. The utilization mode of ceramic foam has, generally, a significant impact on energy conversion and storage efficiency. This study establishes a numerical model, coupled with computational fluid dynamics and dry reforming of methane reaction kinetics, to find the optimal structural parameters of the ceramic foam. A local thermal non-equilibrium model coupled with the P1 approximation has been developed to address the heat-transfer problems, and the non-Darcy flow effect has been considered to calculate the momentum dissipation in the porous zone. Based on ample simulation examples, the effects of porosity and foam cell size on the reaction temperature, surface heat loss, thermal efficiency, CH4/CO2 conversion, H2/CO yield, carbon deposition, and solar-to-chemical efficiency are illustrated in detail. The results indicate that using the ceramic foam with high porosity and large cell size is able to attain the best thermochemical characteristics, of which the validity can be assured, insofar as the various operating conditions in this study are concerned. Furthermore, as compared to the best single-layer structure, the application of the optimized double-layer foam structure is a more effective solution, which is able to further improve the energy storage efficiency by a remarkable 9.23%.