Effects of porosity and multilayers of porous medium on the hydrogen-fueled combustion and micro-thermophotovoltaic.

The premixed H 2 /air combustion with varied porosity of porous medium (PM) is experimentally and numerically studied. The influences of porosity and arrangement of PM as well as the effects of multi-PM-layers on combustion characteristics and energy conversion are comprehensively investigated. The results indicate that a small porosity of porous medium is beneficial to improve flame stability and heat transfer, while it is adverse to the component flow and flame propagation. For the combustor inserted with multi-PM-layers, the larger-small porosities setting balances their opposing effects on the fluidity and the thermal performance, resulting in higher combustion efficiency and radiation temperature. With the increase of flow rate, effects of PM layout and porosity on combustion and heat transfer are remarkably enhanced. Furthermore, the radiation power of the micro thermophotovoltaic (TPV) system is significantly improved with the increase of radiation temperature. It is found that the combustor inserted with three PM layers (porosity p = 0.95 + 0.9+0.85) achieves a high electrical power output and system efficiency, which is more appropriate for the application of micro TPV or micro power generator. It contributes to chemical energy release and heat transmission for further utilization. Geometries of the combustor, Comparison of gas temperature and mass fraction of species. Radiation power, electrical output and efficiency of the combustors, Pictures of premixed hydrogen/air combustion in the combustors. [Display omitted] [ABSTRACT FROM AUTHOR]