Investigation on H2/air combustion with C3H8 addition in the combustor with part/full porous medium

The premixed H-2/air combustion with various propane blended ratios in two size stepped combustors with porous medium is experimentally and numerically studied. In order to improve the energy efficiency and power output of the micro thermophotovoltaic (TPV) system with InGaAsSb PV cells, the effects of step length and porous medium length in the chamber are comprehensively investigated. Moreover, the flow rate and the fuel blend ratio are sufficiently considered. The results indicate that the addition of 5% propane contributes to the modification of the combustion characteristics and flame regime, improving the energy conversion of fuel and thermal performance of the combustor. A big heat recirculation in porous medium and a small heat recirculation in the gap between the porous medium (part inserted) and the step are formed, which effectively boost the thermal performance. It is also noted that the two heat recirculations avail to achieving higher flame temperature and radiation temperature in a small size combustor. With the porous medium part inserted, the larger size combustor obtains higher energy efficiency and better working performance. In particular, the combustor C9-2-22, where the gap and the step length are both 2 mm, gains a power output of 2.91 W and a system efficiency of 2.0% at 5% C3H8-95%H-2 fueled combustion.

Automated summary

The study examined the effects of different propane blended ratios on premixed H-2/air combustion in micro thermophotovoltaic systems, finding that adding 5% propane can improve combustion characteristics and energy conversion efficiency. The formation of heat recirculation in the combustor was noted to enhance thermal performance and achieve higher flame temperature and radiation temperature.