Abstract The premixed H2/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%H2 fueled combustion.

中文翻译：

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部分/全多孔介质燃烧室中添加C3H8的H2/空气燃烧研究

摘要 实验和数值研究了不同丙烷混合比的两级多孔介质阶梯式燃烧器中预混H2/空气燃烧。为了提高采用 InGaAsSb 光伏电池的微型热光伏 (TPV) 系统的能量效率和功率输出，综合研究了腔室中步长和多孔介质长度的影响。此外，充分考虑了流量和燃料混合比。结果表明，5%丙烷的加入有助于改变燃烧特性和火焰状态，提高燃料的能量转换和燃烧器的热性能。在多孔介质中形成大的热循环和在多孔介质（插入部分）与台阶之间的间隙中形成小的热循环，从而有效提高热性能。还应注意，两个热循环有助于在小尺寸燃烧器中实现更高的火焰温度和辐射温度。插入多孔介质部件后，更大尺寸的燃烧器获得更高的能效和更好的工作性能。特别是，间隙和步长均为 2 mm 的燃烧器 C9-2-22，在 5%C3H8-95%H2 燃料燃烧时获得 2.91 W 的功率输出和 2.0% 的系统效率。