Influencing factors of wall temperature and flame stability of micro-combustors in micro-thermophotovoltaic and micro-thermoelectric systems

Among various portable energy systems, micro-thermophotovoltaic and micro-thermoelectric systems gained extensive attention due to compact configuration, no mechanical noise, wide fuel applicability, and high energy density. As a key component, the micro-combustor has always been the focus of research, in which wall temperature and flame stability are major concerns. Previous studies proposed various micro-combustors with bluffbody, backward-facing step, and heat recirculation to obtain suitable wall temperature and wide flame stability. However, the effects of influential parameters are scattered in these studies, which need to be analyzed and summarized for further research. First, the operating principles of these two energy systems are introduced. Then, the effects of geometry configuration, thermal conductivity, operating condition, fuel, and cooling on wall temperature and flame stability are revisited. Conclusions and future recommendations are made to provide a systematic reference for future micro-combustor design and theoretical research.