Thermal performance of micro-combustors with baffles for thermophotovoltaic system

• Micro-combustor with baffles are designed and fabricated.
• The height and location of the baffles are optimized.
• The blowout limit is found to be extended by combustors with baffles.
• Waste heat from exhaust gas is recycled to preheat fresh gas.

This paper presents a hydrogen-fueled micro-combustion system for thermophotovoltaic application. The thermal performances of the micro-combustor with and without baffles have been investigated numerically and experimentally. Dimensionless height λ and distance δ are defined to determine the optimal height and location of the baffles. The highest combustion efficiency is achieved when δ and λ are 0.3 and 0.9, respectively. The blowout limit is extended for the combustors with baffles. Besides, the heat from exhaust gas is recycled to preheat the fresh H2–air mixture, thereby increasing the mean wall temperature. A high H2–air mass flow rate will increase the fresh gas temperature but lead to low heat recovery rate.