Experimental and numerical investigation on H2-fueled thermophotovoltaic micro tube with multi-cavity

To enhance H2-fueled combustion and improve energy efficiency, a micro burner with multi-cavity is proposed, and experimental and numerical investigations are carefully conducted. Effects of equivalence ratio, cavity settings and operating conditions on flow field, species distribution, combustion characteristics and heat transmission are analyzed and discussed. The results show that combustion stability and mean outer wall temperature Tm of the burner with cavity are improved, and the highest Tm can be obtained at equivalence ratio Φ = 0.9. Moreover, the lower inlet-step, which strongly affects the flow field, is beneficial to enhance the heat transmission of the combustor with cavity because of a smaller entropy generation. The setting of cavities in combustion chamber affects the flame stretch and anchoring because of the flow recirculation behind the step/fins, resulting in the enhanced heat transfer of gas-wall and a higher radiation temperature in the burner setting with multi-cavity. It can be further improved via the modification of cavity setup, such as step length and cavity numbers. Besides, the burner with three cavities achieves the highest Tm and radiation power at a higher flow rate, such as the highest power 35.61 W at Vin = 5 m/s and Φ = 0.9.