Investigation on enhancement of energy conversion of H2/CH4 fueled combustion in a micro tube with multi-channel-outlet

Abstract

To improve the flame stability and energy utilization of micro-generators, experimental and numerical investigations of a micro-thermophotovoltaic fueled by H2/CH4 are conducted. The coupling effects of multi-channel-outlet setting of micro tube and CH4 addition on combustion characteristics and thermal performance are compared and analyzed. The results reveal that the multi-channel-outlet of the tube significantly enhances the flame stability of premixed H2/CH4/air and the heat transmission via flow recirculation in the combustion chamber. It also notes that 2.5–10 % CH4 addition effectively affects the flame regime and extends the high-temperature zone to obtain a higher radiation temperature. Burners with larger dimensions achieve a lower wall temperatures but attain a higher radiant power, which can be improved with the extension of the multi-channel-outlet length and burner size. And radiant power increases with increasing fuel flow rate, while energy efficiency is reduced. So, the burner with properly multi-channel-outlet setting and a small fraction of CH4 addition is beneficial to improve system thermal performance. It especially obtains that the burner C6-12 has the highest radiant power of 39.6 W at Vf = 640 mL/min and 7.5 % CH4, and burner C6-20 achieves the highest radiant efficiency of 44.1 % at Vf = 410 mL/min.