Entropy generation and improved thermal performance investigation on a hydrogen-fuelled double-channel microcombustor with Y-shaped internal fins

To enhance the hydrogen-fueled micro-combustor's thermal performance for Thermo-photovoltaic applications, we propose and test a double-channel design featuring Y-shaped internal fins. This study investigates three key parameters in the thermal performance of a micro-combustor: the inlet velocity, the inlet equivalence ratio, and the combustor wall material. Further, we develop a new method to calculate the efficiency and exergy of the micro-combustor by considering the entropy generation and exhaust gas. It is observed that increasing the inlet velocity leads to higher mean wall temperature (MWT), standard deviation of wall temperature (SDWT), and radiation heat release rate. Increasing inlet velocity also enhances the thermodynamic second-law efficiency and exergy. The peaks of MWT and SDWT are achieved when the inlet equivalence ratio approaches unity. The inlet equivalence ratio value of unity also corresponds to the maximum radiation heat rate and improved second-law efficiency and exergy. Finally, changing the combustor wall material reveals that the silicon carbide demonstrates better thermal performance by rising MWT and the uniformity of the combustor wall temperature. Moreover, alterations to the combustor wall materials do not appear to have a significant impact on the heat loss resulting from entropy generation.