Heat transfer enhancement and exergy efficiency improvement of a micro combustor with internal spiral fins for thermophotovoltaic systems

Targeting at addressing the low exergy efficiency of micro thermophotovoltaic (MTPV) system, a novel micro combustor with internal spiral fins is proposed. The geometrical parameters, including internal spiral fin number, length and pitch distance, on the thermal performance and exergy efficiency are numerically investigated. The introduction of internal spiral fins can effectively improve the exergy efficiency and energy output of MTPV system, but with higher pressure loss. The results show that the micro combustor with 8 spiral fins exhibits the highest exergy efficiency of 66.9%, which is 6.9% higher than that of the conventional one at the inlet velocity of 5 m/s. Moreover, the micro combustor with 8 spiral fins obtains the highest energy output is 5.01 W at inlet velocity of 8 m/s. Taking the pressure loss into consideration, the optimal internal spiral fins length of 10 mm is suggested.

Automated summary

By introducing internal spiral fins, the novel micro combustor can effectively improve the energy efficiency and output of micro thermophotovoltaic system, although with increased pressure loss. Experiment results demonstrate that the micro combustor with 8 spiral fins achieves the highest efficiency and energy output at different inlet velocities.