Parametric study of cavity on the performance of a hydrogen-fueled micro planar combustor for thermophotovoltaic applications

Abstract

In order to obtain high energy output power and energy conversion efficiency for micro-thermophotovoltaic system, a hydrogen-fueled micro planar combustor with cavity is designed in this work. Numerical investigations on the performance of micro-cylindrical combustors with and without cavity are executed under different cavity length, outlet size and solid wall materials. Results show that the micro planar combustor with cavity can obtain a higher and more uniform outer wall temperature comparing with the micro planar combustor without cavity. With the reduction of cavity length and outlet size, the energy output and energy conversion efficiency of MTPV is much higher, while the pressure loss becomes larger. Thus, the optimal dimensionless cavity length and outlet size is 3/9 and 5/7 × 1/3, respectively. Furthermore, with the optimal cavity length and outlet size, nickel is used as the solid wall material for higher energy conversion efficiency of MTPV system, which increases to 3.86% at the inlet velocity of 5 m/s. As a result, the micro planar combustor with cavity is more suitable in MTPV system for higher energy output and energy conversion efficiency.