Numerical investigations on the performance enhancement of a hydrogen-fueled micro planar combustor with finned bluff body for thermophotovoltaic applications

To achieve higher power output and energy conversion efficiency for micro-thermophotovoltaic (MTPV) systems, a hydrogen-fueled micro planar combustor with finned bluff body is proposed and compared to the micro planar combustor with/without bluff body. Numerical results indicate that among micro planar combustors without bluff body, with bluff body, and with finned bluff body, the micro planar combustor with finned bluff body obtains a higher and more uniform wall temperature, but the pressure loss is higher. This is due to that the Peclet number near the inner walls is significantly higher compared to those without bluff body, and the Peclet number in the center of the axis is significantly lower, which reveals a stronger convection effect in the non-recirculation region and diffusion effect in the recirculation region. Then, effects of finned bluff body position, fin length/bluff body radius ratio and fin angle on the performance of micro planar combustor are investigated. It is found that the micro planar combustor with a larger finned bluff body position, smaller fin length/bluff body radius ratio and larger fin angle is more practical for MTPV system.