Numerical investigations on thermal performance enhancement of hydrogen-fueled micro planar combustors with injectors for micro-thermophotovoltaic applications

Abstract

In order to address the issue about the low output power of the micro-thermophotovoltaic system, in this work, the inlets of the traditional micro planar combustor are modified into injectors for better thermal performance and higher output power of the micro-thermophotovoltaic system. The thermal performance of traditional and modified micro planar combustors is numerically investigated and compared. It is found that the thermal performance of the modified micro planar combustor is greatly enhanced with the help of the injectors. This is due to that the reduction of the step diameter leads to the rise of the velocity of the inlet flow, resulting in the chemical reaction zone is closer to the center of the combustion chamber in the micro planar combustor. Furthermore, the positive effects and negative effects on thermal performance enhancement brought by the reduction of the step diameter of injectors are vividly discussed under different hydrogen mass flow rate, hydrogen/air equivalence ratio and solid wall material. Finally, some guidelines are proposed for the applications of the micro planar combustors with injectors in the micro-thermophotovoltaic system. This work provides us a simple and practical way to address the issue about the low output power of the micro-thermophotovoltaic system.