Enhancement of Radiative Power Using a Divergent Splitter Plate Design in H2–Air Non-Premixed Micro-Combustor

Abstract

Micro-combustion based power generation devices can be considered as future alternatives to batteries in miniature electronic devices. Micro-combustors operating in non-premixed mode are free from flashback but face the challenge of properly mixing fuel and air within a small volume. In this work, the effect of a divergent fuel–air splitter design on the mixing performance and combustion characteristics of H2–air fueled diffusion micro-combustor is studied. The laminar reacting flow is simulated using the finite volume method and a detailed hydrogen kinetic mechanism. Three divergent splitter designs are compared with the commonly used rectangular splitter to study the effect on radiation power, an essential parameter for thermophotovoltaic power generation. The best-performing divergent and base rectangular splitter designs are investigated in detail. The study shows that the micro-combustor with divergent splitter design reduces mixing distance (Lmix) by 5–23% depending on inlet velocity and channel height. With the divergent splitter, the peak value of the heat release rate also increases slightly, implying enhanced combustion. The divergent splitter increases the high-temperature surface area of the outer wall as compared to the rectangular splitter. This leads to the micro-combustor with divergent splitter producing significantly higher radiation power (>10%) than the rectangular splitter for larger channel heights and higher inlet velocities.