Enhancement of radiative power using a divergent splitter plate design in H2-air non-premixed micro-combustor

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 proper mixing of fuel and air within the 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 Finite Volume Method (FVM) 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 which is an important parameter for thermo photovoltaic (TPV) power generation. The best performing divergent splitter design and the base rectangular splitter design are investigated in detail. The study shows that the micro-combustor with divergent splitter design results in reduction in mixing distance (Lmix) ranging from 5%–23% depending on inlet velocity and channel height. With the divergent splitter, peak value of 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 rectangular splitter. This leads to the micro-combustor with divergent splitter producing significantly higher radiation power (>10%) as compared to rectangular splitter for larger channel heights and higher inlet velocities.