Experimental studies on flame stabilization in a three step rearward facing configuration based micro channel combustor

In this study a detailed experimental analysis on the characterization of flame stability behaviour in a 2.0 mm support diameter micro-combustor with three rearward facing steps has been reported. Premixed mixture of methane–air has been used as a fuel for present investigations. Maximum and minimum diameter in the micro-combustor was maintained at 2 mm and 6 mm respectively. The effect of change in number of steps, length of steps, mixture equivalence ratios (ϕ) and flow rates on stability limits of flame and flame position has been investigated. It was observed that the zone of recirculation created due to the sudden expansion at the rearward step aids in stabilizing the flame inside the micro-combustor and improves the limits of flame stability significantly. The increase in the first and second step length helps in improving the lower and upper flame stability limits. The increase in the third step length affects the flame stability limit at higher flow rates only. Pollutants measurement shows that no NOx emissions were produced and CO emissions increase as the equivalence ratio (ϕ) increases.