ABSTRACT
Experimental investigations were made on the stabilization and dynamics of non-premixed methane-air flame in a series of radial microchannels with a diameter of 60 mm and widths of 2.0, 2.5 and 3.0 mm with a controlled wall temperature profile. Various flame modes, termed periodically rotating flame, stable flame, broken and cellular flames, single broken flame, and periodically splitting flame were observed with high-speed imaging. Regime diagrams of all these stable and unstable flame modes were then drawn for the three channel gap widths. In addition, some critical flame characteristics, such as the mean radii of the stable flames, and the rotating frequencies of the periodically rotating flames were quantitatively assessed. Effects of the fuel/oxidizer inflow rates and the nominal equivalence ratios on these parameters were studied. Furthermore, numerical studies on the flow field were performed, revealing the inner mechanism of various flame modes to a certain extent. Disturbance of the fuel/oxidizer mixing layer for various flow conditions was considered to be greatly responsible for the formation of some flame patterns.
Disclosure of potential conflicts of interest
No potential conflict of interest was reported by the author.