Combustion characteristics of CH₄ in an excess enthalpy combustor

A spiral excess enthalpy combustor with the channel section of 7 mm × 0.6 mm was designed, in which premixed CH₄/air was burned. The temperature distribution on one sidewall of the combustor was measured and an analysis of burned products has been made. The experimental results show that the excess enthalpy combustor can effectively recycle heat from burned gas through counterflow heat transfer and raises the temperature of unburned gas, which is advantageous to flame stabilization in micro channels and extends the combustion limit of premixed CH₄/air. The premixed CH₄/air flame can be stabilized in the center of the combustor. When air excess coefficient is larger than 1.0, CH₄ can completely react with air. When air excess coefficient is smaller than 1.0, unburned H₂ and CO can be detected in products.