Numerical Study on the Effect of Wall Thickness on the Combustion Characteristics of Non-premixed Hydrogen Micro-jet Flame

The effect of wall thickness on the combustion characteristics of nonpremixed hydrogen micro-jet flames was studied by two-dimensional numerical computation with a detailed reaction kinetics for the development of hydrogen micro-burner. The hydrogen jet diffusion flames achieved by micro-tubes with the same inner diameter and length but different wall thicknesses were investigated. The heat exchange between solid tube and gases were included in the numerical computation. The distributions of flame temperature, OH radicals, details of thermal interaction, and combustion efficiency were analyzed for comparison. It was found that the temperature distribution, flame shape, and heat recirculation are changed with the fuel flow velocity, and they are affected by wall thickness. The mechanism of wall thickness on the combustion characteristics of hydrogen jet diffusion flame was clarified. Finally, an interesting numerical experiment was conducted to give a further explanation of the effect of heat recirculation and to provide guidance of the thermal management of the micro-burner.