Effect of a crossed-semicircular-plate on thermal performance of micro-combustor fueled by premixed hydrogen-air mixture

Abstract

A novel crossed semicircular plate has been presented to enhance the thermal efficacy of a micro-combustor. A whirling stream can be generated when the fuel-air mixture is passed around the plate, which boosts the turbulence intensity and residence time of combustion gas. The heat transfer capacity from the flame to the outer wall of the micro-combustor can be promoted by heat conduction of the plate. Moreover, the plate also plays the role of preheating the hydrogen-air mixture. Effects of the design parameters including the mounting position, crossing angle, thickness and thermal conductivity of the plate and the mass flow rate on the thermal performance of a cylindrical micro-combustor with the plate fueled with premixed hydrogen-air mixture were numerically investigated. The findings show the outer wall temperature decreases with the increase of the distance from the inlet to the plate and increases with the increase of the crossing angle, thickness and thermal conductivity of the plate. The maximum outer wall temperature of 1259 K is obtained at a distance of 7 mm, the crossing angle of 120° and the thickness of 0.5 mm. This study offers a conceptual direction for the design and optimization of a micro-combustor.