Experimental investigation on thermal and combustion performance of a combustor with microchannel cooling

Abstract

Microchannel cooling provides an efficient thermal management method for regenerative cooling systems of advanced areo engines. In this study, a prototype combustor with microchannel cooling passages in the walls is experimentally developed. Combustion tests are systematically conducted in a range of air inlet temperature (30–70 °C), equivalence ratios (0.8–1.2) and flow rates of coolant (100–300 kg/m2s) using liquid fuel of ethanol and air mixture. Comparative studies against a combustor without microchannel cooling are also conducted to assess the feasibility of performance enhancement. The introduction of microchannel cooling was found to induce an 80% reduction of the maximum wall temperatures, and a larger than 90% reduction of the streamline wall temperature gradient. The combustor with microchannel cooling also induced a 1%–3.2% increase of the combustion efficiency and a 0.3%–1.7% reduction of the CO emissions in general compared to that without microchannel cooling. The wall temperatures and combustion efficiency of the combustor with microchannel cooling were found to increase with the increase in air inlet temperatures from 30 to 70 °C, whereas they tended to decrease when the equivalence ratio increased from 0.8 to 1.2. Nevertheless, the flow rate of coolant played a negligible role on the combustion performance of the combustor with microchannel cooling.