Research on a Methane-Fueled Low $NOx$ Combustor for a Mach 3 Supersonic Transporter Turbojet Engine

Methane-fueled low $NOx$ combustor research had been conducted under the Japanese supersonic/hypersonic propulsion research program. A unique form of premixture jet swirl combustor (PJSC) was proposed for the ultra low $NOx$ combustor of a Mach 3 turbojet engine. Fuel-air mixing tests and fundamental combustion tests were conducted to obtain the design data and combustion characteristics in the first phase of the research. A single can-type combustor was fabricated and high-temperature and high-pressure combustion tests were carried out for the evaluation on $NOx$ emission reduction capability of the PJSC concept in the second phase. In the final phase of research, a multisector combustor was fabricated and the performance demonstration test was conducted for the final evaluation of the pollutant exhaust emission goals and the combustor performance goals set in the HYPR project. The sequential three-phased program was completed successfully, and the project goals of $NOx$ emission, combustion efficiency, pressure loss and exit gas temperature pattern factor at the Mach 3 cruise condition, together with the ICAO regulatory levels for supersonic aircraft at LTO conditions, were all achieved in the performance demonstration test.