Combustion characteristics of a cavity pilot combustor for small gas turbine applications

Unmanned aerial vehicles (UAVs) have been widely deployed in both military and civilian domains. As future UAV platforms aim for higher flight speeds and extended endurance, their propulsion systems must maintain stable performance over a broad operational envelope, particularly under high throughflow inlet conditions. In this study, a novel small gas turbine combustor is proposed. A prototype combustor was designed and experimentally evaluated for its combustion characteristics. The results demonstrate that this combustor not only preserves structural compactness but also delivers favorable performance under high throughflow conditions, including low total pressure loss, broad ignition and blowout limits, uniform temperature distribution, and high combustion efficiency. Specifically, at an inlet Mach number of 0.30, the total pressure loss was measured at 4.85%. The ignition and blowout limits were recorded at fuel-air ratios of 0.0052 and 0.0044, respectively, under an inlet Mach number of 0.35. At atmospheric pressure and an inlet Mach number of 0.35, the temperature distribution factor at the exit was below 0.14, with peak combustion efficiency reaching 97.45%. Overall, under the present experimental conditions, the proposed combustor shows promising potential for compact high-throughflow combustor.