Computational and Experimental Analysis of a Compact Combustor Integrated Into a JetCat P90 RXi

Abstract

Ultra compact combustors (UCCs) look to reduce the overall combustor length and weight in modern gas turbine engines. Previously, a UCC achieved self-sustained operation at subidle speeds in a JetCat P90 RXi turbine engine with a length savings of 33% relative to the stock combustor. However, that combustor experienced flameout as reactions were pushed out of the primary zone before achieving mass flow rates at the engine's idle condition. A new combustor that utilized a bluff body flame stabilization with a larger combustor volume looked to keep reactions in the primary zone within the same axial dimensions. This design was investigated computationally for generalized flow patterns, pressure losses, exit temperature profiles, and reaction distributions at three engine power conditions. The computational results showed the validity of this new UCC, with a turbine inlet temperature of 1080 K and a pattern factor (PF) of 0.67 at the cruise condition. The combustor was then built and tested in the JetCat P90 RXi with rotating turbomachinery and gaseous propane fuel. The combustor maintained a stable flame from ignition through the 36,000 revolutions per minute idle condition. The engine ran self-sustained from 25,000 to 36,000 revolutions per minute with an average exit gas temperature of 980 K, which is comparable to the stock engine.