Integration Issues of an Ultra-Compact Combustor to a Jet Turbine Engine

Abstract

As aircraft power requirements continue to grow, whether for electrical systems or increased thrust, improved engine efficiency must be found. An Ultra-Compact Combustor (UCC) is a proposed apparatus for accomplishing this task by burning in the circumferential direction as a main combustor or an Inter-Turbine Burner (ITB). In order for the UCC to be viable, it is important to study the effects of feeding the core and circumferential flows from a common gas reservoir. This research effort has developed a new UCC rig that can be configured in multiple arrangements to investigate the integration issues of a circumferential combustor into an axial jet engine for the AFIT Combustion Laboratory. Coupling the combustor required the design of a variable diffuser that can split the flow emanating from a single source typical of a compressor exit into a cavity and core flow for the UCC. Three mass flow splits of 80/20, 70/30, and 60/40 were generated between the core and cavity flow to understand the resultant combustion efficiencies and temperature gains. Chemical analysis software (CHEMKIN) was applied to assist in the prediction of which flow split would produce the best results and testing of this prediction was initiated. The diffuser was designed to interface with both a clean air source of compressed air as well as a vitiated air source emanating from a small jet engine. This enabled investigations into using a UCC as either a main combustor or as an ITB. A new rig has been developed that will facilitate future endeavourers into UCC and ITB research.