"Mechanisms for Enhanced Flow Migration from an Annular, High-g Ultra C" by Andrew E. Cottle, Nicholas A. Gilbert et al. 10.2514/6.2016-1392">
 

Mechanisms for Enhanced Flow Migration from an Annular, High-g Ultra Compact Combustor

Document Type

Conference Proceeding

Publication Date

1-2-2016

Abstract

The Ultra Compact Combustor (UCC) is novel solution to address the challenge of improving gas turbine engine performance. The “high-g” UCC design operates by diverting a portion of axial compressor flow into a circumferential combustion cavity positioned about the engine outer diameter. The cavity provides the necessary residence length and time for combustion within substantially reduced axial lengths; furthermore, high g-loads are induced by the cavity bulk circumferential swirl; these conditions have been shown to substantially reduce flame lengths and improve lean blow-out performance. Experimental work at the Air Force Institute of Technology (AFIT) has facilitated the evolution of an atmospheric UCC test rig with a wide range of capabilities and with established operating maps. Recent work has highlighted an issue with effectively migrating the hot gases out of the combustion cavity radially along a hybrid guide vane. A comprehensive numerical evaluation was accomplished to examine the effects of two potential design iterations. First, the hybrid guide vane geometry was modified to incorporate a radial vane cavity (RVC). The modification was successful in redistributing peak temperatures at the combustor exit at the expense of reduced profile uniformity. The net effect of the RVC, based on combustion efficiency, was negative in lean-cavity conditions, but improved in rich-cavity conditions. The second design change incorporated compound-angle cavity air drivers. Results indicated the compound drivers improved mixing and efficiency within the cavity, consequently encouraging more complete combustion through the remainder of the system. The benefits of the compound air drivers were conclusive, however the design of the RVC will require further study in order to better shape the exit temperature profiles.

Comments

This conference paper is available through subscription or purchase from the publisher, AIAA, using the DOI link below.

Conference session: Combustion II

Author notes:

Andrew Cottle was an AFIT PhD candidate at the time of this conference. (AFIT-ENY-DS-16-D-037, December 2016)

Nicholas Gilbert was an AFIT graduate student (M.S. program) at the time of this conference. (AFIT-ENY-MS-16-M-211, March 2016)

Source Publication

54th AIAA Aerospace Sciences Meeting

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