Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Marcus D. Polanka, PhD.


Since combustion efficiency in modern jet engines has stabilized, attention has turned to improving the combustor by improving the thrust-to-weight ratio. The Ultra Compact Combustor (UCC) is a means to reduce the weight of the combustor while ensuring exhaust meets increasingly stringent government emission standards. Combustion occurs within the UCC under a g-load in the circumferential direction, which maintains combustion efficiency while decreasing axial combustor length. Previous analysis optimized the combustion chamber flame characteristics with a common upstream air source. Previously, issues for the UCC were inspired by integration into a traditional axial turbojet. The focus of this investigation was to increase migration of the hot combustion products to the middle of the hybrid vane’s exit plane. This was done by varying the dimensions of the UCC combustion cavity, the air driver configuration into the cavity, as well as adding a radial vane cavity into the center-body guide vanes. In order to accomplish this, a temperature measurement collection technique called thin filament pyrometry was implemented to obtain high fidelity data. Also, the AFIT UCC required an accurate initial emissions baseline to be established; this baseline consisted of collecting five different gaseous species for each considered geometry. These data points were then compared against each other and previously collected temperature values. Optimal exit efficiency and temperature profiles were obtained through modifications to the hybrid vane passage and the air driver geometry.

AFIT Designator


DTIC Accession Number