Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Aeronautics and Astronautics

First Advisor

Marc D. Polanka, PhD


The Ultra Compact Combustor (UCC) is an innovative combustion system alternative to a traditional turbine engine burner with the potential to improve engine efficiency with a reduced combustor volume. The UCC shortens the axial length of the combustor, and therefore reduces engine weight, by burning in an annulus and swirling the reactants in the circumferential direction. These length and weight improvements can directly lead to an increased thrust-to-weight rating of the engine. The present research included five objectives which advanced the UCC concept on four fronts; cooling UCC turbine vanes, advanced computational modeling of UCC systems, system air split control and combustion characterization with alternate fuel injection designs, and development of a new UCC orientation to correct exit temperature profiles and fit inside an engine case. Objective one focused on cooling of the UCC turbine vanes located radially inward from the circumferential combustor by taking advantage of the unique component configuration in this system. The leading edge of the turbine vanes were positioned axially upstream of the hot combustion gases enabling cool core ow to be ingested into the vane at the leading edge eliminating the need for compressor bleed air. Several cooling schemes were computationally analyzed that included internal and film-cooling concepts. A design was down selected, hardware was 3D printed, and this novel cooling concept was experimentally tested and validated. Objective two demonstrated the benefits of advanced computational modeling in a UCC by incorporating conjugate heat transfer to previously used combustion and turbulent fluid analysis with adiabatic wall treatments. The addition of the conjugate model created more realistic temperature results than the adiabatic model when compared to experimental data at the exit plane of the combustor.

AFIT Designator


DTIC Accession Number