Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Marc D. Polanka, PhD.


Performing combustion in the circumferential direction has a significant potential payoff in terms of saving engine length and subsequently weight. What is not understood is the flame dynamics for a liquid fuel when sprayed into a combustor with centripetal acceleration. This investigation used phase Doppler anemometry (PDA) to characterize a nonreacting liquid spray exiting from a nozzle into a circular cavity with centripetal acceleration. The two-component velocity and size of the droplets in the cavity are measured as a function of centripetal acceleration of the air in the cavity. It was found that the droplets are accelerated by the swirling air flow and that droplet velocity increases with distance from the nozzle. Additionally it was found that water droplets evaporated within 60mm of the nozzle under the high g-load conditions. These measurements will aide in the development of compact combustors for gas turbine engines that use a circumferential cavity with swirling flow to reduce the length of the combustor. Knowing the spray distribution and residence time for the particles will allow optimization of the temperature distribution in the cavity and should enable a minimization of the number of fuel injection sites.

AFIT Designator


DTIC Accession Number