Performing combustion in the circumferential direction has a significant potential payoff in terms of saving engine length and subsequently weight. Key to this process is the high gravitational load placed on the fuel and air. The additional stretching of the flame should increase the flame speed. The induced buoyancy causes unburnt fuel to remain in the cavity while lighter products migrate out. 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. It was also seen that increasing the centripetal acceleration causes the larger droplets to migrate to the outer diameter of the cavity, and that the distribution of droplets is sensitive to changes in the centripetal acceleration. 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.
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