Leakage Assessment of Pressure-Exchange Wave Rotors

Abstract

Control of leakage within wave rotors is recognized as a key requirement for efficient operation. Previous studies suggest that experimentally observed performance degradation is substantially due to flow leakage. This work presents a leakage model for predicting leakage-attributed performance degradation of four-port pressure-exchange wave rotors more accurately than previous single-cavity leakage models. The methodology comprehensively considers the leakage paths of the entire device. It combines a wave-rotor quasi-one-dimensional computational fluid dynamics prediction code, experimentally validated for internal gas dynamics with the generalized flow-circuit-modeling capability of a leakage-flow network solver. The computational fluid dynamics program and the network solver step through a series of iterations by sharing common leakage information. Application to a well-instrumented wave-rotor rig is briefly summarized, providing important guidance for the improvement of leakage and performance. The new approach is anticipated to be useful in enhancing the design, operation, and efficiency of a broad class of wave rotors by better understanding leakage and hence designing sealing features to control leakage flows.