Leakage Assessment of Pressure-Exchange Wave Rotors

Control of leakage within wave rotors has been recognized as a key requirement for efficient operation. Previous numerical simulations have suggested that experimentally observed performance degradation is substantially due to flow leakage. This work documents a research effort to develop a leakage model which is capable of predicting the performance degradation of four-port pressure-exchange wave rotors due to leakage more accurately than previous single-cavity leakage models. This methodology considers comprehensively the leakage paths of the entire device, combining the leakage prediction capability of an experimentally validated wave rotor quasi-one-dimensional computational fluid dynamic (CFD) prediction code with the generalized flow circuit solving capability of a leakage flow network solver. The CFD program and the network solver step through a series of iterations by sharing common leakage information. Application to the NASA Glenn Research Center wave rotor rig is briefly summarized. The capabilities of the new approach are 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.