ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Mechanism of nonsteady leakage flow of wave rotors
Received date: 2016-07-12
Revised date: 2016-10-08
Online published: 2016-10-10
The problem of leakage flow can restrict the performance of a wave rotor. This paper extracts main flow phenomena related to leakage in a wave rotor, and establishes a two-dimensional single passage leakage model. The mechanism of nonsteady leakage flow is analyzed numerically, and the prediction model for loss of unsteady leakage flow is further verified. The results show that there exists pressure oscillation of varying extent in rotor passage, and the oscillation amplitude is related to the gap width. The continuous reflected expansion wave, periodic emerging bow shock and its reflected shock are reasons for pressure oscillation. There exist three main flow stages in the leakage gap during leakage flow process and during which the propagation speed of passage shock and post-shock time-averaging pressure stay unchanged. Within a certain range of gap width, shock Mach number and shock static pressure ratio are both linearly dependent on the nondimensional leakage gap width. When the gap width is increased from 0 to 0.08, the shock Mach number decreases by 7.3%, and the shock static pressure ratio decreases by 10.1%. The propagation of channel shock wave is influenced by leakage flow process via main expansion wave, and shock wave attenuation is essentially the result of superposition of ideal shock wave and expansion wave. The results obtained with leakage loss prediction model is found to be consistent with CFD results.
Key words： gas turbine; wave rotor; single passage model; nonsteady leakage flow; shock wave
LIU Chenyuan , LIU Huoxing . Mechanism of nonsteady leakage flow of wave rotors[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2017 , 38(5) : 120606 -120606 . DOI: 10.7527/S1000-6893.2016.0269
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