Response of a Tandem-Staged Compressor to Circumferential Inflow Distortion

Abstract

Tandem rotor, as a concept promises a higher diffusion capacity than a single rotor. However, it is reported to have a lower operating range than the conventional rotor. Inflow distortion can lead to significant changes in the flow dynamics of the axial-flow compressor. Further, a highly loaded tandem blade is likely to be severely affected due to the inflow distortions. In the present study, circumferential distortion is imposed at the inlet of a tandem stage and its response is studied, using steady and unsteady probes. The performance characteristics and other aerodynamics parameters under the circumferential distortion are compared with the clean inflow case. As expected, the tandem stage experiences a significant drop in the total pressure rise and operating range under circumferential distortion. A large deficit in the total pressure, efficiency, and axial velocity is observed in the distorted region. The casing pressure traces, Morlet wavelet analysis and Fast Fourier Transform techniques are used to analyse the unsteady data. The stall is incepted in the form of a low-intensity spike, which later evolved into a fully grown stall within 2.5 rotor revolutions. Further, the amplitude of the stall cell under the circumferential distortion is found to be higher than the clean flow.

Investigation on the Aerodynamic Performance and Flow Mechanism of Transonic Ultra-Highly Loaded Tandem-Rotor Stage

“…The results showed that the total pressure ratio of the stage increased by 9.3% after the tandem blade was adopted, but the isentropic efficiency decreased by approximately 3%. Kumar et al [16][17][18][19][20] conducted extensive numerical simulation and experimental studies based on the single-stage low-speed tandem rotor. Their research covered various aspects, including the performance of the tandem rotor in off-design conditions [16,17], inflow distortions [18], tip clearance size [19], spike type of stall in the tandem [20], and sweep configurations.…”

“…Kumar et al [16][17][18][19][20] conducted extensive numerical simulation and experimental studies based on the single-stage low-speed tandem rotor. Their research covered various aspects, including the performance of the tandem rotor in off-design conditions [16,17], inflow distortions [18], tip clearance size [19], spike type of stall in the tandem [20], and sweep configurations. Through their studies, the researchers enhanced the understanding of the internal flow mechanism of the tandem rotor.…”