Reduction of the High-Speed Magnetically Suspended Centrifugal Compressor Harmonic Vibration Using Cascaded Phase-Shifted Notch Filters

The inception and evolution of rotating stall in a high-speed centrifugal compressor are characterized during speed transients. Experiments were performed in the Single Stage Centrifugal Compressor (SSCC) facility at Purdue University and include speed transients from sub-idle to full speed at different throttle settings while collecting transient performance data. Results show a substantial difference in the compressor transient performance for accelerations versus decelerations. This difference is associated with the heat transfer between the flow and the hardware. The heat transfer from the hardware to the flow during the decelerations locates the compressor operating condition closer to the surge line and results in a significant reduction in surge margin during decelerations. Additionally, data were acquired from fast-response pressure transducers along the impeller shroud, in the vaneless space, and along the diffuser passages. Two different patterns of flow instabilities, including mild surge and short-length-scale rotating stall, are observed during the decelerations. The instability starts with a small pressure perturbation at the impeller leading edge and quickly develops into a single-lobe rotating stall burst. The stall cell propagates in the direction opposite of impeller rotation at approximately one third of the rotor speed. The rotating stall bursts are observed in both the impeller and diffuser, with the largest magnitudes near the diffuser throat. Furthermore, the flow instability develops into a continuous high frequency stall and remains in the fully developed stall condition.

Download Full-text

Effect of Different Geometrical Inlet Pipes on a High Speed Centrifugal Compressor

Volume 6C: Turbomachinery ◽

10.1115/gt2013-94254 ◽

2013 ◽

Cited By ~ 1

Author(s):

Ce Yang ◽

Ben Zhao ◽

C. C. Ma ◽

Dazhong Lao ◽

Mi Zhou

Keyword(s):

Centrifugal Compressor ◽

High Speed ◽

Pressure Ratio ◽

Inlet Pipe ◽

Unsteady Pressure ◽

Bent Pipe ◽

Low Mass ◽

Compressor Performance ◽

Spectral Frequency ◽

The One

Two different inlet configurations, including a straight pipe and a bent pipe, were experimentally tested and numerically simulated using a high-speed, low-mass flow centrifugal compressor. The pressure ratios of the compressor with the two inlet configurations were tested and then compared to illustrate the effect of the bent inlet pipe on the compressor. Furthermore, different circumferential positions of the bent inlet pipe relative to the volute are discussed for two purposes. One purpose is to describe the changes in the compressor performance that result from altering the circumferential position of the bent inlet pipe relative to the volute. This change in performance may be the so-called clocking effect, and its mechanism is different from the one in multistage turbomachinery. The other purpose is to investigate the unsteady flow for different matching states of the bent inlet pipe and volute. Thus, the frequency spectrum of unsteady pressure fluctuation was applied to analyze the aerodynamic response. Compared with the straight inlet pipe, the experimental results show that the pressure ratio is modulated and that the choke point is shifted in the bent inlet pipe. Similarly, the pressure ratio can be influenced by altering the circumferential position of the bent inlet pipe relative to the volute, which may have an effect on the unsteady pressure in the rotor section. Therefore, the magnitude of interest spectral frequency is significantly changed by clocking the bent inlet pipe.

Download Full-text

Experimental Investigation of Surge and Stall in a High-Speed Centrifugal Compressor

Journal of Propulsion and Power ◽

10.2514/1.b35448 ◽

2015 ◽

Vol 31 (3) ◽

pp. 815-825 ◽

Cited By ~ 14

Author(s):

Zheng Xinqian ◽

Liu Anxiong

Keyword(s):

Experimental Investigation ◽

Centrifugal Compressor ◽

High Speed

Download Full-text

An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

Journal of Turbomachinery ◽

10.1115/1.1343465 ◽

2000 ◽

Vol 123 (2) ◽

pp. 418-428 ◽

Cited By ~ 53

Author(s):

Mark P. Wernet ◽

Michelle M. Bright ◽

Gary J. Skoch

Keyword(s):

Flow Field ◽

Centrifugal Compressor ◽

High Speed ◽

Transient Flow ◽

Dynamic Pressure ◽

Rotating Stall ◽

Transient Pressure ◽

Pressure Transducers ◽

Stable Operating ◽

Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

Download Full-text