Stall inception patterns for three low-solidity cascade diffusers were experimentally investigated to extend the operating range of centrifugal compressor. Pressure fluctuations on the wall and flow distributions at the diffuser inlet were measured, and static pressure-rises across the diffuser vane were also measured to clarify the mechanism of rotating stall inception. In the case of the original diffuser (LSD_O), which had the radius ratio between the impeller outlet and the diffuser vane inlet of 1.10 and a flat plate wing section, a short length-scale stall cell known as a spike first appeared in the positive slope of the diffuser static pressure-raise (after the flat slope was maintained), and then a surge occurred as flow-rate decreased. The propagation speed of short length-scale stall cell was about 13% of the impeller rotation speed. The measured flow distribution at the inlet of the LSD_O suggested that the flow separation occurred in the vaneless space and this separation influenced the rotating stall. In the case of the LSD_A, which had the radius ratio of 1.10 and the NACA 63 wing section, a short length-scale stall cell that was smaller than that of LSD_O was appeared in the positive slope of the diffuser static pressure-raise (without the flat slope). A surge also occurred as further flow-rate decreased. The propagation speed of short length-scale stall cell was about 13% just prior to surge point. In contrast, in the case of LSD_B, which had the radius ratio of 1.05 and the NACA 63 wing section, a small disturbance appeared without spike just prior to surge point and rotating stall did not occur. The small disturbance did not propagate in the circumferential direction. Moreover, the flow separation did not occur in the semi-vaneless space. At the stall inception point of LSD_O and LSD_A, the averaged absolute flow angle at the diffuser inlet agreed with the onset flow angel of rotating stall in vaneless diffuser predicted by Senoo. Therefore, it was considered that the flow separation also occurred in the vaneless space and this separation influenced the rotating stall in the case of LSD_A. Moreover, it was considered that the difference of two stall cell patterns between LSD_O and LSD_A depended on the static pressure-rise characteristic of diffuser determined by the design specifications in case of that the rotating stall occurred in the vaneless space. In contrast, at the point of the small disturbance appeared of LSD_B, the averaged absolute flow angle at the diffuser inlet is smaller than that predicted by Senoo. Therefore, in case of small the radius ratio, the reverse flow in vaneless diffuser is suppressed, and the rotating stall is also suppressed.
Skip Nav Destination
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition
June 11–15, 2012
Copenhagen, Denmark
Conference Sponsors:
- International Gas Turbine Institute
ISBN:
978-0-7918-4474-8
PROCEEDINGS PAPER
Influence of Low-Solidity Cascade Diffuser on Spike Stall Inception in a Centrifugal Compressor
Satoshi Joukou,
Satoshi Joukou
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Search for other works by this author on:
Yasushi Shinkawa,
Yasushi Shinkawa
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Search for other works by this author on:
Toshio Kanno,
Toshio Kanno
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Search for other works by this author on:
Hideo Nishida,
Hideo Nishida
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Search for other works by this author on:
Takahiro Nishioka,
Takahiro Nishioka
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Search for other works by this author on:
Kiyotaka Hiradate
Kiyotaka Hiradate
Hitachi, Ltd., Hitachinaka, Ibaraki, Japan
Search for other works by this author on:
Satoshi Joukou
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Yasushi Shinkawa
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Toshio Kanno
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Hideo Nishida
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Takahiro Nishioka
Hitachi Plant Technologies, Ltd., Tsuchiura, Ibaraki, Japan
Kiyotaka Hiradate
Hitachi, Ltd., Hitachinaka, Ibaraki, Japan
Paper No:
GT2012-69203, pp. 793-802; 10 pages
Published Online:
July 9, 2013
Citation
Joukou, S, Shinkawa, Y, Kanno, T, Nishida, H, Nishioka, T, & Hiradate, K. "Influence of Low-Solidity Cascade Diffuser on Spike Stall Inception in a Centrifugal Compressor." Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 8: Turbomachinery, Parts A, B, and C. Copenhagen, Denmark. June 11–15, 2012. pp. 793-802. ASME. https://doi.org/10.1115/GT2012-69203
Download citation file:
32
Views
Related Proceedings Papers
Related Articles
Stall Behavior in an Ultrahigh-Pressure-Ratio Centrifugal Compressor: Backward-Traveling Rotating Stall
J. Turbomach (October,2022)
The Experimental Study of Matching Between Centrifugal Compressor Impeller and Diffuser
J. Turbomach (January,1999)
Related Chapters
Other Components and Variations
Axial-Flow Compressors
Pulsation and Vibration Analysis of Compression and Pumping Systems
Pipeline Pumping and Compression System: A Practical Approach, Third Edition
Pulsation and Vibration Analysis of Compression and Pumping Systems
Pipeline Pumping and Compression Systems: A Practical Approach, Second Edition