Details
| Original language | English |
|---|---|
| Title of host publication | Turbomachinery |
| Publisher | American Society of Mechanical Engineers(ASME) |
| Number of pages | 13 |
| ISBN (electronic) | 9780791858554 |
| Publication status | Published - 5 Nov 2019 |
| Event | ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019 - Phoenix, United States Duration: 17 Jun 2019 → 21 Jun 2019 |
Publication series
| Name | Proceedings of the ASME Turbo Expo |
|---|---|
| Volume | 2A-2019 |
Abstract
This paper aims at experimentally demonstrating the effects of axial slot casing treatment and tip gap variation on compressor performance, unsteady tip clearance flow, and stall inception features in a highly-loaded mixed-flow compressor at part-speed. Two tip gaps (0.32% and 0.64% of rotor blade chord at mid-span) were tested at three rotational speeds. A semicircular axial slot casing treatment improves compressor stability. The experimental results show that this casing treatment significantly moves the stability limit at partial speeds towards lower mass flow for both tip gaps, compared to the reference case without casing treatment. In the case of the compressor with casing treatment, efficiency increases for the large tip gap and decreases for the small tip gap. Dynamic pressure transducers installed in the casing upstream and along the rotor tip chord direction are used to detect the unsteady behavior of tip region flow and stall inception signals of the compressor. The characteristic frequency in the tip region decreases, and the oscillating amplitude first decreases and then increases during the throttling process, regardless of tip gap size or casing treatment. For axial compressors, by contrast, the observation in previous work has been an increase of the oscillating amplitude with decreasing flow coefficient. This is a surprising result of our work. Neither experiment nor CFD so far was able to explain why the trend in this mixed-flow compressor is different from the trend expected from axial compressors. The compressor stalls through the spike stall inception both with and without casing treatment. This observation also differs from recent studies on axial compressors, which demonstrated that casing treatments could change the type of stall inception. The unstable disturbance indicating initial stall inception initially appears in the blade tip region from blade mid-chord to trailing edge, and then propagates upstream towards the leading edge. This disturbance might be generated by the reversed flow separation near mid-chord.
ASJC Scopus subject areas
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
Turbomachinery. American Society of Mechanical Engineers(ASME), 2019. (Proceedings of the ASME Turbo Expo; Vol. 2A-2019).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Experimental study on the influence of casing treatment on near-stall unsteady behavior of a mixed-flow compressor
AU - Du, Juan
AU - Kauth, Felix
AU - Li, Jichao
AU - Zhang, Qianfeng
AU - Seume, Jörg Reinhart
N1 - Funding information: The authors are grateful for the financial support from the National Key R&D Program of China under Grant Nos. 2016YFB0200901 and the grants of National Nature Science Foundation of China (No. 51676184 and No. 51636001). The authors would also like to thank the German Research Foundation (DFG) for supporting the experiments as part of the Collaborative Research Centre 880 (Sonderforschungsbereich SFB 880).
PY - 2019/11/5
Y1 - 2019/11/5
N2 - This paper aims at experimentally demonstrating the effects of axial slot casing treatment and tip gap variation on compressor performance, unsteady tip clearance flow, and stall inception features in a highly-loaded mixed-flow compressor at part-speed. Two tip gaps (0.32% and 0.64% of rotor blade chord at mid-span) were tested at three rotational speeds. A semicircular axial slot casing treatment improves compressor stability. The experimental results show that this casing treatment significantly moves the stability limit at partial speeds towards lower mass flow for both tip gaps, compared to the reference case without casing treatment. In the case of the compressor with casing treatment, efficiency increases for the large tip gap and decreases for the small tip gap. Dynamic pressure transducers installed in the casing upstream and along the rotor tip chord direction are used to detect the unsteady behavior of tip region flow and stall inception signals of the compressor. The characteristic frequency in the tip region decreases, and the oscillating amplitude first decreases and then increases during the throttling process, regardless of tip gap size or casing treatment. For axial compressors, by contrast, the observation in previous work has been an increase of the oscillating amplitude with decreasing flow coefficient. This is a surprising result of our work. Neither experiment nor CFD so far was able to explain why the trend in this mixed-flow compressor is different from the trend expected from axial compressors. The compressor stalls through the spike stall inception both with and without casing treatment. This observation also differs from recent studies on axial compressors, which demonstrated that casing treatments could change the type of stall inception. The unstable disturbance indicating initial stall inception initially appears in the blade tip region from blade mid-chord to trailing edge, and then propagates upstream towards the leading edge. This disturbance might be generated by the reversed flow separation near mid-chord.
AB - This paper aims at experimentally demonstrating the effects of axial slot casing treatment and tip gap variation on compressor performance, unsteady tip clearance flow, and stall inception features in a highly-loaded mixed-flow compressor at part-speed. Two tip gaps (0.32% and 0.64% of rotor blade chord at mid-span) were tested at three rotational speeds. A semicircular axial slot casing treatment improves compressor stability. The experimental results show that this casing treatment significantly moves the stability limit at partial speeds towards lower mass flow for both tip gaps, compared to the reference case without casing treatment. In the case of the compressor with casing treatment, efficiency increases for the large tip gap and decreases for the small tip gap. Dynamic pressure transducers installed in the casing upstream and along the rotor tip chord direction are used to detect the unsteady behavior of tip region flow and stall inception signals of the compressor. The characteristic frequency in the tip region decreases, and the oscillating amplitude first decreases and then increases during the throttling process, regardless of tip gap size or casing treatment. For axial compressors, by contrast, the observation in previous work has been an increase of the oscillating amplitude with decreasing flow coefficient. This is a surprising result of our work. Neither experiment nor CFD so far was able to explain why the trend in this mixed-flow compressor is different from the trend expected from axial compressors. The compressor stalls through the spike stall inception both with and without casing treatment. This observation also differs from recent studies on axial compressors, which demonstrated that casing treatments could change the type of stall inception. The unstable disturbance indicating initial stall inception initially appears in the blade tip region from blade mid-chord to trailing edge, and then propagates upstream towards the leading edge. This disturbance might be generated by the reversed flow separation near mid-chord.
UR - http://www.scopus.com/inward/record.url?scp=85075558961&partnerID=8YFLogxK
U2 - 10.1115/gt2019-92034
DO - 10.1115/gt2019-92034
M3 - Conference contribution
AN - SCOPUS:85075558961
T3 - Proceedings of the ASME Turbo Expo
BT - Turbomachinery
PB - American Society of Mechanical Engineers(ASME)
T2 - ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019
Y2 - 17 June 2019 through 21 June 2019
ER -