Numerical investigation of the influence of impeller-diffuser gap (A-and B-GaPs) on unsteady flow in a centrifugal pump at part flows

Taiki Takamine, Satoshi Watanabe

研究成果: 書籍/レポート タイプへの寄稿会議への寄与

2 被引用数 (Scopus)

抄録

Because of the high energy density of multi-stage centrifugal pump, it is really important to ensure the reliability of the pumps thus the stability of rotor system in the wide flow rate range. Rotating stall is a well-known unsteady flow phenomenon in which one or several stall cell structures propagate circumferentially in impeller and/or diffuser. Rotating stall alters the peripheral pressure distribution of rotors, and therefore it is often regarded as one of the primary trigger of unstable fluid force acting on the rotor system. One possible factor which could affect the rotating stall is a geometrical relationship between the rotor and the stator. In the present study, unsteady RANS simulations of internal flow in a centrifugal pump are carried out. The pump is the partial model of the final stage of the three-stage centrifugal pump used in our previous study. In order to investigate the effect of the gap between impeller trailing edge and diffuser leading edge on the unsteady flow of the pump, three cases of impeller-diffuser gap is simulated; one is the smaller gap case with original impeller. The other cases are two larger gap cases with only cutting the impeller blades and with cutting the both impeller blades and impeller shroud walls. For all gap cases, the computations are conducted for the nominal flow rate and the low flor rate with 10% of the nominal flow rate. As a result, the rotating stall is observed only in the larger gap case with the cut shroud walls, indicating that the key phenomenon for the stable formation of the stall cell is not only the weakened rotor-stator interaction, but also the other phenomenon attributed to the enlarged gap between the impeller shroud walls and the diffuser walls. In the shroud cut case, a part of the main flow blocked by the stalled region and the secondary flow on the diffuser walls tend to flow into the side gaps more easily than other cases. They might be the important phenomenon associated with the diffuser rotating stall in the enlarged wall gap condition.

本文言語英語
ホスト出版物のタイトルFluid Applications and Systems
出版社American Society of Mechanical Engineers (ASME)
ISBN(電子版)9780791859056
DOI
出版ステータス出版済み - 1月 1 2019
イベントASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019 - San Francisco, 米国
継続期間: 7月 28 20198月 1 2019

出版物シリーズ

名前ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
3B-2019

会議

会議ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
国/地域米国
CitySan Francisco
Period7/28/198/1/19

!!!All Science Journal Classification (ASJC) codes

  • 流体および伝熱

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