Unsteady Flow Characteristics of Tip Clearance in Semi-open Impeller Centrifugal Pump

被引：0
|
作者：
Lu J. [1 ]
Guo L. [1 ]
Wang L. [1 ]
Wang W. [1 ]
Guo P. [1 ]
Luo X. [1 ]
机构：
[1] Faculty of Water Resources and Hydroelectric Engineering, Xi'an University of Technology, Xi'an
来源：
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | 2019年 / 50卷 / 06期
关键词：
Secondary leakage; Semi-open centrifugal pump; Spectrum analysis; Tip leakage vortex;
D O I：
10.6041/j.issn.1000-1298.2019.06.018
中图分类号：
学科分类号：
摘要：
Transient pulsation of tip leakage vortex is an important factor for flow instability and stall of centrifugal impeller. To get an insight into the unsteady flow characteristics in the tip region of a semi-open centrifugal pump, the SST k-ω two-equation model was used to solve the N-S equation. And the fast Fourier transform (FFT) was used to transform the time domain value of vorticity of each monitoring point into frequency domain value, so as to monitor the frequency domain characteristics. The correlation mechanism between the leakage vortex trajectory and the blade loading was studied and the spectral characteristics of the leakage vortex were analyzed. The results showed that the angle θ between the leaking vortex core and the blade bone line was changed periodically with the tip blade loading. The leakage flow accelerated the flow separation at the tip, forming a vortex tube extending from the tip blade surface to the shroud. At 0.75Qd, the 0.51fB in the tip region was the main disturbance signal, which was closely related with the secondary leakage and the unsteady pulsation of the vortex tube. As the flow rate decreased, the disturbance frequency was changed, and the tip leakage vortex crushing position was moved toward the leading edge of the blade. Under the near-stall operating points, the unsteady fluctuation of the leakage flow was aggravated by the pulsation and shedding of the vortex tube, and the tip leakage vortex crushing position was extended to the leading edge of the blade. The unsteady characteristics of the tip leakage flow of the semi-open centrifugal pump were researched, which provided a theoretical basis for the optimal design of the semi-open impeller and the capture of stall signal. © 2019, Chinese Society of Agricultural Machinery. All right reserved.
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页码：163 / 172
页数：9
相关论文
共 30 条
  • [1] Zhou P., Wang F., Yao Z., Analysis of rotating stall cells in an impeller of a centrifugal pump, Journal of Hydraulic Engineering, 46, 9, pp. 1128-1134, (2015)
  • [2] Pan Z., Li J., Li H., Et al., Overview for research on rotating stall of pump, Fluid Machinery, 39, 2, pp. 35-39, (2011)
  • [3] Jia X., Wang Z., Wang J., Leakage flow and leakage vortex in turbomachinery, Journal of Engineering Thermophysics, 24, 5, pp. 753-756, (2003)
  • [4] Zhang D., Shao P., Shi W., Et al., Numerical simulation of tip leakage vortex hydrodynamics characteristics in axial flow pump, Transactions of the Chinese Society for Agricultural Machinery, 45, 3, (2014)
  • [5] Zheng X., Liu A., Sun Z., Investigation of the instability mechanisms in a turbocharger centrifugal compressor with a vaneless diffuser by means of unsteady simulations, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 231, 11, pp. 1558-1567, (2017)
  • [6] Ju W., Xu S., Wang X., Et al., Numerical study on the influence of tip clearance on rotating stall in an unshrouded centrifugal compressor, Proceedings of ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, pp. 1-8, (2017)
  • [7] Boitel G., Fedala D., Myon N., Tip clearance effects on loads and performances of semi-open impeller centrifugal pumps at different specific speeds, IOP Conference Series: Earth and Environmental Science, 49, 3, (2016)
  • [8] Jia X., Cui B., Zhang Y., Et al., Study on internal flow and external performance of a semi-open impeller centrifugal pump with different tip clearances, International Journal of Turbo & Jet-Engines, 32, 1, pp. 1-12, (2015)
  • [9] Cui B., Huang D., Shi P., Et al., Effect of tip clearance on performance of low specific speed centrifugal pump with semi-open impeller, Journal of Drainage and Irrigation Machinery Engineering, 30, 3, pp. 283-288, (2012)
  • [10] Li Y., Shen J., Hong Y., Et al., Numerical investigation of pressure fluctuations on axial-flow pump blades affected by tip-gap size, Transactions of the Chinese Society for Agricultural Machinery, 45, 5, (2014)
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