Research Papers: Flows in Complex Systems

Hydraulic Improvement to Eliminate S-Shaped Curve in Pump Turbine

[+] Author and Article Information
Jun-lian Yin

e-mail: yinjunlian@sina.com

De-zhong Wang

e-mail: dzwang@sjtu.edu.cn
School of Mechanical Engineering,
Shanghai Jiao Tong University,
Shanghai, 200240, China

Xian-zhu Wei

State Key Laboratory of Hydropower Equipment,
Harbin, 150040, China
e-mail: weixianzhu@hit.edu.cn

Le-qin Wang

Zhejiang University,
Hangzhou, 310027, China
e-mail: hj_wlq2@zju.edu.cn

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 30, 2012; final manuscript received January 14, 2013; published online May 23, 2013. Assoc. Editor: Edward M. Bennett.

J. Fluids Eng 135(7), 071105 (May 23, 2013) (6 pages) Paper No: FE-12-1353; doi: 10.1115/1.4023851 History: Received July 30, 2012; Revised January 14, 2013

For pump turbines, an S-shaped curve can lead to failures in synchronization. To improve the hydraulic design, the component that is responsible for the formation of the S-shaped curve was identified by a hydraulic loss analysis using previous computational fluid dynamics (CFD) results, which indicates that the formation of the S-shaped curve can be ascribed to the runner. To improve the hydraulic design of the runner, a simple numerical approach for direct problem analysis was proposed, based on the blade-loading distributions of runners with and without an S-shaped curve, and directly analyzed. It was implied from the differences in the blade-loading distributions that, when the meridional passage was broadened, the formation of the S-shaped curve was suppressed. To validate this, two runners with different meridional sections were designed by means of the inverse design method. Through model tests, it was verified that the S-shaped curve was eliminated completely and the performance curve of the modified hydraulic model satisfied the requirements for safe operation in a pumped storage plant.

Copyright © 2013 by ASME
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Fig. 1

Typical configuration of pump turbine

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Fig. 2

S-shaped curve for pump turbine studied in Ref [8], indicating the good relationship between numerical results and experimental data

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Fig. 3

Profile of hydraulic loss normalized by constant head versus unit flow rate q11

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Fig. 4

Meridional plane with quasiorthotropic grid

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Fig. 5

The meridional plane with quasiorthotropic grid

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Fig. 6

Performance curves in turbine brake mode

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Fig. 7

BLDs of chosen operating points, indicating the spatial evolution of Euler energy along the streamlines, where lines represent Cur1 and circles represent Cur2

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Fig. 8

Differences in BLDs between Cur1 and Cur2, indicating that the Euler energy of Cur2 is larger than that of Cur1

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Fig. 9

Blade-loading distribution applied in inverse design method

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Fig. 10

Dimensions of the meridional passage for the runner of the pump turbine

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Fig. 11

Distributions of maximum spherical diameter (meridional) of the two different meridional sections

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Fig. 12

Inversely designed runner manufactured by Harbin Electric Corporation

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Fig. 13

Performance curves for turbine mode and turbine-braking mode for Model A, indicating serious S-shaped characteristics

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Fig. 14

Performance curves for turbine mode and turbine-braking mode for Model B, indicating stable characteristics

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Fig. 15

Comparison of the enveloped Q–H curves for Model A and Model B



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