Study on Exit Flow of a High-Specific Speed Centrifugal Pump Impeller in Cavitating Condition

In this work, the comparative study has been done for five kinds of design methods of the low specific speed centrifugal pump impeller adopted numerical simulation method by software of Fluent, so that the problems can be solved. Many different design methods exists for the low specific speed centrifugal pump impeller, which caused the design effect difficult to control. The numerical simulation method based on the Reynolds time averaged N-S equations (RANS) and RNG κ-ε turbulence models. Results revealed the inner flow pattern of these impeller, and these results were verified by external characteristic experiment. The research results showed that the design method, which adopted compound impeller with short blades and these short blades turned to the suction surface of long blades. Results proved that its flow distribution is even and external characteristic curve is more ideal.

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1519 Study on Exit Flow of a High-Specific Speed Centrifugal Pump Impeller in Cavitating Condition : Comparison with a Low-Specific Speed Impeller

The Proceedings of the Fluids engineering conference ◽

10.1299/jsmefed.2005.221 ◽

2005 ◽

Vol 2005 (0) ◽

pp. 221

Author(s):

Eiji Asakura ◽

Yutaka Hasegawa ◽

Koji Kikuyama ◽

Hiroki Shintani

Keyword(s):

Centrifugal Pump ◽

Pump Impeller ◽

Low Specific Speed ◽

Specific Speed ◽

Centrifugal Pump Impeller

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The Unsteady Pressure Field in a High Specific Speed Centrifugal Pump Impeller—Part I: Influence of the Volute

Journal of Fluids Engineering ◽

10.1115/1.2823514 ◽

1999 ◽

Vol 121 (3) ◽

pp. 621-626 ◽

Cited By ~ 51

Author(s):

Kevin A. Kaupert ◽

Thomas Staubli

Keyword(s):

Centrifugal Pump ◽

Pressure Field ◽

Volume Flux ◽

Pump Impeller ◽

Impeller Blade ◽

Part Load ◽

Pressure Transducers ◽

Unsteady Pressure ◽

Specific Speed ◽

Centrifugal Pump Impeller

An experimental investigation is presented regarding the unsteady pressure field within a high specific speed centrifugal pump impeller (ωs = 1.7) which operated in a double spiral volute. For this, twenty-five piezoresistive pressure transducers were mounted within a single blade passage and sampled in the rotating impeller frame with a telemetry system. The influence of varying volume flux on the pressure transducers was evaluated in terms of pressure fluctuation magnitudes and phase differences. The magnitude information reveals that the pressure fluctuations from the impeller-volute interaction grew as the volume flux became further removed from the best efficiency point and as the trailing edge of the impeller blade was approached. These fluctuations reached 35% of the pump head in deep part load. The upstream influence of the volute steady pressure field dominates the unsteady pressure field within the impeller at all off design load points. Acquired signal phase information permits the identification of the pressure field unsteadiness within the impeller passage as fundamentally synchronized simultaneously with the volute tongue passing frequency. Special emphasis was placed on the volume flux regime where the pump and impeller pressure discharge characteristic undergo hysteresis, as impeller inlet and outlet recirculation commence and cease. A synthesis of the rotating transducers was performed to obtain unsteady blade loading parameters. The value of the unsteady lift coefficient varies on the order of 200% for a single blade in part load operation (at 45% bep), an abrupt fluctuation occurring as the fore running blade suction side passes a volute tongue. The unsteady moment coefficient and center of pressure are also shown to vary significantly during the impeller-volute tongue interaction.

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