Theoretical Study of Pressure Fluctuations Downstream of a Diffuser Pump Impeller—Part 1: Fundamental Analysis on Rotor-Stator Interaction

1997 ◽  
Vol 119 (3) ◽  
pp. 647-652 ◽  
Author(s):  
W. Qin ◽  
H. Tsukamoto
Keyword(s):  
Unsteady Flow ◽  
Theoretical Study ◽  
Pressure Fluctuations ◽  
Harmonic Component ◽  
Theoretical Method ◽  
Predominant Role ◽  
Pump Impeller ◽  
Singularity Method ◽  
Rotor Stator Interaction ◽  
Impulsive Pressure

A theoretical method was developed to calculate the unsteady flow caused by the interaction between impeller and diffuser vanes in a diffuser pump by using the singularity method. The unsteady flow in the diffuser vane is assumed to be induced by three kinds of unsteady vortices: bound vortices distributed on the impeller blades and diffuser vanes, and free vortices shed from the trailing edge of diffuser vanes. In order to make clear the contribution of each harmonic component of unsteady vortices to unsteady pressure, all the unsteady vortices are expressed in the form of Fourier series. The calculated unsteady pressures downstream of impeller agree well with the corresponding measured ones. Moreover, it was shown that impulsive pressure plays a predominant role for unsteady pressures.

Theoretical Study of Pressure Fluctuations Downstream of a Diffuser Pump Impeller—Part 2: Effects of Volute, Flow Rate and Radial Gap

1997 ◽  
Vol 119 (3) ◽  
pp. 653-658 ◽  
Author(s):  
W. Qin ◽  
H. Tsukamoto
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Flow Rate ◽  
Theoretical Study ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Trailing Edge ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Radial Gap

The fundamental analysis in the first report was extended to calculate the unsteady flow induced by the interaction between impeller blades and diffuser vanes/volute casing in a diffuser pump. The unsteady flow in the diffuser vane passage, as well as the volute casing, is assumed to be induced by the five kinds of singularities—the bound vortices distributed on the impeller blades, diffuser vanes and volute casing wall, the sources at volute outlet, and the free vortices shed from the trailing edge of diffuser vanes. Calculated unsteady pressures agree with the corresponding experimental data. And the calculated results showed the effects of the flow rate, volute casing and the radial gaps between impeller blade trailing edge and diffuser vane leading edge on the magnitude of unsteady pressure downstream of impeller.

Unsteady Hydrodynamic Forces due to Rotor-Stator Interaction on a Diffuser Pump With Identical Number of Vanes on the Impeller and Diffuser

2005 ◽  
Vol 127 (4) ◽  
pp. 743-751 ◽  
Author(s):  
M. Zhang ◽  
H. Tsukamoto
Keyword(s):  
Computational Study ◽  
Pressure Fluctuations ◽  
Vortex Method ◽  
Hydrodynamic Forces ◽  
Pump Impeller ◽  
Vaned Diffuser ◽  
Fluid Forces ◽  
Rotor Stator Interaction ◽  
Identical Number ◽  
Good Agreement

Experimental and computational study was developed for unsteady hydrodynamic forces on a diffuser pump impeller excited by the interaction between the impeller and the vaned diffuser with the same number of vanes as impeller. Unsteady flow calculations are made using commercially available CFD software, CFX-TASCflow, as well as the two-dimensional vortex method. Calculated pressure and fluid forces on the impeller show good agreement with measured ones. It has been demonstrated that the fluid forces on the impeller with the same number of vanes as the vaned diffuser are smaller compared with other combinations of vane numbers. However, the pressure fluctuations are found to be greater than other cases.

Numerical investigation of influence of inlet guide vanes on unsteady flow in a centrifugal pump

2015 ◽  
Vol 229 (18) ◽  
pp. 3405-3416 ◽  
Author(s):  
Wang Yuchuan ◽  
Tan Lei ◽  
Zhu Baoshan ◽  
Cao ShuLiang ◽  
Wang Binbin
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Turbulence Models ◽  
Rotational Frequency ◽  
Pump Impeller ◽  
Guide Vanes ◽  
Pump Performance ◽  
Inlet Guide Vanes ◽  
Dominant Frequencies

The influence of inlet guide vanes on unsteady flow in a centrifugal pump is numerically investigated. The independences of mesh elements, time steps and turbulence models are studied, and the satisfactory agreement between experimental and numerical results of the centrifugal pump performance validates the reliability and accuracy of the numerical model. The frequency characteristics of pressure fluctuations in impeller and volute are nearly the same for the pump without and with inlet guide vanes in the angle range from −36° to +36°. In the pump impeller, the dominant frequencies are mainly the rotational frequency fi (24.17 Hz) or 2 fi, and in volute they are the blade passing frequency fBPF (145 Hz). For the large inlet guide vanes angles of −60°and +60°, the maximum amplitudes of pressure fluctuations in pump impeller and volute are stronger than that in pump without inlet guide vanes. Therefore, the influence of inlet guide vanes on unsteady flow in the centrifugal pump is slight when the inlet guide vanes angles are regulated in a suitable region.

Numerical Analysis of Unsteady Hydrodynamic Forces on a Diffuser Pump Impeller Due to Rotor-Stator Interaction

2002 ◽  
Author(s):  
M. Zhang ◽  
H. Wang ◽  
H. Tsukamoto
Keyword(s):  
Numerical Analysis ◽  
Pressure Fluctuations ◽  
Vortex Method ◽  
Hydrodynamic Forces ◽  
Local Pressure ◽  
Pump Impeller ◽  
Fluid Forces ◽  
Rotor Stator Interaction ◽  
Pipe Systems

The 2-D vortex method and the commercially available CFD software are applied to calculate unsteady hydrodynamic forces on a diffuser pump impeller and the pressure fluctuations caused by the interaction between the impeller and the diffuser vanes. Calculated pressure and fluid forces on the impeller are compared with measured ones. The numerical analysis yields fairly accurate predictions of the fluid forces and the pressure fluctuations in diffuser passages and the pipe systems. It has been demonstrated that the fluid forces caused by the interaction between the rotor and stator vanes are small when the number of vanes on impeller and diffuser is identical. In this case, however, the local pressure fluctuations are larger in diffuser passages and the pipe systems.

scholarly journals Pressure Fluctuation in a Vaned Diffuser Downstream from a Centrifugal Pump Impeller

2003 ◽  
Vol 9 (4) ◽  
pp. 285-292 ◽  
Author(s):  
Akinori Furukawa ◽  
Hisasada Takahara ◽  
Takahiro Nakagawa ◽  
Yusuke Ono
Keyword(s):  
Centrifugal Pump ◽  
Static Pressure ◽  
Pressure Fluctuations ◽  
Flow Analysis ◽  
Inviscid Flow ◽  
Blade Surface ◽  
Pump Impeller ◽  
Vaned Diffuser ◽  
Singularity Method ◽  
Centrifugal Pump Impeller

Periodic flows downstream from a centrifugal pump impeller in vaneless and vaned diffusers were measured by using a single hole yawmeter and a phase-locked sampling method. The flows were also calculated by an inviscid flow analysis using the blade-surface singularity method. The periodic variations in calculated static pressure with the impeller rotating quantitatively agree well with the measured ones. The flow behaviors in the vaned diffuser are discussed, citing measured and calculated results. The potential interaction between the impeller and the diffuser blades appears more strongly than the impeller-wake interaction. The appearance of static pressure fluctuations due to the impeller's rotating in the fully vaned zone is different from that in the semivaned zone of the diffuser. The existence of the peripheral blade surface of the impeller outlet with an outlet edge of the pressure surface causes violent pressure fluctuations in the vaned diffuser.

Relationship Between Unsteady Flow, Pressure Fluctuations, and Noise in a Centrifugal Pump—Part B: Effects of Blade-Tongue Interactions

1995 ◽  
Vol 117 (1) ◽  
pp. 30-35 ◽  
Author(s):  
S. Chu ◽  
R. Dong ◽  
J. Katz
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Difference ◽  
Pressure Fluctuations ◽  
Primary Sources ◽  
Pressure Measurements ◽  
Local Pressure ◽  
Pressure Distributions ◽  
Flow Pressure ◽  
Tip Of The Tongue

Maps of pressure distributions computed using PDV data, combined with noise and local pressure measurements, are used for identifying primary sources of noise in a centrifugal pump. In the vicinity of the impeller pressure minima occur around the blade and near a vortex train generated as a result of non-uniform outflux from the impeller. The pressure everywhere also varies depending on the orientation of the impeller relative to the tongue. Noise peaks are generated when the pressure difference across the tongue is maximum, probably due to tongue oscillations, and when the wake impinges on the tip of the tongue.

scholarly journals Control of the Unsteady Flow in a Stator Blade Row Interacting With Upstream Moving Wakes

1993 ◽  
Author(s):  
T. Valkov ◽  
C. S. Tan
Keyword(s):  
Unsteady Flow ◽  
Pressure Fluctuations ◽  
Spectral Element ◽  
Navier Stokes ◽  
Suction Surface ◽  
Model Calculations ◽  
Blade Loading ◽  
Pressure Surface ◽  
Blade Row ◽  
Stator Blade

A computational approach, based on a spectral-element Navier-Stokes solver, has been applied to the study of the unsteady flow arising from wake-stator interaction. Direct, as well as turbulence-model calculations, provide insight into the mechanics of the unsteady flow and demonstrate the potential for controlling its effects. The results show that the interaction between the wakes and the stator blades produces a characteristic pattern of vortical disturbances, which have been correlated to the pressure fluctuations. Within the stator passage, the wakes migrate towards the pressure surface where they evolve into counter-rotating vortices. These vortices are the dominant source of disturbances over the pressure surface of the stator blade. Over the suction surface of the stator blade, the disturbances are due to the distortion and detachment of boundary layer fluid. They can be reduced by tailoring the blade loading or by applying non-uniform suction.

Design of a Transonic High-Pressure Turbine Stage 2D Section With Reduced Rotor/Stator Interaction

2004 ◽  
Author(s):  
Michele Vascellari ◽  
Re´my De´nos ◽  
Rene´ Van den Braembussche
Keyword(s):  
Rotor Blade ◽  
Static Pressure ◽  
Aerodynamic Force ◽  
Pressure Fluctuations ◽  
Uniform Field ◽  
Turbine Stage ◽  
Rotor Stator Interaction ◽  
Transonic Turbine ◽  
Blade Failure ◽  
Rotor Profiles

In transonic turbine stages, the exit static pressure field of the vane is highly non-uniform in the pitchwise direction. The rotor traverses periodically this non-uniform field and large static pressure fluctuations are observed around the rotor section. As a consequence the rotor blade is submitted to significant variations of its aerodynamic force. This contributes to the high cycle fatigue and may result in unexpected blade failure. In this paper an existing transonic turbine stage section is redesigned in the view of reducing the rotor stator interaction, and in particular the unsteady rotor blade forcing. The first step is the redesign of the stator blade profile to reduce the stator exit pitchwise static pressure gradient. For this purpose, a procedure using a genetic algorithm and an artificial neural network is used. Next, two new rotor profiles are designed and analysed with a quasi 3D Euler unsteady solver in order to investigate their receptivity to the shock interaction. One of the new profiles allows reducing the blade force variation by 50%.

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