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 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.

Fundamental Analysis on Rotor-Stator Interaction in a Diffuser Pump by Vortex Method

2001 ◽  
Vol 123 (4) ◽  
pp. 737-747 ◽  
Author(s):  
H. Wang ◽  
H. Tsukamoto
Keyword(s):  
Numerical Solutions ◽  
Pressure Fluctuations ◽  
Vortex Method ◽  
Solid Boundary ◽  
Vaned Diffuser ◽  
Unsteady Pressure ◽  
Pumping System ◽  
Rotor Stator Interaction ◽  
The Stability ◽  
Stability And Accuracy

A two-dimensional unsteady flow was calculated within a whole stage of a diffuser pump to investigate pressure fluctuations due to the interaction between impeller and diffuser vanes by using the vortex method, in which vortices shedding from solid boundary were determined by the basic governing equation. The Petrov-Galerkin Method was applied to yield the solutions that satisfy the boundary conditions in an integral sense, and it improved the stability and accuracy of the numerical solutions greatly. A new scheme was also proposed to improve the unsteady pressure evaluation by a boundary integration method in the rotor-stator interaction problem. Moreover, for a more realistic prediction of the pressure fluctuations, the inlet flow was supposed to change with time so that pumping system may balance. The calculated time-varying flow rate, total hydraulic head rise and pressure fluctuations in the vaned diffuser passage, were compared with the measured and calculated ones by other methods. Calculated unsteady pressure fluctuations in the vaned diffuser passage showed good agreement with the experimental data and the CFD calculated ones.

scholarly journals The Flow Rate Influence on the Interaction of a Radial Pump Impeller and the Diffuser

2004 ◽  
Vol 10 (4) ◽  
pp. 309-317 ◽  
Author(s):  
A. Akhras ◽  
M. El Hajem ◽  
J.-Y. Champagne ◽  
R. Morel
Keyword(s):  
Flow Rate ◽  
Angular Position ◽  
Operating Conditions ◽  
Laser Doppler Velocimeter ◽  
Pump Impeller ◽  
Vaned Diffuser ◽  
Time Resolved ◽  
Flow Investigation ◽  
Rotor Stator Interaction ◽  
Radial Pump

This article presents the results of a detailed flow investigation within a centrifugal pump equipped with a vaned diffuser. The measurements were made with a laser Doppler velocimeter and were carried out at different operating points. The flow was investigated for different rotor–stator relative positions.Unsteady velocity measurements, obtained in phase with the rotor angular position, gave access to the flow inside the impeller channels where three sections were explored. In the diffuser, five sections were studied. Thus, time resolved details of the flow were examined for a better understanding of the complex unsteady flow existing between the two interacting blade rows.Results obtained at different operating conditions show that the rotor-stator interaction is affected by the diffuser position and the flow rate.

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.

scholarly journals An Experimental Study on the Fluid Forces Induced by Rotor-Stator Interaction in a Centrifugal Pump

2003 ◽  
Vol 9 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Shijie Guo ◽  
Hidenobu Okamoto
Keyword(s):  
Centrifugal Pump ◽  
Static Pressure ◽  
Pressure Fluctuations ◽  
Strong Relationship ◽  
Operating Conditions ◽  
Flow Rates ◽  
Fluid Forces ◽  
Large Pressure ◽  
Rotor Stator Interaction ◽  
Frequency Components

The pressure fluctuations and the radial fluid forces acting on the impeller, the pressures in the volute, as well as the vibration of the shaft in a centrifugal pump were measured simultaneously, and their relationship was investigated. Experiments were done for various diffuser vanes, flow rates, and rotating speeds. It was demonstrated that both the blade-pressure fluctuations and the volute static pressures are nonuniform circumferentially (not axisymmetrical) under off-design operating conditions and that the two have a strong relationship. At high flow rates, the blade pressure fluctuations, induced by rotor-stator interactions, are large in areas where the volute static pressure is low. The traveling directions of the rotating pressure waves, the whirling directions of the radial fluid forces, and the most predominant frequency components of both the fluctuations and the forces are discussed, and an equation for predicting them is introduced. It was also noted that large alternating fluid forces are not necessarily associated with large pressure fluctuations. Furthermore, when measuring the radial fluid forces in the rotating frame, other frequency components, in addition to those related to the products of the diffuser vane number and the rotating frequency, may occur due to the circumferential unevenness of the pressure fluctuations on the impeller. These components are predictable.

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.

Impeller-Diffuser Interaction in Centrifugal Compressors

2012 ◽  
Author(s):  
Chris Robinson ◽  
Michael Casey ◽  
Brad Hutchinson ◽  
Robin Steed
Keyword(s):  
Pressure Ratio ◽  
Pressure Fluctuations ◽  
Peak Efficiency ◽  
Vaned Diffuser ◽  
High Pressure Ratio ◽  
Steady Stage ◽  
Rotor Stator Interaction ◽  
Design Speed ◽  
Steady Simulation ◽  
Cfd Analyses

This paper reports several CFD analyses of a centrifugal compressor stage with a vaned diffuser at high pressure ratio using different techniques to model the rotor-stator interaction. A conventional steady stage calculation with a mixing-plane type interface between the rotor and stator was used as a baseline. This simulation gave excellent agreement with the measured performance characteristics at design speed, demonstrating the ability of the particular steady simulation used to capture the essential features of the blockage interaction between the components. A full annulus simulation using a transient rotor-stator interaction (TRS) method was then used at the peak efficiency point to obtain a fully unsteady reference solution, and this predicted a small increase in peak efficiency. Finally, a computationally less expensive unsteady calculation using a Time Transformation (TT) method was carried out. This gave similar results to the fully transient calculation suggesting that this is an acceptable approach to estimate unsteady blade loading from the interaction. The impeller diffuser spacing was then reduced from 15 to 7% of the impeller tip radius using the more affordable TT approach. This identified an increase in efficiency of 1% and predicted unsteady pressure fluctuations in the impeller which were 116% higher with the closely spaced diffuser.

Sign in / Sign up

Export Citation Format

Share Document