Numerical Simulation of the Dynamic Effects Due to Impeller-Volute Interaction in a Centrifugal Pump

Abstract

This paper shows the capability of a numerical simulation in capturing the dynamic and unsteady flow effects inside a centrifugal pump due to the impeller-volute interaction. The object of the study is a commercial centrifugal water pump with backward curved blades, which is built within a vaneless single tongue volute. For the numerical simulation, the viscous Navier-Stokes equations are handled with an unsteady calculation and the sliding mesh technique is applied to take into account the impeller-volute interaction. In keeping the unsteady terms of the equations active it is possible to correctly simulate the effects of the blade passage in front of the tongue and both the flow and pressure fluctuations induced. Time averaged numerical results are compared with the experimental performance curve and good agreement is found. The numerical flow analysis allows the study of different variables which are always difficult to measure experimentally. The dynamic variables obtained with the proposed numerical model are compared with the experimental data. In particular, the amplitude of the fluctuating pressure field at the blade passing frequency is successfully captured by the model for a wide range of operating flow rates. Therefore, the main achievement of the work is in providing the modeling possibilities for the prediction of the dynamic interaction between the flow at the impeller exit and the volute tongue. Such effects at the blade passing frequency appear to follow a clear flow rate dependent spatial pattern around the volute.

Unsteady Analysis of Impeller-Volute Interaction in Centrifugal Pump

“…He and Sato [27] also developed a three dimensional incompressible viscous flow solver and obtained satisfactory agreement with well established experimental data. Gonzalez et al [28] also validated the capability of CFD in capturing the dynamics and unsteady flow effects inside a centrifugal pump. In addition, with three dimensional numerical study, Gonzalez and Santolaria [29] able to find a plausible explanation for the flow structures inside the pump that is corresponding with the pressure and torque fluctuating values.…”

Development of new “multivolute casing” geometries for radial force reduction in centrifugal pumps

“…Thus, they employed an inviscid solver to obtain the flow field. Gonzalez, Fernandez, Blanco, and Santolaria (2002) investigated gap variation for a pump with a specific speed of N S = 26. They found that an increase by about 50% of the maximum pressure amplitude occurs where the gap distance is reduced from 15.8% to 10% of the impeller radius.…”

Numerical Identification of Key Design Parameters Enhancing the Centrifugal Pump Performance: Impeller, Impeller-Volute, and Impeller-Diffuser

“…This can be done by accounting for the volute and/or the diffuser in the planning, design, and optimization phases at conditions of design and off-design. Many experimental and numerical studies have been carried out on the liquid flow through a centrifugal pump [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], where the effects of the number of impeller blades on the pump's performance were examined experimentally in [11,12]. The effects of the impeller outlet blade angle on the pump's performance were also investigated numerically [13,14], using a CFD code and experimentally in [15].…”

“…The effects of the impeller outlet blade angle on the pump's performance were also investigated numerically [13,14], using a CFD code and experimentally in [15]. In [16] the dynamic effects due to the impeller-volute interaction within a centrifugal pump were numerically investigated, whereas the effects of the volute on velocity and pressure fields were examined in [17,18]. Additional experimental investigation carried out [19] consisted of measuring unsteady velocity, the pressure and flow angle at the centrifugal pump's impeller outlet, with and without volute casing.…”