Numerical Flow Simulation and Cavitation Prediction in a Centrifugal Pump
                        using an SST-SAS Turbulence Model

Computational Fluid Dynamics (CFD) is used to investigate the hydraulic performance of a centrifugal pump within the electrical submersible pump (ESP) unit in single-phase flow. The geometry consists of a three-stage centrifugal pump with an impeller and a diffuser in each stage. The stage performance is influenced by the inlet and outlet conditions of the stage, and therefore, three stages were modeled. The simulations were run at 3,500 RPM for various flow rates within the operating range. The k-ε turbulence model and the shear stress transport (SST) turbulence model were used to compare the capabilities of the model on performance predictions. Simulations were run in steady and unsteady flow conditions with a single vane and a full pitch model. Hydraulic performance such as efficiency, pump head, and break horse power (BHP) obtained from numerical analysis were compared with the test results to validate the CFD model. The comparison results revealed that the CFD overpredicts the pump head and underpredicts the BHP by 5 to 10%. The discrepancy between measurements and predictions are reasonable because the hydraulic leakage and bearing power losses are not modeled in CFD. The overall predicted efficiency is higher than the measurements because of overpredicted head and underpredicted BHP. Comparing numerical simulations with different turbulent models showed no significant difference between the k-ε model and the SST model. The steady/ unsteady flow comparison also showed similarity in the hydraulic performance near the best efficiency point. For design purposes, steady flow simulation with a single vane and the k-ε model were used to cut computational time.

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Application of Wray–Agarwal Turbulence Model in Flow Simulation of a Centrifugal Pump With Semispiral Suction Chamber

Journal of Fluids Engineering ◽

10.1115/1.4049050 ◽

2020 ◽

Vol 143 (3) ◽

Author(s):

Leilei Ji ◽

Wei Li ◽

Weidong Shi ◽

Ramesh K. Agarwal

Keyword(s):

Experimental Data ◽

Centrifugal Pump ◽

Turbulence Model ◽

Full Range ◽

Flow Characteristics ◽

Flow Simulation ◽

Turbulence Models ◽

Internal Flow ◽

Energy Performance ◽

Operating Conditions

Abstract The Wray–Agarwal (WA) turbulence model is selected to simulate the internal and external characteristics of a centrifugal pump with semispiral suction chamber; the numerical results are compared with the experimental data and computed results predicted by standard k–ε, renormalization group (RNG) k–ε, and shear stress transport (SST) k–ω turbulence models. The results show that the WA model could be effectively used to compute the energy performance of centrifugal pump under full range of operating conditions and gives higher accuracy than other models. Overall, the WA model shows closer similarity to the experimental data and gives more uniform flow field in the impeller region compared to that predicted by other models. In prediction of internal flow fields of the pump, overall the WA model is more accurate and efficient being a one-equation model. The control of undamped eddy viscosity variable R (= k/ω) in WA model does not allow the overestimation of turbulent kinetic energy and turbulent eddy frequency obtained with other models, which leads to its advantage in accurate prediction of both internal and external flow characteristics of centrifugal pump.

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