Numerical Investigations of Unsteady Flow in a Centrifugal Pump with a Vaned Diffuser

Abstract

Computational fluid dynamics (CFD) analyses were made to study the unsteady three-dimensional turbulence in the ERCOFTAC centrifugal pump test case. The simulations were carried out using the OpenFOAM Open Source CFD software. The test case consists of an unshrouded centrifugal impeller with seven blades and a radial vaned diffuser with 12 vanes. A large number of measurements are available in the radial gap between the impeller and the diffuse, making this case ideal for validating numerical methods. Results of steady and unsteady calculations of the flow in the pump are compared with the experimental ones, and four different turbulent models are analyzed. The steady simulation uses the frozen rotor concept, while the unsteady simulation uses a fully resolved sliding grid approach. The comparisons show that the unsteady numerical results accurately predict the unsteadiness of the flow, demonstrating the validity and applicability of that methodology for unsteady incompressible turbomachinery flow computations. The steady approach is less accurate, with an unphysical advection of the impeller wakes, but accurate enough for a crude approximation. The different turbulence models predict the flow at the same level of accuracy, with slightly different results.

Comparisons RANS and URANS numerical results with experiments in a vaned diffuser of a centrifugal pump

“…Pavesi et al [2008] and the details of wake transport across the rotor were tracked in 56 continuously running facilities thanks to laser techniques (Akin et al, 1994, Eisele et al, 1997 2004, Feng et al ,2007, Benra et al, 2008, Wuibaut et al, 2000, 2006 [Culver et al, 2009, Petit et al, 2013 2002]…”

Numerical Simulation and Performance Prediction of Centrifugal Pump’s Full Flow Field Based on OpenFOAM

“…All boundary conditions for the transient case were consistent with those for the steady-state case except condition (5). The computational domain of the impeller was defined by the "dynamicMeshDict" file according to the "sliding mesh method" [21,22].…”

“…Due to the expandability and openness of source codes, recently some researches have been carried out on the flow field of pump machines by means of OpenFOAM. Petit et al [4,5] and Nilsson [6], respectively, performed steady-state (frozen rotor method) and transient (sliding grid method) simulations on the flow field of centrifugal pumps and hydro turbines, and compared the results with the actual measurement. Xie [7] used 2D and 3D steady-state and transient methods to simulate the flow fields of a low specific speed centrifugal pump.…”

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

“…13 The CFD results can obtain more detailed flow information than experiments, and help us to deeply understand the unsteady flow in hydro turbo machines. Plenty of comparisons [14][15][16][17][18][19] between computational results and experimental data show that CFD is a reliable tool to simulate unsteady flow in hydro turbo machines.…”