Simulation of the unsteady, incompressible flow in a centrifugal pump with vaned diffuser using staggered and collocated grid methods in 2D

摘要

For the design of turbomachines like compressors, turbines, fans, and centrifugal pumps more and more use is made of commercially available flow simulation software. To the authors best knowledge, in all cases discretization schemes based on a collocated grid are used. However, using a collocated grid method, the incompressible Navier-Stokes equations can suffer from odd-even decoupling. The adaptations necessary to suppress odd-even decoupling in incompressible flows result in calculations which are either less accurate or more time-consuming, especially for unsteady flows. In this paper we consider an alternative method based on a staggered-grid approach. The method is ideally suited for calculating unsteady incompressible flow on highly non-uniform block-structured grids. The unsteady flow in a radial pump with a vaned diffuser is calculated in 2D and compared with results obtained with a commercially available code. The time dependent velocity and pressure fields are validated with experimental results available in literature. The comparison shows that the collocated discretization can achieve the same accuracy as the staggered discretization although calculation time is two times larger.