Numerical calculations of a turbine volute using a 3-D navier-stokes solver

Abstract

The turbine volute is a complex flow device, about which a few papers on both measurements and CFD predictions have appeared. The main reasons for the difficulties being the complicated geometry which hinders measurements to be taken by both intrusive and non-intrusive techniques, and makes the numerical predictions difficult. In this paper, the complex three-dimensional flow through a turbine volute with non-symmetric circular cross-section is studied by using a 3-D Navier-Stokes solver which has been developed by the authors. In this solver, the fully 3-D Reynolds averaged N-S equations coupled with high Reynolds number κ-ε turbulence model together with the wall function under arbitrary curvilinear coordinate system are solved. The Semi-Implicit Method for Pressure-Linked Equations (SIMPLEC algorithm) with the non-staggered grid arrangement is used. In order to eliminate the decoupiing between the velocity and pressure under non-staggered grid system, the physical covariant velocity component is selected as dependent variable in momentum equations and a momentum interpolation approach is employed. The validity of the free-vortex assumption is reviewed. The computation results are compared with a set of experiments performed previously by one of the authors. The flow features in the volute are discussed.