Numerical simulation of high-swirl flow in axial turbine stage

Abstract

This article deals with numerical modelling of flow in an axial turbine stage with prismatic blades which are not equipped with shroud. In this case flow through a radial gap above and below ends of blades leads to generation of strong secondary vortices which significantly affect an effciency of the stage. The main attention is paid to turbulence modelling. Besides a linear model based on Boussinesq approximation a nonlinear model based on higher order closure formula is used. Also an effect of a curvature correction is taken into account.