Characterisation of a refurbished 1½ stage turbine test rig for flowfield mapping behind blading with non-axisymmetric contoured endwalls

Abstract

This paper describes the results, to date, of collaboration between the CSIR (South Africa) and Durham University (UK). Furthermore the paper intends to demonstrate the capability and suitability of a refurbished 1½ stage turbine test rig to performing tests on blading featuring non-axisymmetric endwalls in a lowspeed, rotating environment. The test rig has been refurbished in such a way as to dramatically improve the measurement standards and to provide the highest degree of commonality with Durham University’s equipment to ensure a common research thread. The characterisation of this turbine has revealed reduced power output levels when compared to the design data as a result of the tip vortex flows and an underturning from the rotor as a result of the low Mach numbers. Although the results consistently yield lower power for the contoured rotor it is close to the experimental uncertainty. In addition the use of rapidly prototyped blading has allowed for the manufacture of complex geometries at low cost, but with the addition of some new challenges