Heat Transfer Optimised Turbine Rotor Blades: An Experimental Study Using Transient Techniques

Abstract

Conventionally, high pressure turbine blading is optimized for aerodynamic performance without any film cooling applied to the surfaces of the blades. It is considered that modern boundary layer prediction techniques are now sufficiently accurate to allow the heat transfer to be considered at the profile design stage. Two turbine rotor profiles were designed, each with a heat-transfer-optimised pressure surface, and a detailed experimental study using transient techniques in the Oxford cascade tunnel was made. The results show that significant reductions in pressure surface heat transfer can be achieved by boundary layer optimization without compromising the aerodynamic efficiency of the blades. A description of the profiles is given, together with transfer rate measurements, pressure distribution, and aerodynamic loss measurements (a technique developed to measure aerodymanic loss in a transient cascade is described) and flow visualisation photographs.