The Measurement and Prediction of Boundary Layer Entropy Generation Rate

In this paper hot wire measurements of the boundary layer velocity profiles at discrete locations along the suction surface of a turbine blade profile are presented. The measured aerodynamic data is transformed into thermodynamic data by way of the entropy function for the investigated Reynolds numbers of 76,000, 120,000 and 185,000 based on inlet velocity and chord length. The measurements are compared with predictions obtained from a commercially available computational fluid dynamics code and a prediction technique based on semi-empirical correlations. Interestingly the accuracy of the relatively simple semi-empirical technique, in respect to entropy production, is found to be comparable to that of the time consuming CFD code over the range of Reynolds numbers tested.