Numerical and Experimental Investigations Into the Aerodynamic Performance of a Supersonic Turbine Blade Profile

Abstract

This paper presents results of numerical and experimental investigations in order to validate the aerodynamic performance of a supersonic tip section profile which will be used in the next generation low pressure steam turbines. The tip section profile design was derived using the “design-by-analysis” method with respect to the supersonic inlet and outlet conditions. The measurements were taken in the high speed cascade wind tunnel of Siemens Power Generation in Mu¨lheim, Germany. The outlet Mach number ranged from Ma2 = 1.2 to Ma2 = 1.8, where one subsonic and one supersonic inlet Mach number were set. The Reynolds number was Re2 = 4.5 E05 and superheated steam was used as a working medium. As a very important geometrical parameter, the pitch-to-chord ratio was varied for different aerodynamic parameters. The experiments include detailed measurements of the blade surface pressure distribution, flow visualization measurements using the Schlieren technique, wake flow measurements employing pneumatic probes as well as side wall pressure measurements. The computational investigations were carried out using an inviscid Euler method coupled with a fast viscous integral boundary-layer method. This paper is organized into two main areas including firstly, a description of the experimental set up, secondly, the discussion and comparison on the results of experimental and numerical investigations.