Influences of Manufacturing Tolerances and Surface Roughness of Blades on the Performance of Turbines

Abstract

The costs of the manufacturing of turbine blades are very dependent on the manufacturing tolerances and the quality of the surface. A good performance of a turbine needs a certain smoothness of the surface and small tolerances. For an optimisation of the costs it is necessary to know the influences of roughness and tolerances on the performance of a turbine. In our institute measurements were carried out with thinned and thickened blades mounted in a turbine, which represents different manufacturing tolerances. In addition measurements on a turbine with roughened blades were done. From these measurements a conclusion on the aerodynamical and thermodynamical behavior of the turbine is obtained. The paper gives a summary of the measurements and shows how the performance of a turbine is affected by the roughness and the profile tolerances.