Surface-Curvature-Distribution Effects on Turbine-Cascade Performance

Abstract

The manufacturing accuracy of turbine blades is judged by the difference between the designed and produced location of each point around the airfoils. This paper shows that the design-point and off-design-point aerodynamic and heat transfer performance of turbine cascades is affected significantly by the distribution of curvature along the suction and pressure surfaces, and less significantly by the exact location of each one point. The performances of turbine blades designed with continuous slope of curvature distribution, and with slight discontinuities in the slope of curvature, are examined using a computer program for various design and off-design flow conditions. The accuracy of the computations is checked by comparison of computational results with cascade solutions of known experimental output. It is concluded that the accuracy in local curvature is Just as important as the design-location-by-manufactured-location accuracy of each point on the blade.