Application of Nonseries Airfoil Design Technology to Highly Loaded Turbine Exit Guide Vanes

Abstract

Common practice in turbine exit guide vane design is to utilize standard series airfoils. This paper presents results of an analytical and experimental program where the performance of a series airfoil is compared to an equivalent nonseries airfoil. The nonseries airfoil is designed by selecting airfoil camber and thickness distributions which reduce the potential for suction surface separation. Airfoil pressure distribution and boundary layer analysis techniques are used to identify the optimum nonseries airfoil. Back-to-back annular cascade tests of equivalent series and nonseries airfoils substantiate analytical predictions. The tests indicate nonseries airfoil design technology enables diffusing airfoils to be designed with improved performance at higher loading levels than presently obtainable with equivalent series airfoils.