Transient Analysis of Ceramic Vanes for Heavy Duty Gas Turbines

Abstract

A transient analysis of thermal stresses in ceramic stationary vanes is presented. The application of ceramics to gas turbines represents an alternate approach for designers to increase operating temperatures. Highly dense silicon carbide and silicon nitride vanes are analyzed for application in a heavy duty gas turbine. The most severe thermal loading condition for this turbine is imposed on the vanes. The purpose of this paper is to present the effect of ceramic material, vane size, air foil, cross-sectional geometry, and gas inlet temperature on the thermal response of ceramic vanes.

Design and Analysis of a Ceramic Stator Vane

“…Following the design guidelines for brittle components that are to operate uncooled in a rapidly changing temperature field, a threepiece assembly, airfoil, and upper and lower end caps emerged as a candidate to replace the cooled, one-piece metal first-stage stator vane commonly used. The sizing of the airfoil was determined on the basis of the two-dimensional analysis of Schaller and Rahaim (1). A comparison of the maximum tensile stress with the observed tensile strength of Si 3 N 4 pointed to an airfoil cross section scaled down to half the size of the metal vane airfoil as a reasonable compromise with the airfoil height-towidth ratio and the total number of vanes (double) needed.…”