Compression Structured Ceramic Turbine Rotor Concept

Abstract

This paper summarizes highlights of a design study conducted by the General Electric Company, Evendale, Ohio, to evaluate a “Novel Ceramic Turbine Rotor Concept” (AF Aero Propulsion Laboratory Contract Number F33615-78-C-2041). The “Novel” feature of this ceramic turbine rotor design involves maintaining the ceramic rotating components in a state of compression at all operating conditions. Many ceramic materials being considered for gas turbine components today display compressive strengths ranging from three to eight times their tensile strengths. Utilizing the high compressive strengths of ceramics in gas turbines for improving ceramic turbine structural integrity has interested engineers in recent years as evidenced by a number of patents and reports issued on Compression Structured Ceramic Turbines with one as early as 1968.^1,2,3,4 Turbine blades designed to be in compression could greatly enhance the reliability of the ceramic hot section components. A design of this nature was accomplished in this contractual effort by using an air-cooled, high strength, lightweight rotating composite containment hoop at the outer diameter of the ceramic turbine tip cooling fins which in turn support the ceramic turbine blades in compression against the turbine wheel. A brief description of the detailed structural and thermal analysis and projected comparable performance between the Compression Structured Ceramic Turbine and an equivalent air-cooled metallic baseline turbine is given.