Ceramic Stationary Gas Turbine Development Program — Design and Test of a First Stage Ceramic Nozzle

Abstract

The goal of the Ceramic Stationary Gas Turbine(CSGT) Development Program, under the sponsorship of the United States Department of Energy (DOE), Office of Industrial Technologies (OIT), is to improve the performance (fuel efficiency, output power, exhaust emissions) of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Phase II of this program includes detailed engine and component design, procurement and testing. This paper will review the design and test of the first stage ceramic nozzle for the Centaur 50S engine. For this test an uncooled monolithic ceramic nozzle made from SN-88 silicon nitride(NGK Insulators Ltd.) was used. A major challenge in the successful introduction of ceramic parts into a gas turbine is the design of the interface between the ceramic parts and metallic components. The design and attachment of the ceramic nozzle was greatly influenced by these considerations. Metallic components in the stationary structure of the turbine have been added or redesigned to retrofit the ceramic nozzle into the all metallic Centaur 50S engine. This paper will also discuss special handling and assembly techniques used to install the ceramic nozzle into the engine. Trial assemblies were used in the engine build process, this proved most beneficial in identifying problems and reducing the risk of damage to the ceramic nozzles. Assembly techniques were designed to reduce assembly loads and to eliminate blind assemblies. Before installing any ceramic nozzles into the engine they were first required to successfully pass both mechanical and thermal proof tests. Details of these proof tests and the final full load engine test will be described in this paper. The engine test was run at a turbine rotor inlet temperature(TRIT) of 1010°C. Total number of engine starts was six, and the total run time was approximately 10 hours.