Ceramic Gas Turbine Technology Development

Abstract

Under the U.S. Dept. of Energy/National Aeronautics and Space Administration (DOE/NASA) funded Ceramic Turbine Engine Demonstration Project, formerly the Advanced Turbine Technology Applications Project (ATTAP), AlliedSignal Engines is addressing the remaining critical concerns slowing the commercialization of structural ceramics in gas turbine engines. These issues include demonstration of ceramic component reliability, readiness of ceramic suppliers to support ceramic production needs, and development of ceramic design technologies. The AlliedSignal/Garrett Model 331-200[CT] Auxiliary Power Unit (APU) is being used as a ceramics test bed engine. The first-stage turbine blades and nozzles were redesigned using ceramic materials, employing the design methods developed during the earlier DOE/NASA-funded Advanced Gas Turbine (AGT) and ATTAP programs. Ceramic engine components have been fabricated and are now being evaluated in laboratory engine testing. The fabrication processes for these components will provide the framework for a demonstration of manufacturing process scale-up to the minimum level for commercial viability. The laboratory engine testing is helping to refine the component designs and focus the development of ceramic component technologies. Extended engine endurance testing and field testing in commercial aircraft is planned to demonstrate ceramic component reliability. Significant progress has been made during 1994. An engine with ceramic turbine nozzles was successfully operated and engine tests in the laboratory are continuing to gather useful data. An engine equipped with ceramic blades was also tested, but blade fractures occurred, interrupting operation. An extensive investigation has identified possible vibration and contact problems. Investigative evaluation efforts are continuing to identify the problem source and determine go-forward plans for ceramic blade development. Component design technologies have progressed in the areas of modeling particle impact pulverization, development of a ceramic hot corrosion environmental life model, and methods for evaluating ceramic contact damage. The planned ceramic manufacturing scale-up was initiated with two ceramics vendors, Norton Advanced Ceramics (East Granby, CT) and AlliedSignal Ceramic Components (Torrance, CA). The scaleup demonstration program is emphasizing improvement of ceramic processing yields and increased production rates. Work summarized in this paper was funded by the U.S. Dept. of Energy (DOE) Office of Transportation Technologies, as part of the Turbine Engine Technologies Program, and administered by the NASA Lewis Research Center, Cleveland, OH under Contract No. DEN3-335.