Keiichiro Watanabe

Development of Ceramic Gas Turbine Components for the CGT301 Engine

NGK Insulators, Ltd. (NGK) has undertaken the research and development on the fabrication processes of high-heat-resistant ceramic components for the CGT301, which is a 300kW recuperative industrial ceramic gas turbine engine. This program is under the New Sunshine Project, funded by the Ministry of International Trade and Industry (MITI), and has been guided by the Agency of Industrial Science & Technology (AIST) since 1988. The New Energy and Industrial Technology Development Organization (NEDO) is the main contractor.The fabrication techniques for ceramic components, such as turbine blades, turbine nozzles, combustor liners, gas-path parts, and heat exchanger elements, for the 1,200°C engine were developed by 1993. Development for the 1,350°C engine has been underway since 1994. The baseline conditions for fabricating of all ceramic components have been established.This paper reports on the development of ceramic gas turbine components, and the improved accuracies of their shapes as well as improved reliability from the results of the interim appraisal conducted in 1994.Copyright

Development of Silicon Nitride Radial Turbine Rotors

To examine the possible use of ceramics as key components for automotive gas turbines, studies were conducted on radial turbine rotors made of SN-88, a newly developed, heat resistant silicon nitride. The flexural strength of MOR bars cut from various portions of the rotor was measured, and three rotors were subjected to cold spin burst testing. Time dependent strength of the rotor at high temperatures was estimated by static fatigue rupture data of tensile test pieces at temperatures up to 1400°C for up to 1000hrs. The allowable stress at an arbitrary temperature and time to failure were explained well in terms of the Larson-Miller parameter. High temperature durability was also evaluated by hot-gas spin tests. The results of these tests suggest the possibility of fabricating reliable ceramic components which might enable the realization of ceramic gas turbine engines.