Development and Evaluation of Ceramic Components for Small Gas Turbine Engine
The 300kW class CGT project in Japan administered by the New Energy and Industrial Technology Development Organization (NEDO) under the sponsorship of the Ministry of International Trade and Industry (MITI) was completed in March, 1999 after 11 years. The purposes of the project were energy conservation and environmental protection. The CGT302 group of the CGT project, in cooperation with Kawasaki Heavy Industries, Ltd. (KHI), achieved all of the project targets. The targets included the turbine inlet temperature (TIT) of 1350°C, a thermal efficiency of 42%, emissions below 70ppm, and a 1000hr engine durability test carried out at 1200°C1). To achieve such targets Kyocera has been developing various ceramic components such as large-sized stationary components, monolithic rotors and ceramic shrouds with abradable seal. These components have been successfully fabricated with SN281 and SN282. Damage was caused as a result of contact between the turbine blades and the shrouds. In order to reduce such damages, the shroud has been modified to incorporate an abradable material newly developed for this application, and an engine test has been carried out successfully with no damage. For practical use, the greatest concern is the durability of ceramic components. The ceramic components were evaluated in a 1000hr long term durability test. There were, however, some troubles for the GGT rotors and the engines were broken when the durability tests were carried out. Finally, only the combustor survived the 1000hr engine test at 1200°C. The material characteristics of the survived combustor along with other broken components were analyzed after the long-term engine tests. The test results revealed no obvious change in mechanical properties nor in blade shape. In this paper, the development of selected components is presented along with the evaluation results of components exposed to the long-term engine tests.