Ceramic Turbine Joint Structure with Metal Shaft for Aircraft Gas Turbine Engine

In recent years, the turbine inlet temperature becomes higher and higher to grow up the power of gas turbine engines in recent years. So hot section parts, such as combustor and turbine, are generally designed as cooling structures made of heat resistant metals. On the other hand, the high temperature properties of the ceramic materials offer the potential of higher turbine operating temperatures with no cooling techniques and therefore the ceramic components with higher temperature limits are becoming more attractive. In this study, the ceramic turbine is applied in the aircraft gas turbine engine. For gas turbine engines, tight fit configuration is generally taken for the joint structure between a ceramic turbine and a metal shaft, and its constrain force transmits the drive torque and withstands the thrust force acted on the turbine. Since the constrain force is decreased due to the difference of the thermal expansion rate between ceramic and metal at the high temperature condition, the initial constrain force should be taken large enough considering the decrease of the constrain force. But if the fit is too tight, the ceramic turbine will be cracked at the jointing process. So an optimization is necessary to balance these