Thermal Expansion Accommodation in a Jet Engine Frame

Abstract

A prime consideration in the design of turbomachinery hot section structural frames is thermal fatigue caused by differential heating of the frame basic structural elements. This paper describes the general thermal deflection pattern of a frame and some design features which can accommodate this relative expansion without excessive stress. Also discussed is a particular combination of design features which provide increased tolerance for thermal expansion while maintaining a large mechanical stiffness as is often required for a high bypass ratio turbofan engine application. This unique combination of frame design features, developed under NASA contract NAS3-20643 to NASA-Lewis Research Center with Mr. Carl C. Ciepluch as the Lewis Project Manager, represents a significant contribution to state of the art frame design.