Which load arises from compression and tension between stationary cases and the rotor system due to thermal expansion?

• A. Weight Of The Rotating Mass
• B. Axial Forces From Power Changes And Thrust Loadings
• C. Compression And Tension Loads
• D. Gyroscopic Effect

Answer: (C)

When parts heat up, they don’t all expand by the same amount. The stationary outer cases and the rotor can grow differently, and because the rotor is constrained by the casing, this differential thermal expansion creates axial stresses along the shaft. Some regions are driven into compression as the rotor pushes against the case, while other regions experience tension as the parts are restrained from freely expanding. These axial stresses are the compression and tension loads caused by thermal expansion. Other options describe loads from gravity, changes in thrust or power, or gyroscopic effects, which are not about thermal growth and the resulting axial stress between rotor and case.