15.8 - Bearings and Seals Flashcards
Which direction is axial load?
Thrust direction
What are the two main frames of a jet engine which support the internal bearings and transfer the load to the pylon?
Fan frame
Turbine frame
What loads are ball bearings designed for?
Radial or thrust loads (axial)
What are the three types of roller bearings?
Cylindrical
Spherical
Tapered
What is the benefit of using roller bearings over ball bearings?
Better radial loads due to increased surface area contact
What are the two types of seals used in a jet engine bearing?
Labyrinth or carbon rubbing
What are interstage seals used for?
To prevent gas leaking into cavities between the turbine discs
What type of bearing will take thrust loads axially?
Ball bearings
What are rolling elements of bearings usually made from?
Steel alloys
What types of oil seals are used in the main bearings?
Labyrinth and/or carbon rubbing
As well as oil, what can labyrinth seals also be used for?
Air seals.
They can control the outflow of air at the turbine
Where would you find squeeze film bearings in an engine?
On the LP compressor section
What is the main purpose of a squeeze film bearing?
It minimises the effects of vibration
What is the purpose of a pressure balance seal?
It ensures the location bearing is adequately loaded throughout the engine thrust range
What would happen to oil indications if a bearing seal failed?
High oil consumption would be seen
