Engine Lubrication System

Abstract

Within a turbofan engine the lubrication system serves several functions essential to the safe and reliable operation of the engine. These functions are:

• Lubrication of the rotor bearings

• Lubrication of the gears and bearings of the gearboxes

• Cooling of the bearings especially in the turbine area

• Removal of the contaminants from the lubricant

• Support of the sealing of the carbon bearing seals

• Supplying of a squeeze film between the bearing outer races and their housings for oil dampened bearings. Oil damping dampens the transmission of dynamic loads of the rotors to the casings. This feature reduces the vibration levels and the fatigue loads for the casings.

The lubricant reduces friction by replacing solid friction with fluid friction. Thus it must be able to provide a stable film between metal surfaces moving relative to each other at high relative velocities under high loads and high temperatures.