The Working of Turbine Engine Lubrication Systems

As aircraft burn large quantities of fuel during flight, the engines generate an intense amount of heat that spreads to the surrounding components. While half of this heat is flushed out as exhaust, the other half remains absorbed by the engine, posing a problem that could lead to damage of parts or even failure of the system as a whole. To mitigate this issue, aircraft utilize lubricant cooling systems to reduce the heat of the engine and its surrounding parts.

For standard gas turbine engines, both wet and dry sump lubrication systems can be utilized. While the wet sump has lubricant stored within the engine, the dry sump utilizes an external tank. Alongside the heat created through combustion, the friction between metal components also generates heat. Lubricating oil is thus used to provide a protective film layer on parts, replacing metal to metal friction with fluid friction. By reducing the friction between engine parts, efficiency of the system is also improved.

The lubricating oil acts somewhat like a sponge, absorbing the heat from the component it is coated on. After cooling the component, the oil transfers the heat to the oil cooling system in which it is cooled by a radiator. While cooling and lubricating the engine, the oil also acts as a cleaner and protector of the engine system. As the oil passes through components, it picks up and collects various particles that may damage parts, bringing them to a filter where they are then removed from the system. By coating the various parts in lubricant, the oil also serves as a temporary shield from corrosion.

While oil accounts for nearly half of the cooling in a system, some aircraft also utilize air cooling alongside the lubricant. By using captured bleed air, the turbine disks, blades, and vanes reduce their radiating heat and cool down. With the use of air alongside an oil cooling system, the amount of oil needed for cooling the engine and surrounding components is reduced.