Turbine Engine Lubrication; Cooling and Sealing. Flashcards
What is the primary function of a turbine engine’s lubrication system?
To prevent metal to metal contact.
What are the secondary functions of a turbine engine’s lubrication system? 4
Cooling, cleaning, sealing and the reduction of corrosion.
What type of oil is typically used in turbine engines?
Turbine engines usually use synthetic oils.
What type of oil system is typically used in modern turbine engines, the PRV systems or the full flow system?
The full flow system
Compared to a reciprocating engine, is the oil consumption on a turbine engine high or low?
Low
What type oil pump is usually used in turbine engines?
Turbine engines usually ultilise gear type oil pumps.
Do oil pump driveshafts incorporate a weak shear point, as driveshafts in fuel pumps might?
No
What is the function of a bypass valve?
To open and allow oil to pass, in the event that a filter or heat exchanger becomes blocked.
What is the function of magnetic plugs/chip detectors in turbine engine lubrication systems?
To remove ferrous metal debris and warn of impending gearbox component (gears/ bearings) failure.
How are bearing chambers normally cooled?
By lubricating oil
How are modern turbine blades cooled?
Modern blades are cooled by passing relatively cooler air through and over them.
How do engine designers ensure cooling air does not flow in the reverse direction?
By ensuring a positive pressure gradient between the compressor air and the pressure of the combustion gases.
What are the functions of air seals in a turbine engine? 2
- To control cooling airflow by pressurising labyrinth and carbon oil seals.
- To cool hot section areas.
Do hydraulic seals allow a controlled flow of air across the seal?
No
What type of seal comprises a metal ring housed in a close fitting static groove?
A ring seal
