15.10 Lubrication Systems Flashcards
(31 cards)
What is the function of the lubrication system?
-distribute oil to bearing compartments and gearboxes
What types of sump pumps can be used?
Wet and dry
How does a dry pump differ?
They use an external supply tank
Does the full flow system have the ability to regulate oil pressure?
No
What influences oil pressure?
Temperature due to Low viscosity
What drives the supply pump?
The N2 rotor system via the gearbox
What will leakage in the oil system lead to in a full flow system?
Increase in total flow area and decrease in oil pressure
The pressure relief valve installed between the delivery side and suction side serves what function in a full flow system?
Stopping too excessive pressure
What is the difference with a constant pressure system?
AKA regulated pressure system
It has a pressure regulating valve which holds pressure regardless of idle or max speed on the N2 rotor
What are the disadvantage of full flow system?
-The system requires a relatively high oil pressure when engines are idle leading to very high pressure at higher speeds
-a significant rise in oil temperature will occur after a power reduction
What are the advantages of the full flow system?
It is simple and requires little maintenance
In the exhaust turbine bearing what methods are used to cool and why is it critical?
-Air and oil in some cases
The oil is usually passed through a cooler
-High heat
What is the oil container constructed from?
Aluminium allow and silicone for fire resistance
What are the two ways to fill oil?
Gravity and pressure
What are the key components of an oil tank?
-Check valve to prevent spills
-Scupper to catch spills and drain overboard
-Strainer
What are the most common types of oil pump?
Gear (most common)
Gerotor
How can capacity be altered on a gerotor pump?
Varied size of the elements
Where is the pressure regulating valve located?
In the pressure side
When are oil pressure relief valves especially important?
When there is a cooler in the system
Where is the last chance filter located?
Before each nozzle
What are the two types of oil cooler?
Fuel and air
What is a hot tank system?
When the cooler is in the the supply line
What is the function of the breather?
Removes air from scavenge oil through a de aerator
What are the two types of monitoring system transmitters?
Capacitance and reed switch
