Lubrication Chapter 9 Overview

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Questions and Answers

What is the primary function of magnetic plugs in the scavenge side of the oil system?

To maintain oil temperature during operation

To filter out large particles from the oil

To lubricate the bearings more effectively

To collect ferrite debris from bearing chambers (correct)

Where are coarse strainers typically located in an oil lubrication system?

At the outlet of the water tank

Within the engine block

At the entry point of the oil pumps

At the oil tank outlet or before the oil pumps (correct)

What is a key feature of the oil pump drive-shafts in an engine?

They are designed to ensure continuous oil supply even under damage. (correct)

They allow for easy replacement without engine shutdown.

They incorporate a weak shear neck to protect against damage.

They reduce the pressure during normal operation to save oil.

Which filter type is considered a 'last chance' filter in the oil lubrication system?

Thread-type oil filter Signup and view all the answers

Which component is used in a Pressure Relief Valve system to manage oil flow?

A spring-loaded valve. Signup and view all the answers

What method is typically used for cleaning cleanable filters?

Using traditional hand cleaning with solvent Signup and view all the answers

What is the primary function of the Fuel-cooled Oil Cooler?

To facilitate the transfer of heat from oil to fuel. Signup and view all the answers

What should happen if the level of contamination on the filter exceeds manufacturer limits?

The oil must be drained, re-serviced, and the engine inspected Signup and view all the answers

How do gear pumps function within an oil pump assembly?

Through intermeshing steel gears that create pressure. Signup and view all the answers

What distinguishes the air-cooled oil cooler from the fuel-cooled oil cooler?

The cooling medium employed—air versus fuel. Signup and view all the answers

Which type of oil is commonly used in modern gas turbine engines?

Synthetic oil such as Mobil jet type II Signup and view all the answers

What is the purpose of the oil pump's assembly integrating both supply and scavenge pumps?

To ensure efficient circulation of oil within the system. Signup and view all the answers

How is the oil quantity typically monitored in an aircraft engine?

Using a sight glass or cockpit gauge Signup and view all the answers

What color is the warning for low oil pressure in aircraft engines?

Red Signup and view all the answers

What is a significant characteristic of the magnetic chip detector in an engine?

It detects particulate contamination in the oil. Signup and view all the answers

What is the purpose of fitting a 'pop up indicator' on a filter housing?

To provide a visual warning of a partially blocked filter Signup and view all the answers

What additional feature is essential for an efficient lubrication system?

Having a means to drain and replenish the lubrication system. Signup and view all the answers

In which scenario would the oil pump failure most critically affect engine operation?

At high speeds requiring maximum oil flow. Signup and view all the answers

What is a primary function of the lubrication system in a turbine engine?

Providing lubrication and cooling for gears and bearings Signup and view all the answers

What happens to the magnetic plug during maintenance inspection?

It is removed without oil loss Signup and view all the answers

Which characteristic is essential for aviation lubricants at high altitudes?

Low volatility to reduce evaporation Signup and view all the answers

What is the main advantage of using a dry sump lubrication system in modern turbine engines?

It enables effective separation and management of oil with pressure and scavenge systems Signup and view all the answers

Which system is considered the oldest design for lubrication in engines?

Wet sump lubrication system Signup and view all the answers

What is one of the critical requirements for aviation lubricants regarding temperature?

They require a wide temperature range Signup and view all the answers

What does oil damping do in the context of engine lubrication?

Reduces vibration in moving parts Signup and view all the answers

What aspect of oil is crucial to protect non-corrosion resistant materials in a lubrication system?

Excellent film strength to protect surfaces Signup and view all the answers

Which aspect of the lubrication system directly impacts the cooling of hot engine parts?

The method of lubrication provided Signup and view all the answers

What results from the cleaning function of the lubrication system?

Removal of metal particles to prevent damage Signup and view all the answers

What is a significant disadvantage of a wet sump lubrication system?

It is not suitable for modern high-performance engines Signup and view all the answers

What role does the pressure relief valve serve in a full flow oil system?

Returns excess oil to the supply pump Signup and view all the answers

Which component is immediately after the oil pump in the lubrication system operation?

Main oil filter Signup and view all the answers

What is the primary function of the Magnetic Chip Detector in the oil system?

To remove ferrous metal chips from the oil Signup and view all the answers

How does the deoiler contribute to the functioning of the oil system?

By removing oil mist from the breather air Signup and view all the answers

What is the purpose of the oil temperature sensor in the scavenge line?

To measure oil temperature prior to returning it to the tank Signup and view all the answers

In what sequence does oil flow from the tank to the engine in the lubrication system?

Pressure pump → Main oil filter → Fuel oil cooler Signup and view all the answers

What determines the size of the pressure pump in a full flow oil system?

The flow required at maximum engine RPM Signup and view all the answers

What happens to the oil if the pressure before the main oil filter exceeds the set pressure?

It is returned to the oil tank through the pressure relief valve Signup and view all the answers

Which component distributes oil to the bearing compartments and gearboxes?

Manifold Signup and view all the answers

What is the correct function of the scavenge line in the oil system?

It removes used oil from compartments Signup and view all the answers

Study Notes

Chapter 9: Lubrication

Lubrication System Requirement: Provide lubrication and cooling for all gears, bearings, and splines. It must also collect foreign matter.
Lubrication System Function: Protecting lubricated components from corrosion. Oil must function without significant deterioration.
Turbine Engine Lubrication Purpose: Lubricate mating parts to reduce friction and wear, clean moving parts, cool hot components, damp oil for vibration reduction.

Introduction

Introduction to Lubrication System: Key facts about the system.
Requirement of Lubrication System: The necessary functions of the system.
Types of Oil System: Different types of oil systems.
Operation of Oil System: How the oil system functions.
Components of Oil System: All components of the system.
Important Facts on Oil System: Key information and facts about the system.
Recap: Summary of the key information discussed.

Wet Sump Lubrication System

Wet Sump System: The oldest design, less common now. Oil is kept within a sump, partially or fully immersing lubricated engine parts.

Dry Sump Lubrication System

Modern Turbine Engine: Axial flow configuration often utilizes this system.
Subsystem Components: Includes Pressure, Scavenge, and Breather Vent.
Operation: Oil supplied by a pump and returned to tank by scavenge pumps, by pressure.

A Full Flow Type Oil System (Dry Sump)

Oil Flow Rate: Achieved by dispensing oil based on maximum RPM. Excess oil returned via pressure relief valve to the main supply pump.
Pump Size: Determined by flow requirements at maximum engine speed.

Operation of Oil System

Operation (Supply): Oil flows from tank to pressure stage and main filter. Excess pressure bypasses oil filter and returns to the tank. Oil further passes through heat exchangers and then manifold to the bearing compartments and gearboxes.
Operation (Scavenge Line): Oil removed from compartments and gearboxes by scavenge pumps. Magnetic chip detector helps remove ferrous metal chips from bearings. Then it flows to Electric Magnetic Chip Detector and Oil Temperature Sensor before returning to the Oil Tank.
Operation (Breather Line): Oil mist removed from the breather air by a centrifugal filter. Oil then flows to tank and breather air is vented overboard. Oil mist at the LP Turbine is flushed out from the exhaust.

Components of Oil System

Oil Tank: Usually mounted on the engine, a separate unit, but can be part of the external gearbox. It must allow for draining/replenishing. A sight glass or dipstick needed for checking levels.
Pump Assembly: Vital for engine operation. Drive shafts not weak; used for continuous oil supply, regardless of damage. Often combines supply and scavenge pumps. Gear type or vane type pumps are used to maintain consistent and required pressure.
Gear Type Pump: Pair of intermeshing steel gears in a close-fitting aluminum casing. Oil drawn in when rotated and carried to the outlet. Often for feed pumps and/or scavenge pumps.
Other Pump Types (Vane type): Components like oil inlet, sliding vane, rotor, and eccentric rotor all contributing to oil pressure and transfer.
Pressure Relief Valve System: Oil flow to the bearing chamber is limited by pressure in feedline. Uses a spring-loaded valve, which directs excess oil back to the tank or pressure pump inlet.
Fuel-cooled Oil Cooler: Uses fuel to cool down oil, with a matrix and baffle plates to direct oil flow. Large number of tubes used to transfer heat from oil to the fuel.
Air/Oil Heat Exchanger: Utilizes air to cool the engine oil.
Air-cooled Oil Cooler: Uses atmospheric or ram air to cool engine oil, similar to fuel-cooled coolers but using the outside air.
Centrifugal Breather: Removes oil mist from breather air, filters the mixture, and vents via the overboard vent.
Magnetic Chip Detector: Magnetic plugs that collect ferrous debris from oil to provide warning of bearing or spline failure without inspecting the filters. Easily removable and reused.
Filters: Used to keep foreign matter from circulating through the lubrication system. Strainers placed at oil tank and inlet in oil pumps. A fine filter is fitted at the pump to keep out small particles that would block feed channels.

Important Facts on Oil System

Engine Oil Type: Modern gas turbine engines utilize synthetic oil (e.g., Mobil jet type II oil, Exxon 2380), for lubrication.
Tank Inspection: The oil tank is inspected 10 minutes after engine shutdown and filled up to the neck.
Oil Level Check: Oil quantity can be read from a sight glass or gauge in the cockpit, or via LED engine display.
Critical Warnings: Low oil pressure and high oil temperature are critical warnings requiring immediate engine shutdown.

Recap

Purpose of Lubrication: Key requirements and principles of lubrication.
Comparison of Systems: Differing functions between wet and dry sump systems.
Schematic Explanation: Functionality of components in the full lubrication system.
Critical Operational Facts: Crucial operational processes and warnings.

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Description

Explore the key concepts of lubrication systems in this quiz based on Chapter 9. Learn about the requirements, functions, and types of oil systems, as well as the operation and components involved. This comprehensive overview will enhance your understanding of lubrication in turbine engines.