Gas Turbines Flashcards
What is the definition of a working fluid?
Any liquid or gas that can do by expansion or flow
What is the definition of a turbine
A bladed spool designed to rotate when acted on
Process of induction
Air is drawn into the intake trunking
LP compressor process
Air drawn in to the axial flow compressor. This used divergent passages within the rotor blades to increase the pressure of the air. Thanks air is continuously compressed as it travels
HP compressor process
Air leaving the LP compressor enters the HP and the same process is repeated but slowing down the air which raises the pressure
What is the pressure level created by the compressors
19:1
What is the combustion process
The combustion chamber on the GT mix the compressed air and atomised fuel. An ignitor provides a high tension spark to ignite the air and fuel mixture
Not all air is used what does it do
Majority of air initially for combustion cools the chamber and is burnt further down and expands becoming the working fluid
Combustion can air use
Primary: 15% atomise fuel
Secondary: 10% complete combustion of fuel and provides a layer of air between the fuel and flame tube preventing impingement
Tertiary: 75% becomes the working fluid
HP/LP Turbines process
Hot expanded gases leave combustion chambers are the driving force for turbines
These turbines drive the compressors connected by their own shaft
How much energy is lost in the turbines
A third
What is used as lubrication to the turbine
Ox22
What are magnet chip detectors used for
Fitted into the scavange oil system to collect ferrous debris
How often are the mag chip inspected
24 hourly by propulsion section
What’s the purpose of a gas turbine
To convert heat energy into rotary motion for ship propulsion
