thermodynamic combustion cycle
Name the 4 part process cycle of the OTTO cycle
- Isentropic compression
- Heat addition
- Isentropic expansion
- Exhaust
What is the compression cycle of an engine called?
Brayton cycle it is a continous flow engine
Name the 2 types of gas turbines
- Axial (expensive)
- Centrifugal (Cheap)
What is the good about the gas turbine?
- Cheap to run
- High power
What are the operating considerations of a GT?
- Fuel economy
- Engine hour economy
What are the requirements of a compressor?
- Large amount of air
- Efficient
- Stable
- Compact
What is the difference between Axial & Centrifugal compressors?
- Centrifugal changes air direction
- Axial smaller
- Centrifugal easier to fix
How does an axial compressor work?
Draws air in along a torturous path through rotating blades to increase pressure.
Name 3 types of compressor blades
- Solid root
- Fir tree root
- Dovetail Root
Name 3 types of seals on the lub oil system
- Lip
- Mechanical
- Labrinth
Change unit
In the CU oil system the most common elements for lubrication are?
- Bearings
- Pumps
- Filters
- Coolers
- Tanks
Name 3 uses of air bleeds.
- Cooling
- Sealing
- Bearing mist lub
What does air bleed do?
Directs air to maintain optimum engine temp
Name 2 uses for the High pressure shut off cock (HPSOC)
- Shut off fuel
- Recirc fuel
Types of combustion chambers
What are the 3 methods of combustion in Gas turbines?
- Can-annular
- Annular
- Radial
Name the requirements for a combustion chamber
- Efficient
- Easy ignition
- Clean exhaust
- Stable temp
Fuel injector
What is the purpose of the Burner?
Deliver atomised fuel to combustion chamber
How is a GT started?
A HV spark igniter
Describe High energy ignition unit
Mounted on the module & convert LV DC to HV
Describe the Turbine design layout
- LP & HP casings made from titanium
- Nozzle guide vanes direct high temps
- HP turbine drives the HP compressor
What do Splitter/silencers do?
- Reduces noise
- Reduces turbulance
Name the 4 types of fire supressant used
Under control of MEO1 ,key switch box local to module
- Halon
- 1301 BTM
- CO2
- Water mist/nitrogen
Why are GT cleaned?
- Remove Corrosive deposits
- Extend life
Describe 2 types of borescope
- Rigid-Allows access to remote areas in straight line
- Flexible-Use fibre optics
