The document discusses the components and workings of a gas turbine engine. It describes the main components as a compressor, combustion chamber, and turbine. The compressor increases the pressure of air taken in, the combustion chamber mixes and burns the compressed air with fuel, and the turbine extracts energy from the expanding gas to power the compressor and provide output power. Gas turbines work on the Brayton cycle of continuous combustion of fuel to power rotation and can have single or multi-shaft configurations.

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Chapter 4
A gas turbine is a type of internal combustion engine. Used in application such as:
• Locomotives
• Power generation
• Aircraft propulsion
Dr.Khaled S. Al-Zahrani
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2. 11/20/2011
Gas turbine consist of:
1- Compressor:
A mechanical device that increases the pressure of a
gas by reducing its volume.
1. 1 The reciprocating air compressor
• Two stroke engine
• No camshaft
• Pressure differential operated valves
• Very high compression pressure
• Intermittent flow of air (-ve)
Dr.Khaled S. Al-Zahrani
1.2 Rotary air compressors
• Centrifugal
• The axial-flow
• The positive displacement
• Continues flow
• Deals with large quantity of air
• Moderate to high pressure range (10:1)
• High speed up to 30000rpm
Dr.Khaled S. Al-Zahrani
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2- Combustion Chamber:
A chamber where the air and fuel been mixed and burned
• Tubular
• Annular
• Tubo-annular
Dr.Khaled S. Al-Zahrani
3- Turbine:
Turbine is a rotary engine that extract energy from a fluid and converts it
into useful work.
There are two type of Turbine:
• Reaction (UK, Sir Parson)
• Impulse (Swedish, Gustaf)
Dr.Khaled S. Al-Zahrani
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4 – Auxiliary systems:
1. Fuel system
2. Starting system
• Air motors
• Diesel engines
• Electric motors
3. Lube oil system
4. Cooling system
5. Silencer
Dr.Khaled S. Al-Zahrani
Gas turbine mimic the working principal of the Windmill
But the moving air or gas is controlled and directed against the blades of the
turbine wheel
Dr.Khaled S. Al-Zahrani
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Also mimic the working principal of Internal Combustion engine:
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Open Closed
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Single Shaft Multi-Shaft
Multi-shaft turbine can be:
1. Parallel
Part load
Two C.C
Control T3
2. Series:
Independent shaft speed
Dr.Khaled S. Al-Zahrani
Brayton Cycle
Dr.Khaled S. Al-Zahrani
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Compressor work: 𝑊 𝐶 = 𝐶 𝑃 𝑚 𝑎 (𝑇2 − 𝑇1 )
Turbine Work: 𝑊 𝑇 = 𝐶 𝑃 𝑚 𝑔 (𝑇3 − 𝑇4 )
Network output: 𝑊 𝑛𝑒𝑡 = 𝑊 𝑇 − 𝑊 𝐶 If 𝑚 𝑎 = 𝑚 𝑔
= 𝑇3 − 𝑇4 − 𝑇2 − 𝑇1
Heat Supplied: 𝑄 𝑖𝑛 = 𝑚 𝑓 × 𝐶. 𝑉
= 𝐶 𝑃 𝑚 𝑓 (𝑇3 − 𝑇2 )
𝑚𝑓
Fuel Consumption: 𝑆𝑓𝑐 =
𝑊 𝑛𝑒𝑡
Dr.Khaled S. Al-Zahrani
Thermal efficiency:
𝑊 𝑛𝑒𝑡
𝜂 𝑡ℎ = 𝑄 𝑖𝑛
𝑊 𝑇 − 𝑊𝑐
=
𝑚 𝑓 × 𝐶. 𝑉
𝑇3 − 𝑇4 − (𝑇2 − 𝑇1 )
=
𝑇3 − 𝑇2
Dr.Khaled S. Al-Zahrani
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8. 11/20/2011
rp
rp
Appling Gas Laws
𝑃2 𝑃3
𝑟𝑃 = =
𝑃1 𝑃4
𝑇2 1 1
1− 1−
= 𝑟𝑃 𝛾 → 𝑇2 = 𝑇1 × 𝑟 𝑃 𝛾
𝑇1 −1−
1
→ 𝑇1 = 𝑇2 × 𝑟 𝑃 𝛾
− 1−
1
1 1 𝜂 𝑡ℎ = 1 − (𝑟 𝑝) 𝛾
𝑇3 1− −1−
= 𝑟𝑃 𝛾 → 𝑇4 = 𝑇3 × 𝑟 𝑃 𝛾
𝑇4 1−
1
→ 𝑇3 = 𝑇4 × 𝑟 𝑃 𝛾
Dr.Khaled S. Al-Zahrani
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9. 11/20/2011
Answer all 17 questions.
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