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Gas Turbine Cycle – Brayton Cycle !"oule Cy

1-2. Isentropic Compression ofAir.

2-3. $eat %ows into the system3-4. Isentropic &xpansion.4-1. $eat is re'ected from thesystem.

• Pressure Ratio =

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)pen Cycle Gas Turbine*Actual Brayton Cycle

1 – 2’ Irreversible Adiabatic compression2’ – 3 $eat %ows into the system3 – 4’ Irreversible Adiabatic &xpansion4 – 1 $eat is re'ected from the system.

 

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)pen Cycle Gas Turbine*Actual Brayton Cycle

 

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Combined Cycle +owGeneration

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,ey +oints of Combination

•

Basic ob'ective is to increase total e-ciency• Cycles woring with dierent /edia or 0ame media can be

• 1ormally they are classed as 2Topping3 and 2Bottoming3 cy

• In the 2Topping3 cycle combination ma'or portion of heat is to the 4rst cycle.

• 2Bottoming3 cycle utili5es waste heat produced in the 4rst c

generate power at a lower temperature.• Combining cycle maes use of waste heat rather than re'ect

the environment.

• /ost common type of combination is Gas Turbine 6 0team TuCombination.

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Basic Con4guration of CC

7.8. 9.:.Ge;. . @. Bo

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 Thermodynamics of CCs

Gas

Turbine

Steam Power PlantC

it!"e-!eat it!out"e-!eat

Average Temperatureof the heat0upplied oC

D E =9D 9=D – :9D 8>D – 9D ;D – >D ;D – >D

Carnote-ciencyF

:8 – := :; – ;: 9= – ;D

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Illustrative &xample

+ress

oss gas sbar

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Illustrative &xample

 

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Illustrative &xample

8>>

;;<

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Illustrative &xample

 

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Illustrative &xample

 

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