All about Combined Cycle Power Plant, Combustion Chamber and Gas Turbine Blade Cooling. This presentation contains deep knowledge about related topic. I hope this will help you. Best of Luck.

1. Shree S’ad Vidhya Mandal Institute of Technology
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4. 1.Introduction about Combustion Chamber.
2.Requirement of Combustion Chamber.
3.Types of Combustion Chamber.
4.Factors affecting on Combustion Chamber.
Content4

5. 1. Introduction about Combustion Chamber
 The combustion of a fuel is a chemical combination of constituents of fuel with
Oxygen as a result heat is produced.
 Main purpose of gas turbine combustion is to introduce heat energy into mass
of air compressed by compressor.
 By burning the fuel in it, the product of combustion can be expanded to get
useful work output.
 Design & development of gas turbine is difficult compared to diesel engine due
to high temperature, large flow & high heat energy release.
 Main problem associated of gas turbine combustion chamber is to make steady
& stable flame flame in combustion chamber.
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6. 2. Requirement of Combustion Chamber
Following are the requirement of Combustion Chamber,
 To achieve high power output.
 To achieve high thermal efficiency.
 Smooth running of engine.
 To avoid knocking & detonation.
 Long life of engine.
 Minimum maintenance of engine.
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7. 3. Types of Combustion Chamber
The combustion chamber of gas turbine can be classified into three main
groups,
 Tabular or Can Type,
 Annular Type,
 Turbo – Annular or Can-Annular Type.
A. Tabular or Can Type:- In this case some tubular flame tubes are arranged
around engine centre line. Every flame tube is contained in an outer case.
 The several flame tubes are interconnected so as to operate in the same
conditions of pressure.
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8.  Can Type Combustion Chamber

9. Types of Combustion Chamber(Cont.)
B. Annular Type:- this type of combustor consists of a single flame tube with
annulus form that is contained in a inner and an outer casings.
 The main advantage is that on same performances it is shorter than a tubular
chamber with saving of weight & cost of the losses of Production.
 The pressure leaks in this combustion chamber is lower.
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10.  Annular Type Combustion Chamber
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11. Types of Combustion Chamber(Cont.)
C. Can – Annular Type:- it consists of several flame tubes that are fitted in a
single casing.
 The air flow is similar to the tubular chambers.
 This configuration joins the advantage of maintenance easiness of the tubular
chambers with the compactness of annular chambers.
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12. 4. Factor Affecting on Combustion Chamber
The factors affecting the performance of Combustion Chamber are,
 Pressure Loss,
 Combustion Efficiency,
 Combustion Intensity,
 Combustion Chamber Length,
 Temperature Distribution,
 Stability,
 Starting & Initiation of Combustion,
 Carbon Deposit & Smoke,
 Combustion Chamber Life.
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14. 1.Introduction of Combined Cycle Power Plant.
2.Advantages of Combined Cycle Power Plant.
3.Features of Combined Cycle Power Plant.
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15. 1. Introduction of Combined Cycle Power Plant
 As the name implies it is a combination of two cycle operating at different
temperatures, which could operate independently.
 The heat rejected by higher temperature cycle is recovered & used by lower
temperature cycle to produce additional power to improve efficiency.
 Exhaust gases coming from gas turbine has high temperature so it carries large
amount of energy.
 This heat energy may be utilized to produce steam in Heat Recovery Steam
Generator (HRSG).
 This steam expanded in steam turbine to develop additional power. This
combination is called Combined Cycle Power Plant.
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16.  Combined Cycle Power Plant
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17. 2. Advantages of Combined Cycle Power Plant
Advantages of Combined Cycle Power Plant is given below,
 High overall plant efficiency,
 Simplicity of operation,
 Great operating flexibility,
 Less water required,
 Low pollution level,
 Peak & base load application,
 Possibility of Co-generation.
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18. 3. Features of Combined Cycle Power Plant
 Use the hot exhaust gas from gas turbines to make steam, which drives a steam
turbine which drives a generator to produce electricity.
 Extra electricity produced from the same amount of turbine energy that makes
a combined cycle plant much more efficient.
 Overall efficiency of converting fuel to electricity is greater than a peaking
plant 44 to 52%.
 The steam portion of combined cycle plants takes approximately 1.5 to 3 hours
to heat up.
 The combine cycle system cost is obviously a more expensive capital
expenditure than a peaking plant.
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20. 1.Introduction of Combined Cycle Power Plant.
2.Advantages of Combined Cycle Power Plant.
3.Features of Combined Cycle Power Plant.
Content20

21.  The efficiency and power output of gas turbine increases with higher turbine
inlet gas temperature.
 Blade cooling is to keep the metal temperature at the safe level in order to
ensure a long creep a life and low oxidation rates.
 Cooling air around the 650°C is extracted from the compressor and passes
through the airfoils.
 The hot gases and cooling air ,the temperature of blades can be lowered to
approximately 1000°C.
 Maximum cooling with minimum cooling air is needed for effective blade
cooling.
1. Gas Turbine Blade Cooling
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22. 2. Types of blade cooling
Two types of blade cooling
1.Internal blade cooling
a) Convection cooling
b) Impingement cooling
2.External cooling
a) Film cooling
b) Pin fin cooling
c) Transpiration cooling
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23. Internal cooling
a) Convection Cooling:-
 It works by passing cooling air through passages internal to the blade.
 Heat is transferred by conduction through the blade, and then by convection
into the air flowing inside of the blade.
 A large internal surface area is desirable for this method, so the cooling paths
tend to be serpentine and full of small fins.
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Blade Cooling (Cont.)

24. b) Impingement Cooling:-
 A variation of convection cooling, impingement cooling, works by hitting
the inner surface of the blade with high velocity air.
 This allows more heat to be transferred by convection than regular
convection cooling does.
 Impingement cooling is used in the regions of greatest heat loads.
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Blade Cooling (Cont.)
Internal cooling

25. a) Film Cooling:-
 Film cooling is a widely used type, allows for higher heat transfer rates
than either convection and impingement cooling.
 This technique consists of pumping the cooling air out of the blade through
multiple small holes in the structure.
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Blade Cooling (Cont.)
External cooling

26. b) Pin Fin Cooling:-
 In the narrow trailing edge film cooling is used to enhance heat transfer from
the blade. There is an array of pin fins on the blade surface.
 Heat transfer takes place from this array and through the side walls.
c) Transpiration Cooling:-
 It is similar to film cooling in that it creates a thin film of cooling air on the
blade, but it is different in that air is "leaked" through a porous shell rather than
injected through holes.
 This type of cooling is effective at high temperatures as it uniformly covers the
entire blade with cool air
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Blade Cooling (Cont.)
External cooling

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