GAS TURBINE ENGINE 1

8/7/2019 GAS TURBINE ENGINE 1

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WHAT IS A TURBINE?

y Gas turbine is the internal combustion enginesinvolving heat energy and mechanical energy has thesole parameters.

y

The main function is to convert the chemical energyof a liquid fuel into mechanical energy by internalcombustion. Gaseous products of a fuel are expandedthrough the turbine.

y The gas turbine is the power developing unit amongvarious means of producing mechanical power due to

its exceptional reliability, freedom from vibration andability to large power.y Its used in various fields viz (majorly in) aircrafts,

trains, ships tank and power plants.y A gas turbine can accelerate air to create thrust (aero

engines) or drive generators to make electricity, or turn

m1

m13


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Slide 2

m1 Instead ofmajorly i have written like this check itmamatha, 3/26/2011

m13 addded pointmake it easymamatha, 3/26/2011


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Brayton Cycle

Unlike diesels, operate on STEADY-FLOW cycle

Open cycle, unheated engine

1-2: Compression

2-3: Combustion

3-4: Expansion throughTurbine and Exhaust Nozzle

(4-1: Atmospheric Pressure)


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Slide 4

m3 If u use T-S dig u try to explain only P-v dig but study T-S dig for question they ll try to askmamatha, 3/26/2011


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Brayton Cycle

m4


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Slide 5

m4 delete or use other slide for ur comfortmamatha, 3/26/2011


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Basic Components


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Basic Components

CompressorCompressor It Draws air in & compresses it

Supplies high pressure air for combustion process

m5


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Slide 7

m5 try to make it easy as required for u

try to put slide no 10 to 13 after slide no 7 for continuty of compressor part

try to add other points

mamatha, 3/26/2011


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Basic Components

Combustion ChamberCombustion Chamber Fuel pumped in and ignited to burn with compressed air

Where air & fuel are mixed, ignited, and burned

Spark plugs used to ignite fuel

m6


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Slide 8

m6 make the point to easy

use slide no 15 next to this slide for continutymamatha, 3/26/2011


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Basic Components

TurbineTurbine Hot gases converted to work

Can drive compressor & external load

m10


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Slide 9

m10 try to add points and put slide no 16 . 17 . 18 next to these slide for continutymamatha, 3/26/2011


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Compressor

Supplies high pressure air for combustionprocess

Compressor types

Radial/centrifugal flow compressor

Axial flow compressor


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Compressor

Radial/centrifugal flow Adv: simple design, good for

low compression ratios (5:1)

Disadv: Difficult to stage, lessefficient

Axial flow Good for high compression

ratios (20:1)

Most commonly used


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Compressor

Controlling Load on Compressor

To ensure maximum efficiency and allow

for flexibility, compressor can be split intoHP & LP sections

Vane control: inlet vanes/nozzle angles canbe varied to control air flow

Compressor Stall

Interruption of air flow due to turbulence


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Use of Compressed Air

Primary Air (30%) Passes directly to combustor for combustion

process Secondary Air (65%)

Passes through holes in perforated inner shell &mixes with combustion gases

More efficient secondary systems (cooling, sealing)

Film Cooling Air (5%) Insulates/cools turbine blades


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Combustion Chambers

Types Can: for small, centrifugal compressors

Annular: for larger, axial compressors (LM 2500) Can-annular: rarely used

m7


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Slide 14

m7 delete the slidemamatha, 3/26/2011


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The Combustor


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Slide 15

m8 try to expain types with details by using previous slidemamatha, 3/26/2011


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The Turbine


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Turbines

Consists of one or more stages designed todevelop rotational energy

Single shaft

Power coupling on same shaft as turbine

Same shaft drives rotor of compressor and powercomponents

m9


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Slide 17

m9 mamatha, 3/26/2011


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Blade Cooling


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Gas Turbine Accessory Systems

Starting System

To get compressor initially rotated, HP air used(can use electrical also)

Once at certain RPM, fuel injected and sparkignited

Power Transmission System Reduction gears used to transfer torque

With split shaft, turbines can run @ differentspeeds


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Advantages

Gas turbines when compared to other enginestype have very good power to weight ratio.

Gas turbine engines are compact in size.

Excess heat generated by engines can be used forother applications. For example: Preheating ofair before it enters the combustion chamber.

Gas turbines have good thermal efficiency and

therefore good fuel efficiency when inprolonged use under a constant load.


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Disadvantages

Gas turbines are very expensive. The high engine speed which turbines run at

causes problems when designing andmanufacturing turbine parts .The harshconditions within a gas turbine mean that thematerials used and the design must be thoughtthrough.

At low engine speed (idling) are when the load

fluctuates the efficiency of gas turbines is verylow. The very hot exhaust gases make gas turbines

very unsuitable for many uses.


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Gas Turbine Applications

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GAS TURBINE ENGINE 1