workingofturbojet pdf v1

7/29/2019 WorkingOfTurbojet PDF v1

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Turbojet Engine

Applied Thermodynamics

A jet engine having a turbine-drivencompressor and developing thrust from theexhaust of hot gases is a turbojet engine.

This topic illustrates the working of aturbojet engine.

Turbojet Engine


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Thermodynamic Cycles

Two Isothermal processes and two adiabaticprocesses constitute a carnot cycle.

Two Adiabatic processes and two Constantpressure processes constitute a Brayton cycle.


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Brayton cycle is represented in P-v and T-s diagrams

Thermodynamic Cycles


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Working of a Turbojet Engine

In a turbojet engine, air enters axially into the rotor at state 1 and leaves the stator rotor assembly inAxial direction at state 2.

Axial Flow Compressor (process 1-2)


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Then, air enters the combustion chamber in which fuel is mixed with air.

High energy igniter supplies necessary spark at the starting of the cycle.

Combustion Chamber (process 2-3)


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The burnt Air fuel mixture is expanded in an Axial flow turbine.

The work output of turbine is equal to work input of compressor.

So, net work done by the Turbojet engine is Zero.

Axial Flow Turbine (process 3-4)


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High pressure gases expand through nozzle which converts all pressure energy to Kinetic Energy.

Nozzle (process 4-5)


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High Velocity jet of gases coming out of Nozzle gives the necessary thrust to move the engine forward.(Newtons Third law of motion).

Pressure Velocity variation in nozzle


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Resources

Books:

1. Gas Turbines by Cohen and Rogers2. IC Engines and Gas Turbines by Gill Smith

Reference Links:

1. www.asme.org


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What is the difference between Rockets and jetengines?

Jet engines work on Newtons III law of motion

Turbojet is an external combustion engine

Rockets operate at higher mach number than jetengines

Jet engines are self breathing engines


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Net Work Output of Turbojet engine is

Same as Compressor Work

Same as turbine Work

Zero

Equal to Wc- Wt


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Inlet temperature of air entering Turbojet depends on

Altitude of operation of flight

Monsoon conditions

Climatic conditions

It is always constant


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Where do we see the application of Turbojet engine?

Civil Aircrafts

Submarine

Helicopters

Rockets


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Answer Key

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32

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Answer(s)Question No.

workingofturbojet pdf v1

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