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Introduction to

Jet & Rocket Propulsion(Subject Code : 10ME662)

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Jet & Rocket Propulsion(Introduction)

(Subject Code: 10ME662)

Department of Mechanical Engineering

R.V.College of Engineering

Bangalore 560059

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Jet & Rocket Propulsion, Lesson PlanSub Code : 10ME662 CIE Marks : 100

Hrs/Week : 3 Exam Hours : 3 hrs

Total Hrs. : 33 SEE Marks : 100

Credits : 03

Ch.

No.Description Hours

No. of questions to be

answered

Unit-1

1 Basic Principles of Air-Breathing Propulsion 41 out of 2

2 Turbomachinery in Air-Breathing Propulsion 4

Unit-2

3 Engine Characteristics 31 out of 2

4 Air-Breathing Engine Efficiencies 4

Unit-3

5 Basic Principles of Rocket Propulsion 31 out of 2

6 Nozzle Theory & Thermodynamic Relations 3

Unit-4

7 Solid Propellant Rockets 31 out of 2

8 Liquid Propellant Rockets 3

Unit-5

9 Advanced Propulsion Systems 31 out of 2

10 Criteria for Selection of Rocket Propulsion Systems 3

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Newtons 2ndLaw

Basic physics demands that every vehicle that requires

motion must have a force to start, maintain or change that

motion and be governed by the equation F = ma.

If the vehicle has to move fast, then we need to know how

the vehicle accelerates. So we rearrange this equation to a =

(F/m).

For simplistic discussion, let us assume mas the weight of

the vehicle. if more accelerationand hence higher speed -

is to be achieved, we need a larger force For a lighter weight

mor a combination of both.

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Newtons 3rdLaw

According to the 3rdlaw, every action has an equal and opposite

reaction, or, a force in one direction produces an equal force inthe opposite direction.

Therefore, to move a vehicle in a given direction, we must

produce a force in the opposite direction.

For a propeller aircraft, the propeller moves enough air

backwards producing a force that moves the aircraft forward.

For a jet aircraft, the engine moves air and combustion products

backwards producing the force to move the aircraft forward.

For a rocket, propellants are burned in the combustion chamber

and accelerated through a nozzle producing a force to propel the

rocket in the desired opposite direction.

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Classification of jet propulsion

Jet Propulsion

Air-breathing Non Air-breathing

Reciprocating

Turboshaft

Turboprop

Turbojet

Turbofan

Ramjet

Solid rockets

Liquid rockets

Hybrid rockets

Nuclear rockets

Electric rockets

Does not use atmospheric

air to support combustion

Uses atmospheric air to

support combustion

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Air-breathing propulsion

Operating principle: Collect mass from the surroundings and set it in motion

backwards, using the reaction force to propel a vehicle. Various steps are:

Draw in air

Compress it

Add fuel and burn (convert chemical to thermal energy)

Expand through a turbine to drive the compressor (extract work)

Then either

Expand in a nozzle to convert thermal energy to kinetic energy and

momentum (turbojet),or

Expand in a second turbine (extract work), use this to drive a shaft for

a fan (turbofan),or a propeller (turboprop).The fan or propeller

imparts kinetic energy and momentum to the air.

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Non air-breathing propulsion (Rocket Propulsion)

Operating principle: Take mass stored in a vehicle and expel it backwards,

using the reaction force to propel the vehicle. Various steps are:

Store propellant (chemical energy)

Burn propellant (convert chemical to thermal energy)

Expand through nozzle (convert thermal energy to kinetic energy and

momentum)