Rahul Yadav rpt

8/3/2019 Rahul Yadav rpt

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SEMINAR REPORT

ON

ADVANCED PROPULSION SYSTEM

BACHELOR OF TECHNOLOGY

MECHANICAL ENGINEERING

SESSION 2010 2011

RAHUL YADAV

0803240037

ABES ENGINEERING COLLEGE, GHAZIABAD


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CONTENTS

1. Meaning of Propulsion and Propulsion System2. Basic principle of Propulsion

3. Application of Propulsion System

4. Need of Advanced Propulsion System

5. Different Advanced Propulsion System

6. Detail of different Advanced Propulsion System

7. Conclusion

8. References


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MEANING OF PROPULSION AND PROPULSION SYSTEM

Propulsion word is derived from two Latin words: pro meaning before or forward and peller

meaning to drive. Propulsion means to push forward or drive an object forward. A Propulsion

System is a machine that produces thrust to push an object forward. On airplanes trust is

usually generated through some application ofNewtons third law of action and reaction. A

gas, or working fluid, is accelerated by the engine, and the reaction to this acceleration

produces a force on the engine.


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BASIC PRINCIPLE OF PROPULSION

The principle of propulsion depends on the following two laws: -

(i)Newtons third law of motion

(ii) Law of conservation of momentum

The motion of a rocket is an interesting application of Newtons third law of motion &

momentum principle. The rocket expels a jet of hot gases from its tail. This is say, an action

force. The jet of hot gases exerts a force on the rocket, propelling it forward; this is thereaction force.From the momentum point of view, the hot gases acquire momentum in the

backward direction & the rocket acquires an equal amount of momentum in the forward

direction. A balloon shooting forward (when the mouth of the balloon filled with air is

released) and a rocket hurtling into space are propelled by similar forces. The air in a closed

balloon exerts a uniform outward force. But when air rushes out of its neck (similar to

exhaust gases leaving rockets) disturbs this equilibrium. Thus an equal and opposite force is

exerted on the surface opposite to the neck. This drives the balloon forward.
http://library.thinkquest.org/03oct/02144/basics/newton3.htmhttp://library.thinkquest.org/03oct/02144/basics/newton3.htmhttp://library.thinkquest.org/03oct/02144/basics/newton3.htmhttp://library.thinkquest.org/03oct/02144/basics/newton3.htm


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APPLICATION OF PROPULSION SYSTEM

The main application of propulsion system is in the field of space research. Different

propulsion systems are used to propel the rockets in the space. When a satellite is needed to

fix in the orbit of earth, it is required to send it through very high velocity, here the

propulsion systems are used. But the techniques used in these days are very costly and less

efficient hence we need Advanced Propulsion system.


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NEED OF ADVANCED PROPULSION SYSTEM

Even though modern chemical rockets have sent us to the Moon, to build large space

settlements we will need something more. Today, the high cost of launching into space limits

the number of people who go there. Advanced propulsion, however, offers a chance to

dramatically lower launch costs and increase efficiency. Furthermore, many of the ideas

being proposed would allow us to move around the solar system much quicker than we do

today. Instead of months to Mars, it would be weeks. Years to Jupiter would be months. And

centuries to the stars would become years.


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DIFFERENT ADVANCED PROPULSION SYSTEMS

1. Nuclear Fusion Propulsion

2. Electromagnetic Propulsion

3. Electrostatic Propulsion

4. Laser Propulsion

5. Microwave Propulsion

6. Air breathing Propulsion

7. Antimatter Propulsion

8. Tether Technology


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DETAILS OF DIFFERENT ADVANCED PROPULSION

SYSTEMS

1. Nuclear Fusion Propulsion

Principle:

In nuclear fusion, lighter nuclei (lighter than iron) fuse to form a heavier nucleus. In this

process they release energy. This energy is used to heat the propellants forming gaseous

products providing thrust to the rocket.

Explanation:

The best example of energy generated by fusion is our sun, in which the heat energy is

produced by the fusion of two hydrogen isotope atoms to form helium.

1H2 + 1H

22He4 + Energy

There is a difference in mass between the two original lightweight nuclei and single product

nucleus. Here also, the energy is liberated according to mass defect concept explained in

nuclear fission. This results in release of tremendous amount of energy. This energy is used

to heat propellants, which form gaseous products. These gases are forced out through nozzle

producing thrust.

Advantages:

A fusion propulsion rocket will have much greater specific impulse. A chemical rocketengine has a specific impulse of about 450 seconds. A fusion rocket could have an estimated
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specific impulse of 130,000 seconds. This large specific impulse would greatly increase the

speed of rockets making the missions faster (it could cut down the number of days by about

50%) and make manned missions easier.

Fusion-powered rockets would use hydrogen as a propellant. Hydrogen is present in the

atmosphere of many planets. So as the spacecraft travels through space it could replenish its

supply ofhydrogen from any planet's atmosphere. This propulsion technique is currently not

being used, as it requires very high temperatures to initiate the fission process.

2. Electromagnetic Propulsion

Plasma Electromagnetic propulsion is a type of electric propulsion in which propellant isheated to a state and then accelerated. Electromagnetic devices pass a large current through a

small amount of gas to ionize the propellant. The ionized propellant ( plasma) is accelerated

by an electromagnetic force called the Lorentz force.

Principle:

The VASIMR engine creates plasma under extremely hot conditions and then expels that

plasma to provide thrust.

Parts

There are three basic cells in the VASIMR engine.

Forward cell

A neutral propellant gas is injected into this chamber. It is then ionized and plasma is created.
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Central cell

In this cell, this electrically charged gas is heated to create a desired density. This is done

using electromagnetic energy.

Aft cell

After heating, the plasma it enters a two-stage hybrid nozzle at the aft cell. This cell is used to

exhaust the plasma to generate thrust.

A magnetic nozzle is used to convert the energy of the plasma into velocity of the exhaust

gases. In the second stage, the plasma detaches from the magneticfield and is exhausted to

provide modulated thrust. The magneticfield that is used to expel the plasma also protects the

spacecraft because it keeps the plasma from touching the shell of the spacecraft. Plasma

would likely destroy any material it came in contact with. The temperature of the plasma

exiting the nozzle is as hot as 180 million degrees Fahrenheit (100 million degrees Celsius).

That's 25,000 times hotter than gases expelled from the space shuttle.

Working:

The steps in producing thrust are as follows:

The propellant (hydrogen) is first ionized by electromagnetic waves.

Then it is transferred to the central chamber. This chamber is threaded with magnetic fields.

The ions spiral around the magnetic field lines with a certain natural frequency. By

bombarding them with radio waves of the same frequency, the system heats the ions to 10

million Kelvin's.

A magnetic nozzle converts the spiraling motion into axial motion, driving the hydrogen

ions out the back of the rocket and producing thrust. There is a magnetic choke using which

the rocket exhaust can be controlled. When we close the choke, the number of ions gettingforced out of the nozzle decreases. Thus the thrust is less. But the temperature is kept
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constant, thus increasing the specificimpulse. Conversely, by opening the choke, more ions

are forced out of the nozzle increasing the thrust. As temperature is constant, specific impulse

decreases. A spacecraft would use low gear to climb out of planetary orbit, and high gear for

interplanetary cruise. Thus VASIMR can work in both high gear and low gear unlike all the

present technologies

3. Electrostatic Propulsion

This technique of propulsion utilizes electrostatic energy, i.e. energy due to electric charges

on materials is used to propel rockets. Since ions are used for this, the technique is also called

as ion propulsion technique.

Principle:

In an ion rocket, the electrons from the atoms are striped off. Thus they are converted to ions.

These atoms now have a net positive electric charge. Electrical forces accelerate these ions to

high temperature without the use ofthermalenergy.

Working:

The propellant used in this technique is xenon, a heavy inert gas. The energy, which propels

the xenonjet, is the electrical energy from solar cells. This electricity is supplied to both the

ionization chamber and to the neutralizer at the nozzle of the rocket. The propellant is

pumped into the ionization chamber where the propellant atoms get ionized. The process

takes place as follows: In the ionization chamber, electric field provides velocity to ions. This

provides thrust to the rocket as per the law of conservation of momentum (see Physics

World). Ionization is done by electron bombardment of the neutral atoms. Positive ions are

produced by electronbombardment of neutral propellant atoms in a discharge chamber. The

impact of an electron on a xenon atom knocks away one ofxenon's 54 electrons. This results

in a xenon atom with a positive charge, or what is known as an ion. Two molybdenum grids

with a potential of 1,300 volts then accelerate these xenon ions between them, driving the

ions out the exhaust at over 30 kilometers per second. The exhaust of the rocket must be

neutral. That is because, if only positive ions are emitted, the knocked off electrons are left
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olybdenum.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electrons.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electrons.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/molybdenum.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ion.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electrons.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electron_bombardment.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electron_bombardment.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ionization.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://library.thinkquest.org/03oct/02144/basics/intro.htmhttp://library.thinkquest.org/03oct/02144/basics/intro.htmhttp://window_open%28%27../glossary/velocity.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electric_field.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ionization.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ionization.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ionization.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/solar_cells.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/xenon.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/thermal_energy.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/electrons.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ion.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/ion.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/specific_impulse.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');http://window_open%28%27../glossary/specific_impulse.html','title','toolbar=no,location=no,directories=no,status=no,scrollbars=yes,menubar=no,resizable=no,width=440,height=300');


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behind and the spacecraft becomes negatively charged. So after a certain amount of time, the

spacecraft would attract all the emitted positive ions and the propulsion system would not do

its function of creating thrust. In order to ensure that exhaust is neutral, neutralizer emits

exactly the same number of electrons into the ion stream (exhaust), as there are ions. This

prevents the spacecraft from charging to a large negative potential.

Advantages:

Ion engine propellants are chosen for a combination of low ionization potential, high atomic

weight, handling, and storage properties. This technique of propulsion is still in its

developmental stages.

4. Laser Propulsion

Working Principle

The principle of laser propulsion is that it uses mirror to focus the incoming laser beam. This

beam strikes the propellant, which is lined at the bottom of the spacecraft. The gases

produced propel the spacecraft forward. The spacecraft consists of 2 components-The light

source, which is the high precision laser powered beam and spacecraft designed as a highly

polished parabolic mirror capable of receiving light. Prior to the liftoff, a jet of compressed

air is used to spin the spacecraft. This stabilizes the spacecraft. Once the spacecraft is

spinning at a constant rate, the laser beam is used which propels the spacecraft into space.
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The laser beam is maintained at a fixed position on the ground so that the mirror focuses the

beam. The bottom of the spacecraft is lined with a thin coat of propellant.When the laser

pulses strike the propellant it leads to rapid heating of air. This forces the vehicle in direction

opposite to the laser beam source (i.e. away from the earth). The pulsing of laser beam

continuously propels the rocket forward.

5. Microwave Propulsion

Microwaves are very short waves of electromagnetic energy traveling at the speed of light.

Their wavelength varies 30 cm to 0.3 cm.

Construction:

The microwave light craft is equipped with two powerful magnets and three types of

propulsion engines. Large number of antennas, built on the top of the craft, receives

microwaves and converts it into electricity required for launching. The electricity produced

ionizes the air and propels the craft forward. Upon reaching a high altitude the light craft tilts

sideways. Part of the microwave power reflected from the front of the ship is used to heat the

air. This allows the spacecraft to cut through the air up to 25 times faster with respect to the

speed of sound. The other half is converted into electricity by the receiving antenna. This

electricity produced help in energizing the engines, which help in accelerating air around the

craft.
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NASA researchers are working to develop a system that relies on microwaves beamed either

from satellite or from a fixed point on earth. Their goal is to transport payloads and people

into the low earth orbit for approximately about $100 per pound. This cost is roughly 1

percent of the total cost of launching the same payload with the help of a space shuttle.

Advantages:

They can be used for transmitting information from one place to another as they can

penetrate haze, light rain, snow and smoke

Short microwaves (that are few inches long) are used in remote sensing.

A magnetron is used for generation of microwaves. Magnetron is a vacuum tube containing a

cylindrical cathode and coaxial anode. Between the cathode and anode, electrons move in

curved path due to the influence of electric and magnetic fields. The movement of electrons

towards anode results in emission of energy. This energy is transported to a wave-guide.

Wave-guide consists of a rectangular tube whose one end is connected to microwave power

source and at the other end delivery of power takes place. The function of wave-guide is totake input from the microwave source and deliver it at the other end with undiminished
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intensity. Because of the above-discussed advantages microwaves can be used for propulsion

of light crafts. Microwave propulsion has an advantage over laser propulsion, as it is cheaper.

6. Air Breathing Rocket

As it has been explained in the earlier section, a liquid oxidizer and fuel are combined and

burned to produce high pressure, high velocity stream of hot gases in conventional rocket

engines Air breathing rockets use oxidizer but the source is the oxygen from the atmosphere

rather than stored liquid oxygen. The spacecraft is built with intake vents that breathe in

oxygen as the vehicle flies. This oxygen is combined with the rocket fuel and combustion

takes place. Initially rockets are used to propel until the air breathing rockets reach twice the

speed of sound. At this stage, atmospheric oxygen would mix with fuel to propel the vehicle

10 to 12 times the speed of sound. Air breathing rockets are launched horizontally so that

they can capture sufficient air required to break through the earth's atmosphere. Air-

augmented rockets can be used to launch the air breathing rockets. After the lift-off the

rockets are turned off and the propulsion system is used to support the combustion process.

Airaugmented rockets are normal rocket engines with the exception that at high speeds it

enhances the oxidization of the fuel with the air in the atmosphere. They are placed in ducts,

which capture air. The idea behind the design of air-breathing rockets is to reduce the cost of

placing the spacecraft in the orbit, cut weight and increase efficiency. Currently, it costs

about $10,000 per pound to launch an object into space. The aim is to reduce this price to

about few hundred dollars per pound. The weight of the vehicle would be reduced by 50

percent, as it carries no oxidizer.

Air-breathing rocket engines could make future space travel like today's air travel. Hueter,

manager of NASA's Advanced Reusable Technologies, quoted this statement.
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7. Antimatter Spacecraft

What is antimatter? Antimatter as the name suggests, is exactly the opposite of normal

matter. These particles are mirror image of matter. Antimatter is of the same size as normal

matter, but has opposite properties (like electrical charge). Some of the examples of

antimatter particles are Positron- They are electrons with a positive charge. Discovery of

positron in 1932 by Carl Anderson proved that antimatter exists. Anti-protonsprotons that

have a negative charge Because of this difference between the natures of the two particles,

antimatter and matter, they attract each other and upon collision they produce a brilliant flash

of light. Due to this collision the entire mass of both the particles is converted into energy.

This energy released can be used to propel the spacecrafts. As we now know what are

antimatter particles, let us see the working of antimatter engines.

Engines:

To understand the working of anti-matter engines let us first see the construction of an

antimatter engine. It is made up of 3 main components

Payload section - this is used to store the antimatter and separate it from matter.

Storage system- to produce energy

Magnetic rocket nozzle thrusterproduces sufficient thrust to propel the spacecraft

Payload section is made up of magnetic storage rings. They are storage rings with magnetic

field. They continuously move the antimatter particles in a ring until they are required to
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liberate energy. When the energy is needed antimatter particle is released and directed

towards the matter to produce energy. This operation is carried out in the storage system. A

long magnetic nozzle (nozzle operating on magnetic energy) transfers the energy released to

a thruster that produces the necessary thrust to propel the spacecraft forward. The antimatter

propulsion technique has some pros and cons.

Merits of using this propulsion system

Efficient as 100 percent of mass of matter and antimatter is converted into energy

Produces a large amount of energy that is about 1000 times nuclear fission energy and

about 300 times more than nuclear fusion energy.

It would allow the spacecrafts to reach the nearby stars and solar system in a fraction of

time that is required by space shuttles using hydrogen-oxygen fuel.

Fuel required will be less as energy produced per gram increases.

Demerit
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-Lack of antimatter substance existing in the universe.

8. Tether Technology

Attach any mass to a string, spin it round and round, suddenly let go of the string and marvel

at the speed at which it flies. Well, this precisely explains the principle behind tether

technology, which is being researched upon for cheaper means of launching shuttles into

space.

Principle:

In tether technology, cables, miles long, are stationed in an orbit around the earth. On one end

there is a shuttle and on the other end of the tether would be a counter mass. This system

picks up spacecraft in low orbits and hurls them into higher orbits or towards other planets.

Working:

As discussed previously, using the technologies that we have today, the mass to be carried to

space is placed into a low-earth orbit by a rocket. It is then boosted to higher orbits or into

space (towards other planets, i.e. destination) by rocket thrusters. Though efficient, this

method proves very costly. One of the methods, which is efficient and is also cost effective,

is to use space tethers. When the new satellite or space probe is launched, the spinning tether

system captures it and flings it farther from Earth. Now, the principle used is that of

momentum exchange. This means that the momentum of the spinning tether would be

employed to boost the satellite or the shuttle. So as the tether boosts the body further into

space, it itself comes closer to the earth than it was. So after the tether has boosted bodies for

a certain number of times, it falls back to earth.
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CONCLUSION

These techniques are being developed to reduce the cost of sending payload in space and

increase efficiency. Space agencies are testing some of these techniques and exploring others

to devise method for thrust generation. Currently, it costs about $10,000 per pound to launch

an object into space. The space agencies are trying to reduce this price to about few hundred

dollars per pound.


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REFERENCES

www.en.wikipedia.org

www.space.com

www.settlement.arc.nasa.gov

www.grc.nasa.gov

www.library.thinkquest.org

Documents

Rahul Yadav rpt