I welcome all of you to this course Fundamentals
of Aerospace Propulsion. And if you look at
it is quite exiting and fascinating subject
so far aerospace propulsion is concerned.
And when you look at an open sky, whether
during the night time or in the day time,
you will be wondering what really it contains,
am I right? All of you will be have a wonder,
how it is. If you look at a sky in the nighttime
particular dark peach night without any cloud,
we will see that lot of stars will be twinkling
at you. Whenever I see that I remember a song
twinkle twinkle little star, how I wonder
what do you want and that still is remaining
in my mind from the childhood. And I hope
and I am sure that lot of you will be having
similar feeling to look at what it contains,
why it is twinkling, how many stars will be
there.
Can anybody tell me how many stars will be
there in the sky? There are two hundred billion
galaxies right, according to the scientist
estimation as of now. One galaxies will be
containing something three hundred billion
stars, and we are in a galaxy known as milk
way and where sun is the one of the star it
supports all our you know energy requirement
all the life in this solar systems. And this
if you look at always man is has desire to
look at wonders and how it will understand
the thing, and this is a revolution due to
the development of science and technology.
Do not think that this modern scientist have
found out this. This was their in our scriptures
also about very exact next of that like for
example, people where thinking the whole universe
is expanding one day, it will contract that
is nothing, but your big bank theory. So and
that you know desire to know and other things,
which have made us to think about how to go
about it, how to move about it. If you look
at it like today we are in moon machine India
is having a very prestige’s moon machine,
how to move about it how to go to a moon and
sea. And so also there are planetary machines
of USA and USSR’s and China and several
other countries, now these as motivated in
off lead to look at how to have in better
propulsive devices such that we can you know
meet our requirements. And beside this there
are several other application like satellites
and others which will be helpful not only
for the winning a war, but also for civilian
applications. And besides this you might be
knowing you might be wondering how one can
really fly because whenever I see in this
beautiful campus of IIT Kanpur, birds I always
feel how they fly and this kind of questions
comes to the mind of the from the time memorial
that how does a bird fly.
Can we not fly like a bird and there are several
stories, I will tell you a story what my grandmother
had told me when I was a child. She told me
that my great great great grandfather had
attempted to fly like a bird, whether it is
a stories or reality I do not know, but it
was being placed on me as a reality. So, who
was trying to stop a wing to is very arm,
made out of bamboo, but unfortunately he made
an accident which was killed him in the process
that is why it became a story. And similar
stories you may find in our mythology studying
from Hanuman to Jambavan and several others
that is a another mythological story, I would
like to share with you that is about Greek
mythology.
There are two persons one is father Deadalus
and his son Icarus who were imprison in the
Alexandria the great king Minos. And they
try to escape from the jail made a conspiration
and by using the principle of the flying,
and they made the wing made out of walks and
feathers you know like Icarus who is a young
and enthusiastic. He did not listen to the
advice of his father, and he flied upward
to a very high height and because of sun,
the waxes got melted and he dipped into them
Mediterranean seas. As a result, he was been
caught and put into jail.
So, if you look at there are several atoms
several things have been twelve stories are
being floating around how many failures they
have made, but still people have tried. And
later on there is a what do call the Sir William
Caley who was made a basically a what do call
mimic the flight of a kite, and made a what
to call a glide in 1804. And after hundred
years there was a person known as Wright Brother
who made a epoke of flying an aircraft will
be discussing more about Wright brothers achievements
and their start of the era of the aerospace
propulsion you might be knowing the story
of Wright brothers and other things.
Now, let us ask a question, what do you mean
by propulsion? Can anybody tell me like what
do you mean by propulsion? Propulsion is basically
stands from a word know as propel, it is basically
warm, what it means? It means to propel, two
propel means to make or a cause emotion to
an object or a body. And when we are trying
to impart a motion to a body or object, what
we need to do. We will have to apply a force,
is it possible that we can apply a force in,
certainly no, it will be unbalance force such
that it will be overcoming the inertia or
a registries. And it must be in a specified
direction, specified direction means for a
particular direction whether it will be forward
or a backward or a sidewise.
So, this definition clearly indicates the
existence of a body and a force to drive or
push a vehicle, and this motion will be in
a preferred direction that is a for example,
if I look at I walk is it in a preferred direction,
how I am walking, is it I am applying a force
or not. And even am I applying force, how
it is acting on the body. So, these questions
all of you will be knowing, but we will be
discussing in just to make in more clear and
have a feel for it. So, if you look at these
are basic principle or what you call we mean
propulsion. Now when you talk about propulsions,
suppose a insect is moving or a what do call
a snake is moving on the grass or a ground
or a fish is moving in the water, we look
all it has a propulsion or we look all it
into something else.
Naturally propulsion, but we never use those
term, whenever it is moving very often; however,
because it is a related to the motion, it
is related to flying a force which will make
it the motion, in a particular direction.
So, therefore, we call it as a propulsion;
however, there as several devices which are
like automobiles, trains and ships which are
being to be propel and for that we need to
have engines. Similarly, we will be looking
at in this air aerospace propulsion, the propulsive
devices are a craft, missiles and spacecraft
and several others one can think of but we
will be concentrating on this.
Then question arises what is the basic principle,
which will be you know governing the propulsion
process. So, we know that one has to apply
a force, and it will cause an motion. Now
whenever it will cause an motion then naturally
laws of motion comes into picture. You must
have studied all this thing in high school,
but do you have a feel for it? What is this
laws, if I say what is first law, what is
second law of motion, and third of motion.
Some of you may tell me what it is in words.
But did you experience those things that is
more important to have experience then mugging
it of or remembering certain laws are applying
it in mathematical sense.
I will take an example, what a child experience
this law or not. If you look at a child may
be two years or one and half years child will
it be experience this laws of motion or not?
But you know if they are experiencing, but
whereas, when we grow up we are not experience,
I will give an example how they are experiencing.
And you might have observe a child as kept
a toy in one place you will move around and
come and see whether the toy is lying there
are not in same exactly same place.
Let us say a baby or a child is playing with
a car toy and you will push the car in a particular
direction such that it will move and reach
and you are catching; a let say ball you know
lot of children like to play with the ball.
Like you will be throwing to a ball another
person another child will catch it or sometimes
in of single child is not having way to play
or interact now a days it is the go up the
wall. So, they will be what you call throwing
the ball towards the wall and it bound it
back and they catch it. So, what it indicates
that is they are experiencing all the three
laws of motion. What are those first law of
motion can anybody tell me like a what is
the first law of motion?
Professor: No, please tell me in a words,
inertia is ok, that means, a body will remain
in the state of rest are of in uniform motion
along a straight line, unless it is acted
upon by an unbalance force. What is that unbalance
force; that means, if it is there, I will
apply a force, will it moving? It is not moving,
I am applying a force, but if I will apply
more force than it is moving; that means,
a force, which is acting is unbalance force
that will make a body to move. Now how will
relate this unbalance force to the change
in the motion; something you changing in the
motion.
And in this case, there is a friction which
is occurring, there is a friction. So, whenever
friction is there, this force whatever I am
applying must overcome the frictional forces
between the surface and the body. Now then
only it will move, it will make a move or
it will be in motion or motion is important
to the body. Now if you look at like what
really changing, whenever an unbalance force
a being acted upon a body, what is being change,
there will be change in moment; that means,
rate of change of momentum will be proportional
to force.
So, therefore, in that case that we call it
as a second law of motion and these momentum
will be in the direction of the applied force
or the unbalance force. So, unbalance force
acting on the body produces and acceleration,
because there is a change in the momentum
of the body mass can be changing or so also
velocity are both of them will be changing,
but when will consider the mass to be constant
then change in velocity with the respect to
time we call it as a acceleration.
So, therefore, generally, we consider the
second law of motion in which unbalance force
is propositional to mass and acceleration
a body is known as a can be expressed is a
mathematical formula which all of you know
F is equal to ma. F is the force, m is the
mass of the body which is about to move, and
a is the acceleration imparted to the body
due to the unbalance force and the direction
of this motion will be always along the unbalance
force and force is a vector quantity that
all of you known. So, therefore, this is the
law second law of motion then what is the
third law of motion every action as an equal,
but opposite reaction.
When you talk about this every acting force
for an every acting force there is an equal,
but opposite reacting force what is the meaning,
where this forces will be acting? Will it
be acting in the same object or will it be
acting in the different object? It will be
certainly know if it will be acting in the
same object, therefore, there would not to
be any motion, it will be in equilibrium.
When it is acting on the opposite then there
will be having motion. So, this is the third
law of motion.
So, as I told you to impart a motion to vehicle
reacting force must be acting on the vehicle
that is very important; otherwise, there would
not be any motion. I will take an example,
this is a canon, canon will be you know like
imparting a motion to a ball which is their
due to the explosion inside the canon. As
a result the reacting force will be on the
ball and the reacting force on the canon,
now if you look at this canon it is made you
know the mass will be very very high as compared
to the ball mass. So, therefore, the opposite
force, which will be acting on a canon will
be very very small.
I remember that when I was in high school,
I was in NCC, my instructor ask me to keep
the bought of the gun that is the 303 gun
you know you must might be knowing, along
with the body, but unfortunately I do not
listen to his advise. And then I got a pen
wherever I trigger the bullet, and it came
and hit my body, because it is moving so opposite
reaction is there. Similarly several other
things one can think of right for example,
like there is in the swimming pool, there
will be a spring boat on which we will try
to push and then you will be jumped and put
into the what you call swimming pool. So,
this is a another example. The way we walk
is also by the third law of motion right and
in a our scriptures we talk about ever action
as a equal, but opposite reaction that is
known as law of mass law of what you call
Karma. So, that some of you may not be knowing
what is that, now this people are not worried
about, but it is very important to look at
back law of karma which is similar to the
law third law of motion.
So, we will take a balloon which is in flatted
one and it is in equilibrium, because the
pressure which is acting on this balloon which
is in equilibrium with the atmosphere. But
however, it is having higher pressure you
may think how it is happening because it is
a elastic medium. So, whenever it is in equilibrium,
and if I remove this steam or allow the air
to move what will happen, the air will be
moving out of these balloon, and there will
an acting force action or the action force
and there will be a reacting force along with
these direction. As a result that balloon
will move away from the same place. This a
typical experiment what people do at least
it is there in high school book, but nobody
does experiment today either in the high school
or in the secondary school or even in engineering
college that is the fate of the our education
system which is very bad.
Now if you look at this is the basic principle
by which the rocket engines you know being
what. So, I will show you a figure where the
the the hard gases will be jetted outer to
the nozzle, as a result it will impart a trust
and which will be must be much higher than
the weight. So, that and also the frictional
forces that drag. So, that it will make a
move. So, this is basic principle of the rocket
propulsion now we will take this balloon and
look at what will be the gas turbine propulsion.
I will take an example, now before getting
into that I would like to ask you we are talking
about aerospace propulsion. But is there any
occasion for as to think about about life
propulsion; that means, we propel our life
you take a birth; from the birth to the death
is a one journey in a particular direction,
any of you have wonder, any time how I will
propel my life. So, that my life will be smooth
and good, I can contribute, I can reach an
excellent state, I do not think some of you
might be thinking or some of you may not be
thinking right and that is the main objective
of all education according to me not that
what do we do.
So, I would ask you people to think about
this impart and aspect of how to propelling
a life which is more important than your aerospace
propulsion. Because of that people do not
know how to propel a live all the problems,
what we are facing in the society is being
cause because of you know not adhering to
the principles of humanity. So, I do not want
to get into that, but rather I will suggest
that let us say that there is a balloon which
is acted upon the pressure in acting have
seen and their pressure is release here. Whenever
the stem is being you know being opened as
a result it will be like a nozzle, it will
moving, but what will happen, after the air
all the pressured air we going out then the
balloon will be flat, and it would not move
at all.
Suppose I will take this example and then
or analysis, I will think of how I will make
it a continuous. What is the way can anybody
tell me, I want to make it to move. So, what
is the way out make my balloon to be moving
forever or as long as I wish that means, I
need to supply the air continuously. How I
can do that, I can think of may be pushing
some air, when I will say push some air what
I will have to do, I will have to think of
using a compression or you can think of using
an air inter.
But the compression will be having some mechanical
component. So, this component which will have
a mechanical rotor, it will move and it will
injects the air into that, but whenever I
am having these moment of the compression
mechanical I need to move it. How I will make
it to move, this compression because I love
to have to a another device which will give
the power for the compressor blades to rotate,
such that air can come in. And for that I
need a turbine and when I need a turbine,
but how this turbine will move it cannot move
of its own. So, naturally I will have to give
some energy, because if I ask where thus this
force comes it comes from the energy; without
energy can I have a have a force certainly
no, it is not possible. So, what I will have
to do, I will have to use a energy. Energy
can be any source, it can be chemical energy,
it can be nuclear energy, it can be solar
energy, it can be any other form as a made
of fact; energy having different forms.
So, naturally I will have to using a some
energy source, so that I can extract some
mechanical work in that turbine and which
will run the compression. So for that I need
have a combustion chamber, where I will be
using some chemical energy for this example
and that itself. And if you look at it gas
turbine, it is having how many components;
one is the air intake through which air will
be entering into the chamber and the compressor
which will be setting the air and also rising
the pressure and there is a combustion chamber
which will give some amount of energy to sustain
it. It will be expanded it in a turbine and
this hot gas will be expanded in a nozzle
further to give a trust and these comprises
of you gas turbine engine.
So, this is a balloon analogy what I call
of a gas turbine engine and if you look at
whole this concepts having three components
as I told, that means, the propulsion processes
involve propulsion at three. One propelling
force at the trust, and other is motion cause
due to the thrust, which is a basically a
flight dynamics or aero dynamics one can think
of. And vehicle body are involve whenever
we talk about body, you know body is basically
in a structural thing, so that will be come
under structural engineering. And then what
will be looking at propelling force, and it
is the force which will be trying to generate.
And whenever we generate this force, we need
to use the energy now we will be thinking
about how to use this energy for generating
a torque or a thrust or a force such that
it can make it to move. So, whole of this
air can propulsion or the aerospace propulsion
is related to how to utilize this energy for
generating thrust or a force for making it
to move move or imparting a motion to a vehicle.
So, this is the part which will be concentrating
that means, we will be looking at aerothermodynamics
of the propulsion.
So, with this we will be covering the subjects
in a following manner as I told you, let us
look at typical gas turbine engine which looks
like a air intake, and this is a compression
this a combustion chamber, which is quite
looks to be complex. And the turbine which
is having two stages, there are several blades
involve and this having a nozzle. Keep in
mind that have not shown here in air intake
through which air will be entering into this
engine. Now this is basically a gas turbine
engines. So, as I told you that we will be
looking at the whole kind of a aerospace propulsion
and which is aerothermodynamics of the propulsion
or aerospace propulsion which will be covering
in this course.
And in this course, we will be doing in this
way, in following way because as I told that
I will be starting with the introduction to
propulsion, and basically I have already introduce
you something. But I will be giving you overall
view of the whole gamete of propulsion in
a very nozzle and then will be concentrating
only on the gas turbine engine and the rocket
engines for that we need to review. The basics
of thermodynamics that is the review of the
basic thermodynamics then will be looking
at what are the equations that governs that
is a conservation equations which will using.
That is one dimensional a isentropic flow
and whenever we talk about this flow it will
be at high velocity and then there might be
a chances of you formation of shock.
So, we will be discussing about normal shock,
oblique shock and then will be moving into
a Rayleigh flow and Fanno flow. And some of
you might be knowing, but will have to recap
which you let relook at it from the different
angle, and as I told that will be mainly dealing
with the chemical energy for our you know
propulsion devices. So, therefore, we will
be looking at elements of combustion. Till
this portion of the course which will be basically
being covered to make you a depth in the fundamentals
which are equal to delving into the aerospace
propulsion.
After this we will be looking at derivation
of the thrust equation, in which performance
parameters both air breathing and non air
breathing engine will be covering. And then
will be looking at cycle analysis of air breathing
engines, I will be talking about real cycle
analysis, ideal cycle analysis, how we can
use for the design of an aircraft or aero
engines particularly. And then will be looking
at briefly about solid rocket engine, liquid
rocket engines and hybrid engines etcetera.
And for this that is who will be referring
several books and which I have just jotted
down few of them.
And for the aero engines will be looking at
this gas turbine propulsion publish by Anamaya.
And Fundamental of Combustion will looking
at what you call by myself D. P Mishra, and
Engineering Thermodynamics will be looking
at some portion by the Cengage 2000. Beside
this will be referring this book Mechanics
and Thermodynamics of the Propulsion by Hill
and Peterson, and there is a very classic
book the Sutton G, P. and Biblarz, Rocket
Propulsion Element will be using it. And beside
this, the Aerodynamics of Gas Turbine rocket
propulsion - Oates. And all these books except
the first one available in the library, and
I hope that it will be you can use, you can
refer any other book as a matter fact. So,
my suggestion would be, you should you know
try to have your own notes that will be useful
for to cater to your needs
Now, we will be moving into the, what you
call history of propulsion; question arises
why will look at history, because it is a
very very boring subject. At least to me,
it was a quit boring subject to look at history,
am I right? Some of you may not like into
look at history, although our mind always
move to the past or it will be moving to the
future, but really remain in the present state
that is the nature of the mind. Am I right
or wrong? So, always reading about the past
or imagining about the further whether bad
or good or ugly. So, there but however, we
need to look at the history of the propulsion
or history of any other things just to look
at what we can do such that we can act today
for the better future. So, therefore, we need
to look at the history of propulsion.
I will just give a bar side view of the history
of propulsion, if some you where interested
you can make a on that, it is a very worst.
But I will start with a a very what you call
a Alexanderia scientist who was living in
Alexanderia in 150s name is Hero, who design
a aeropile in 150 B.C. - Before Christ. And
he has come up with a device which is shown
to be here. I think it looks little awkward
to look at today is not that compact, and
then you know jazzy to look at, but still
then it gives a very great principle.
For example, it contains a bowl, which is
shown here; and this bowl contains water,
and it is having a close with a lead and from
this lead, there are operate tube which goes
to this kind of a chamber, which is spherical
in nature - hollow spherical. And similarly,
this is having a another operate which connected.
Keep in mind that this hollow sphere is having
a two nozzles which is opposite direction,
whenever this water is boiled steam is being
formed, and this is being boiled using a wood
by burning of wood. Earlier days wood was
a major fuel, and in feature I guess that
will be the only fuel after may be fifty or
hundred year, because it is renewable in nature.
So, therefore, this steam whenever it will
go through this and it will be jetted to this
nozzle it will give a couple and that is nothing
but your reactive forces or reactive thrust,
so that demonstrate the reactive thrust principles.
If you look at 150 B.C people were not knowing
what are the laws of motion, but they have
devise this thing, they have come up with
this idea, it is a marvelous idea when I think
of. It may looks to be trivial today, but
if you look at 150 B.C., it was a great thing.
What it says to us, so for history is concerned;
that means, you should not be bog down by
the principles, which is not there, but however,
you can do the design, you can think of that
is the mind. In modern days the peoples mind
is restricted and constricted by these laws,
which are being formalized. Newton’s came
in 17th century, but Hero who was really hero
who found out that what is to be done and
this principle is being utilize later on for
the development now.
And I will just tell you a brief history very
much like this 900 around 900, the Chinese
and of course, there is a controversy Indians
found out the black powder. What is the constituent
of this black power, which is also known as
gunpowder. Do you know which is used for your
rockets, rockets and then you know for your
bomb in Diwali festivals. And then they found
out the way of attacking enemies or defending
the enemies discovery of fire arrow. Later
on around 1500, 1150 AD, the Chinese people
made a rocket, which is similar to our fire
rocket, if you look at history. But it was
a making an epoke have a impact later on this
Mongols and other warrior groups in Arab countries
and other things Japanese, you know like samurai
is another thing, they learn these techniques
so also Indians. And it spread to the all
the thing, because it was driven by the winning
a war. So, if you look at today also the arsenals
and the all aerospace related things are being
misused abused by the the armies and politicians
is very important to note. So, therefore,
one has to worry about.
Later on, there are several other things which
I am not talking about it. In 1760 the Tipu
Sultan of Mysore who fought four wars right,
and he won all three wars created a havoc,
but unfortunately he lost the fourth Mysore
war to the Britisher and he was killed. And
they were using a what you call missiles or
the rockets, basically he is the missile man.
Although we know in modern days, the Abdul
Kalam is the missile man. But Tipu Sultan
and was the missile man of this country, who
are having created lot of things. And the
Britishers took their rocketry systems to
the England, there is a person known as Congreve,
who really made several investigation and
tried to mimic this design and was successful,
they use against Napoleon in 1812 and won
the war, against Napoleon one of it. So, what
I am saying this is a that means, the rocketry
is started basically from India and which
we do not know.
Then of course, the 1719 John Barber England
got a patent in gas turbine engine, this is
long time back, but it was not being used,
why it was not being? You got a patent got
patent means, basically an idea which was
you know put in his name, so that other people
cannot copy it, but why it was not coming
up… But, later on in 1851 Hennery Gifford
use a steam engine to have the first aircraft
flight from the Paris to the trapper at a
kilometer of you know at a speed of 11 kilometer
per hour. It was a very very small, if I look
at person can run, you know in this 11-kilometer,
wow more than that even. A normal man can
walk may be 7 to 8 kilometer per hour. But
what was the thing I guess when I investigated
I found that there was a balloon in that which
was making it to drift and this engine which
was a very bulky was not producing any thrust.
That is my interpretation some of you may
look at it. So, therefore, it is the wind
which made the move, and it was floating only
you know, so that was the my interpretation.
So, it is very important to look at that.
Now having said this thing and if you look
at the steam engine at that time was very
very popular. I will tell you another thing
the subject thermodynamics, you know was really
developed because of steam engine that means,
the engineering need not to be come after
the science. That means, if you are good enough
in science, it does not guarantee you that
engineering would engineering should come
up. So, engineering come first or science
of course, is required for to have a good
engineering, but it is not that way. So, in
other words, what I would like to suggest
one should not be bog down by the constant
of the development in science so far engineering
is concerned.
How you can develop, engineering is concern,
then there will be some ingredients with the
minds of the people that make useful thing,
I will be discussing little later on. So,
if you look at 1870 the George Brayton demonstrated
Brayton cycle which we will be discussing
in this course very often. And using a reciprocating
engine, generally it is today it is Brayton
cycle is whenever Brayton cycle being discussed,
it is for the gas turbine engine, but it was
started with a reciprocating engine. And as
I told there is a epoke making event by the
Wright brothers, who really you know for the
first time make an aircraft to fly in 1903
and that is the history being created, which
uses the 12 horse power engines.
And 1909, Roger Ravaud Gnome use a rotary
engine aircraft, and covered a great non-stop
distance of 180 kilometer created a world
record for endurance flight, because it was
flying for a longer period of time. And if
you look at this is a turbo you know like
a kind it is a quite a good event and but
I am always you know fascinated about the
Rene Lorin who invented two things so far
aerospace propulsion is concerned. But he
invented several other things he was a very
innovative person. So, 1913 he patents the
design of the ramjet engines and I will tell
you also how he talked air breathing engine
little later on that is 1908.
So, 1916 Auguste Rateau suggested using exhaust
power compression to improve the performance
engine that means, he was the first person
to introduce a turbocharger to the aircraft
engines. And 1930, the Frank Whittle submitted
his first patent on the jet engine generally
the what you call frank whittle is known as
the father of the gas turbine or the jet engines
am I right? But however, there is a person
von Ohain’s who is really the father of
the turbo jet engines who made it in 1938.
And whereas, of course, the Frank Whittle,
1941, he found a turbojet engine to power
an aircraft. But if you look at most of you
may not be knowing who is this von Ohain.
We will be discussing about it. I will just
look at what is the adversity of a person
scientist one who designed this rocket sled,
and it looks to be a very very awkward and
you know to our mind. But to if you look at
he used a series of rockets attached to the
sled, and he sit down the chair and fire the
rocket and it flew for sometimes in the passes
he lost his life, what a great sacrifice he
has made for us to think about. Today we are
very much frightened and we are having we
are suffering from the fear and which is being
circulated by these market forces.
So, therefore, and I am always fascinated
about another person who is a visionary who
is basically an artist, he is not a he was
not a scientist. But the kind of imagination
he was having it is much higher than the modern
engineer can think of. So, what I will say,
I will stop over here. We will discuss in
the next class that is tomorrow which we will
have an media lab. Thank you.
