I prepared it for my friend.. :P

1. CRYOGENIC ROCKET ENGINE

2. Introduction
 A cryogenic rocket engine is a rocket engine that uses
a cryogenic fuel or oxidizer, that is, its fuel or oxidizer are
gasses liquefied and stored at very low temperatures.
 Rocket engines need high mass flow rate of both oxidizer
and fuel to generate a sufficient thrust.
 The liquid oxygen (LOX) oxidizer and liquid hydrogen (LH2)
fuel combination is one of the most widely used.

3. History
 Space travel was mainly developed by the Russians and the
Americans.
The Russians were the first to reach into space.
 Solid-fuel rocket engines were the first engines created by man.
 All the current Rockets run on Liquid-propellant rockets.
 The first operational cryogenic rocket engine was the 1961
NASA design the RL-10 LOX LH2 rocket engine, which was used
in the Saturn 1 rocket employed in the early stages of
the Apollo moon landing program.

4. Meaning Of Cryogenics
 Cryogenics originated from two Greek words “kyros”
which means cold or freezing and “genes” which means
born or produced
 Cryogenics is the study of very low temperatures or the
production of the same
 In physics, cryogenics is the study of the operations at
very low temperature (below −150 °C, −238 °F or 123 K)
and the behavior of materials at these temperatures .

5. Cryogenic technology in rocket
engine
 Cryogenic technology involves the use of rocket
propellants at extremely low temperatures.
 The combination:- Liquid Oxygen (LOX) & Liquid
Hydrogen (LH2) offers the highest energy efficiency for
rocket engines.
 Oxygen remains at liquid only at temperatures below -
183 ° C and hydrogen below - 253 ° C.

6. Principle
 The basic principle driving a rocket engine are:
(i) Newton 's third law of motion
 (ii) Law of conservation of momentum
 In principle, cryogenic rocket engines generate thrust like all
other rocket engines-by accelerating an impulse carrier to
high speeds.
 The chemical energy stored in the fuel is converted into
kinetic energy by burning it in the thrust chamber and
subsequent expansion in the nozzle, in the process creating
thrust.

7. The first Operational Cryogenic
Engine

8. Components of a Cryogenic Rocket
 the thrust chamber or combustion chamber
 pyrotechnic igniter
 fuel injector
 fuel turbo-pumps
 gas turbine
 cryo valves
 Regulators
 the fuel tanks
 rocket engine nozzle

10. Construction and Working

11.  Gas Generator:
 The main function of gas generator is delivery of sufficient amount of
driver gas at designed temperature a pressure which generates
continuous propellant supply of thrust chamber.

12.  Turbo Pumps:
 They receive liquid propellants at low pressure from vehicle tanks
which are then supplied to the combustion chamber. Generally,
radial and axial turbines are used.

13.  Pump:
 In simple words, pump adds energy to propellants through the
rotation. The material used for all the turbo machinery chambers
are: Al alloys, H.S.S, S.S, and NiTi-Co based alloys

14.  Thrust Chamber:
 Thrust is generated in thrust chamber by the efficiency conversion of
Chemical energy in to gases kinetic energy This can be obtain by
combustion of liquid propellants. In the combustion chamber followed
by the acceleration of hot gases throw conversion/diversion section of
nozzle to acquire high gas velocities and hands thrust.

15.  Nozzle:
The pressure generated in combustion chamber can be used increased thrust
by acceleration of combustion gas to high supersonic velocity. Nozzle generally
passes parabolic enters. (Because when high velocities gases entrance and at
exit of nozzle, pressure of exhaust gas increases with high value and hence
velocity and hence velocities reduces). The thrust equation of 1D-flows of ideal
gas at constant pressure is:
F = mue + (Pe – P ) Ae
Where :Ue is exhaust gas value at exist area.
Ae and Pe is respective pressure and area.
P is ambient pressure.

16. Cryogenic propellant
 In a cryogenic propellant the fuel and the oxidizer are in the form of
very cold, liquefied gases.
 Super cooled gases used as liquid fuels are called cryogenic fuels as
they stay in liquid form even though they are at a temperature lower
than the freezing point.
 To store these propellants aboard a rocket is a very difficult task as they
have very low densities.
 Thus by cooling and compressing them into liquids, we can vastly
increase their density and make it possible to store them in large
quantities in smaller tanks.

17.  The propellant combination used is that of liquid oxygen
and liquid hydrogen.
 Liquid oxygen being the oxidizer and
liquid hydrogen being the fuel.
 Liquid oxygen boils at 297oF and liquid hydrogen boils at
423oF.

18. Working of Cryogenic Propellants
Special insulated containers and vents are used to prevent
gas from the evaporating liquids to escape.
 The liquid fuel and oxidizer are fed from the storage tank
to an expansion chamber.
 Then it is injected into the combustion chamber.
 In this chamber, they are mixed and ignited by a flame
or spark.

19. Advantages
 High Energy per unit mass:
Propellants like oxygen and hydrogen in liquid form give very high amounts
of energy per unit mass due to which the amount of fuel to be carried
aboard the rockets decreases.
 Clean Fuels
Hydrogen and oxygen are extremely clean fuels. When they combine, they
give out only water. This water is thrown out of the nozzle in form of very hot
vapour. Thus the rocket is nothing but a high burning steam engine
 Economical
Use of oxygen and hydrogen as fuels is very economical, as liquid oxygen
costs less than gasoline.

20. Disadvantages
 Boil off Rate
 Highly reactive gases
 Leakage
 Hydrogen Embrittlement
 Zero Gravity conditions

21. Why didn't the Cryogenic Engine of
India ignite?
 The GSLV D3, which lifted off well from Sriharikota on Thursday, April 15, 2010
later plunged into the sea as the indigenous cryogenic engine failed to
ignite.
 The vehicle lifted off as planned at 4.27 p.m. and its performance was
normal up to the end of its second stage till 293 seconds from the lift-off.
 An authoritative former ISRO official said: “It is very clear that the cryogenic
engine did not ignite when you look at the curve [of the vehicle's
trajectory]
 the vehicle developed problems when the cryogenic upper stage should
have ignited 304 seconds after the lift-off, and it fell into the sea

22. The next generation of the Rocket
Engines
 All rocket engines burn their fuel to generate thrust . If any other engine can
generate enough thrust, that can also be used as a rocket engine
 There are a lot of plans for new engines that the NASA scientists are still working
with. One of them is the “ Xenon ion Engine”. This engine accelerate ions or
atomic particles to extremely high speeds to create thrust more efficiently.
NASA's Deep Space-1 spacecraft will be the first to use ion engines for
propulsion.
 There are some alternative solutions like Nuclear thermal rocket engines, Solar
thermal rockets, the electric rocket etc.
 We are looking forward that in the near future there will be some good
technology to take us into space

24. Your Queries??

25. Thank you