cryogenic engine ppt by santosh

CRYOGENIC

ROCKET ENGINE

CONTENTS

1.CRYOGENICS ?

2.INTRODUCTION

3.HISTORY OF CRE

4.CONSTRUCTION

5.WORKING

6.APPLICATIONS

7.REFERENCES

CRYOGENICS

The word ‘cryogenics’ is derived from Greek,

meaning “production of freezing cold”.

cryogenics is the study of the production and

behaviour of materials at very

low temperatures (below −150 °C, −238 °F or 123 K).

Rather than the relative temperature scales of

Celsius and Fahrenheit, cryogenicists use the

absolute temperature scales. These are Kelvin (SI

units) or Rankine scale (Imperial and US units).

Oxygen liquifies at -183c(90k)

Hydrogen liquifies at -253c(20k)

INTRODUCTION

A cryogenic engine is a rocket engine that uses

a cryogenic fuel .

Cryogenic fuels are fuels that require storage at

extremely low temperatures in order to maintain

them in a liquid state.

Various cryogenic fuel-oxidizer combinations have

been tried, but the combination of liquid hydrogen

(LH2) fuel and the liquid oxygen (LOX) oxidizer is

one of the most widely used.

PRINCIPLE

The basic principle driving a rocket engine are:

Newton third law of motion

Law of conservation of momentum

In principle, cryogenic rocket engine derives 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 the fuel in the thrust

chamber and subsequent expansion in the nozzle to

produce thrust

HISTORYo American and Soviet engineers independently, all discovered

that rocket engines need high mass flow rate of both oxidizer

and fuel to generate a sufficient thrust.

o At that time oxygen and low molecular weight hydrocarbons

were used as oxidizer and fuel pair. At room temperature and

pressure, both are in gaseous state. Hypothetically, if

propellants had been stored as pressurized gases, the size and

mass of fuel tanks themselves would severely decrease rocket

efficiency.

o Therefore, to get the required mass flow rate, the only option

was to cool the propellants down to cryogenic temperatures

(below −150 °C, −238 °F), converting them to liquid form.

Hence, all cryogenic rocket engines are also, by definition,

either liquid-propellant rocket engines or hybrid rocket engines

The RL10 was the first

liquid hydrogen

cryogenic rocket engine

to be built in the United

States, and

development of the

engine by Marshall

Space Flight

Center and Pratt &

Whitney began in the

1950s, with the first flight

occurring in 1961.

These engines were one

of the main factors

of NASA's success in

reaching the Moon by

LPSC MAHENDRAGIRI On 1 February 2014, this unit was renamed as Indian

Space Research Organisation (ISRO) Propulsion

Complex and was also made an autonomous

department under ISRO. The main activities carried

out at here are:

Assembly and integration of liquid engines and

stages

Testing of liquid engines and stages

High altitude test facilities for upper stage engines

Propellant storage facilities

C E 7.5

The specifications and key characteristics of the

engine are:

Operating Cycle – Staged combustion

Propellant Combination – LOX / LH2

Maximum thrust (Vacuum) – 75 kN

Operating Thrust Range (as demonstrated during

GSLV Mk2 D5 flight) – 73.55 kN to 82 kN

Chamber Pressure (Nom) – 58 bar

Engine Mixture ratio (Oxidizer/Fuel by mass) –

5.05

Engine Specific Impulse - 454 ± 3 seconds

(4.452 ± 0.029 km/s)

Engine Burn Duration (Nom) – 720 seconds

Propellant Mass – 12800 kg

Two independent regulators: thrust control and

mixture ratio control

Steering during thrust: provided by two gimbaled

steering engines

C E 20The specifications of the engine as

listed on the LPSC handouts:

Operating Cycle - Gas Generator

Propellant Combination - LOX / LH2

Thrust Nominal (Vacuum) - 200 kN

Operating Thrust Range - 180 kN to 220 kN (To be set at any fix values)

Chamber Pressure (Nom) - 6 MPa

Engine Mixture ratio (Oxidizer/Fuel by weight) - 5.05

Engine Specific Impulse - 443 ± 3 seconds (4.344 ± 0.029 km/s)

Engine Burn Duration (Nom) - 595 seconds

Total Flow rate - 462 kg/s

Nozzle Area ratio - 100

Mass - 588 kg

CONSTRUCTIONThe major components of a cryogenic rocket engine are:

1.The combustion chamber (thrust chamber)

2. Pyrotechnic initiator

3.Fuel injector

4.Fuel cryopumps,

5.oxidizer cryopumps

6.Gas turbine

7. cryo valves,

8.regulators,

9.The fuel tanks, and

10. rocket engine nozzle.

PRESSURE FED SYSTEM PUMP FED SYSTEM

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.

COMPARISON

Solid -fuel

advantages

Solid -fuel

disadvantages

Liquid-fuel

advantages

Liquid-fuel

disadvantages

Very stable,

durable

Can’t be turned off.

Once the burn starts ,

it goes on until the fuel

is used up.

Variable thrust-

The amount of fuel

and rate of burn can

be changed in flight

Fragile, more

complex parts

Fuel system is

simpler, safer and

cheaper

Low efficiency Relatively high

efficiency

Highly complex

system and

requires high

maintenance

More thrust for a

similar rocket size

Fuel decomposes,

must be replaced

Liquid-fuel boosters

are more easily re-

useable.

Oxidizer(liquid

oxygen) must be

kept extremely cold

DISADVANTAGES

Cryogenic liquids difficult to store for longer periods

High density requires larger tanks

Highly reactive gases

Leakage problems

Boil off rate

Hydrogen embrittlement

Zero gravity conditions

APPLICATIONS OF CRYOGENICS

Cryogenic fuels

Liquid nitrogen: used in cryo-therapy, as a coolant, cryonic

preservation

Nuclear magnetic resonance spectroscopy: NMR is one of the

most common methods to determine the physical and chemical

properties of atoms by detecting the radio frequency absorbed

and subsequent relaxation of nuclei in a magnetic field.

Frozen food: Cryogenic gases are used in transportation of

large masses of frozen food.

Blood banking: Certain rare blood groups are stored at low

temperatures, such as −165 °C.

And many more…..

INDIAs ROAD TO

CRE

An Indian-made cryogenically-powered rocket,

launch vehicle GSLV-D5, carrying a GSAT-14

satellite, blasts off from the Satish Dhawan Space

Centre at Sriharikota, some 110 kilometers (69

miles) north east of Chennai on January 5, 2014

(AFP Photo / STR)

REFERENCES

http://en.wikipedia.org/wiki/solar tree

http://articles.economictimes.indiatimes.com/

http://en.wikipedia.org/wiki/solar energy

http://books.google.co.in/books?id=wm6uAIiuCc8C&

http://en.wikipedia.org/wiki/renewablesenergies

http://library.thinkquest.org/

http://isro.org/

http://howstuffworks.com/