Rocket propulsion introduction

this ppt contains basic information regarding the rocket propulsion

1. Rocket propulsion By Morla Raghuram Asst. Professor

2. Rocket working principle Newton third law of motion Law of conservation of momentum 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 Rockets obtain thrust by reaction from the ejection of fast moving exhaust fluid from rocket engine.

3. Difference b/w jet and rocket engine Jet engine Air breathing engine It cannot be operated in vacuum Thrust produced depends on altitude and flight velocity. Friction increases with flight speed Oxygen supply depends on atmospheric conditions. It carries only fuel Rocket engine Non air breathing engine Space travel possible Trust production does not depends on altitude. It offers no surface drag. No gravitational effect. Rate of climb increases with altitude. It carries oxidizer as well as fuel .

4. Construction and working A rocket is a non air breathing engine and it has a few moving parts. It carries fuel and oxidizer on the board of the craft. The high pressure gases coming from the combustion chamber act as rocket propellants. These gases expand through the nozzle, and produces thrust on the rocket.

5. Solid propellant rocket

6. Solid propellant rocket Solid propellant rocket burns a solid block made of fuel, oxidizer, and binder (plastic or rubber). The block is called grain. Ammonium per chlorate oxidizer and other chlorine compounds are toxic, corrosive, and damage the ozone layer. Ammonium nitrate oxidizer is hygroscopic, but is usually more desirable, because it is safe, cheap, and smokeless.

7. Solid propellant rocket Solid propellant rocket is inexpensive, but has a low specific impulse (2-3 km/s), has to carry heavy casing, and cannot be throttled or stopped; it burns until all the grain is exhausted. When used in outer space, they may produce space junk in the form of micrometer-size aluminum oxide particles and centimeter-size slag.

8. Applications Assisted take off of missiles and projectiles. Small range rockets.

9. LIQUID PROPELLANT ROCKETS Fuel and oxidizer mixed in the mixing chamber and preheated to suitable temperature . Then it is injected in the combustion chamber. Where the mixture is ignited by an electric torch. The steam is produced by mixing a very high concentrated H2O2 with KMNO4. The pumps are driven by a steam turbine. Constructional details Fuel tank Oxidizer tank Fuel pump Oxidizer pump Injector Steam turbine Combustion chamber Control valves

10. LIQUID PROPELLANT ROCKET

11. Analysis of Rocket Propulsion Thrust(F)=Momentum thrust+ Pressure thrust Momentum thrust=M(jet velocity – propellant entry velocity) i.e., M ( V jet –V i ) But, oxygen and fuel are stored within rocket itself, thus entry of propellant relative to rocket is zero. So, Momentum thrust= MV jet Pressure thrust =( p e -p a ) A e where P e is exit pressure P a is air pressure

12. Analysis of Rocket Propulsion Specific thrust= Ratio of thrust developed to mass flow rate of propellant. Specific impulse = Total impulse= product of specific impulse and weight flow rate of propellant used. total impulse =F

13. Analysis of Rocket Propulsion

14. Analysis of Rocket Propulsion

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17. Analysis of Rocket Propulsion