An Introduction toSpace Propulsion.ppt

1、An Introduction to Space Propulsion,Stephen Hevert Visiting Assistant Professor Metropolitan State College of Denver,http:/ Is Propulsion?,Initiating or changing the motion of a body Translational (linear, moving faster or slower) Rotational (turning about an axis) Space propulsion Rocket launches C

2、ontrolling satellite motion Maneuvering spacecraft Jet propulsion Using the momentum of ejected mass (propellant) to create a reaction force, inducing motion,At one time it was believed that rockets could not work in a vacuum - they needed air to push against!,,Jet Propulsion Classifications,Air-Bre

3、athing Systems Also called duct propulsion. Vehicle carries own fuel; surrounding air (an oxidizer) is used for combustion and thrust generation Gas turbine engines on aircraft,Rocket Propulsion Vehicle carries own fuel and oxidizer, or other expelled propellant to generate thrust: Can operate outsi

4、de of the Earths atmosphere Launch vehicles, upper stages, Earth orbiting satellites and interplanetary spacecraft or,Space Propulsion Applications,Launch Vehicles Ballistic Missiles Earth Orbiting Satellites Upper Stages Interplanetary Spacecraft Manned Spaceflight,www.army-,en.wikipedia.org,,,www.

5、psrd.hawaii.edu,Space Propulsion Functions,Primary propulsion Launch and ascent Maneuvering Orbit transfer, station keeping, trajectory correction Auxiliary propulsion Attitude control Reaction control Momentum management,www.nasm.si.edu,www.ksc.nasa.gov,A Brief History of Rocketry,China (300 B.C.)

6、Earliest recorded use of rockets Black powder Russia (early 1900s) Konstantin Tsiolkovsky Orbital mechanics, rocket equation United States (1920s) Robert Goddard First liquid fueled rocket (1926) Germany (1940s) Wernher von Braun V-2 Hermann Oberth,Prof. Tsiolkovsky,,Space Propulsion System Classifi

7、cations,Stored Gas,Chemical,Electric,Advanced,ElectrothermalElectrostaticElectrodynamic,NuclearSolar thermalLaserAntimatter,Liquid,Solid,Hybrid,Pump Fed,Pressure Fed,Monopropellant,Bipropellant,Space propulsion systems are classified by the type of energy source used.,Stored Gas Propulsion,Primary o

8、r auxiliary propulsion. High pressure gas (propellant) is fed to low pressure nozzles through pressure regulator. Release of gas through nozzles (thrusters) generates thrust. Currently used for momentum management of the Spitzer Space telescope. Propellants include nitrogen, helium, nitrous oxide, b

9、utane. Very simple in concept.,Chemical Propulsion Classifications,Liquid Propellant Pump Fed Launch vehicles, large upper stages Pressure Fed Smaller upper stages, spacecraft Monopropellant Fuel only Bipropellant Fuel & oxidizer Solid Propellant Launch vehicles, Space Shuttle, spacecraft Fuel/ox in

10、 solid binder Hybrid Solid fuel/liquid ox Sounding rockets, X Prize,www.aerospaceweb.org,,news.bbc.co.uk,Monopropellant Systems,Hydrazine fuel is most common monopropellant. N2H4 Decomposed in thruster using catalyst to produce hot gas for thrust. Older systems used hydrogen peroxide before the deve

11、lopment of hydrazine catalysts. Typically operate in blowdown mode (pressurant and fuel in common tank).,Monopropellant Systems,,,Bipropellant Systems,A fuel and an oxidizer are fed to the engine through an injector and combust in the thrust chamber. Hypergolic: no igniter needed - propellants react

12、 on contact in engine. Cryogenic propellants include LOX (-423 F) and LH2 (-297 F). Igniter required Storable propellants include kerosene (RP-1), hydrazine, nitrogen tetroxide (N2O4), monomethylhydrazine (MMH),Liquid Propellant Systems,Pump fed systems Propellant delivered to engine using turbopump

13、 Gas turbine drives centrifugal or axial flow pumps Large, high thrust, long burn systems: launch vehicles, space shuttle Different cycles developed.,Photos history.nasa.gov,F-1 Engine Turbopump,H-1 Engine Turbopump,F-1 engine turbopump:55,000 bhp turbine drive15,471 gpm (RP-1)24,811 gpm (LOX),A 35x

14、15x4.5 (ave. depth) backyard pool holds about 18,000 gallons of water. How quickly could the F-1 pump empty it?,Ans: In 27 seconds!,Rocket Engine Power Cycles,Gas Generator Cycle Simplest Most common Small amount of fuel and oxidizer fed to gas generator Gas generator combustion products drive turbi

15、ne Turbine powers fuel and oxidizer pumps Turbine exhaust can be vented through pipe/nozzle, or dumped into nozzle Saturn V F-1 engine used gas generator cycle,www.aero.org/publications/ crosslink/winter2004/03_sidebar3.html,,Rocket Engine Power Cycles - cont,Expander Fuel is heated by nozzle and th

16、rust chamber to increase energy content Sufficient energy provided to drive turbine Turbine exhaust is fed to injector and burned in thrust chamber Higher performance than gas generator cycle Pratt-Whitney RL-10,www.aero.org/publications/ crosslink/winter2004/03_sidebar3.html,science.nasa.gov,Rocket

17、 Engine Power Cycles - cont,Staged Combustion Fuel and oxidizer burned in preburners (fuel/ox rich) Combustion products drive turbine Turbine exhaust fed to injector at high pressure Used for high pressure engines Most complex, requires sophisticated turbomachinery Not very common SSME (2700 psia),w

18、ww.aero.org/publications/ crosslink/winter2004/03_sidebar3.html,,shuttle.msfc.nasa.gov,The Big Engines,www.nationalmuseum.af.mil,Solid Propellant Motors,Fuel and oxidizer are in solid binder. Single use - no restart capability. Lower performance than liquid systems, but much simpler. Applications in

19、clude launch vehicles, upper stages, and space vehicles.,www.aerospaceweb.org,,Hybrid Motors,Combination liquid-solid propellant Solid fuel Liquid oxidizer Multi-start capability Terminate flow of oxidizer Fuels consist of rubber or plastic base, and are inert. Just about anything that burns Oxidize

20、rs include LO2, hydrogen peroxide (N2O2) and nitrous oxide (NO2) Shut-down/restart capability.,Rocket Performance Calculations,Thrust & Specific Impulse Thrust is the amount of force generated by the rocket. Specific impulse is a measure or engine performance (analogous to miles per gallon) Units ar

21、e seconds,Rocket Equation,Rocket equation assumes no losses (gravity effects, aerodynamic drag). Actually very accurate for short burns in Earth orbit or in deep space!,Specific Impulse Comparison,Stored gas Monopropellant hydrazine Solid rocket motors Hybrid rockets Storable bipropellants LOX/LH2,6

22、0-179 sec 185-235 sec 280-300 sec 290-340 sec 300-330 sec 450 sec,Specific impulse depends on many factors: altitude, nozzle expansion ratio, mixture ratio (bipropellants), combustion temperature.,Mission Delta-V Requirements,LEO = Low Earth orbit (approx. 274 km),Propellant Calculation Exercise,Det

23、ermine the mass of propellant to send a 2500 kg spacecraft from LEO to Mars (0.7 yr mission). Assume the 2500 kg includes the propellant on-board at the start of the burn. Assume our engine has a specific impulse of 310 sec (typical of a small bipropellant engine). Use the rocket equation:,Most of o

24、ur spacecraft is propellant! Only 383 kg is left for structure, etc! How could we improve this?,Electric Propulsion,Classifications Electrothermal Electrostatic Electromagnetic Characteristics Very low thrust Very high Isp 1000 sec Requires large amounts of power (kilowatts),This image of a xenon io

25、n engine, photographed through a port of the vacuum chamber where it was being tested at NASAs Jet Propulsion Laboratory, shows the faint blue glow of charged atoms being emitted from the engine. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propel

26、ling a spacecraft.,www-ssc.igpp.ucla.edu,Electrothermal Propulsion,Electrical power is used to add energy to exhaust products Resistojet Catalytic decomposition of hydrazine is augmented with high power electric heater 800 5,000 W Arcjet High voltage arc at nozzle throat adds thermal energy to exhau

27、st Various gaseous or vaporized propellants can be used.,rocket.itsc.uah.edu,,www.nasa.gov,,Electrostatic Propulsion,Xenon Ion Thruster Xenon propellant Electrostatic forces are used to accelerate charged particles to very high velocities Xenon is ionized by electron bombardment Thermionic cathode P

28、ositively charged particles accelerated by grid Electrons routed to second anode and injected into beam to neutralize,www.plasma.inpe.br,aerospace.engin.umich.edu,ESAs SMART-1 uses a xenon ion propulsion system (XIPS),Electromagnetic Propulsion,Electromagnetic forces are used to accelerate a plasma

29、A gas consisting of positive ions, electrons 5000 9000 R Neutral beam is produced Higher thrust per unit area than electrostatic thruster Classifications Magnetoplasmadynamic Pulsed plasma Electric discharge creates plasam from solid Telfon Hall effect Developed in Russia Flew on U.S. STEx mission (

30、1998),www.nasa.gov,The Future,Interplanetary travel will require advanced forms of propulsion technology: Antimatter Nuclear fusion Non-rocket methods,References,Theory and design Sutton, G. P. and Biblarz, O., Rocket Propulsion Elements, 7th ed. ,Wiley, 1987 A classic; covers most propulsion techno

31、logies Huzel, D.K, and Huang, D. H., Modern Engineering for Design of Liquid Propellant Rocket Engines (revised edition), Progress in Aeronautics and Astronautics, Vol. 147, American Institute for Aeronautics and Astronautics, 1992 Dieter Huzel was one of the German engineers who came to the U.S. af

32、ter WW II. Humble, R. W., et. al., Space Propulsion Design and Anaylsis (revised edition), McGraw-Hill, 1995 Covers chemical (liquid, solid, hybrid), nuclear, electric, and advanced propulsion systems for deep space travel,References - cont,Rocket engine history Macinnes, P., Rockets: Sulfur, Sputni

33、k and Scramjets, Allen & Unwin, 2003 Clary, D. A., Rocket Man: Robert H. Goddard and the Birth of the Space Age, Hyperion Special Markets, 2003 Ordway, F. I. and Sharpe, M., The Rocket Team, Apogee Books, 2003 The story of Werner von Braun, the V-2 and the transition of the German engineers to the United States following WW II Sutton, G. P., History of Liquid Propellant Rocket Engines, American Institute for Aeronautics and Astronautics, 2006 New, over 800 pages of rocket engine history,When things go bad,http:/