MAE 5391: Rocket Propulsion Overview of Propulsion Systems
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MAE 5391: Rocket Propulsio Overview of Propulsion Sys
description
MAE 5391: Rocket Propulsion Overview of Propulsion Systems. Rocket Technologies. Propulsion Technology Options. Thermodynamic Systems (TE KE) Cold Gas Thrusters Liquids Monopropellants Bipropellants Solids Hybrids Nuclear (NE TE KE) Electric Systems - PowerPoint PPT Presentation
Transcript of MAE 5391: Rocket Propulsion Overview of Propulsion Systems
MAE 5391: Rocket PropulsionOverview of Propulsion Systems
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Propulsion Technology Options Thermodynamic Systems (TE KE)
Cold Gas Thrusters Liquids
• Monopropellants• Bipropellants
Solids Hybrids
Nuclear (NE TE KE) Electric Systems
Electrothermal (Resistance Heating) Electrostatic (Ion with E field F=qE) Electromagnetic (plasma with B field F=JxB)
With the exception of electrostatic and electromagnetic, all use concept of gas at some temp flowing though a converging/diverging nozzle!
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Chemical Limitations
Why we have thermo!
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2 /1
0
0
pp
MTRV eu
exit
Vexit= nozzle exit velocity (m/s)
Ru= universal gas constant (8314.41 J/kmol*K)T0= chamber temperature (K)Pe= exit pressure (Pa)P0= chamber pressure (Pa)M= molecular mass of gas (kg/kmol)= ratio of specific heats (no dimensions)
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Cold Gas
Gas MolecularWeight
SpecificImpulse (sec)
Air 28.9 74Argon 39.9 57CO2 44.0 67
Helium 4.0 179Hydrogen 2.0 296Nitrogen 28.0 80Methane 16.0 114
1.5 litre X 600 barNitrogen tanks
Fill/drain valve
Two stage regulator (feed pressure ~ 4bar)
Thruster (0.01N,1.3 *10-5 kg/s,throat diameter0.0133 cm)
Stop valve
Microsat cold gaspropulsion systemlayout proposal
Cold Gas: Expand a pressurized gas through a nozzle
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Liquid MonopropellantParameter Value
Catalyst LCH 227/202
Steady-state thrust (N) 11.1 - 31.2
Isp (sec) 228 - 235
Propellant specific gravity 1.023
Average Density Isp ( sec) 236.8
Rated total impulse (Nsec) 124,700
Total pulses 12,405
Minimum impulse bit (Nsec) 0.56
Feed pressure (bar) 6.7 - 24.1
Chamber pressure (bar) 4.5 - 12.4
Nozzle expansion ratio 61:1
Mass flow rate (gm/sec) 5.0 - 13.1
Valve power 27 W max @ 28 VDC
Thruster mass (kg) 0.52
3 N2H4 4 NH3 + N2 + 336,280 joules
MonoProp: Decompose a single propellant and expand the exhaust through a nozzle
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Liquid Bi-Propellant
Storable Isp 250-320 secfinert=0.03-.13
Cryogenic Isp 320 – 452 secfinert=0.09-0.2
BiProp: Combust (burn) two propellants (fuel + oxidizer) in a combustion chamber and expand exhaust through a nozzle
Finert = 0.04-0.2 Finert=0.11-0.31
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Solids Composite propellant, consisting of an
oxidizing agent, such as ammonium nitrate or ammonium perchlorate intimately mixed with an organic or metallic fuel and binder.
Thrust function of burn area, Isp = 250-300 secFinert=0.06-0.38, 2/3 of motors have fiinert below 0.2
AdvantagesSimpleReliableHigh density IspNo chamber cooling
DisadvantagesCracks=disasterCan’t restartHard to stopModest Isp
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When solids go bad!
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Hybrids
Isp= 290-350 secFinert=0.2
Hybrid: Bipropellant system with liquid oxidizer (usually) and a solid fuel
Catalyst Pack
Combustion Chamber
Nozzle
Test Stand
Load Cell
Fuel Element
H2O2/PE Hybrid Test Set-Up
Polyethylene fuel rod
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Nuclear Thermal Propulsion
NERVA Program Thrust = 890,000N Isp = 838 sec Working fluid = Hydrogen Test time = 30 minutes Stopped in 1972 Finert=0.5-0.7 (shielding)
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Electrothermal-Resistojets
Nozzle
Thermocouple tapping
Stainless steel outer1225W Cartridge heater
Water inlet
Heater thermocouple
Power inputSintered stainlesswater distribution ring
Sintered stainless filterPressure tapping
SiC Heat transfer medium
Cutaway of Mark- III Resistojet
Working Fluid
Thrust (mN) Isp (sec) Power (W) Cp (kJ/kg K) Tc (K)
hydrogen 37 546 100 14.32 1000
water 93 219 100 2.3 1000
nitrous oxide 141 144 100 1.0 1000
Electrothermal-- electrical energy is used to directly heat a working fluid. The resulting hot gas is then expanded through a converging-diverging nozzle to achieve high exhaust velocities. These systems convert thermal energy to kinetic energy
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Electrothermal-Arcjets
In an arcjet, the working gas is injected in a chamber through which an electric arc is struck. The gas is heated to very high temperature (3000 – 4000 K), Arc temp =10,000K on average, and much greater in certain regions in the arc.
Power = 1.8 kW, Isp = 502, Thrust = 0.2N, Propellant = hydrazine
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Electrostatic-Ion Propulsion Electrostatic-- electrical energy is directly converted into
kinetic energy. Electrostatic forces are applied to charged particles to accelerate the propellant.
Deep Space 1 = 4.2 kW, Thrust = 165 mN, Isp = 3800 sec7000 hours of operation is becoming the standard!
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Electromagnetic-MPD Thruster Electromagnetic-- electromagnetic forces directly
accelerate the reaction mass. This is done by the interaction of electric and magnetic fields on a highly ionised propellant plasma.
NH3 MPD, F=23 mN, Isp= 600 sec, P=430 W Stuttgart, Isp=5000sec, F=100N, P=6 MW, hydrogen
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Pulsed Plasma Thrusters
Ctrigger
CMain
Rtrigger
CenterElectrode
IntermediateElectrode
OuterElectrode
Teflon Annulus
PPUSpacecraftGround
Isp = 500-1500 secP = 1 – 100 WThrust = 5mN/W
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Hall Effect Thruster
Power = 50W – 25kWIsp = 500 – 3000 secThrust = 5 mN- 1N
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Propulsion System “Cost” Performance issues
Mass Volume Time (thrust) Power Safety Logistics Integration Technical Risk
The “best” (lowest “cost”) option optimizes these issues for a given set of mission requirements
