Propulsion Systems Design • Rocket engine basics • Survey of the technologies • Propellant feed systems • Propulsion systems design © 2016 David L. Akin - All rights reserved http://spacecraft.ssl.umd.edu U N I V E R S I T Y O F Rocket Propulsion MARYLAND 1 ENAE 791 - Launch and Entry Vehicle Design Liquid Rocket Engine Cutaway U N I V E R S I T Y O F Rocket Propulsion MARYLAND 2 ENAE 791 - Launch and Entry Vehicle Design Thermal Rocket Exhaust Velocity • Exhaust velocity is ! + γ −1. 2γ ℜT - % p ( γ 0 ! 0 ' e * Ve = -1 −' * 0 γ −1 M - & p ) 0 ! , 0 / where M ≡ average molecular weight of exhaust Joules ℜ ≡ universal gas const.= 8314.3 mole°K γ ≡ ratio of specific heats ≈1.2 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 3 ENAE 791 - Launch and Entry Vehicle Design €€ € € Ideal Thermal Rocket Exhaust Velocity • Ideal exhaust velocity is ! 2γ ℜT V = 0 ! e γ −1 M • Tis corresponds to an ideally expanded nozzle • All thermal energy converted to kinetic energy of exhaust • Only a function of temperature and molecular weight! U N I V E R S I T Y O F Rocket Propulsion MARYLAND 4 ENAE 791 - Launch and Entry Vehicle Design € Thermal Rocket Performance • Trust is ! T = m˙ Ve + ( pe − pamb)Ae • Effective exhaust velocity ! A " c % T m˙ c c V p p e $ I = ' ! = ⇒ = e + ( e − amb) $ sp ' m˙ # g0 & • Expansion ratio 1 1 * γ −1- γ −1# & γ # & γ At # γ +1& pe γ +1, pe / = % ( % ( ,1 −% ( / A $ 2 ' $ p ' γ −1, $ p ' / e 0 + 0 . U N I V E R S I T Y O F Rocket Propulsion MARYLAND 5 ENAE 791 - Launch and Entry Vehicle Design € € € € A Word About Specific Impulse • Defined as “thrust/propellant used” – English units: lbs thrust/(lbs prop/sec)=sec – Metric units: N thrust/(kg prop/sec)=m/sec • Two ways to regard discrepancy - – “lbs” is not mass in English units - should be slugs – Isp = “thrust/weight flow rate of propellant” • If the real intent of specific impulse is T I = and T = mV˙ then I = V !!! sp m˙ e sp e U N I V E R S I T Y O F Rocket Propulsion MARYLAND 6 ENAE 791 - Launch and Entry Vehicle Design Nozzle Design • Pressure ratio p0/pe=100 (1470 psi-->14.7 psi) Ae/At=11.9 • Pressure ratio p0/pe=1000 (1470 psi-->1.47 psi) Ae/At=71.6 • Difference between sea level and ideal vacuum Ve ! γ −1 # & γ Ve pe ! = 1−% ( V $ p ' ! e,ideal 0 • Isp,vacuum=455 sec --> Isp,sl=333 sec U N I V E R S I T Y O F Rocket Propulsion MARYLAND 7 ENAE 791 - Launch and Entry Vehicle Design € Solid Rocket Motor From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 8 ENAE 791 - Launch and Entry Vehicle Design Solid Propellant Combustion Characteristics From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 9 ENAE 791 - Launch and Entry Vehicle Design Solid Grain Configurations From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 10 ENAE 791 - Launch and Entry Vehicle Design Short-Grain Solid Configurations From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 11 ENAE 791 - Launch and Entry Vehicle Design Gemini Retrograde Engine U N I V E R S I T Y O F Rocket Propulsion MARYLAND 12 ENAE 791 - Launch and Entry Vehicle Design Advanced Grain Configurations From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 13 ENAE 791 - Launch and Entry Vehicle Design Liquid Rocket Engine U N I V E R S I T Y O F Rocket Propulsion MARYLAND 14 ENAE 791 - Launch and Entry Vehicle Design Liquid Propellant Feed Systems U N I V E R S I T Y O F Rocket Propulsion MARYLAND 15 ENAE 791 - Launch and Entry Vehicle Design Space Shuttle OMS Engine From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 16 ENAE 791 - Launch and Entry Vehicle Design Turbopump Fed Liquid Rocket Engine From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 17 ENAE 791 - Launch and Entry Vehicle Design Sample Pump-fed Engine Cycles From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 18 ENAE 791 - Launch and Entry Vehicle Design Gas Generator Engine Schematic U N I V E R S I T Y O F Rocket Propulsion MARYLAND 19 ENAE 791 - Launch and Entry Vehicle Design SpaceX Merlin 1d Engines U N I V E R S I T Y O F Rocket Propulsion MARYLAND 20 ENAE 791 - Launch and Entry Vehicle Design Falcon 9 Octoweb Engine Mount U N I V E R S I T Y O F Rocket Propulsion MARYLAND 21 ENAE 791 - Launch and Entry Vehicle Design Staged-Combustion Engine Schematic U N I V E R S I T Y O F Rocket Propulsion MARYLAND 22 ENAE 791 - Launch and Entry Vehicle Design RD-180 Engine(s) (Atlas V) U N I V E R S I T Y O F Rocket Propulsion MARYLAND 23 ENAE 791 - Launch and Entry Vehicle Design SSME Powerhead Configuration U N I V E R S I T Y O F Rocket Propulsion MARYLAND 24 ENAE 791 - Launch and Entry Vehicle Design SSME Engine Cycle From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 25 ENAE 791 - Launch and Entry Vehicle Design Liquid Rocket Engine Cutaway From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 26 ENAE 791 - Launch and Entry Vehicle Design H-1 Engine Injector Plate U N I V E R S I T Y O F Rocket Propulsion MARYLAND 27 ENAE 791 - Launch and Entry Vehicle Design Injector Concepts From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 28 ENAE 791 - Launch and Entry Vehicle Design TR-201 Engine (LM Descent/Delta) U N I V E R S I T Y O F Rocket Propulsion MARYLAND 29 ENAE 791 - Launch and Entry Vehicle Design Solid Rocket Nozzle (Heat-Sink) From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 30 ENAE 791 - Launch and Entry Vehicle Design Ablative Nozzle Schematic From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 31 ENAE 791 - Launch and Entry Vehicle Design Active Chamber Cooling Schematic From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 32 ENAE 791 - Launch and Entry Vehicle Design Boundary Layer Cooling Approaches From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 33 ENAE 791 - Launch and Entry Vehicle Design Hybrid Rocket Schematic From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 34 ENAE 791 - Launch and Entry Vehicle Design Hybrid Rocket Combustion From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 35 ENAE 791 - Launch and Entry Vehicle Design Thrust Vector Control Approaches From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 1986 U N I V E R S I T Y O F Rocket Propulsion MARYLAND 36 ENAE 791 - Launch and Entry Vehicle Design Gemini Entry Reaction Control System U N I V E R S I T Y O F Rocket Propulsion MARYLAND 37 ENAE 791 - Launch and Entry Vehicle Design Apollo Reaction Control System Thrusters U N I V E R S I T Y O F Rocket Propulsion MARYLAND 38 ENAE 791 - Launch and Entry Vehicle Design RCS Quad U N I V E R S I T Y O F Rocket Propulsion MARYLAND 39 ENAE 791 - Launch and Entry Vehicle Design Apollo CSM RCS Assembly U N I V E R S I T Y O F Rocket Propulsion MARYLAND 40 ENAE 791 - Launch and Entry Vehicle Design Lunar Module Reaction Control System U N I V E R S I T Y O F Rocket Propulsion MARYLAND 41 ENAE 791 - Launch and Entry Vehicle Design LM RCS Quad U N I V E R S I T Y O F Rocket Propulsion MARYLAND 42 ENAE 791 - Launch and Entry Vehicle Design Viking Aeroshell RCS Thruster U N I V E R S I T Y O F Rocket Propulsion MARYLAND 43 ENAE 791 - Launch and Entry Vehicle Design Viking RCS Thruster Schematic U N I V E R S I T Y O F Rocket Propulsion MARYLAND 44 ENAE 791 - Launch and Entry Vehicle Design Space Shuttle Primary RCS Engine From G.