Propulsion Systems Design • Lecture #23 - November 12, 2019 • Rocket engine basics • Survey of the technologies • Propellant feed systems • Propulsion systems design © 2019 David L. Akin - All rights reserved http://spacecraft.ssl.umd.edu U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 1 Team Project #2 - Due 12/5/19 • Based on ENAE 484 teams • Requirements document draft – Level 1 requirements – Start of flow-down to levels 2, 3, 4… • Concept of operations • Prioritized list of trade studies • Analysis results to date on top-priority studies • Conceptual/“strawman” design (CAD, mass est.) • Plans for Spring term (notional schedule) U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 2 Propulsion Taxonomy Mass Expulsion Non-Mass Expulsion Thermal Non-Thermal Ion Chemical Non-Chemical Solar Sail MPD Laser Sail Nuclear Monopropellants Bipropellants Beamed Electrical Microwave Sail Cold Gas Solar MagnetoPlasma Solids Hybrids Liquids Air-Breathing ED Tether Pressure-Fed Pump-Fed U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 3 Thermal Rocket Exhaust Velocity • Exhaust velocity is γ − 1 γ 2γ ℜTo pe ve = 1 − γ − 1 M¯ ( po ) where M¯ ≡ average molecular weight of exhaust Joules ℜ ≡ universal gas constant = 8314.3 moleoK γ ≡ ratio of specific heats ≈ 1.2 U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 4 Ideal Thermal Rocket Exhaust Velocity • Ideal exhaust velocity is 2γ ℜTo ve,ideal = γ − 1 M¯ • This 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 5 Thermal Rocket Performance • Thrust is · T = mve + (pe − pamb)Ae • Effective exhaust velocity · Ae c T = mc ⟹ c = ve + (pe − pamb) Isp = m· ( go ) • Expansion ratio 1 γ − 1 1 γ γ A γ + 1 γ − 1 p γ + 1 p t = e 1 − e Ae ( 2 ) ( po ) γ − 1 ( po ) U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 6 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 vacuum Ve γ − 1 γ − 1 γ γ ve1 po − pe1 = γ − 1 γ − 1 ve2 γ γ po − pe2 • Isp,vacuum=455 sec --> Isp,sl=397 sec U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 7 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 8 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 9 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 10 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 11 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 12 Liquid Rocket Engine U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 13 Liquid Propellant Feed Systems U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 14 Space Shuttle OMS Engine From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 2001 U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 15 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 16 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 17 Gas Generator Engine Schematic U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 18 SpaceX Merlin 1D Engines U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 19 Falcon 9 Octoweb Engine Mount U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 20 Staged-Combustion Engine Schematic U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 21 RD-180 Engine(s) (Atlas V) U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 22 SSME Powerhead Configuration U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 23 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 24 Liquid Rocket Engine Cutaway From G. P. Sutton, Rocket Propulsion Elements (5th ed.) John Wiley and Sons, 2001 U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 25 H-1 Engine Injector Plate U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 26 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 27 TR-201 Engine (LM Descent/Delta) U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 28 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 29 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 30 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 31 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 32 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 33 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 34 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 Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 35 Reaction Control Systems • Thruster control of vehicle attitude and translation • “Bang-bang” control algorithms • Design goals: – Minimize coupling (pure forces for translation; pure moments for rotation)except for pure entry vehicles – Minimize duty cycle (use propellant as sparingly as possible) – Meet requirements for maximum rotational and linear accelerations U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 36 Single-Axis Equations of Motion ⌧ = I✓¨ ⌧ t = ✓˙ + C I 1 ⌧ at t = 0, ✓˙ = ✓˙ = t = ✓˙ ✓˙ o ) I − o 1 ⌧ t2 + ✓˙ t = ✓ + C 2 I o 2 1 ⌧ at t = 0, ✓ = ✓ = t2 + ✓˙ t = ✓ ✓ o ) 2 I o − o 1 2 ⌧ ✓˙2 ✓˙ = (✓ ✓ ) 2 − o I − o U N I V E R S I T Y O⇣ F ⌘ Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 37 Attitude Trajectories in the Phase Plane 3.00% 2.00% 1.00% 0.00% !20.00% !10.00% 0.00% 10.00% 20.00% 30.00% 40.00% !1.00% tau/I=0% !0.001% !0.002% !2.00% !0.003% !0.004% !3.00% U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 38 Gemini Entry Reaction Control System U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 39 Apollo Reaction Control System U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles of Space Systems Design MARYLAND 40 RCS Quad U N I V E R S I T Y O F Propulsion Systems Design ENAE 483/788D - Principles