Propulsion Systems Design - PDF Free Download

Liquid Rocket Engine Cutaway 2

Thermal Rocket Exhaust Velocity Exhaust velocity is!!! where V e = 2γ γ 1 RT 0 M + - % 1 p ( e - ' * - & p 0 ), γ 1 M average molecular weight of exhaust R universal gas const.= 8314.3 Joules mole K γ ratio of specific heats 1.2 γ. 0 0 0 / 3

Ideal Thermal Rocket Exhaust Velocity Ideal exhaust velocity is! 2γ RT V! e = 0 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! 4

Thermal Rocket Performance Thrust is! T = m V e + ( p e p amb )A e Effective exhaust velocity! T = m c c = V! e + p e p amb Expansion ratio A t # = γ +1 & % ( A e $ 2 ' 1 γ 1 # % $ p e p 0 ( ) A e m 1 * & γ γ +1, # ( ' γ 1 1 p e, %, $ p 0 + & ( ' γ 1 γ " I sp = c % $ ' # g 0 & - / / /. 5

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 I sp = Ṫ m and T = ṁv e then I sp = V e!!! 6

Nozzle Design Pressure ratio p 0 /p e =100 (1470 psi-->14.7 psi) A e /A t =11.9 Pressure ratio p 0 /p e =1000 (1470 psi-->1.47 psi) A e /A t =71.6 Difference between sea level and ideal vacuum V e!!! V # e = 1 p e % V e,ideal $ I sp,vacuum =455 sec --> I sp,sl =333 sec p 0 & ( ' γ 1 γ 7

Solid Rocket Motor From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 8

Solid Propellant Combustion Characteristics From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 9

Solid Grain Configurations From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 10

Short-Grain Solid Configurations From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 11

Gemini Retrograde Engine 12

Advanced Grain Configurations From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 13

Liquid Rocket Engine 14

Liquid Propellant Feed Systems 15

Space Shuttle OMS Engine From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 16

Turbopump Fed Liquid Rocket Engine From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 17

Sample Pump-fed Engine Cycles From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 18

Gas Generator Engine Schematic 19

SpaceX Merlin 1d Engines 20

Falcon 9 Octoweb Engine Mount 21

Staged-Combustion Engine Schematic 22

RD-180 Engine(s) (Atlas V) 23

SSME Powerhead Configuration 24

SSME Engine Cycle From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 25

Liquid Rocket Engine Cutaway From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 26

H-1 Engine Injector Plate 27

Injector Concepts From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 28

TR-201 Engine (LM Descent/Delta) 29

Solid Rocket Nozzle (Heat-Sink) From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 30

Ablative Nozzle Schematic From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 31

Active Chamber Cooling Schematic From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 32

Boundary Layer Cooling Approaches From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 33

Hybrid Rocket Schematic From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 34

Hybrid Rocket Combustion From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 35

Thrust Vector Control Approaches From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 36

Gemini Entry Reaction Control System 37

Apollo Reaction Control System Thrusters 38

RCS Quad 39

Apollo CSM RCS Assembly 40

Lunar Module Reaction Control System 41

LM RCS Quad 42

Viking Aeroshell RCS Thruster 43

Viking RCS Thruster Schematic 44

Space Shuttle Primary RCS Engine From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 45

Monopropellant Engine Design From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 46

Cold-gas Propellant Performance From G. P. Sutton, Elements (5th ed.) John Wiley and Sons, 1986 47

Total Impulse Total impulse I t is the total thrust-time product for the propulsion system, with units <N-sec>!!!! To assess cold-gas systems, we can examine total impulse per unit volume of propellant storage I t = Tt = ṁv e t 48 t = V ṁ I t = V v e I t V = v e

Performance of Cold-Gas Systems 49

Self-Pressurizing Propellants (CO 2 ) 50

Self-Pressurizing Propellants (N 2 O) Density! 1300 kg/m 3 Density! 625 kg/m 3 51

N 2 O Performance Augmentation Nominal cold-gas exhaust velocity ~600 m/sec N 2 O dissociates in the presence of a heated catalyst engine temperature ~1300 C exhaust velocity ~1800 m/sec NOFB (Nitrous Oxide Fuel Blend) - store premixed N 2 O/hydrocarbon mixture exhaust velocity >3000 m/sec 2N 2 O! 2N 2 + O 2 52

Pressurization System Analysis P g0, V g Adiabatic Expansion of Pressurizing Gas P gf, V g p g,0 V g γ = p g, f V g γ + p l V l γ Known quantities: P L, V L Initial P L, V L Final P g,0 =Initial gas pressure P g,f =Final gas pressure P L =Operating pressure of propellant tank(s) V L =Volume of propellant tank(s) Solve for gas volume V g 53!

Boost Module Propellant Tanks Gross mass 23,000 kg Inert mass 2300 kg Propellant mass 20,700 kg Mixture ratio N 2 O 4 /A50 = 1.8 (by mass) N 2 O 4 tank Mass = 13,310 kg Density = 1450 kg/m 3 Volume = 9.177 m 3 --> r sphere =1.299 m Aerozine 50 tank Mass = 7390 kg Density = 900 kg/m 3 Volume = 8.214 m 3 --> r sphere =1.252 m 54

Boost Module Main Propulsion Total propellant volume V L = 17.39 m 3 Assume engine pressure p 0 = 250 psi Tank pressure p L = 1.25*p 0 = 312 psi Final GHe pressure p g,f = 75 psi + p L = 388 psi Initial GHe pressure p g,0 = 4500 psi Conversion factor 1 psi = 6892 Pa Ratio of specific heats for He = 1.67!( 4500 psi)v 1.67 g = ( 388 psi)v 1.67 g + 312 psi V g = 3.713 m 3 Ideal gas: T=300 K --> ρ=49.7 kg/m 3 (4500 psi = 31.04 MPa) M He =185.1 kg 55 ( ) 1.67 ( ) 17.39 m 3 ρ He = p M g,0 RT 0