rockets and how they work by jan-erik rønningen norwegian rocket technology [...
TRANSCRIPT
Rockets and how they work
By Jan-Erik RønningenNorwegian Rocket Technology[ [email protected] ][ www.rocketconsult.no ]
Version: 1.30 2008
Contents
Rocket history Rocket Principle Fundamental Rocket Elements The Solid Propellant Rocket The Liquid Propellant Rocket The Hybrid Rocket Motor
Rocket History 1 The Chinese is claimed by many to be the
inventor of the black powder (about 200 B.C) and thus the rockets
Newer findings indicate that it is India that should be honored instead
However, old Chinese documents describe long tradition in making various black powder charges for use in firecrackers and rockets mostly for frighten bad spirits during religious happenings and during various festivals and celebrations.
The Chinese also developed rockets and flame torches to be used in combat against their main enemy, the Mongols.
Rocket History 2 The Arabs learned the art of rocketry
from the Mongols and the Europeans from the Arabs.
The Europeans developed the rocket technology further, i.e. between the 14th and 16th century: A English munch named Roger
Beacon improved the black powder prescription for use as rocket propellant, fire crackers and for use in canons.
A French man improved the hit accuracy of his artillery rockets by launching them from tubes.
An Italian (Fontana) experimented with rocket powered surface torpedoes which could ran into the cavalry or set ships on fire. One successfully did!!
Rocket History 3 The interest of the rocket as a weapon
went into a hibernation during the 17th century, mainly because of the poor accuracy compare to the more accurate and destructive canon. Further improvements were necessary.
A new dawn of rocketry appeared during the 18th century and especially some hundred years after Sir Isacc Newton had published his famous three laws.
During the 19th and 20th century many men were to become well know: Ziolkowsky, Hermann Oberth, Robert H. Goddard, Eugen Sänger, Werner von Braun, Korolev and many more
Rocket History 4 After the WWII the race for space
between USA and former Soviet escalated and accelerated the development of rocket technology to what we know and use today.
Sputnik I – World first artificial satellite launched 4. October 1957
Apollo 11 and Neil Armstrong – First man on the Moon20. July 1969
Vostok 1 and Yuri A, Gagarin – First man in space 12. April 1961
The Rocket Principle 1
Newtons 2. law:
Newtons 3. law: force = opposite force
amdt
vmdF
)(
Rocketdt
dp
Exhaustdt
dp
dt
vmd
dt
dp exhaust
Rocket
)(
The Rocket Principle 2 A chemical rocket is a reaction device
that brings with itself the oxygen needed for combustion and thus for generating thrust for positive propulsion
Rocket Elements – Main Parts
Convergent Divergentsection section
t ei
c
VeVtVc
c : chamberi : entrancet : throate : exitV: velocity
F
Rocket Elements - Thrust
impulseexhaustexhaustexhaust
exhaust
productsreaction
rocket
Fvmvdt
dm
dt
vmd
dt
dp
_)(
Ambient Pressure
Ambient Pressure
Ambient Pressure
Exit Pressure
)(_ aeeeforcepressure PPAPAF
)(_ aeeeforcepressureimpulse PPAvmFFF
F
Rocket Elements - Nozzle Flow
[4]
or
0
:expression above thetingDifferenta
const. lnlnln
:eq.1 of logaritm natural thenow take weproceeding Before
[3]
:as writtenbe can 2 eq. flow, ldimensiona-one and change potential no assume weSince
height :z and )( weight specific : speed, : vdensity, : pressure,:p
:where
line) streama along (const. [2] 0)(5.0
:friction) no (assuming equation Bernoullifamous the toleading
flow, particle fluidsteady a describe toutlilized be canlaw second Newtons
[1] .
:states mass of onconservati theconduit, a varying ghflow throu fluida When
2
2
A
dAd
v
dv
v
dv
A
dAd
vA
v
dv
v
dp
g
dzvddp
constvAm
0! dA/dv 1, MaWhen
[10] 1dv
dA
:gives eq.8 of grearrangin A
1 Ma :flow Supersonic
1 Ma :flow Subsonic
:conclude can we whichFrom
[9] )1(
dp
:us gives eq.8 and 4 Eq.
[8] )1(
1
v
dv
:form toeq.7 withmerged befurther can 3 Eq.
[7] 1
:as writtenbe 6 eq. now with can 5 Eq.
[6] and
:density withpressure of s variation torelated is sound of speed
theless), friction and (adiabatic flow isentropic assume We
[5] 1
:gives [4] [3]
2
2
2
2
22
2
2
Mav
A
Ma
Ma
A
dA
MaA
dA
A
dAMa
v
dp
a
vMa
pa
A
dA
ddpv
v
dp
s
Flow
Flow
Pe>Pa (under expansion)
Rocket Elements - Nozzle Flow
M~0 M=1 M>3P=Pk Ph~0.5Pk PeSubsonic Transonic Supersonic
Pe=Pa (optimum expantion)
Pe<Pa (over expansion)
Entrance Throat Exit
Rocket Elements - Nozzle Flow
0.15 0.2 0.25 0.3X-posisjon
-0.05
0
0.05
Y-p
osi
sjon
AM3.43.23.02.82.62.42.22.01.81.61.41.21.00.80.60.40.20.0
Laval dyse, ekspansjonsforhold=8.3
Machtall konturer [-]
Rocket Elements - Total Impulse
0,00
5000,00
10000,00
15000,00
20000,00
25000,00
30000,00
35000,00
0,000 1,000 2,000 3,000 4,000 5,000 6,000 7,000
Time (s)
Th
rus
t (N
)
b
tb
t tFdttFI 0
)(
Static Firing a Rocket Motor
NSR 30kN Hybrid Rocket Motor, 20s test
Rocket Elements - Specific ImpulseSpecific Impuls Values for Various Chemical Propellants
830
1442 14701825 1880
22002600 2630
3240
3796
10000
0
2000
4000
6000
8000
10000
12000
75% KNO3 +15% S +10% C
H2O2 +KMnO4
65% KNO3 +35%
C6H14O6
75% KClO4+ 17.5%Asphalt +7.5% Oil
82%NH4NO3 +
11% HTPB +7% Additives
60% NG +40% NC
78%NH4ClO4 +
15% HTPB +7% AL
RFNA + RP1 LO2 + HTPB LO2 + LH LH2 + U235
Sp
ec
ific
Imp
uls
[N
s/k
g]
Non Chemical
Rocket Propellant Condition Exampel of Use ISP [Ns/kg]Black Powder (75%KNO3 + 15%S + 10%C) Pressed Powder Fireworks 830Hydrogen Peroxide H2O2(l) + Potassium Permanganat KMnO4(s) Liquid/Solid Hobby Rockets 1442Candy Propellant (65%KNO3 + 35%C6H14O6) Hot Casted Hobby Rockets 147075% KClO4 + 17.5% Asphalt/Tar + 7.5% Oil Casted Hobby Rockets 182582% NH4NO3 + 11% HTPB + 7% Additives Casted Gassgenerator 1880Double Base (60% Nitroglycerine + 40% Nitrcellulose) Extruded Missiles 220078% NH4ClO4 + 15% HTPB + 7% Al Casted Ariane 5 SRB 2600RFNA + Kerosene (RP1) (1.43 Mixtureratio) Liquid X-1 Rocket Plane 2630LOX + HTPB Liquid/Solid Launch Vehicle 3240LOX + LH (3.40 Mixtureratio) Liquid Ariane 5 1.stage 3796LH + Solid Core Nuclear Reactor (Fisson of U235) Liquid/Solid Nerva Test Motor 10000
d
bsp m
tFI
The Solid Propellant RocketConstruction:
Motor Case Thermal Insulation
Propellant NozzleIgniter
Solid Propellant Rocket
PARAMETER CHARACTERISTIC VALUE RANGE
Specific Impulse [m/s] 2000-2600
Burn rate [mm/s] 1-15
Chamber Pressure [MPa] 7-20
Combustion Efficiency [-] 0.95-0.98
Thrust to Weight Ratio High
Throttle? Difficult
Stop and Restart? Not Practical
Lifetime? Long (7 to 15 years)
The Solid Propellant RocketPropellant Mixing:
300 gallon approx. 1200kg of propellant
The Solid Propellant RocketPropellant Grain Geometry:
Advanced Grain Burn Evolution
The Solid Propellant RocketAriane 5 Solid Rocket Booster:
DATA for one SRBPropellant: HTPBPropellant Mass: 237T(158 cars)Motor Mass: 273T(182 cars)Thrust: 5400kN (about 550T!!!!)Burn Time: 130s (2.16min)Mass Consumption: 1.82T/sTVC: +/-6deg vectorable nozzle
The Liquid Propellant RocketConstructions:
The Liquid Propellant Rocket
PARAMETER CHARACTERISTIC VALUE RANGE
Specific Impulse [m/s] 2500-3800
Burn Rate [mm/s] N.A
Chamber Pressure [MPa] 2-10
Combustion Efficiency [-] 0.95-0.98
Thrust to Weight Ratio Low
Throttle? Easy
Stop and Restart? Easy
Lifetime? Very Long (> 10 years)
The Liquid Propellant Rocket
The Liquid Propellant Rocket
The Liquid Propellant Rocket
The Hybrid Rocket
NozzleCombustion ChamberPressurized Nitrogen or Helium
Start/stop Valve and pressureregulator
Valve Electronics
Check Valve Solid Grain“Mixing” ZoneInjector
Liquid
Flow Valve and Regulatorwith control electronics
The Hybrid Rocket
PARAMETER CHARACTERISTIC VALUE RANGE
Specific Impulse [m/s] 2100-3200
Regression rate [mm/s] 0.2-5
Chamber Pressure [MPa] 2-5
Combustion Efficiency [-] 0.90-0.95
Thrust to Weight Ratio Medium
Throttle? Easy
Stop and Restart? Easy
Lifetime? Very Long (>10 years)
The Hybrid Rocket
Combustion Principle – The Candle Light
Air Air
Paraffin Wax
Liquid
Gas (H, C)
The Hybrid Rocket
The Hybrid Rocket
How is it to work as an “rocket scientist”?