Outline
- Introduction (en français /
in french)
- Ramjet
- Scramjet
- PDE
- Conclusions
The Ramjet Pioneers (1913-1947)
- René LORIN, FR (patent, 1913)
- Albert FONO, GE (patent, 1928)
- M. STECHKIN, SSSR (ramjet theory, 1929)
- René LEDUC, FR (patent, 1933)
- Other contributions :
- FR : Marcel WANNER, Maurice ROY, Georges BRUN
- GE : Eugen SÄNGER, Alexander LIPPISCH, O. PABST, M.
TROMMSDORFF, H. WALTER
- SSSR : MM. BONDARYUK, DUDAKOV, MERKULOV, POBEDONOSTSEV,
TSANDER, ZOUYEV
- UK : BRISTOL
- USA : Roy MARQUARDT, APL/JHU
The French word "statoréacteur" has been created in 1945 by
Maurice ROY (before : "trompes ou tuyères thermopropulsives"). The
British adopted "Athodyd" (AeroTHermODYnamic Duct) before using ramjet. In
Germany ramjet has been called "Lorinflugrohr" or "Staustrahltriebwerke". In
SSSR, ramjet was named PVRD.
Some References Relating to Ramjet/Scramjet
- Books :
- Aircraft and Missile Propulsion, Vols I and II, M.J.
Zucrow, John Wiley, C. Son, Inc., 1958
- Aircraft Propulsion, P.J. Mc Mahon, Harpert Row, 1971
- The Rocket Ramjet Reader, CSD/UTC, ~ 1980
- Hypersonic Airbreathing Propulsion, W.H. Heiser, D.T.
Pratt, AIAA Education Series, 1994
- Some Fundamentals on the Performance of Ramjets with
Subsonic and Supersonic Combustion, TNO Prints Maurits Laboratory, 2000
- Recent French Articles :
- Statoréacteurs et superstatoréacteurs, A.
Chevalier, Science et Défense, 1993
- Statoréacteurs et superstatoréacteurs, des
moteurs pour demain, A. Chevalier, Science et Défense, 1995
- Le statoréacteur, technologie d'avenir, F. Falempin,
Colloque AAAF Aérodynamique et Propulsion des Véhicules à
Grande Vitesse, 28-30 mars 2001
- Ramjets et Scramjets, B. Petit, Encyclopedia of Physical
Science and Technology, Vol. 13, 2002
- Les statoréacteurs en France (1913-1992),
l'Aéronautique et l'Astronautique n° 153, 1999/2
Main Principle of the Ramjet
Basic design
- The air inlet/diffuser admits air to the engine, reduces air
velocity and develops ram pressure.
- The combustor adds heat and mass to the compressed air by
burning a fuel. The nozzle converts some of the thermal energy of the hot
combustion products to kinetic energy to produce thrust.
- Compression is given by the vehicle speed (bad performance at
low speed, auxiliary bosster needed to reach interesting performances).
- No moving parts, flexibility in geometrical design.
- High thrust per unit frontal area.
Flight Range of Ramjet Propelled Vehicles
Consumption of
air-breathing engines (Pratt & Whitney)
The hypersonic funnel (Mc Donnell
Douglas)
The First Developments and Applications (1945 to 1970)
- Experimental vehicles and missiles (mainly with front air
intake and jettisoned boosters)
- French achievements (more than 200 flight tests) :
- ONERA Stataltex : M=5 at 25000 m (1965), M=3,8 at 39000 m
- Arsenal (>> SFECMAS >> Nord Aviation >>
Aerospatiale >> EADS) and SNCASE (>> Sud Aviation >>
Aerospatiale >> EADS)
- SE 4400 : M=3,7 at 22000 m (1957)
- CT41, M=3 at 23000 m
- VEGA, M=4,2 at 25000 m (1961)
- MATRA, Snecma (ST 401, ST 402, ST 407)
- Leduc and Griffon 2 (turboramjet)
- SSSR : SA4 Ganef - SA6 Gainful (SAN3 Goblet) ; Ramjets
developed by NIITP ?
- Sweden : RR2, RRX-1, RRX-5
- UK : Bristol Siddeley Thor (Bloodhound) and Odin (Sea Dart)
- USA :
-
- RJ30, 31, 34, 37, 43, 57, 59 (Marquardt)
- RJ55 (Curtiss Wright)
- CIM10A/B : Bomarc/Super Bomarc
Some Poorly Known Achievements
- FR :
- SE X 422 (the first french cruise missile)
- ONERA SCORPION project (M6 missile)
- SSSR : Burya 2 (intercontinental strategic missile)
- USA : D21 (reconnaissance drone
The SE X 422 Demonstrator
- Prototype of a long range cruise missile
- mT = 1900 kg ; Ø 500 mm liquid fueled ramjet
- 3 successful tests in 1967 (Hammaguir and Levant Island)
Ref : Les engins à
statoréacteur du Groupe Technique de Cannes, L. Trousse,
L'Aéronautique et l'Astronautique, n° 153, 1999/2
The ONERA SCORPION Project
- SCORPION : Statoréacteur Cruciforme comme ORgane Portant
Intégré à Orifices Nasaux
- Prototype of a long range ground to air missile (M = 6, 600 km)
; Ø 220 mm liquid fueled ramjet (demonstrator)
- Successful ground tests of the fully integrated vehicle in the
S4 MA wind tunnel (1973-1974)
Operational lay-out
Model for S4 wind-tunnel testing
The Russian Burya (storm) Missile
- Development of an intercontinental strategic missile, similar
to the US XSM64 Navaho (Lavotchkin, parallel development Buran by Miassischev)
- mT = 216 t (including the two kerosene/nitric acid
fueled boosters) - Bondyaruk's ramjet RD012U, Ø 1700 mm
- MMAX = 3,15 ; 8000 km expected range
- 5 successful tests ; project cancelled in 1958
Ref : Aviation Week
and Space Technology, November 2, 1992, p. 50
The Supersonic Reconnaissance Drone Lockheed D21 Tagboard
- Black program ($2B) disclosed around 1990
- mT = 5 t ; Marquardt RJ43MA11 JP7 fueled ramjet,
Ø 711 mm
- D21 : launched from a Lockheed M12 aircraft at high
supersonic speed (programme cancelled in 1966 after a collision during
separation)
- D21B : launched from a Boeing B52 bomber with a booster
- MMAX = 4 at 30000 m ; endurance 4 h at M = 3,8 and
24000 m
- No recovery device
Ladies in waiting, a pictorial
review of Davis Monthan AFB, S. Wonderly, C.R. Dunham, Squadron/Signal
Publications, 1991
The Modern Ramjet for Missile Applications
- Integrated booster: ejectable booster nozzle or nozzleless
booster
- Flame stabilization by recirculation zones
Thor ramjet
(Bloodhound)
Integrated rocket ramjet (S225XR
project)
Modern Ramjet Propelled Missiles
- Air to air missiles
- MBDA Meteor (development)
- Vympel RVV-AE-PD R77M (AA12 Adder, development)
- Kentron ?
- Air to surface missiles
- EADS/AMM
- ASMP
- ASMP-A (development)
- Radouga Kh41 Moskit
- Zvezda Kh31P (AS17 Krypton)
- Antiship missiles
- Machinostroenie 3K55 Yakhont (SSN26)
- Radouga 3M80/82 Moskit (SSN22 Sunburn)
- CPMEC C301 (coast to ship)
- Hsiung Feng 3
A Classification of Ramjets According to the Fuel
- Pure fuel
- gas (hydrogen : stored liquid but injected gaseous after
wall cooling)
- liquid or slurry
- LFRJ (Liquid Fuel Ramjet)
- solid
- in bulk: SFRJ (Solid Fuel Ramjet)
- powdery
- Solid propellant gas generator ? Ducted rocket (DR) or Ram
rocket
- Unchocked Flow
- Chocked or Variable Flow
ANNG Project
The LFRJ
- Liquid fuels
- kerosenes or synthetic hydrocarbon fuels
Examples :
- USA :
- RJ1, RJ4 (tetrahydrodi (methycyclopentadiene)), RJ5
(perhydrodi (norbornadiene)), RJ6 (blend RJ5-JP10), RJ9
- - boranes (abandoned) .
- FR :
- CSD07T, CSD15T (developed and produced by IFP,
derivatives of norbornadiene)
- endothermal fuels
Example
Choice of the fuel is a compromise between specific impulse Is,
density/volumic specific impulse (dIs), mixture ratio and possibly cooling
capability and cracking properties. Combustion mechanisms : spray
combustion
RASCAL : RAmjet Small
CALibre
Use of a Slurry in the LFRJ
- Kerosene + boron particles (50 to 70 % mass content)
- FR : CHEOPS program ; US programs ; Russian programs ?
The SFRJ
- Solid fuels
- Polymer possibly loaded with metal particles (Mg, Al or B)
- Combustion mechanisms : pyrolysis and diffusion flame
- Good performance for high Mach number cruise but moderate
variability of the fuel regression rate, having an effect on the combustion
chamber design ; self modulation of the fuel mass flow rate and of the mixture
ratio
- Limited number of applications
The Ramjet Burning a Metal Powder
- A technology imported in France (ONERA) and successfully
demonstrated at middle scale (Ø 200 mm)
- Advantages : high performance, high density, management of a
cool fuel, high modulation rate, relative insensivity of the loading
- Drawbacks: a secondary gaseous source (gas generator and
cooler) is needed to fluidize the powder, preparation of the loading and
control of the flow rate are critical
The Ducted Rocket (DR)
- Principle :
- A "gas" generator is providing the fuel species which are
injected in the ramjet combustion chamber (GFRJ)
- The "gas" generator is working like a solid propellant
rocket, except that the solid propellant has a low oxidizer content
- The "gas" generator products can contain a high fraction of
fuel particles (Mg, Al, B, C) to enhance the performances
- The first operational missile using such a concept has been the
Russian SA6 Gainful (Mg). Work began in France at ONERA around 1972 (A. Moutet)
and related propellant activity was shared quickly with SNPE ("aerogols")
- A large variety of composite propellants for DR is now
available for missiles applications, for instance :
- propellants for "low" IR signature missiles
("aérolite")
- high density, high performance propellants
("aérofluolèbe")
- propellants for VFDR and UFDR C
- ombustion mechanisms are conventional one-phase or two-phase
ones
The VFDR
- Throttling of the gas generator mass flow rate by variation of
its throat, that gives a thrust modulation capability to the ramjet. But
throttling of hot gases, possibly containing solid particles, is technically
difficult
- Solution adopted on the Meteor (BVRAAM) ramjet
Source : PROTAC S.A.
The UFDR- The French "Rustique" Concept
- No chocked throat between the gas generator and the ramjet
combustion chamber ; the gas generator solid propellant burning rate depends on
the combustion chamber pressure ; self-modulation of the mixture ratio can be
obtained by giving a right value to the solid propellant pressure exponent
- Whole ramjet operation starting from the nozzleless booster
ignition order (munition style)
- Concept successfully demonstrated in flight through the MPSR
and MPSR2 programs (MATRA, ONERA, SNPE) ; no current applications
Scientific Issues of Ramjet
- Air intakes : the design is critical (efficiency on the whole
flight range, sensitivity to flow distorsions, participation to instabilities)
- Combustion chamber
- combustion efficiency
- lean and rich stability limits
- wall cooling
- operating instabilities
Combustion Efficiency and Stability Limits
- Combustion efficiency and stability limits are depending on
several parameters : fuel, equivalence ratio, air stagnation pressure and
temperature
- Experimental approach through tests : expensive
- The ONERA's approach, the research ramjet :
- a modular design reproducing the main features of an actual
ramjet
- the capability to get a detailed characterization of the
reactive flow by using the most advanced optical diagnostics (LDV, LIF,
PLIF
)
- a tool for validation the 3D turbulent reactive two phase
flow codes (MBDA-ONERA)
Combustion Chamber Wall Cooling
- Passive thermal protections
- different materials (silicone based) are available
- Active thermal protection
- a portion of the air flow entering is bypassed to protect
the case and is reinjected in the combustion chamber through perforations
- compatibility with booster integration demonstrated ;
concept rather interesting for combustion stability
- solution limited to flight Mach number less than 4
- Some successful developments of all composite cases,
application to ASMP-A
Operating Instabilities
- Different types of instability :
- overall instability involving the air intake(s) :
low/medium frequency (100 to 300 Hz) ; generally cured by improving the air
intake(s)
- combustion chamber acoustical instability : from medium to
high frequency ; the highest frequencies (tangential modes) are the most
dangerous, inducing an accelerated consumption of the thermal protections
- Mainly faced on LFRJ ; some instabilities on DR connected to
specific solid propellant combustion phenomena
- Numerical prediction of ramjet instabilities is not yet
achieved. Different solutions are however known to reduce or suppress the
instability levels, like :
- geometrical devices : baffles, local caps
- modification of the injection devices or controlled
distribution of the fuel
- A compromise between performance and instability level is
generally sought
Some Unconventional Applications of Ramjet
- Integrated ramjet in wing
- RAMAC (RAM ACcelerator) : launching of a small mass at a very
high speed from a tube (NASA, NLR, ISL)
- Nuclear ramjet : PLUTO US program (nuclear reactor TORY II C),
cancelled in 1965 ; concept revisited in the USA ?
- MHD ramjet : AJAX/NEVA project (Leninetz)
- a fascinating concept, but beyond the present technical
possibilities
Simplified scheme of scramjet with MHD
control under « AJAX » concept
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