SOME TRENDS IN IMPROVING HYPERSONIC VEHICLES

Transcription

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XIV ISABE, 5-10 September, Florence, Italy
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SOME TRENDS IN IMPROVING HYPERSONIC
VEHICLES’ AERODYNAMICS AND PROPULSION
(Fundamentals of AJAX Project)
V.I. Golovitchev, and J. Hansson
Thermo- and Fluid Dynamics
Chalmers University of Technology
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Golovitchev, V.I., and Hansson, J.
S-41 296 Göteborg, Sweden
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CONCEPT OF ”HYPERSONIC POWERPLANT”
Main features:
System Utilizes Total Available Energy Normally Not Recovered:
heat built-up by aerodynamic drag to reform hydrocarbon fuel in lack of oxygen
products of reformation are superior to pure hydrogen in ignition quality
proper choice of fuel composition to reduce the amount of soot formed in the
reformation process
bypass of a part of the available flow kinetic energy to drive supersonic MHD generator /
accelerator (electro-magnetic turbine)
external energy is used to reduce the total vehicle and local drags by forming ”thermal
spikes”
electrical energy is used to enhance combustion in the scram-jet engine
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PREVIOUS PUBLICATIONS
Harsha, P., and Gur’janov, E.P., ”AJAX: New Directions in Hypersonic Technology”, AIAA
Paper 96-4609, 7th Aerospace Planes and Hypersonic Technology Meeting, Norfolk, Va.,
April 1996
Bruno, C., Czysz, P.A., and Murthy, S.N.B., ”Electro-Magnetic Interactions in Hypersonic
Propulsion Systems”, AIAA Paper 97-3389, 33rd AIAA/ASME/SAE/ASEE Joint Propulsion
Conference, Seattle, Wa, July 1997
Bruno, C., and Czysz, P.A., ”Electro-Magnetic-Chemical Hypersonic Propulsion System”,
AIAA Paper 98-1582, 8th Aerospace Planes and Hypersonic Technology Meeting, Norfolk,
Va., April 1998
Brichkin, D.I., Kuranov, A.L., and Sheikin, E.G., ”MHD-Technology for Scramjet Control,
AIAA Paper 98-1642, 8th Aerospace Planes and Hypersonic Technology Meeting, Norfolk,
Va., April 1998
Bruno, C., Golovitchev, V.I. and Tret’jakov, P.K., ”New Trends in Improving Hypersonic
Vehicles and Propulsion: Flow Control by External Energy Supply” ISTS 98-o-1-8V, 21st
ISTS, Sonic City, Omiya, Japan, May 1998
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----- FUEL REFORMATION STUDY ----Soot Formation Model
(3)
1111111111
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HYDROCARBON FUEL
(8)
(5)
Radicals
(1)
000000000
111111111
111111111
000000000
000000000
111111111
000000000
111111111
000000000
111111111
000000000
111111111
GASEOUS
COMBUSTION PRODUCTS
Precursor
(8)
Soot
Particles
(7)
Soot
Particles
Soot
Particles
(7)
Soot
Particles
(2)
Acetylene
(6)
(4)
Structure of the phenomenological model (Surovikin’s model)
of soot formation and oxidation.
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----- Soot Formation Model----( formation path through propargyl radical)
H2C
C
C
C3H3
+
C3H3
CH
CH
C
H2C
C
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----- Soot Formation Model----( formation path through HACA process)
H
C
C
H
H
+H
C
H
C
+C2H2
H
H
H
C
-H
C
C
H
C
H
H
C
C
C
H
H
H
C
H
+C2H2
+H
(-C2H)
H
H
C
H
C
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H
C
C
C
H
H
C
H
C
C
H
H
C
+C2H2
C
C
H
H
C
C
C
C
H
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----- SOOT FORMATION MODEL----(formation of curved PAH 6/5 as soot precursors)
H
H
C
C
C
+C2H2
-H
C
+H
-H2
+C2H2
+H
+C2H2
-H
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Table 1:
Processes and rate constants of the soot model
No Model
1.
2.
3.
4.
5.
6.
7.
8.
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sub , process
Fuel (+water)
consumption
Precursor radical
formation
Acetylene
formation
Precursor radical
oxidation
Acetylene
oxidation
Soot particle
inception
Soot particle
growth
Soot particle
oxidation
Reaction
rate constants
A
i
E
i
(mol,cc,s)
(cal/mol)
E5 )
k5 = A5 exp(, RT
1.001010
5.00104
E6 )
k6 = A6 exp(, RT
4.20104
1.20104
2.00101
4.4610,3
1.51105
2.13101
3.00104
1.52104
9.70104
4.10103
Detailed chemistry
Detailed chemistry
up to A2R5
Detailed chemistry
Detailed chemistry
Detailed chemistry
Nagle and StricklandConstable constants:
EA )
kA = AA exp(, RT
kB = AB exp(, ERTB )
ET )
kT = AT exp(, RT
EZ )
kZ = AZ exp(+ RT
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REFORMATION OF CH4 /H2 O MIXTURES
Code used is STANJAN, Version 4.8C, May 1992
Table 2: COMPOSITIONS OF REFORMED CH4 /H2 O MIXTURES
Species
C(S)=graphite
C(S)=C60
H2 O=
0.0
0.20
.3333
0.0
0.20
0.3333
CH4
5.1777E-03 6.0520E-03 6.5931E-03 7.2265E-02 6.7374E-02 6.4345E-02
H2 O
0.0
4.8484E-05 3.1665E-04
0.0
3.1639E-05 5.3885E-05
H2
6.6515E-01 6.8887E-01 7.1022E-01 9.0124E-01 8.0737E-01 7.4463E-01
H
4.9137E-04 1.7000E-04 4.9390E-05 7.7242E-05 5.5933E-05 4.3183E-05
CO
0.0
7.8020E-02 1.4444E-01
0.0
1.0667E-01 1.7757E-01
CH3
9.4124E-05 3.6897E-05 1.1304E-05 9.4124E-05 1.1510E-04 9.1936E-05
C 2 H2
7.0310E-03 1.2539E-03 1.4323E-04 1.5198E-02 1.1349E-02 8.9060E-03
C 2 H4
2.5125E-04 1.1206E-04 3.6877E-05 3.7913E-03 3.1609E-03 2.7379E-03
C(S)
3.2177E-01 2.2544E-01 1.3817E-01 7.0594E-03 3.7196E-03 1.4937E-03
Teq ,K
2024.3
1874.2
1725.3
1763.
1732.0
1708.2
Note: Initial mixture parameters: pressure, Po =10.0 bar, temperature, To = 3000.0 K
Concentrations are in mole fractions
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C60 is fullerene - a molecular form of carbon
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REFORMATION OF KEROSENE/H2O MIXTURES
Table 3: COMPOSITIONS OF REFORMED KEROSENE/H2 O MIXTURES
Species
C(S)=graphite
C(S)=C60
H2 O=
0.0
0.20
.3333
0.0
0.20
0.3333
CH4
1.6374E-03 1.6493E-03 1.6612E-03 1.9421E-02 1.9415E-02 1.9436E-02
H2 O
0.0
4.5657E-07 9.4920E-07
0.0
2.5120E-06 4.8678E-06
H2
4.8674E-01 4.9250E-01 4.9808E-01 9.0684E-01 8.9015E-01 8.7470E-01
H
3.3227E-03 3.2411E-03 3.1544E-03 7.3010E-04 6.7860E-04 6.3191E-04
CO
0.0
1.1925E-02 2.3380E-02
0.0
2.0987E-02 4.0328E-02
CH3
2.6845E-04 2.6083E-04 3.2009E-04 3.8415E-04 3.6380E-04 3.4528E-04
C 2 H2
6.3462E-02 5.8866E-02 5.4475E-02 5.3532E-02 5.0463E-02 4.7662E-02
C 2 H4
3.4617E-04 3.3307E-04 3.6877E-05 2.4029E-03 2.3426E-03 2.2883E-03
C(S)
4.4063E-01 4.2816E-01 4.1607E-01 1.5218E-02 1.4267E-02 1.3389E-03
Teq ,K
2389.7
2383.4
2376.6
2061.1
2051.2
2041.6
Concentrations are in mole fractions (fuel is fully decomposed)
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REFORMATION OF METHANOL, CH3 OH
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Table 4: COMPOSITIONS OF REFORMED METHANOL/H2 O MIXTURES
Species
C(S)=graphite
C(S)=C60
H2 O=
0.0
0.20
.3333
0.0
0.20
0.3333
CH4
9.6024E-05 1.4846E-06
3.0502E-04 1.4874E-06
H2 O
2.2800E-03 7.1149E-02
7.4660E-04 7.1096E-02
H2
6.6088E-01 6.1668E-01
6.6244E-01 6.1673E-01
H
4.1336E-03 5.1655E-03
3.9964E-03 5.1613E-03
OH
2.9592E-06 1.3012E-04
9.2560E-07 1.2988E-04
CO
3.3007E-01 3.0132E-01
3.3217E-01 3.0138E-01
CO2
1.8375E-04 5.4986E-03
6.0637E-05 5.4956E-03
CH3
1.0723E-05 2.1968E-07
3.2918E-05 2.1991E-07
C 2 H2
2.4380E-05 1.2795E-08
2.3136E-04 1.2823E-08
C(S)
2.3103E-03 5.6506E-05
0.0
0.0
Teq ,K
2502.7
2548.0
2494.3
2547.88
Concentrations are in mole fractions
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IGNITION QUALITY OF REFORMED FUEL
The code used is SENKIN-CRS4, Version 2.8C, February 1994
( CH4/H2O mixtures )
0
10
−1
−1
10
10
−2
−2
10
10
−3
−3
10
Mass fraction
Mass fraction
10
−4
10
C(s)
CH4
CO
CO2
H2
O2
OH
−5
10
−6
10
−7
10
−4
10
C(s)
CH4
CO
CO2
H2
O2
OH
−5
10
−6
10
−7
10
−8
−8
10
10
−9
10
( CH4/H2O mixtures )
0
10
−9
−9
10
−8
10
−7
10
−6
10
−5
10
Time, s
−4
10
(a) all species included
−3
10
−2
10
10
−7
10
−6
10
−5
−4
10
10
−3
10
−2
10
Time, s
(b) only H2 , CO, and CH4
Fuel reformation conditions: CH4 /H2 O:1.0/0.25, Po =30.0 bar, To = 3000.0 K
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Composition vs time histories for reformed fuel, C(s) is graphite, Po = 1.0 bar, To = 1000.0 K
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FLAME ACCELERATION IN TUBES
Previous Studies:
H. Gg. Wagner, Some Experiments about Flame Acceleration, Fuel-Air Explosions,
University of Waterloo Press, Montreal, Quebec, 1982. Montreal, Quebec, 1982.
M. Sichel, and C.W. Kauffman, University of Michigan, 1984, High Pressure Generation.
A.K. Oppenheim and H.E. Stewart, Pulsed Jet Generator for Premixed Charge Engines,
US Patent 4,926,818, 22 May 1990.
J. Chomiak, Flame Acceleration in Tubes - Some Basic Considerations, Archivum
Combustionis, Vol. 15, No. 3-4, 1995.
T.F. Kanzleiter, K.O. Fisher, Multi-Compartment Hydrogen Deflagration Experiments and
Model Development, Nuclear Engineering and Design, 146, pp. 417-426, 1994
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GASDYNAMIC THEORY OF DETONATION
(Application of detonation)
t + (u)x = 0
(u)t + (u + P )x = 0
et + ((e + P )u)x = 0
e = 21 u + ;
cp
= P
+
q;
=
,1
cv
8
<
gas is unburned
q = : qq if
if gas is burned
8
< > 0 endothermic
q , q = : < 0 exthermic
2
2
0
1
1
Initial conditions:
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0
q/c1 2=11.57, =1.4, c1 =354 m/s, (15% H2/85% air), un =0.4 m/s, (M1)B = 4.9
Detonations: a) strong -
= 0.31, Sf /F 18, F/F=1.115; b) weak - = 0.327, Sf /F 4860.
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DETONATION OF H2/O2 MIXTURES
(Stoichiometric mixture)
P
T
V
H
U
S
W
(atm)
(K)
(cm3/gm)
(erg/gm)
(erg/gm)
(erg/gm-K)
(gm/mole)
H
OH
HO2
H2
H2O
H2O2
O
O2
INITIAL STATE:
1.0000E+00
3.0000E+02
2.0496E+03
4.4704E+07
-2.0320E+09
1.3402E+08
1.2010E+01
Mole Fractions
0.0000E+00
0.0000E+00
0.0000E+00
6.6667E-01
0.0000E+00
0.0000E+00
0.0000E+00
3.3333E-01
C-J DETONATION PROPERTIES (cm/s)
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EQUILIBRIUM STATE:
1.8669E+01
3.6787E+03
1.1147E+03
2.8371E+10
7.2839E+09
1.7423E+08
1.4505E+01
8.1030E-02
1.3460E-01
1.8639E-04
1.6248E-01
5.3471E-01
2.0505E-05
3.8536E-02
4.8431E-02
2.8364E+05
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DETONATION OF H2/O2 MIXTURES
(Fuel rich mixture - easy to detonate)
P
T
V
H
U
S
W
(atm)
(K)
(cm3/gm)
(erg/gm)
(erg/gm)
(erg/gm-K)
(gm/mole)
H
OH
HO2
H2
H2O
H2O2
O
O2
INITIAL STATE:
1.0000E+00
3.0000E+02
3.9078E+03
8.4932E+07
-3.8746E+09
2.3003E+08
6.2992E+00
Mole Fractions
0.0000E+00
0.0000E+00
0.0000E+00
8.5714E-01
0.0000E+00
0.0000E+00
0.0000E+00
1.4286E-01
C-J DETONATION PROPERTIES (cm/s)
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EQUILIBRIUM STATE:
1.6032E+01
3.0527E+03
2.1737E+03
4.6398E+10
1.1087E+10
2.9632E+08
7.1879E+00
3.6925E-02
6.3863E-03
2.9338E-07
6.3710E-01
3.1932E-01
1.6103E-07
2.2526E-04
4.4566E-05
3.6624E+05
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----- The PaSR model - - - Part I ----(Flame with reconnections model)
uL
c0
Flame surface
c
Fresh mixture
I
ck
uL
Burnt gases
c
II
Front intersection
Mathematical formulation:
dc = c , ck = c = ck , c
d
res
c mix
0
Analytical solution - L. A. Vulis, 1959:
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ck =co = +mix + +c ;
res
mix
c
c=co = + c + ;
res
mix
c
ck ( c ) , rate multiplier
dc = ck
=
d mix + c
c mix + c
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----- The PaSR model - - - Part II ----a) model generalization:
1: dcdk = fr (c) = (r00 , r0 )!_ r (c) , Arrhenius kinetics;
ck j = co;
2: fr (c) = , Dhmix (co , 2c + ck ) c, ck
=0
mix
2
b) model generic relations:
ck , co
fr (c)
ck
c,
1
= fr (c) = term , term ;
fr (ck ) + (@ fr=@ c)j (c , ck ) = ,(c , ck )=c
= c + (1 , )co;
= + ;
mix
= ,(@ fr=@ c)j = ,fr o=(cso + term )
1
2
c=ck
c=ck
2
c) rate expression
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ck , co = f (c ) ( c ) = csofr o ;
r k
mix + c cso + term ck j = co; s , reference species
2
=0
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----- The PaSR model - - - Part III ----d) limiting case:
if fr o mix
term the model reduces to
,cso=mix
2
the eddy break-up model
e) definition of mix :
from RNG viscosity definition follows
v
u
2
u
t = l (1 + t ck = )2
p
s
=
(
l + t + 2 l st );
l
q
p
mix = 2 l st=k = 2c = l= k
1 2
where st is the ”standard” k- value the kinematic viscosity,
l= 1=2 is the Kolmogorov time.
and k
=( )
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ENHANCED TURBULENT DEFLAGRATION MODE
(numerical modeling)
t=0.80 ms
1.54 ms
2.03 ms
2.52 ms
3.50 ms
Mixture temperature plots at different instants illustrating enhanced flame propagation
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initiated by a powerful spark in a duct with orifice plates.
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ENHANCED DEFLAGRATION MODE
(numerical modeling)
t=7.5 ms
t=10.5 ms
t=11.0 ms
t=11.6 ms
Temperature scale
Temperature plots at different instants illustrating enhanced flame propagation in the 2-volume
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confinement with a narrow passage and an opening at a right upper corner of the receiver volume.
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VALIDATION OF H2/AIR CHEMICAL MODEL
5
10
10
10
Experiment, 1 atm
Experiment, 2 atm
Calculation, 1 atm
Calculation, 2 atm
Balakrish. & Williams
Balakrish. & Williams
Miller et al.
Miller et al.
4
3
φ=1
4
10
Ignition delay, µsec
Ignition delay time, µsec
10
2
3
10
2
10
To= 950 K
T0=1000 K
To=1100 K
φ=1
10
1
1
0.70
0.80
0.90
1.00
1000/T, K
1.10
1.20
10
1
10
Pressure, bars
Ignition delays for a stoichiometric H2 -Air mixture as functions of pressures and
temperatures at the ”extended” second explosion limit conditions.
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ENHANCED DEFLAGRATION MODE
(One Possible Explanation)
Sensitivity Analysis
Enhanced Deflagration Mode
Sensitivity Analysis
(Stoichiometric H2/Air Mixture)
(Stoichiometric H2−Air Mixture)
(Stoichiometric H2/Air Mixture)
4e+05
10000
3.5e+05
Po=2.0 bar, To=900 K, tign=8.5 ms
Temperature/rate Sensitivity
Po=1.0 bar, To=900 K, tign=4.6 ms
5000
Pressure, in bar
Temperature/rate Sensitivity
10000
0
3e+05
Igniter room
Receiver room
2.5e+05
2e+05
−5000
5000
0
−5000
1.5e+05
−10000
0
5
10
15
20
Reaction numbers
25
30
(c) 1.0 bar
1e+05
0.0e+00
−10000
5.0e−03
1.0e−02
Time. in sec
(d)
1.5e−02
0
5
10
15
20
Reaction numbers
25
30
(e) 2.0 bar
Absolute sensitivity coefficients for the H2 /O2 reaction mechanism at the end of ignition period;
c) t = 4.6 ms, d) pressure vs time histories in donor (pre-detonation) and receiver volumes, e) t = 8.5 ms.
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THEORETICAL ANALYSIS OF NON-UNIFORM
SUPERSONIC FLOWS
(Simulation of aerodynamic spike effects)
Parameters characterizing non-uniform flows - initiated by S. Guvernuk, 1996:
u = f (y)uo; h = g(y)ho; uo = f (0); ho = g(0)
for uniform flow
f (y) = g(y) = 1
Generalized ”Reynolds” analogy:
M2 =
u2
2
f
2
2
=
M
o = mMo
( , 1)h
g
Possible flow regimes:
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m<1: wake-like ) flow with recirculation zones,
m=1: ) steady-state flows around the body,
m>1: jet-like ) non-steady (resonant tube) flows
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SIMULATION OF AERODYNAMIC SPIKE EFFECT
(A bead projection to a supersonic stream)
a)
b)
c)
The bead was projected to a M1 =2.0 flow from a front end of the cylinder;
1 - bead , 2 - blunt body. The snapshots correspond to different moments a), b), and c)
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DRAG REDUCTION BY A COUNTER-FLOW MASS
INJECTION
(Shkval rocket-torpedo)
Drag is reduced by creating a local supercavitating ”envelope” of air and combustion
products ( 50 %) bubbles in which weapon exceeds a speed 230 mph - a ”bubble” spike.
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DRAG REDUCTION BY A ”FLAME” SPIKE
(Counterflow injection of combustible gases)
a)
b)
The hydrogen was injected into a M1 =2.0 flow through a fuel needle with a conical tip;
a) no hydrogen injection, b) injection of hydrogen (GH2 =0.002) and combustion.
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DRAG REDUCTION BY A ”FLAME” SPIKE
(Some practical applications)
(f)
(g)
(h)
f) Effect of the spike length on 1 -pressure drag, 2 -base drag, 3 - hydrogen combustion
Reduction of pressure drag as a function of a relative mass flow rate, G,
for fuels of different heat values: g) model experiments, 1-Hu=120 MJ/kg, 2-Hu=16.7 MJ/kg,
3-Hu=13.4 MJ/kg h) real projectile: 1-Hu=16.7 MJ/kg, 2-Hu=13.6 MJ/kg, and 3-Hu=9.0 MJ/kg
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LAY-OUT OF AERODYNAMIC EXPERIMENTS
( Generation of the laser ”air-spike”)
Hardware components: CO2 -laser, 1- focusing lens, 2- plenum chamber, 3- nozzle,
4- testing body, 5- diffuser, 6- strain balance, 7- test section, 8-exhaust chamber
(Novosibirsk, Russia, Tret’akov et al)
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LASER PULSE PARAMETERS
(Drag reduction by the laser ”air-spike”)
(i) laser pulse
(j) laser power
(p) 1-Impulse of the CO2 laser at f=45 kHz, 2-the passed and 3-absorbed radiation, 4-the ”effective” impulse
(q) Average and peak laser power as a function of the pulse repetition frequency
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DRAG REDUCTION BY A LASER AEROSPIKE
( Effect of a focused laser beam on the M=2.0 flow around a cone-cylinder)
(k) no laser beam
(l) there is a laser beam
Effect of a focused laser beam at f= 25 kHz. Photos of the upper row are the superpositions of 200 individual
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i) snapshots presented in the lower row. In the photo j), the ”bifurcated” shock is well pronounced.
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LASER ENERGY SUPPLY TO A SUPERSONIC FLOW
(Flow gasdynamic structure in the vicinity of the ”hot” spot)
1-shock wave (experiment), 2-shock wave (analytical solution), 3,4-shock wave (numerical
solution, =1.2, and 1.67), 5-thermal wake (experiment), 6-thermal wake (estimation)
Nothing particular - all structural elements are predictands.
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(How to focus a laser beam?)
Standard scheme of a CO2-laser beam focusing
Escaping discharge gas velocity behind the light ”detonation” front is defined by
u3
Vd
=
=
Vd(1 , 1=3)
2
_
[2( , 1)J=
3]1=3;
and directed depending on the wave propagation regime - detonation or deflagration,
&
J_ is the laser pulse power
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Predictions (bifurcated shock formation) and Experimental Snapshots
a) predictions
b) f=50 kHz
a) Density field in the presence of a ”hot” in a free stream M1 =2.0; Rq =0.15, Qo =25.0
b) Schlieren picture of a laser spark, f=50 kHz, a focal point position, dj =20 mm.
”Fixed” position of the ”hot” spot in the modeling is equivalent to the energy release
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front propagation with the speed of the feeding air flow
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(Predictions and Experimental Snapshots)
a) predictions
b) f=100 kHz
a) Density field in the presence of a ”hot” in a free stream M1 =2.0; Rq =0.15, Qo =25.0
b) Schlieren picture of a laser spark, f=100 kHz, a focal point position, dj =20 mm .
At f=100 kHz the shock structure ”has no time” to be developed.
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( Effect of a pulsed laser beam frequency on the M=3.0
flow structure around a sphere)
a) no energy release
b) energy release at f= 2.0
Mach number distributions without and with the energy release; f is the normalized frequency.
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( Effect of a pulsed laser beam frequency on the M=3.0
flow structure around a sphere)
(m) f=0.5
(n) f=5.0
Pressure histories at the sphere stagnation point at different (normalized) pulse frequencies
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RESULTS OF AERODYNAMIC EXPERIMENTS
(Drag reduction by a laser ”air-spike”)
1.0
Relative drag, Cx/Cxo
0.8
M=2.0
0.6
hemisphere (calc.)
hemisphere
cone−cylinder (lf=23)
cone−cylinder (If=13)
cone−cylinder (lf=23)
0.4
0.2
0.0
20.0
40.0
60.0
Pulse frequency, kHz
80.0
100.0
Relative drag reduction vs the laser pulse frequency.
&
Two data sets for the cone-cylinder are obtained at same conditions, Cxo is free stream drag
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SIMULATION OF AERODYNAMIC SPIKE EFFECT
(Theoretical analysis of non-uniform supersonic flows)
Some specific non-uniformities:
,by
,
ae
f (y) = 1 , a ;
g(y) = 1 + c , cf 2(y)
1
2
More specific expression for m:
y
m = 1 + k( R )2 + :::
o
2a(1 + c)
k = 1 , a bRo2;
where Ro is a body size across
From above relation,a specific role of Ro follows
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THE EFFECT OF A ” HOT SPOT ” SIZE
( Observation made by Georgievsky and Levin, 1996)
(o)
&
(p)
Supersonic M1 =3.0 flow around a sphere in the presence of energy release.
Isolines of Mach number: a) Rq =0.5, b) Rq =0.25, Qo =25
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THE EFFECT OF A ” HOT SPOT ” SIZE
( continuation )
(q)
(r)
c) Isolines of Mach number, and d) Velocity vector field
&
in the presence of a ”hot” spot before the sphere, Rq =0.125, Qo =25, M1 =3.0
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DRAG REDUCTION AND EFFICIENCY OF ENERGY USE
Qs Energy fed into the stream
N Power of the reference engine:
Z
p
1
=
~
Qs = 1Qo( ) Rq V e, r z dV;
1
1
N = 2 Ro 1M1 ( p1 ) =
1
Cq = N=Qs; Q~ o = Qo1( p1 ), =
3 2
2
( 2 + 2)
2
3
3 2
3 2
1
Table 4: Comparison with the reference engine performance
Rq =Ro
zq =Ro
1.25
1.5
1.75
2.0
2.5
3.0
0.125 1.00 (0.25) 0.94 (4.31) 0.85 (10.3) 0.80 (13.7) 0.75 (16.7) 0.69 (20.4)
0.250
0.87 (1.37) 0.82 (2.11) 0.71 (3.05) 0.66 (3.38)
0.500 0.83 (0.47) 0.78 (0.58) 0.72 (0.76) 0.65 (0.92) 0.60 (1.02) 0.55 (1.18)
Note: Data listed in the table are: Cx , drag reduction (Cq , index of efficiency)
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MODEL OF ”COLD” NON-IDEAL PLASMA
( Debye - Hückel Approach)
Includes an increase in energy due to the Coulomb field:
ECoul = 12 V
X
i
eza noi 'i;
where 'i is the field potential due to an ion cloud, zi a number of e- charges on the i-particle.
The Poisson equation for the collective effect potential
4' , 2'
=
= (lD ),1
=
;
v
u
u
t 4e2 X noi zi2
kT i
0
(lD is the characteristic Debye length)
has the spherically symmetric solution
' = ezr i exp (, lr );
D
In the limit of r/lD 1
1 X
F = Fp:g: , e kTV ) 2 ( nizi 2) 23 ;
i
1 X
3
X
e
PV = kT Ni , 3 ( kTV ) 2 ( nizi 2) 23 :
i
{z i
}
|
Charged particle numbers ni are calculated using the Saha equations.
2 3
(
3
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HOW TO PRODUCE THE ”HOT” SPOT?
By electron beam?
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INITIAL STATE:
P (atm)
1.0000E+00
T (K)
3.0000E+02
V (cm3/gm)
1.0324E+03
H (erg/gm)
2.1802E+07
U (erg/gm)
-1.0242E+09
S (erg/gm-K)
7.2041E+07
W (gm/mole)
2.3844E+01
Mole Fractions
O2
1.7361E-01
NO
0.0000E+00
O
0.0000E+00
N
0.0000E+00
AR
1.7361E-04
NO+
0.0000E+00
N+
0.0000E+00
E
1.7361E-01
O+
0.0000E+00
N2+
0.0000E+00
O2+
0.0000E+00
NO20.0000E+00
O0.0000E+00
O20.0000E+00
AR+
0.0000E+00
N2
6.5260E-01
C-J DETONATION VELOCITY (cm/s)
EQUILIBRIUM STATE:
7.9731E+00
1.7350E+03
5.9795E+02
5.7813E+09
9.5061E+08
8.0786E+07
2.9862E+01
4.5648E-02
1.5952E-03
4.8180E-06
3.3291E-12
2.1743E-04
8.5047E-29
0.0000E+00
4.6319E-02
0.0000E+00
0.0000E+00
0.0000E+00
1.6282E-01
2.5829E-04
8.0340E-03
0.0000E+00
7.3511E-01
1.3166E+05
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in the presence of heavy ions?
&
INITIAL STATE:
P (atm)
1.0000E+00
T (K)
3.0000E+02
V (cm3/gm)
9.3069E+02
H (erg/gm)
4.5334E+10
U (erg/gm)
4.4391E+10
S (erg/gm-K)
7.1499E+07
W (gm/mole)
2.6449E+01
Mole Fractions
O2
1.7508E-01
NO
0.0000E+00
O
0.0000E+00
N
0.0000E+00
AR
1.7508E-04
NO+
0.0000E+00
N+
0.0000E+00
E
8.3319E-02
O+
0.0000E+00
N2+
6.5811E-02
O2+
1.7508E-02
NO20.0000E+00
O0.0000E+00
O20.0000E+00
AR+
0.0000E+00
N2
6.5811E-01
C-J DETONATION VELOCITY (cm/s)
EQUILIBRIUM STATE:
2.4472E+01
4.1657E+03
5.1619E+02
6.2540E+10
4.9740E+10
9.4629E+07
2.7060E+01
9.2809E-02
8.4705E-02
1.2374E-01
5.3152E-04
1.7912E-04
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
6.9803E-01
2.2293E+05
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by fission products (4He++)?
&
INITIAL STATE:
P (atm)
1.0000E+00
T (K)
3.0000E+02
V (cm3/gm)
1.0031E+03
H (erg/gm)
1.6830E+11
U (erg/gm)
1.6729E+11
S (erg/gm-K)
7.7850E+07
W (gm/mole)
2.4539E+01
Mole Fractions
O2
1.7361E-01
NO
0.0000E+00
O
0.0000E+00
N
0.0000E+00
HE
0.0000E+00
NO+
0.0000E+00
N+
0.0000E+00
E
0.0000E+00
O+
0.0000E+00
N2+
0.0000E+00
O2+
0.0000E+00
NO20.0000E+00
O0.0000E+00
O20.0000E+00
HE++
4.7361E-02
N2
6.5260E-01
C-J DETONATION PROPERTIES (m/s)
EQUILIBRIUM STATE:
4.9050E+01
7.0510E+03
5.4799E+02
2.0606E+11
1.7883E+11
1.1434E+08
2.1525E+01
5.4382E-04
1.4168E-02
1.4144E-01
9.9236E-02
4.5229E-02
1.4457E-01
2.1247E-03
2.3231E-07
2.8142E-03
2.5308E-03
2.5539E-04
1.2572E-13
4.2757E-09
9.9429E-12
1.9542E-10
4.3988E-01
3.2809E+05
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Pressure dependence
&
INITIAL STATE:
P (atm)
1.0000E-01
T (K)
3.0000E+02
V (cm3/gm)
9.3069E+03
H (erg/gm)
4.5334E+10
U (erg/gm)
4.4391E+10
S (erg/gm-K)
7.8737E+07
W (gm/mole)
2.6449E+01
Mole Fractions
O2
1.7508E-01
NO
0.0000E+00
O
0.0000E+00
N
0.0000E+00
AR
1.7508E-04
NO+
0.0000E+00
N+
0.0000E+00
E
8.3319E-02
O+
0.0000E+00
N2+
6.5811E-02
O2+
1.7508E-02
NO20.0000E+00
O0.0000E+00
O20.0000E+00
AR+
0.0000E+00
N2
6.5811E-01
C-J DETONATION VELOCITY (m/s)
EQUILIBRIUM STATE:
2.2825E+00
3.7709E+03
5.1364E+03
6.1304E+10
4.9425E+10
1.0170E+08
2.6393E+01
7.7608E-02
5.9018E-02
1.7012E-01
4.0011E-04
1.7471E-04
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
6.9268E-01
2.1431E+05
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MICROWAVE-INDUCED ENERGY SUPPLY TO SUPERSONIC FLOWS
(Mirabo’s lightcraft is a different system)
This is just a plenum chamber outside the vehicle. What it could rely on?
Pinj/P
P, BAR
T, K
RHO, KG/CU M
H, KJ/KG
U, KJ/KG
Ae/At
CSTAR, M/SEC
Ivac, M/SEC
&
INJECTOR COMB END THROAT
EXIT
EXIT
EXIT
EXIT
1.0000
1.2063
1.9447
267.45
630.51 1037.75 1477.84
53.317
44.198
27.416 0.19935 0.08456 0.05138 0.03608
[20000.0] 19591.35 18382.89 10661.39 9747.83 9227.82 8855.58
3.2759-1 2.7822-1 1.8870-1 2.9577-3 1.4138-3 9.2186-4 6.8159-4
115617.9 113979.0 106723.8 57697.1 52248.5 49370.6 47450.0
99342.2 98092.8 92194.3 50957.0 46267.5 43797.4 42156.8
PERFORMANCE PARAMETERS - BONNIE’S CODE HAS BEEN USED
1.5800
1.0000
25.000
50.000
75.000
100.00
6150.9
6150.9
6150.9
6150.9
6150.9
6150.9
10585.1
7662.6 11389.2 11789.1 11994.8 12129.6
System performance is high, but drag reduction should be ineffective.
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DRAG REDUCTION PHENOMENON IS PLASMA
SPECIFIC? NO!
” ... These effects, observed in discharges in various gases (air, CO2 , Ar, He) at pressures of
3-30 torr, and for Mach numbers M 1.5 - 4.5, are surprisingly similar in both atomic and
molecular gases, despite fundamental differences in mechanisms of ionization and molecular energy transfer... They also persist for a long time after the discharge is off.
( 1 ms in air).”
Adamovich I.V., at al., AIAA Journal, vol. 36, No.5, May, 1998
The phenomena can be attributed to the finite-rate plasma energy ”thermalization”.
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CONCLUSIONS - CRUISE MISSILE CONCEPT
At first, to accelerate the missile to flight Mach 6-8 by external rocket boosters
Use reformation of hydrocarbon fuel CH /H O mixtures recovering drag losses, normally
4
2
not used in conventional systems. The cooling effect of fuel reformation is sufficient for
thermal protection of vehicle
Reformed fuel has a high ignition and combustion potentials, providing also incipient
soot facilitating the operation of the MHD propulsion system, if the letter will be used
The energy bypass can be also achieved with fuel reformation rather than with
supersonic MHD propulsion system analyzed by Prof. P.A.Czysz to avoid high M
operation conditions in the engine
The enhanced turbulent deflagration of rich mixture of reformed fuel products initiated
by a high power spark in ”flame holders” of a special geometry looks promising for
scram-jet reducing need in LOX in comparison with rocket ejector ram-jet
The concentrated energy drag reduction concept has proven to be effective for the
cruise range vehicles. preventing the missile deceleration with the benefit that the spike
”products” could envelope the missile in a film of ionized gas which would be impervious
to radar pulses, thereby rendering it electronically ”invisible”. The infra-red penalty at
close range would be significantly offset by the high speed of the flight.
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ABSTRACT
Among new conceptual trends in improving supersonic and
hypersonic aerodynamics, the use of combustion or plasma
energy release within selected portions of the flow are reviewed
and evaluated with application to vehicle aerodynamics formally
relegated to the long-range aircraft, named AJAX, which, if ever
built, could cruise at hypersonic speeds. The technical details of
a conceivable AJAX design are discussed briefly; the emphasis
is placed on fundamental concepts of chemical physics and
reactive fluid and plasma dynamics (fuel reformation, enhanced
deflagration, and general drag reduction) which these details
could be based on to render them applicable to any relevant
hypersonic vehicle, including long-range cruise missiles.
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ACKNOWLEDGMENTS
Discussions with Prof. V.A. Levin, Prof. P. Czycz, Prof. C. Bruno, and Prof. L.-E. Eriksson
and kind help of our PhD student N. Nordin are gratefully acknowledged.
Courtesy of Prof. Tretjakov in supplying both available and unpublished experimental
data is especially recognized.
This work was partially supported by Chalmers Combustion Engine Research Center.
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SOME TRENDS IN IMPROVING HYPERSONIC VEHICLES

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