plasma sheathing control using boundary layer stabilization … · 2011. 5. 15. · q m, tw a-368...
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Physical Sciences Inc. 20 New England Business Center Andover, MA 01810
VG06-206
Plasma Sheathing Control Using Boundary Layer Stabilization and Additives
Hartmut H. Legner, John F. Cronin and W. Terry RawlinsPhysical Sciences, Inc., Andover, MA
Substitute Speaker: Dr. Robert F. Weiss, Physical Sciences Inc.
Paper Presented atAFOSR Workshop on Communications Through Plasma
During Hypersonic Flight
29 August 2006, Boston, MA
Acknowledgement of Support and DisclaimerThis material is based upon work supported by the United States Air Force under Contract Number FA8718-05-C-0054. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the United States Air Force.
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1. REPORT DATE 29 AUG 2006 2. REPORT TYPE
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4. TITLE AND SUBTITLE Plasma Sheathing Control Using Boundary Layer Stabilization and Additives
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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
VG06-206-1
Acknowledgment and Note
• This Phase I SBIR effort was sponsored by two AFRL organizations: SNHE and VAAC, with additional interest from a third organization: VSBXT
• The technical monitor is Dr. James Ernstmeyer of AFRL/SNHE at Hanscom AFB, MA
• Special note: This presentation provides a general overview of potential sheathing solutions. Specific results and designs have SBIR rights and ITAR restrictions. The detailed report can be obtained from Dr. Ernstmeyer.
VG06-206-2
Outline
• Plasma sheathing control objectives
• Three techniques– Boundary layer stabilization by extreme cooling– Liquid injection into boundary layer flow– Electrophilic material in heat shield material
• Application to hypersonic vehicles
• Summary
VG06-206-3
Plasma Sheathing Control Objectives
• Control sheathing via temperature and chemistry
• Reduce electron density, ne
• Reduce boundary layer thickness, δ
ShockWave
. .... .. . ..
.....
. .. .Heatshield Dust
Injection
Boundary Layer
HydrideMaterial
Antenna• Reduce ne• Reduce δ
H-9935
VG06-206-4
Plasma Sheath Attenuation ReductionBRV, 50 kft, ne = 1.8 x 1012/cm3, 0.130 atm, νc = 1.3x1010 S-1
Boundary Layer Thickness Reduction7x101
Frequency, ghz
delta=1.4 cm
delta=1.2 cm
delta=1.0 cmdelta=0.8 cm
delta=0.6 cm
Atte
nuat
ion,
db
6x101
5x101
4x101
3x101
2x101
1x101
00 1 2 3 4 5 6 7 8 9 10
G-9836a
L S Band X Band
VG06-206-5
Plasma Sheath Attenuation ReductionBRV, 50 kft, Delta = 1.4 cm, 0.130 atm, νc = 1.3x1010 S-1
Electron Density Reduction
0.001
0.010
0.100
1.000
10.000
100.000
0 2 4 6 8 10 12Frequency, ghz
Atte
nuat
ion,
db
1.80E+121.00E+111.00E+101.00E+09
H-9940
L S Band X Band
ne (cm-3)
VG06-206-6
Extreme Surface Cooling Using Hydride Materials
• Extreme cooling stabilizes hypersonic boundary layer– Secondary mode unstable at high edge mach number– Remain below Me2nd mode for laminar flow
• Hydride cooling works over a large range of heating conditions– Amount of hydride (material thickness) controls “cool time”
• Hydrogen gas released during low-temperature ablation process– 15-20 kJ/gm H2 , heat of desorption (and adsorption)
Hydride cooling works over wide range of trans-atmospheric flight conditions
VG06-206-7
Hydride Cooling for Typical Surface Heating Flux50 W/cm2
Computations performed using PSI’svalidated thermal response code
VG06-206-8
Cooling Stabilization Boundary forTrans-atmospheric Trajectory Points
Hypersonic VehicleTrajectory
Hypersonic VehicleTrajectory with5 Deg Change
Me2
Second Mode(No Cooling Stabilization)
Cooling Stabilization
104 105 106 107 108 109
8
7
6
5
4
3
2
1
Edge
Mac
hN
umbe
r,M
e
Location-based Reynolds Number, Rex H-7446a
VG06-206-9
Liquid Injection
• NASA RAM C-III Flight Experiment 1973– ne(cm-3) at boundary layer standoff distance 4 cm, 71-72 km altitude
• No injection: 3.9x1010
• Water: 4.8x109
• Freon-3: 3.8x108
– Blunt vehicle, Teflon frustum, 5000 ppm alkali impurities, pulsed injection
• Employed Non-equilibrum Boundary Layer (NEBL) code to compute effects of injectant on downstream electron density– Same trans-atmospheric flight conditions as hydride– Instantaneous vaporization– 50 ppm alkali in carbon phenolic heatshield– Wall cooling effects
Water injection showed insignificant effects, but Freon-3 resulted in orders of magnitude ne reduction depending on boundary layer cooling
VG06-206-10
Freon Injection Cases
Freon Injection, 1,0.8,0.55 PRAE 8
1.0000E+00
1.0000E+01
1.0000E+02
1.0000E+03
1.0000E+04
1.0000E+05
1.0000E+06
1.0000E+07
1.0000E+08
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18Y, cm
Ne,
e/cc
No InjectionFreonTwall*0.8Twall*0.55
H-7298
ne(cm-3) T(ok)
Freon Injection, 1,0.8,0.55 PRAE 8
1000
1500
2000
2500
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18Y, cm
T,K
No InjectionFreonTwall*0.8"Twall*0.55
H-7299
VG06-206-11
Heatshield Electrophilic Scavenging Computations
• Electrophilic particles take up electrons efficiently by the reaction
P + e- P-
• Applied heterogeneous chemistry model, Caledonia (1986)– Electrophilic specie concentration (ppm)– Particle size (Å)– Work function (eV)– Temperature (K)
ka
kd
VG06-206-12
Electron Density Reduction
20 Å, 5eV
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
1.00E+10
1.00E+11
1.00E+12
0 20 40 60 80 100 120 140X, cm
Ne,
e/cc
Base 1 ppm 10 ppm 20 ppm 30 ppm
H-8603
Large potential sheathing reduction usinglow concentration of electrophilic material
VG06-206-13
Vehicle Application
None, small if injectedSmallVery small• Power Impact
Very smallModestSmall• Weight Impact
Very smallModestSmall• Volume Impact
Design
Compatible, distributed in heatshield or injected
CompatibleCompatible
Compatible, distributed in heatshield or injected
CompatibleCompatible• Waverider
• Bi-conic
Configuration
Some velocity dependenceContinuous or pulsed
Some velocity dependence5-20 s, pulse
Velocity dependent5-20 s
• Velocity• Time
Altitude History
ContinuousMultiple control applicationsMultiple applications
ContinuousMultiple control applicationsOne-time control• Weapon
• Surveillance
Missions
Incorporation ofElectrophilic SpeciesAdditive Injection
Boundary LayerTransition Control
Plasma Sheathing Control Techniques
Requirements
VG06-206-14
Summary
• Three general techniques to control plasma sheathing have been identified.
• All three schemes are potentially viable for application to hypersonic cruise vehicles.
• Experimental validation and multi-phase modeling simulations are needed to pursue this promising technology further.
Backup Charts
VG06-206-16
Metallic Hydrides
Heats of Desorption (and Adsorption)
• High energy, low temperature ablators
H2 Flow as a Function of Heating Rate for LaNi5H6
H2 Pressure Above LaNi5H6 (—) and (V0.89Ti0.11 )0.95Fe0.05Hx(•–•)
• Transition metal hydrides– AxBl-XHy type compounds– decompose rapidly and endothermically
to produce H2
AxBl-x Hy → AxBl-x + y/2 H2
LaNi5H6 = LaNi5 + 3 H2 ∆H = 15.1 kJ/gm H2
and(V0.89Ti0.11)0.95Fe0.05Hx, = (V0.89Ti0.11)0.95Fe0.05Hx-1 + 1/2H2 ∆H = 21.5 kJ/gm H2
140
120
100
80
60
40
20
00 20 40 60 80 100 120 140 160 180 200
Heating Rate (watts/cm2) D-1302
H2
Flow
Rat
e(s
ccm
/cm
2 /se
c)
1000
100
10
1
0.1
0.01
0.001
0.0001200 220 240 260 280 300 320 340 360 380 400
D-1303Temperature (K)
Pre
ssur
e(a
tm)
VG06-206-17
Boundary Layer Models
• Non-Equilibrium BL (NEBL) Code– implicit, fully-coupled model– unique chemistry models
• TURBL– 8 equation turbulence model– temperature fluctuations mirror plasma
behavior• REACH (developed by SAIC)
– 3D BL Code
F-
NO+COF+
ElectrostaticProbe Data
NA+
NA+
eNEBLSolution
NO+
COF+F-
105
104
103
102
100 0.2 0.4 0.6 0.8 1.0
X/L
Pea
kE
lect
ron
Den
sity
(Arb
itrar
yU
nits
)
A-7921
InviscidFlow Field(2IT/3IS)
CaseInputs StreamtubeShock Layer
p
B.L.Code
(NEBL)
Inviscid ShockLayer Species
Electron ProfilesCaseInputs
CaseInputs Ablation
(CMA)
m, TwQ
A-368
NEBL Calculation
NEBL Methodology
REACH Simulation1014
1013
1012
1011
1010
109
1080 10 20 30 40
Time (s)
Elec
tron
Den
sity
(#/c
m3 )
D-4163b
Windward
Leeward
α ~ 4 deg~
TeflonRMV-340131 kft
VG06-206-18
Water Injection Cases
ne(cm-3) T(ok)
Water Injection, PRAE 8
1.0000E+05
1.0000E+06
1.0000E+07
1.0000E+08
1.0000E+09
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16
Y, cm
Ne,
e/cc
No InjectionWaterWater, Twall*0.8Water, Twall*0.55
H-7296
Water Injection, PRAE 8
1000
1500
2000
2500
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16Y, cm
T,K
No InjectionWaterWater, Twall*0.8Water, Twall*0.55
H-7297
VG06-206-19
Freon InjectionSynergistic Effects: Hydride Cooling and Injection
0
500
1000
1500
2000
2500
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18Y, cm
T,K
No InjectionFreonFreon, Twall*0.8Freon, Twall*0.55Freon, Twall*0.1
H-9974
1.0000E-02
1.0000E-01
1.0000E+00
1.0000E+01
1.0000E+02
1.0000E+03
1.0000E+04
1.0000E+05
1.0000E+06
1.0000E+07
1.0000E+08
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18Y, cm
Ne,
e/cc
No InjectionFreonFreon, Twall*0.8Freon, Twall*0.55Freon, Twall*0.1
H-9973
ne(cm-3) T(ok)