Influence of MHD Flow Control

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Influence of MHD Flow Control on Radiative Heat
Transfer in Super-Orbital Reentry
Flight Tomoyuki Yoshino, Takayasu Fujino and
Motoo Ishikawa University of Tsukuba, Japan
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MHD Flow Control
Applying magnetic field
Reentry
Reduction of flow velocity in shock layer
Increase of shock standoffdistance Reduction of
convective heat transfer
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Objective

• Palmer() suggested probability that expansion
  of shock layer by applying magnetic field led to
  increase in radiative wall heat flux.
• No studies have carried out on numerical
  analyses for MHD flow control considering
  radiative wall heat flux.

To investigate influence of expansion of shock
layer by MHD flow control on radiative wall heat
flux under condition of super-orbital reentry
flight
() Palmer G. Magnetic field effects on the
computed flow over a Mars return aerobrake, J.
Thermophysics and Heat Transfer, Vol. 7, No. 2
(1993), pp. 294-301.
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Numerical Method for Plasma Flows
2-D computational magnetohydrodynamic analysis
Eleven chemical species N, O,
N2, O2, NO, N, O, N2, O2, NO, e- Parks
chemical kinetic model Parks two temperature
model Ttr Translational-Rotat
ional Temperature Tve
Vibrational-Electronic-Electron Temperature Low
magnetic Reynolds number model including Hall
effect
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Assessment of Radiative Wall Heat Flux
Structured package for radiation analysis
SPRADIAN()

• SPRADIAN obtains emission coefficients by
  considering
• bound-bound (N2, O2, NO, N2, N, O, N, O)
• bound-free (N, O, O)
• free-free (N2, N, O, N2, O2, NO, N, O)
• radiations.
• And then, radiative wall heat flux is calculated
  by integration of radiative transfer equation all
  over shock layer.

Fujita K., and Abe T. SPRADIAN, Structured
Package for Radiation Analysis Theory and
Applications, ISAS Report No. 66, 1997.
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Numerical Conditions
Magnetic field distribution
Flight condition (MUSES-C reentry 64 km)
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Distributions of Static Pressure
MHD on (0.3 T)
MHD off
22,000
12, Pa
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Radiative and Convective Wall Heat Flux
Convective wall heat flux and total wall heat flux
Radiative wall heat flux
5 up
64 up
29 down
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Radiation Density toward Stagnation Point
Line spectra emissions of N and O atoms
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Radiation Density toward Stagnation Point
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Temperatures along Stagnation Line
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Chemical Composition along Stagnation Line
MHD off MHD on (0.3 T)
Neutral species
Ionic species
Chemical composition is no altered by applying
magnetic field.
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Mass Fraction of Nitrogen Atomic Ion (N)
MHD off
MHD on (0.3 T)
0.15
0
Applying magnetic field leads to increase in
monatomic ion species. decrease in neutral
species and molecules.
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Radiation Density toward Stagnation Point
Continuous spectra emission of N
N
N
N
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Conclusions

• Radiative wall heat flux is significantly
  increased by applying MHD flow control.
• The main factor of increase of radiative wall
  heat flux is increase in emission area due to
  expansion of shock layer.
• At stagnation point, convective wall heat flux
  with magnetic field of about 0.3 T decreases by
  29 and radiative wall heat flux with magnetic
  field increases by 64 compared to those without
  magnetic field. As a result, total wall heat flux
  with magnetic field becomes 5 larger than that
  without magnetic field.

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Radiation Density toward Stagnation Point
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Radiation Density toward Surface Point of
Downstream Wall
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Configuration of MUSES-C and Computational Grid
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Mass Density of Mixture Gas
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Spectral Distribution of Emission Coefficient
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Spectral Distribution of Emission Coefficient
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Spectral Distribution of Emission Coefficient
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Spectral Distribution of Emission Coefficient
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Spectral Distribution of Emission Coefficient
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Spectral Distribution of Emission Coefficient
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Basic Equations for Gasdynamics
Mass conservation equations
Convection terms ? AUSM-DV scheam
(N,O,N,O,N2,O2,NO,N2,O2,NO,e-)
Parks Two-Temperature Model
Momentum conservation equations
11 Chemical Species and Parks chemical kinetic
model
Total energy conservation equation
Vibrational-electronic-electron energy
conservation equation
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Basic Equations for Electrodynamics
Steady Maxwell Equations
The generalized Ohms law
Galerkin finite element method
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Previous numerical studies Relations
between drag and altitude
Future Work
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Relations between flight velocity and flight
altitude
Future Work
Externally applied magnetic field dipole magnet
We will examine influences of MHD flow control
utilizing real air-core circular magnet on the
flight trajectory and aerodynamic heating.
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Distribution of Externally Applied Magnetic Field
The present study varies the value of the
parameter B0 over a range of 0.0 to 0.5 T.
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Magnet Conditions
Rmag
L Self inductance I Coil current
Basic Equation for Externally Applied Magnetic
field
Biot-Savart law
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The case to increase wall heat flux(altitude 71
km, coil outer radius 0.2 m)
Flight condition Altitude 71 km Velocity 7.0
km/s
reattachment point
cyclic domain
Wall heat flux
Stream line for plasma flow
Excessively and locally strong magnetic field
generates cyclic domain.
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Magnetic field distribution
In the case of relatively large magnet (Rmag0.8)
Blunt body with large radius of curvature
Blunt body with small radius of curvature
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Relations between Maximum wall heat flux
and magnet outer radius
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Distribution of Lorentz force
71km
59km
12000
N/m3
Rmag0.6
Rmag0.6
0
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Distribution of Wall Heat Flux
(Altitude 63 km)
Freestream condition Pressure 14.0
Pa Temerature 237.1 K Velocity 6.2 km/s
(Altitude 63 km)