April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Chamber Dynamics and Clearing Code Development Effort
A. R. Raffray, F. Najmabadi, Z. Dragojlovic
University of California, San Diego
A. Hassanein
Argonne National Laboratory
P. Sharpe
INEEL
HAPL ReviewGA, San Diego
April 4-5, 2002
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Chamber Physics ModelingChamber RegionSource Wall Region
Driver beams
Momentum input
Momentum Conservation Equations
Wall momentum transfer(impulse)
Fluid wall momentum
equations
Energy Equations Phase change
Condensation
Conduction
Energy input
Thermal capacity
Radiation transport
Transport + deposition
Condensation
Pressure (T)
Impulse
Pressure (T)
Pressure (density)
Viscous dissipation
Mass input
Mass Conservation Equations (multi-phase, multi-species)
Evaporation,Sputtering,Other mass transfer
Condensation
Evacuation
Energy deposition
Convection
Thermal stress
Stress/strain analysis
Condensation Aerosol formation
Thermal shock
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Statements of work:
• Initiate development of a fully integrated computer code to model and study the chamber dynamic behavior.
• Deliver the core of the code including the input/output interfaces, the geometry definition and the numerical solution control for multi-species (multi-fluid), 2-D transient compressible Navier Stokes equations.
• Scoping studies to assess importance of different phenomena for inclusion in the code.
• Develop simple modules defining the physics of the different phenomena.
Chamber Dynamics and Clearing 2001 Statement of Work (I)
• Single species code with rectangular domain completed using progressive approach
- 1-D --> 2-D- inviscid --> viscous
(to be presented by Z. Dragojlovic)
• Results presented at last meeting for poor effectiveness of conduction, convection and radiation to cool protective gas
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Statements of work:
• Provide modules for chamber wall interaction modules which will include physics of melting; evaporation and sublimation; sputtering; macroscopic erosion; and condensation and redeposition.
• Scope the range of chamber dynamics and clearing experiments that can be carried out in a facility producing 100-1000 J of X-ray.
Chamber Dynamics and Clearing 2001 Statement of Work (II)
Wall interaction module developed as 1-D transient thermal model with ion and photon energy deposition, including melting and sublimation effect
Scoping analyses performed to decide on relative importance of other erosion mechanisms (ANL)
Sputtering and RES modeling equations provided by ANL, to be coded at UCSD
(to be presented by R. Raffray)
Completed
(to be presented by F. Najmabadi)
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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• Ion and photon energy deposition calculations based on spectra
- Photon attenuation based on total photon attenuation coefficient in material
- Use of SRIM tabulated data for ion stopping power as a function of energy
• Transient Thermal Model
- 1-D geometry with temperature-dependent properties
- Melting included by step increase in enthalpy at MP
- Evaporation included based on equilibrium data as a function of surface temperature and corresponding
vapor pressure- For C, sublimation based on latest recommendation from
Philipps
• Model calibrated and example cases run
• To be linked to gas dynamic code
Wall Interaction Module Has Been Developed
Example IFE Chamber Wall Configuration UnderEnergy Deposition
Photons
Melt Layer
Re- radiation
q'''(from photons and ions)
q''(subl./evap.)
q''(cond.)
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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• Scoping analysis performed - Vaporization, physical sputtering, chemical sputtering, radiation enhanced sublimation
Other Erosion Processes to be Added (ANL)
• These results indicate need to include RES and chemical sputtering for C (both increase with
temperature)
• Physical sputtering relatively less important for both C and W for minimally attenuated ions
(does not vary with temperature and peaks at ion energies of ~ 1keV)
Plots illustrating relative importance of erosion mechanisms for C and W for 154 MJ NRL DD target spectra
Chamber radius = 6.5 m.
CFC-2002U
Tungsten
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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• Recommended models (equations) provided for inclusion in wall interaction module for physical and chemical sputtering and
radiation enhanced sublimation - Model based on analytical and semi-empirical approach
• Calibration runs will be done
• Further effort required for macroscopic erosion- Scoping analysis
- Model development
Models Provided for RES, Chemical Sputtering and Physical Sputtering (ANL)
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Comparison Runs for Energy Deposition and Thermal Analysis (UCSD, UW and ANL)
• Prior results did not match very well
• We decided to:- Compare input data and resolve any differences- Run a few example cases for energy deposition and temperature
calculations
• Stopping power and energy deposition quite consistent now
• Very useful exercise
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Spatial Profile of Volumetric Energy Deposition in C and W for Direct Drive Target Spectra
• Tabulated data from SRIM for ion stopping power used as input
1x107
1x108
1x109
1x1010
1x1011
1x1012
1x10-8 1x10-7 1x10-6 1x10-5 1x10-4 1x10-3 1x10-2
Debris ions,W
Fast ions, C
Photons, W
Photons, C
Fast ions, W
Penetration depth (m)
Energy Deposition as a Function of PenetrationDepth for 401 MJ NRL DD Target
Debris ions, C
C density = 2000 kg/m3
W density = 19,350 kg/m3
1x106
1x107
1x108
1x109
1x1010
1x1011
1x10-8 1x10-7 1x10-6 1x10-5 1x10-4 1x10-3 1x10-2
Debris ions,W
Fast ions, C
Photons, W
Photons, C
Fast ions, W
Penetration depth (m)
Energy Deposition as a Function of PenetrationDepth for 154 MJ NRL DD Target
Debris ions, CC density = 2000 kg/m3
W density = 19,350 kg/m3
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Spatial and Temporal Heat Generation Profiles in C and W for 154MJ Direct Drive Target Spectra
0.0x100
1.0x1016
2.0x1016
3.0x1016
4.0x1016
5.0x1016
Temporal and Spatial Profile of Ion Power Deposition inC Armor from 154 MJ DD Target Spectrum
0.0x100
1.0x1016
2.0x1016
3.0x1016
4.0x1016
5.0x1016
Temporal and Spatial Profile of Ion Power Deposition inW Armor from 154 MJ DD Target Spectrum
• Assumption of estimating time from center of chamber at t = 0 is reasonable based on discussion with J. Perkins and J. Latkowski
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Temperature History of C and W Armor Subject to 154MJ Direct Drive Target Spectra with No Protective Gas
• Initial photon temperature peak is dependent on photon spread time (sub-ns from J. Perkins and J. Latkowski)
400
600
800
1000
1200
1400
1600
1800
1.0x10-12 1.0x10-11 1.0x10-10 1.0x10-9 1.0x10-8 1.0x10-7 1.0x10-6
Surface
1 micron
5 microns
10 microns
100 microns3-mm Tungsten slab
Density = 19350 kg/m3
Coolant Temp. = 500°C
h =10 kW/m2-K154 MJ DD Target SpectraPhoton energy dep. only
Time (s)
200
600
1000
1400
1800
2200
2600
3000
Surface
1 micron
5 microns
10 microns
100 microns
Time (s)
3-mm Tungsten slab
Density = 19350 kg/m3
Coolant Temp. = 500°C
h =10 kW/m2-K154 MJ DD Target Spectra
400
600
800
1000
1200
1400
1600
1800
2000Surface
1 micron
5 microns
10 microns
100 microns
Time (s)
3-mm Carbon Slab
Density= 2000 kg/m3
Coolant Temperature = 500°C
h =10 kW/m2-K154 MJ DD Target Spectra
Sublimation Loss = 9x10-18 m
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Future Effort (1)
• Document and release stage 1 code
• Exercise stage1 code:
- Investigate effectiveness of convection for cooling the chamber gas
- Assess effect of penetrations on the chamber gas behavior including interaction with mirrors
- Investigate armor mass transfer from one part of the chamber to another including to mirror
- Assess different buffer gas instead of Xe
- Assess chamber clearing (exhaust) to identify range of desirable base pressures
- Assess experimental tests that can be performed in simulation experiments
April 4-5, 2002 A. R. Raffray, et al., Chamber Clearing Code Development
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Future Effort (2)
• Implement development of stage 2 code - Extend the capability of the code (full inclusion of multi-species capability)
- Implement adaptive mesh routines for cases with high transient gradients and start implementation if necessary
- Work with INEEL to implement aerosol formation and transport models in the stage 2 code- Low probability for aerosol formation for dry wall concepts- However, major effect on target and driver even with minimal formation- Possible background plasma effect to slow down and stop ions (behavior of these
particles)
- Work with ANL to implement more sophisticated wall interaction models in stage 2 code
- Brittle destruction of carbon-based material- Droplets formation and splashing for metallic walls
• Develop a 0-D multi-species model to assess the range of species (neutral and plasma) that should be taken into accounts (S. Krasheninnikov)- If plasma effects are shown to be important, implement model in chamber
dynamics code