openfoam in welding applications - chalmershani/ofgbg12/slides/alirezajavidi.pdfopenfoam in welding...
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OpenFOAM in Welding applications
Gothenburg Region OpenFOAM User Group Meeting, November 14th, 2012
Alireza Javidi1
1University West, Department of Engineering Science, Trollhättan
1. Arc2. Energy coupling between solid and fluid3. Arc and coupling4. Melting and phase change
Sketch of the cross section of a TIG torch
Tungsten Inert Gas welding
Picture of a TIG torch
Ar shielding gas inlet
Governing equations: thermal fluid part
•(Steady) continuity equation
0 u(T)
•(Steady) momentum conservation equation
hTuhhu )( (T)(T)
BJPIuTuuT T
)(
32)()(
•(Steady) enthalpy conservation equation
uuuu (T)(T)
h
TeCJkTQEJuPPu
p
Brad )(2
5)(
Joule heatingTransport ofelectron enthalpy
Lorentz force
Governing equations: electromagnetic part
Electric potential :
with:
VE
V)( TJ
0)( VT
: current densityJ
)(T : electric conductivity
Magnetic potential :A
V
with:
VTA 02 )(
AB
Argon plasma density as function of temperature.
Specific heat as function of temperature
Argon plasma electric conductivity as function of temperature
Ar shielding gas inlet
CathodeTip
Cathodea
ABCathodea
BCAnode Nozzle Inlet Outlet
u 0 0 0 0 0 parabolic
h or T 20000K Linearb linearb linearc 0 300K 0
V or J 0 0 0 0
A
Temperature along the radial direction, 1 mm above the anode
chtMultiRegionFoam
The solver is based on combination of heatConductionFoam and buoyantFoamfor conjugate heat transfer between a solid region and fluid region.
“0”“topAir”
“U”“T”“p”
“bottomSolid”“cp” “K”“T”“rho”
“constant”regionProperties“topAir”
“polyMesh”thermophysicalPropertiesg
“bottomSolid”“polyMesh”
“system”controlDict“topAir”
fvSystemfvSolution
“bottomSolid” fvSystemfvSolution
= ∑
1. Energy balance at cathode/sheath interface2. Energy balance at sheath/presheath interface3. Current density conservation