OpenFOAM in Welding applications Alireza Javidi 1 1 University West, - - PowerPoint PPT Presentation

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OpenFOAM in Welding applications Alireza Javidi 1 1 University West, Department of Engineering Science, Trollhttan Gothenburg Region OpenFOAM User Group Meeting, November 14 th , 2012 1. Arc 2. Energy coupling between solid and fluid 3. Arc and

SLIDE 1

OpenFOAM in Welding applications

Gothenburg Region OpenFOAM User Group Meeting, November 14th, 2012 Alireza Javidi1

1University West, Department of Engineering Science, Trollhättan

SLIDE 2

1. Arc
2. Energy coupling between solid and fluid
3. Arc and coupling
4. Melting and phase change

SLIDE 3

Sketch of the cross section of a TIG torch

Tungsten Inert Gas welding

Picture of a TIG torch

Ar shielding gas inlet

SLIDE 4

Governing equations: thermal fluid part

(Steady) continuity equation

 

   u  (T) 

(Steady) momentum conservation equation

   

 

h T u h h u          ) (      (T) (T)

 

B J P I u T u u T

                        ) ( 3 2 ) ( ) (  

(Steady) enthalpy conservation equation

   

u u u u     (T) (T)        

 

                    h T eC J k T Q E J u P P u

p B rad

) ( 2 5 ) (     

Joule heating Transport of electron enthalpy Lorentz force

SLIDE 5

Governing equations: electromagnetic part

Electric potential

:

with:

V E   

V ) (    T J  

 

) (     V T 

: current density

J  ) (T 

: electric conductivity

Magnetic potential

:

A  V with: V T A   

) (    A B     

SLIDE 6

Argon plasma density as function of temperature.

SLIDE 7

Specific heat as function of temperature

SLIDE 8

Argon plasma electric conductivity as function of temperature

SLIDE 9

Ar shielding gas inlet

Cathode Tip Cathodea AB Cathodea BC Anode Nozzle Inlet Outlet u

parabolic

h or T

20000K Linearb linearb linearc 300K

V or J A

SLIDE 10

Temperature along the radial direction, 1 mm above the anode

SLIDE 11

chtMultiRegionFoam The solver is based on combination of heatConductionFoam and buoyantFoam for conjugate heat transfer between a solid region and fluid region.

“0” “topAir” “U” “T” “p” “bottomSolid” “cp” “K” “T” “rho” “constant”

regionProperties

“topAir” “polyMesh”

thermophysicalProperties g

“bottomSolid” “polyMesh” “system”

controlDict

“topAir” fvSystem fvSolution “bottomSolid” fvSystem fvSolution

SLIDE 12

SLIDE 13

= ∑

SLIDE 14

1. Energy balance at cathode/sheath interface
2. Energy balance at sheath/presheath interface
3. Current density conservation