[Steve01]

Dear all,
I'm trying to simulate a thin strip casting prozess between two rotating rolls. For that I want to simulate the heat exchange between the casting rool and melt pool during the liquid steel is solidify on the surface of the roll.
Due the rotation of the casting roll the solidified material on the roll surface be removed from the domain.
Therefore I generate the two separate parts casting roll (solid) and melt pool (Fluid), as you can see in the first picture "Geometry". I don't put them together in a component group, so in the meshing step there is a contact between the two parts (picture "contact").


In FLUENT:

Setup settings:


General: Solver: pressure-based; velocity formulation: absolute; time: trasient; gravity activated: Y(m/s2)=-9.81


Models:
1.) Solidification/melting on (also the energy equation) --> activate "Include pull velocities"
2.) Realizable K-epsilon model with standard wall function


Materials:
1.) liquid steel (fluid) for the melt pool
2.) cooper (solid) for the casting roll


Cell Zone Conditions:
1.) casting_roll: material: copper; activate: mesh motion: Rotation-Axis-Direction X=0 Y=0 Z=-1, Speed (rpm) =19.1, relative to cell zone: absolute
2.) melt_pool: material: liquid_steel, no other changes


Boundary Conditions:
1.) inlet_melt: velocity inlet, direction X=0 Y=0 Z=-1, velocity magnitude 1.5 m/s, temperature 1810 K
2.) outlet_strip: velocity inlet, direction: X=0 Y=-1 Z=0, velocity magnitude 0.58 m/s --> pull velocity
3.) thermal walls to the surrounding like melt_pool_surface, pool_side_plate, ...
4.) symmetry boundaries


Mesh Interface between the casting roll and melt pool (contact):
contact between: casting_roll_outer_surface and contact_surface_pool (I define the contact in the meshing step)
So Fluent generates:
1.) interface:
casting_roll_outer_surface
contact_surface_pool
2.) walls
casting_roll_outer_surface_trg_wall
contact_surface_pool_src_wall
wall-4: Adjacent Cell Zone: melt_pool_domain, motion: rotation relative to adjacent Cell Zone, direction X=0 Y=0 Z=-1, Speed (rpm) = 0
wall-4-shadow: Adjacent Cell Zone: casting_roll_domain

Currently I don't activate the interface Option "coupled Wall".

However, after the initialization of the solution the liquid fraction for the both domains casting_roll and melt_pool is 1, although the casting_roll_domain ist define as solid cell zone (see picture "temperature" and "liquid_fraction").
Is there a method to change this or do I have a mistake somewhere?




Further Question:

I would like to set the heat transfer coefficient at the contact surface between solid and fluid as constant. After research I found the following forum post:

Is it possible to set constant heat transfer coefficient at a wall?

The author gives the following as a possible solution:


#include "udf.h"
static real h = 0.; /* heat transfer coefficient (W/m^2 C)*/
DEFINE_ADJUST(htc_adjust, domain)
{
h = 120;/* Define the heat transfer coefficient. */
}
DEFINE_HEAT_FLUX(heat_flux, f, t, c0, t0, cid, cir)
{
cid[0] = 0.;
cid[1] = h;
cid[2] = h;
cid[3] = 0.;
}


So I try to add the UDF. But I get the following error:
line 3: parse error

Anybody know a solution?


Thanks in advance for your support

Best regards
Steve