[KaWen]

I'm doing things about laser melting materials, and the models include the gas phase as well as the metal phase. The VOF, melting and solidification models were opened in the FLUENT software, and a surface heat source was used between the two phases, taking into account the shallow depth of the laser action.The model is shown in the figure.

1.According to the information in the forum, I tried writing UDFs, adding a surface heat source at the two-phase interface (z=0) and including a gradient that causes my heat source not to act on the gas phase , can I set the heat source to act only on the metallic phase, even though I have added the statement (z<=0&&C_VOF(c, sec_th)>0.05 && C_VOF(c, sec_th)<1), but it doesn't seem to work?

2.Whenever I calculate a certain time step, it always pops up: Divergence detected in AMG solver: temperature Divergence detected in AMG solver: temperature Error at host: floating point exception

Any tips or ideas on how to use this in ANSYS Fluent are greatly appreciated, thank you very much!




DEFINE_ADJUST(store_VOF_gradient, domain)
{
Thread *t;
Thread *ppt;
Thread **pt;
cell_t c;
int phase_domain_index = 1;
Domain *pDomain = DOMAIN_SUB_DOMAIN(domain, phase_domain_index);
Alloc_Storage_Vars(pDomain, SV_VOF_RG, SV_VOF_G, SV_NULL);
Scalar_Reconstruction(pDomain, SV_VOF, -1, SV_VOF_RG, NULL);
Scalar_Derivatives(pDomain, SV_VOF, -1, SV_VOF_G, SV_VOF_RG, Vof_Deriv_Accumulate);

mp_thread_loop_c(t, domain, pt)
{
if (FLUID_THREAD_P(t))
{
ppt = pt[phase_domain_index];
begin_c_loop(c, t)
{
C_UDMI(c, t, 0) = C_VOF_G(c, ppt)[0];
C_UDMI(c, t, 1) = C_VOF_G(c, ppt)[1];
C_UDMI(c, t, 2) = C_VOF_G(c, ppt)[2];
C_UDMI(c, t, 3) = sqrt(C_UDMI(c, t, 0)*C_UDMI(c, t, 0) + C_UDMI(c, t, 1)*C_UDMI(c, t, 1) + C_UDMI(c, t, 2)*C_UDMI(c, t, 2)); // magnitude of gradient of volume fraction

C_UDMI(c, t, 4) = C_UDMI(c, t, 0) / C_UDMI(c, t, 3); // nx -> x gradient of volume fraction divided by magnitude of gradient of volume fraction

C_UDMI(c, t, 5) = C_UDMI(c, t, 1) / C_UDMI(c, t, 3); // ny -> y gradient of volume fraction divided by magnitude of gradient of volume fraction

C_UDMI(c, t, 6) = C_UDMI(c, t, 2) / C_UDMI(c, t, 3); // nz -> z gradient of volume fraction divided by magnitude of gradient of volume fraction
}
end_c_loop(c, t)
}
}
Free_Storage_Vars(pDomain, SV_VOF_RG, SV_VOF_G, SV_NULL);


}

DEFINE_SOURCE(heat_source, c, t, dS, eqn)

{

Thread *pri_th;

Thread *sec_th;

real source;

real xc[ND_ND], time; // Define face centroid vector, time

time = RP_Get_Real("flow-time"); // Acquire time from Fluent solver

C_CENTROID(xc, c, t); // Acquire the cell centroid location

real T = C_T(c, t);

pri_th = THREAD_SUB_THREAD(t, 0);

sec_th = THREAD_SUB_THREAD(t, 1);

real alpha = C_VOF(c, sec_th); // cell volume fraction





real r = sqrt(pow(xc[0] + xx0 - v*time, 2.0) + pow(xc[1], 2.0));

if (z<=0&&C_VOF(c, sec_th)>0.05 && C_VOF(c, sec_th)<1)

{

if (C_T(c, t) < 3500)

{

source = (((2 * A*P) / (pi*R*R))*exp((-2 * (r*r)) / (R*R)))*C_UDMI(c, t, 3);

dS[eqn] = 0.0;