[Nishan]

I am trying to simulate 2D multiphase flow and heat transfer in porous media in FLUENT. My domain is simple square domain with the liquid flow coming in from the top boundary. The side boundaries are symmetry. Half of the bottom boundary is heat inlet while the other half is flow outlet. The phase change from liquid to vapor occurs near the heated boundary.

I am incorporating momentum source terms in x and y directions for just the liquid phase. First I use DEFINE_ADJUST to store a value in C_UDSI and then i use C_UDISI_G to calculate the source terms.I tried comparing between simulations with the momentum source and no source terms but the results are identical. I displayed some messages within the code and found that nothing is being stored in C_UDSI. Can anybody tell me where I am going wrong in the code?? The code is written below.

DEFINE_ADJUST(cap_pressure, domain)
{
Thread *t;

real eps = 0.4;
real K = 10 ^ -11;
real sig = 0.0738;

cell_t c;
real a;

Domain *liquiddomain = DOMAIN_SUB_DOMAIN(domain, 0); /* Getting liquid domain from the mixture domain passed onto the DEFINE_ADJUST macro*/

Thread *mixture = Lookup_Thread(domain, 1); /*Here 1 is the zone id for the interior domain in boundary conditions panel*/

Thread *liq = THREAD_SUB_THREAD(mixture, 0);


thread_loop_c(t, liquiddomain) /*should it be just domain or liquiddomain??*/ /*Both doesnt work*/
{
if (t == liq)
{
begin_c_loop(c, t)
{
a = C_VOF(c, t);

C_UDSI(c, t, 0) = sqrt(eps / K) *sig*(1.417*(1 - a) - 2.12*(1 - a)*(1 - a) + 1.263*(1 - a)*(1 - a)*(1 - a));
}
end_c_loop(c, t)
}
}
}

DEFINE_SOURCE(liquid_x, c, t, ds, eqn)
{
real source = 0.0;
real a = C_VOF(c, t);

source = -a*C_UDSI_G(c, t, 0)[0];

ds[eqn] = 0;

return source;
}

DEFINE_SOURCE(liquid_y, c, t, ds, eqn)
{
real source = 0.0;
real b = C_VOF(c, t);

source = -b*C_UDSI_G(c, t, 0)[1];

ds[eqn] = 0;

return source;
}

[kirmaks]

Hallo,

please check if this solution works (You need to populate gradients in DEFINE_ADJUST):

UDF-How to calculate gradient of a scalar

Best regards, Maks