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Fluent RPI model( wall boiling model)

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Old   July 31, 2022, 10:12
Default Fluent RPI model( wall boiling model)
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Pual KHAN
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I'm working on simulation of subcooled boiling in Fluent.
1. Does anyone has the RPI UDF handy? I was wondering if it is possible to send me the RPI UDF.
2. I noticed that a lot of modified wall boiling models which considering sliding bubbles based on the RPI wall boiling model,Does anyone has the UDF of modified RPI model ?

I can give some money, so please email me. 583062347@qq.com
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Old   May 25, 2023, 04:36
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sachin
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Dear all,
I am working on coupling the wall boiling and population balance model in Ansys fluent. In Fluent, by default, both are not coupled. If wall boiling is enabled the population balance is inactive and vice versa.
So I want to give the RPI model as UDF and use the default population balance model in Fluent? I have tried for it. But not getting proper results. I am attaching the code here.
#include "udf.h"
#include "sg_mphase.h"
#include "flow.h"
#include "mem.h"

DEFINE_HEAT_FLUX(rpimodel,f,t,c0,t0,cid,cir)
{
real area1, area2, stn, rho_L, cp_L, vel_L;
real k_L, fre, dbw, rho_g, n_site, hfg, h;
real tke, qw, x_vel_L, y_vel_L;

real K = 1.8;
real cmu = 0.09;
rho_L = C_R(c0,t0);
rho_g = 0.8756;
hfg = 2225000; // latent heat in J/kg
cp_L = C_CP(c0,t0);
qw = 202000; // in W/m2
x_vel_L = C_U(c0, t0);
y_vel_L = C_V(c0, t0);

vel_L = sqrt((x_vel_L*x_vel_L)+(y_vel_L*y_vel_L));

dbw = C_UDMI(c0,t0,36);
n_site = C_UDMI(c0,t0,42);
fre = C_UDMI(c0,t0,43);
tke = C_K(c0,t0);

h = (rho_L*cp_L*pow(cmu, 0.25)*pow(tke,0.5)*qw)/(F_T(f,t)-C_T(c0,t0));
stn = h/(rho_L*vel_L*cp_L);
area2 = K*0.785*pow(dbw,2)*n_site;
area1 = 1 - area2;
cid [0] = 0;
cid [1] = area1*stn*rho_L*cp_L*vel_L + (area2*1.2615*pow(k_L*rho_L*cp_L*fre,0.5));
cid [2] = -cid [1];
cir [0] = -0.5235*pow(dbw,3)*hfg*rho_g*fre*n_site;
cir [1] = 0;
cir [2] = 0;
}

The code is predicting wrong wall temperature values.

Regards,
Sachin
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