October 17, 2023 at 5:56 pmRobbie CrosbySubscriber
Hello, I am trying to create a UDF to fit a numerical model which must be applied as UDFs in ANSYS Fluent to model a phase change material in a porous medium. I have attached the mathematical model I am trying to follow as well as my current code. I am currently stuck on getting the interstitial heat transfer coefficient to come up as a UDF, that can be selected in ANSYS Fluent, for the non-equilibrium model of porous medium. Any help would be greatly appreciated. Should it be define_profile or define_property
#define Tsolidus 300.0
#define Tliquidus 304.0
#define L_f 250 //Latent heat of fusion
#define UDM_RHO_F_PREV 0 // UDM index for storing previous rho_f
#define UDM_LAMBDA_PREV 1 // UDM index for storing previous lambda
DEFINE_PROFILE(h_sfq, c, t)
real dl, epsilon, mu, nu, pr, rho_pcm, u, v, mu_pcm, k_pcm, Re_d, h_sfq, local_h_sfq;
dl = 0.0194; //Diameter Matlab
epsilon = 0.85; //Porosity Matlab
mu = C_MU_L(c, t); // Laminar viscosity
rho_pcm = C_R(c, t); // Density
nu = mu/rho_pcm; // Kinematic Viscosity
pr = nu/rng_alpha(1., mu, mu); // Prandtl Number
u = C_U(c, t);
v = C_V(c, t);
mu_pcm = C_MU_L(c ,t);
k_pcm = C_K_L(c, t);
Re_d = (rho_pcm * sqrt(u*u + v*v) *dl) / (epsilon * mu_pcm);
if (Re_d > 0 && Re_d <= 40)
local_h_sfq = (0.76 * pow(Re_d, 0.4) * pow(pr, 0.37) * k_pcm)/dl;
else if (Re_d > 40 && Re_d <= 1000)
local_h_sfq = (0.52 * pow(Re_d, 0.5) * pow(pr, 0.37) * k_pcm)/dl;
else if (Re_d > 1000 && Re_d <= 20000)
local_h_sfq = (0.26 * pow(Re_d, 0.6) * pow(pr, 0.37) * k_pcm)/dl;
October 27, 2023 at 11:31 amAtharva NagarkarSubscriber
The DEFINE_PROFILE macro is used to define a custom boundary profile or cell zone condition that varies as a function of spatial coordinates or time while you can use the DEFINE_PROPERTY to specify a custom material property in Ansys Fluent for single-phase and multiphase flows. Based on this, the DEFINE_PROPERTY macro would be more suited for your use.
Please find the links from the Ansys UDF Manual related to both these macros. Check sections 2.3.29 and 2.3.30. I would also request you to have a look at the examples given below these sections to understand the use of these DEFINE macros.
If you are not able to access the link, please refer to this forum discussion: Using Help with links (ansys.com)
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