# UDF for thermophysical propreties of nanofluid

 Register Blogs Members List Search Today's Posts Mark Forums Read

 January 26, 2021, 10:38 UDF for thermophysical propreties of nanofluid #1 New Member   Maroua Mekcem Join Date: Jan 2021 Posts: 1 Rep Power: 0 HI , I'm not too familiar with UDF ,i'm a begginer. I searched a lot and i didn't understand from where the equations dependent to temperature come ??(conductivity,viscosity,Cp,Density of base fluid)- i mentionned the equations with bold please help me. Here an exemple: Brinkman model #include "udf.h" #define fi 0.02 #define ro_s 3950 /*#define cp_f 1845*/ DEFINE_PROPERTY(cell_density, cell, thread) { real ro_nf; real ro_f; real tt= C_T(cell, thread); ro_f=1000*(1-((tt+15.7917)*((tt-277.1363)*(tt-277.1363)/(508929.2*(tt-205.0204))))); ro_nf=(((1-fi)*(ro_f))+(fi*(ro_s))); return ro_nf; } DEFINE_SPECIFIC_HEAT(cell_specific_heat, T, Tref, h, yi) { real cp; real cp_f; real cp_s; real ro_f; cp_s= 765; cp_f=9616.873445-48.73648329*T+0.1444662*((pow((T) ,2)))-0.000141414*((pow((T) ,3))); ro_f=1000*(1-((T+15.7917)*((T-277.1363)*(T-277.1363)/(508929.2*(T-205.0204))))); cp=((1-fi)*(ro_f*(cp_f))+(fi*(ro_s*(cp_s))))/(((1-fi)*ro_f)+fi*ro_s); *h = cp*(T-Tref); return cp; } DEFINE_PROPERTY(thermal_conductivity, cell, thread) { real tt= C_T(cell, thread); real mu_f; real ro_f; real k_eff; real ks; real kf; real Re; real Pr; real cp_f; cp_f =9616.873445-48.73648329*tt+0.1444662*((pow((tt) ,2)))-0.000141414*((pow((tt) ,3))); kf=-1.1245+0.009734*tt-0.000013158*tt*tt; ks=35; mu_f=0.02165-0.0001208*tt+(1.7184e-7)*tt*tt; ro_f=1000*(1-((tt+15.7917)*((tt-277.1363)*(tt-277.1363)/(508929.2*(tt-205.0204))))); Re= (2*ro_f*tt*1.3806488e-23)/((22/7)*25e-9*(mu_f*mu_f)); Pr= (mu_f*cp_f)/(kf); k_eff=kf*(1+(4.4*(pow((Re) ,0.4)))*(pow((Pr) ,0.66))*(pow((tt/273.15) ,10))*(pow((ks/kf) ,0.03))*(pow((fi) ,0.66))); return k_eff; } DEFINE_PROPERTY(viscosity, cell, thread) { real mu_f; real mu_eff; real tt= C_T(cell, thread); mu_f=0.02165-0.0001208*tt+(1.7184e-7)*tt*tt; mu_eff =mu_f/(pow((1-fi) ,2.5)); return mu_eff; }

 Tags cfd code, model equation, nano fluid, thermophysicalproperties, udf code