A DEFINE_HEAT_FLUX function allows you to customize how diffusive and radiative heat fluxes between a cell and a neighboring wall are to be computed in the energy equation. You can use this DEFINE macro to specify one or both types of heat fluxes. The argument f is the index of the wall face, Thread pointer t points to the thread of the wall face, c0 is the index of the cell next to the wall, and Thread pointer t0 points to the thread of the cell. Your UDF needs to specify the diffusive heat flux coefficient ( cid), and the radiative heat flux coefficient ( cir). With these inputs, diffusive heat flux ( qid) and radiative heat flux ( qir), respectively, will then be computed by FLUENT using the following equations:
qid = cid[0] + cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t) - cid[3]*pow(F_T(f,t),4)
qir = cir[0] + cir[1]*C_T(c0,t0) - cir[2]*F_T(f,t) - cir[3]*pow(F_T(f,t),4) |