# UDF for mass transfer from DPM to continuous phase

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 September 22, 2022, 10:52 UDF for mass transfer from DPM to continuous phase #1 New Member   mpcaixeta Join Date: Sep 2022 Posts: 1 Rep Power: 0 Hi, I'm modeling a bubble/liquid (ozone/water) system using DPM approach. I want to describe the ozone mass transfer from the gas phase (inert DPM particle) to the liquid phase (dissolved ozone as a species), but I'm not finding any related information to combine a DPM udf with a species transport udf describing a mass transfer. I wrote the algorithm to calculate the ozone mass transfer (see below), but now it is necessary to call some macro or macros so the udf can be available to be hooked into Fluent. I searched in the UDF manual, but I could not relate any macro that just promotes this type of calculation, It would be the DEFINE_DPM_SOURCE? but this is just a kl_o3 calculation (output variable). Can anyone help me with this please!? Thanks in advance! /* UDF to calculate the gas mass transfer coefficient from the bubble surface */ #include "udf.h" #define D_o3 1.76e-9 /* Ozone difusivity */ #define Pi 3.141592 /* Pi number */ #define L 0.2 /* column length */ real u_bmag; /* bubble velocity magnitude */ real u_rel; /* relative velocity between the bubble and the continuous phase */ real t_c; /* contact time between the bubble and the continuous phase */ real kl_o3;/* Ozone mass transfer coefficient */ u_bmag = sqrt(P_VEL(p)[0] * P_VEL(p)[0] + P_VEL(p)[1] * P_VEL(p)[1] + P_VEL(p)[2] * P_VEL(p)[2]); u_rel = fabs(C_U(c, t) - u_bmag); t_c = (L - P_POS(p)[1]) / u_rel; kl_o3 = sqrt(D_o3 / (Pi*t_c)); /* Higbie penetration model */ Last edited by mpcaixeta; September 29, 2022 at 11:11.

 Tags dpm fluent model, mass transfer model, species mass transfer, udf