Fluids

Fluids

UDF for a spray dryer

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    • basbas34
      Subscriber

      Hi,

      I'm trying to model changing density of a particle during its residence inside the dryer. I tried to make a udf for chaning density, but ended up with a changing density of my inlet of particles (see UDF below). I'm using a DPM model with a viscous rng k-e model. I was wondering if someone could give me clue how to change my code to specify it to the particle during residence instead to the inlet?


      #include "udf.h"

      DEFINE DPM SCALAR UPDATE(name,c,t,initialize,p)

      {

      real rho;

      real flow_time = RP_Get_Real("flow-time");

      if (flow_time < 12)

      rho = rho = 42.87*exp(-1.525*flow_time)+486.2*exp(-0.2367*flow_time); 

      else

      rho = 42.87*exp(-1.525*12)+486.2*exp(-0.2367*12);

      return (rho);

      }

    • Rob
      Ansys Employee
      You're linking the density to the solver time, you need to look for the residence time. Try using TP_TIME(tp) https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v211/en/flu_udf/flu_udf_sec_define_dpm_scalar_update.html instead. I've not checked the macro so feed back if it works (or not).
    • basbas34
      Subscriber
      i tried to open the link but can't due to student licensing
    • Rob
      Ansys Employee
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