Learning Forum

[Mash]

I am trying to model a heterogeneous reaction of a multicomponent particle using the DPM_Heat_Mass UDF. Therefore, I want to calculate the species distribution inside every particle. Is it possible to access the particle integration time step size for an implicite tracking scheme with enabled accuracy control?nJust to be clear I need the particle integration time step size not the particle interation time step size.n

[DrAmine]

Have you already checked the documentation?n

[Mash]

Thanks for your answer.nYes, I checked the documentation. I couldn?t find anything in the UDF Manual and Theory Guide. nThe particle iteration time step size would be fairly easy to access via P_DT(p). Nevertheless, I am interested in how fluent calculates the time step size of every iteration within this particle time step. I need that to solve the differential equations of my particle model for the species distribution.nThe DPM_Heat_Mass UDF is called several times per particle iteration, as far as I understood for every point of the particle trajectory. However, I couldn?t find how to access the time between two consecutive calls of the DPM_Heat_Mass UDF by fluent within one particle iteration. Fluent solves those equations with an implicite Euler, so the value should be stored somewhere and therefore be accessible. I hope my line of thinking is reasonable up to this point.n

[Rob]

Have a look in the /src folder for the macros (that's in the manual somewhere) as is how to tell the solver to retain data at the end of the step (we throw away gradients etc otherwise). n

[DrAmine]

P_DT is the time step size used by Fluent to calculate the particle trajectory in each cell.n