Fluids

Fluids

Heat/mass transfer between DPM components

    • ibmb2020
      Subscriber

      Hello,

      I am trying to simulate solid rocket motor flow with aluminum combustion in it. The gas species mixture is my continuous phase. Al and Al2O3 are my DPM components.

      Summary of physics behind, Al solid (or liquid does not matter) coming from burning propellant surface, and reacting with O2 exists in mixture species and turns into Al2O3 (liquid). So I just decided to use multi-component DPM (Al and Al2O3) and wrote define_heat_and_mass transfer UDF for it (I know the empirical equation for Al2O3 mass generation, so no need to solve any chemical kinetics). Compiled and read under UDF>Heat/Mass Transfer. Under multi-component settings, Al mass frac set to 1, Al2O3 is set to 0 since there is no Al2O3 at the beginning and evaporating species selected not-vaporizing for both components. When I run the simulation, it seems like there is no Al2O3 generation (although, i am giving source terms to dydt array), and my all Al evaporating (even tough there is no evaporation rule is selected).

      Is there a way to enforce mass/heat transfer between DPM components (Al and Al2O3 in my case)? It seems like this heat_mass_transfer UDF works only for mass/heat transfer between continuous and discrete phases.

    • Surya Deb
      Ansys Employee
      Hello,
      Do you need to have a multi component droplet? Does Al2O3 stay as droplets in the system? If not, then you can have Al2O3 as a separate liquid species and just have Al as the DPM droplet. Then you can specify mass transfer accordingly.
      Regards SD
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