DPM Particle Heating UDF

CC96CC96 Member
edited October 12 in Fluids

Hello Everyone,

Recently I've been working on a discrete phase modelling for small particles inside a fluid. The reason why I am using DPM is because of low volume fraction and ability to track particles with discrete phase modelling.

I succesfully formed my model. However to further improve, I have to include additional inputs.

I have to apply heat source to the particles depending on their location. I know that there is no possible option to implement particle heat source so I am using DPM_LAW to include that additional heating as a temperature change to the particle. However, with the temperature change, fluid near the particle has to be updated, but I see no change in the fluid velocity or temperature. So DPM_LAW only changing particle temperature. I tried using DPM_Source to add energy source to the cell that particle is in.

I am able to add some kind of source to the cell but I am not sure it is the true way to do that. So I am probably missing a point and misunderstood something on the UDF manual.

But why not when I change the particle temperature through DPM_LAW, it is not directly added to the energy equation for heat transfer calculations. And is there a better way to do what I am trying to do? I mean adding a energy source to the cell is too much. By the way I enabled coupled solution, so interactions between fluid and particles are included.


Thank you in advance for any kind of information you can provide regarding this issue.


Stay Safe!

Answers

  • RobRob UKForum Coordinator

    I'm not sure how the law would change a particle temperature. What is the physical mechanism you're trying to replicate?

  • CC96CC96 Member
    edited October 13

    Hello and thanks for quick reply.


    Well I have solid particles inside a fluid and due to that solids optical properties particles generate additional heat. I manage to change particle temperature with custom law of heating. I simply assign a different value of TP_T(tp) by changing the inert heating law. However, I realized that this only changes particles temperature but I also have to modify the energy source in continous phase so that, the extra heat generation I have would be implemented to the continous phase. When I did go through the UDF materials online I found that people are doing what I am trying to do using Custom Law (DPM_LAW) and DPM_SOURCE combined. But when I write my own code for DPM_Source nothing changes, I can not add an extra energy source to continous phase.

    S->energy += TP_MASS(tp)*CP_PHOSP*(TP_T(tp)-TP_T0(tp));

    I used this but I see no change. But when I erase particle temperature from the equation and apply

    S->energy += TP_MASS(tp)*CP_PHOSP*20;

    I see an extra energy source to continous phase. But since particles temperature (heat generation rate) varies with location, I have to include TP(tp) in the equation.

    So am I understanding the DPM_Source UDF correctly or am I missing something? Or the physical mechanism I try to model requires some other approach.

    I hope I manage to express myself clearly. Again thank you for your interest.

    Ps. Using DPM is important because I do track particle and need particle trajectory information.

  • RobRob UKForum Coordinator

    DEFINE_DPM_SOURCE will add/remove stuff from the carrier phase, and is covered in the UDF manual. I've asked if there is an equivalent for the particle but sharing that information will depend if it's public domain or not (and whether there is one).

  • RobRob UKForum Coordinator
    edited October 13

    DEFINE_DPM_LAW will allow you to heat up the particle, but read the text associated with it VERY carefully to see where that heat comes from.

  • CC96CC96 Member

    Thank you for the information. I think I understand my issue and you are right using DPM_LAW particle temperature changes and DPM_Source is the true way to influence carrier phase. So I am on the right track, just need to read UDF manual carefully and build up the case better.


    Stay Safe!

  • RobRob UKForum Coordinator

    Thanks, you too.

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