Fluids

Fluids

What is the best way to import tabulated values for example air Thermal Conductivity vs Temperature?

    • Randy92
      Subscriber

      I'm working with very high temperatures and I got txt files with data for Density, Cp, Thermal Conductivity and Viscosity values at different Temperatures. I don't have experience with UDF and C programming. Is there an easy way to import or read this data? Or do I have to learn C programming and write an UDF?

    • DrAmine
      Ansys Employee
      You will need to learn C to include these tables. For Air we have however Real Gas Property Tables which you might use directly (after creating the tables) or you use temperature dependent functions to incorporate what you have in your tables.
    • Randy92
      Subscriber
      Thank you for your answer. Can I just paste the values of my table in the RGP Table Data Set? And I can see that RGP is only available for Density.
    • Randy92
      Subscriber
      And what about the Read Table function? I can read txt files with it but can I use this for the air properties?
    • DrAmine
      Ansys Employee
      You can read the tables using C and do interpolation there. Only of couple of things can be adjusted using Tables in Ansys Fluent. I can tell that material properties do not belong to these parameters. So you require UDF/C.
    • DrAmine
      Ansys Employee
      No: RGP is a genialized property table which is very accurate. You do not to use your own tables.
    • Randy92
      Subscriber
      Ok. Why is it when I asked my friend, who is a programmer, to help me with C to write something that can read the tabulated data he says this is something very complex that will take a long time and it is not realistic for me, a person with no programming experience, to learn this and do it myself within an realisitic time frame? Is he right or does he somehow not understand what I have to do. I found an example of someone making a UDF for air viscosity vs temperature (something I have to do as well).

      ***Edited by DrAmine: removed external link**
      When I showed him this and told him we at least have something that we can use/copy he still wasn't positive. Maybe it is an improvement for the next version, to make Ansys read data from excel or something. I just don't understand why this has to be so complicated xd.
    • aitor.amatriain
      Subscriber
      Why don't you fit the data to a polynomial?
    • DrAmine
      Ansys Employee
      wrote it: why not fitting data to polynomial?
      I can understand that you do not want to dive into programming and to have things done using C and you expect to have that already in Ansys Fluent: I can understand that. We actually are working on extending 1D or 3D Tables so that it is not required to code anything. This will be added in the future.
    • Randy92
      Subscriber
      Ok, that sounds good but I assume this won't be happening anytime soon?
      I'm trying to put this (see figure) into an Expression right now but the Units are a headache. If I use Polynomial than the powers have to be discrete numbers right?


    • DrAmine
      Ansys Employee
      Use Fluent Expressions and you will be happy
    • DrAmine
      Ansys Employee
      For heat capacity you will require UDF though.
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