Fluids

Fluids

Topics related to Fluent, CFX, Turbogrid and more.

    • Joscha Hoppe
      Subscriber
    • SRP
      Ansys Employee

      Hi,

      I suggest you to check ansys customization manual: A.5. Variables (ansys.com)

      Hope this helps you. Let me know if you have any question.

      Thank you.

    • Rob
      Forum Moderator

      You may want to review C syntax, I don't think 10^(-4) will work. 

      Is the viscosity change linked to the solution time, or time since the fluid exceeded a certain temperature? What happens if it cools down again? 

    • Joscha Hoppe
      Subscriber

      Thank you very much for the answers!
      Rob you were right, but the viscosity change i got was wrong since the whole viscosity changed with time and that was not what i wanted.
      The viscosity is supposed to change since the fluid exceed a certain temperature. It is supposed to be a simulation of a polymerization process, where the viscosity increases with time. Therefore the after cooling down the viscosity doesnt change. 
      I read that i might need a UDS for it, but i would like to know if there is a more simple way.
      Greetings

    • Rob
      Forum Moderator

      It's complicated, and to an extent beyond where I can help given the nature of the Forum. 

      You can use a scalar to track what material has hit the critical temperature, and you can use an additional scalar to track the age of the first one. 

      Back into "common knowledge" where I can comment. If a part of your system starts to polymerise does it trigger the whole lot to, or is the initiation temperature still important. The wonders of an old A-level chemistry education. 

    • Joscha Hoppe
      Subscriber

      Okay, thank you. The initiation temperature is still important. I am simulating a moving porous medium where the polymer is moving through a die, there it becomes heated and then the polymerization reaction starts and the viscosity rises. at the same time the fluid is still moving through the die.

    • Rob
      Forum Moderator

      That may become difficult to converge as you start pushing very viscous material through parts of the domain. 

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