## Fluids

#### Changing Boundary Condition Temperature

• knuckshuk
Subscriber

Hi!

I am trying to simulate retort heating for sterilization. The heating will be in all direction of the walls.

So I have a real factory data temperature of the retort and would like to set a BC out of it. In exact, I want to set my boundary condition to follow the retort temperature per minute. The data I have is something like this,

t = 0min, T = 10

t=1min, T = 20.. etc

So what I did from watching tutorial is to write a UDF attached below. But the result shows that the outer walls do not change temperature. I see that the simulation result shows heating form the middle instead of the outer walls. One problem that I found is that I noticed that when I attached the file to the BC temperature tab, it does not take into account the time, only the temperature. May I know if i can fix the UDF? Or am I not able to do so with this kind of UDF?

The real data is not linear, the attached file is just an example. It involved heating, sterilizing and cooling so the best fit equation is not accurate to be modelled using an expression.

• Surya Deb
Ansys Employee
Hello, nAs ANSYS Employees, we cannot download an attachment. Can you please take a screenshot of your UDF and embed it in the post?nA DEFINE_PROFILE UDF should be able to handle the variation of temperature with time.nAlso it is not clear when you say it does not take into account the time. nIf the problem is transient and you are using proper flow time macros to vary your temperature, then Fluent should be able to interpolate and apply the variation.nRegards,nSuryan
• knuckshuk
Subscriber
Hi! I followed a tutorial and this is what I attachednnnOn the tutorial video that i watched,
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, they attached similar UDF (velocity instead of temperature).The 'does not take into account the time' means that I attached the temperature column to the temperature for the BC but did not attach the time column anywhere else. The result shows that the BC temperature is stuck on the first temperature written. Is it possible for me to use this type of UDF instead of the DEFINE_PROFILE UDF? n
• DrAmine
Ansys Employee
That is transient table profile and not an UDF.n
• knuckshuk
Subscriber
Oh, is it possible to use this table then? I have 158 data pointsn