## Fluids

#### parameter of convection

• Jonn
Subscriber

good morning

I am studying the temperature change of a wall, but when I enter a parameter Convection for both sides,

When starting the calculation, the temperature does not take its initial value as 303 K .

But when I have one parameter of convection , I don't have this problem

Is there a modeling method?

• RK
Ansys Employee
Hello,
You can set the initial value to 303 K and initialize it.
• Jonn
Subscriber
Hello
When I set the initial value to 303K and initialize it. The results appear like this
The initial temperature should be when the calculation is started
T_inlet= 303k
T_outlet= 297k
Is there a way to set each side individually?

• DrAmine
Ansys Employee
I do not understand the setup. Inlet or pure walls?
• DrAmine
Ansys Employee
Okay you have only solid with two walls having mixed or thermal boundary condition or at least the left one using temporal profile. I do not now understand the problem as I do not see a problem
• Jonn
Subscriber
I am studying the temperature change at the outlet side of a single layer wall
The entrance and exit is a wall
I give the inlet side a variable temperature that starts with a value 303k and increases with time. File UDF and a heat transfer coefficient h=24
For the outlet side, i give it a constant temperature 297k and a heat transfer coefficient h=7
But when I start the calculation, the initial values of the two walls are not the same as the values I entered ''see the picture ''

• Rob
Ansys Employee
Can you post an image of the mesh?
• Jonn
Subscriber
To simplify the idea I said I have one layer but I have two layers
and for the mesh I think is good

• DrAmine
Ansys Employee
At inlet you give T=303 K + 1 K /15 [s] * time and HTC. So actually you are not providing the temperature boundary directly but a robin like BC: convective BC. Fluent will need to calculate the boundary temperature based on that: balancing the convection outside with conduction inside.
• Jonn
Subscriber
OK thank you sir