Boundary Condition for wallHEatTransfer without modelling the Fluid
 

Hi everybody,

I have a Simulation wich I would like to seperate into 2 Sub Simulation and merge them afterwards to Speed up the time.
It is about a heat flow trough a solid material (e.g.) and then a a Transfer to flowing air.

Is it possible to assume in the solid Modell a Heat transfer coefficient [W/m²K] and initialize the Temperatur Field for this solid material without simulationg the fluid?

If I have a fluid I can do this by using something this right?:
type wallHeatTransfer;
Tinf uniform 363;
alphaWall uniform -10;
value uniform 1;

is there a something similar like FluidHeatTransfer with a given Reference Temperature of the fluid?

Best wishes

Andreas

hi there


I have used the following BC and recived quite good results:

Alu_to_Luft
{
type externalWallHeatFluxTemperature;
kappa solidThermo; -
// q uniform 1000; //heat flux [W/m^2]
Ta uniform 300.0; //ambient temperature [K]
h uniform 25.0; //heat transfer coefficient [W/m^2/K]
thicknessLayers (0.008); //(0.001 0.002 0.003 0.004); //list of thicknesses per layer [m]
kappaLayers (0.024); //(0.024 0.024 0.024 0.024); //list of thermal conductivites per layer [W/m/K]
value uniform 320.0; //initialization temperatur [K]
kappaName none;
Qr none;
relaxation 1;
}

Hi Ohlzen-Wendy

I am trying to use the same BC. However I don't understand the meaning of kappa , solidThermo-fluidThermo etc. kappaName, layers etc inputs that are needed. where can I find information about this? I am very new to OpenFOam. Request you help. Thanks.

hi Anirudh_Deodhar,

if you are using this boundary you have differnet options:
1) you a defining a heat flux (W/m²)
2) you are defining an ambient Temeratur Ta for the fluid and the heat transfer coefficent h. Sometimes given as alpha

The layers are optional.
kappa solidThermo means you are calculating the solid side of the heat transfer. in my case i simulate a solid without modelling the fluid.
if you have a fluid and dont want to modell the solid you have to use fluidThermo.

best wishes

Andreas

Thanks lot Andreas. That was very helpful. Is there any source of learning all such things? Or is it just through forums like these?
-Anirudh

Hi Anirudh,

I think this forum is a good source for OpenFOAM and google^^

And of course the given tutorials of openFOAM. In some cases they are very helpful

best wishes

Andreas

In fluidThermo, if we give thermal conductivity of solid as input, and change material as per my requirement, it is not working. the following is the format I used

type externalWallHeatFluxTemperature;
mode coefficient;
Ta constant 330;
h uniform 19;
thicknessLayers ( 0.04 );
kappaLayers ( 50 );
kappaMethod fluidThermo;
value uniform 309;

My question is , Is there any effect of change in thermal conductivity on this boundary condition