Thermal analysis simulation

[Kshitish]

Hi all,

I am new to Elmer and I want to perform a thermal analysis simulation on my PCB. For testing and learning purpose, currently my PCB geometry only consists of one IC and the PCB itself. I know the power dissipation for the IC from its datasheet. I want to observe the temperature of the PCB under different ambient temperatures (25 deg C, 71 deg C).

The power dissipation given in the datasheet is 610 mW, that I am entering in Integral Heat Source. I have assumed the weight of the IC to be 1 gm, so hence my W/kg would be 610, which I have entered in Body Force.

I am entering the ambient temperature 25 deg C (298K) in the Boundary conditions tab as the Dirichlet temperature condition.

The upper limit of the output temperature scale comes out as the ambient temperature itself, no matter what value I enter in the body force.

1) Am I entering the values in the correct tabs?
2) Do I need to enter any additional conditions?
3) Is my mesh geometry accurate?

I am attaching the project file.
https://drive.google.com/file/d/1r5L12u ... drive_link

Thanks a lot in advance for any assistance.

[kevinarden]

Mesh is a problem. Elmer exchanges data between bodies through shared nodes. It is possible to have a non-conforming mesh at the interface between bodies, but then you have to define mortar conditions. For heat to flow from body to body those bodies have to share nodes, or get mortar to define the sharing.

model.PNG

(555.86 KiB) Not downloaded yet

[Neo]

I am newbie working on a similar problem, where I only know the ambient room temperature and the power dissipation of each chip. I am entering the ambient room temperature as a boundary condition and the power dissipation as heat source. I am running a steady state simulation as of now. I want to observe the rise in temperature of the chips due to the power dissipation. But in the results, I am getting the ambient temperature for each surface. Here is a screenshot of the results and my simulation files.

[kevinarden]

Mesh looks OK
You have defined 1 body force.
You need to assign every body an initial condition temperature, or else there default is zero.
You have no defined boundary conditions. You need to define which boundaries will radiate heat out of the system and define the external temperature and emissivity for idealized radiation, or otherwise define the allowed heat flux.

The default on an undefined boundary is no heat loss.