Boundary Condition: unable to fix some trouble with detailed geometry

[Rheen Mendoza]

Hello All,

I would like to seek advice about the boundary condition issue.

I'm having trouble when doing the boundary conditions of my detail in THERM 7.8.  The detail have been converted to DXF files and transferred to Therm using 'underlay' and autoconvert. Then I used W7.8 and Optics 6 for the glass.

Despite following the boundary conditions step by step, as shown in the below images, I keep encountering errors. I've attempted to troubleshoot by deleting and retracing the drawings, but I'm uncertain if there are any overlapping regions (although upon zooming in, I haven't noticed any).

[Robin Mitchell]

It looks like you might have points that are too close together but not close enough together to be merged automatically.

If you can share your file, I (or others on this forum) can take a look and see what the problem is. 

Robin

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Robin Mitchell

Building Technology and Urban Systems Division
Energy Technologies Area
Lawrence Berkeley National Laboratory

[Robin Mitchell]

Never mind, I see you attached the file. 

Robin

[Rheen Mendoza]

Hi Robin,

I tried to increase the mesh, iteration and mesh tolerance, unchecking the "Always check for overlapping polygons" in the Options/Preferences/Drawing options and simplifying some of the geometry,  thinking that THERM might just be at limit due to the geometry but I'm still getting this overlapping regions.   

Appreciate if anyone also could help as I tried re-tracing the geometry but still getting this same issue.

I've attached my latest Therm model (Therm 7.8) for reference.

Thank you.

Rheen

[Jonathan Spencer]

The underlying issue here is the dxf import geometry. You've got points basically on top of each other which Therm doesn't like. And at the same time, your settings in these files are probably making the problems harder to solve.

To make boundary conditions work try:

Float Tolerance 0.01mm

Checking Tolerance 0.03mm

These settings should stop it from trying to tell you every polygon is overlapping like the SPLAN 16 screenshot there. And it will make redrawing and bucket filling geometry easier while you fix things up.

You will still need to go around and address the problem points one by one. There are multiple instances of "extra" points on polygons. Sometimes they are so close together you can only find them by dragging the point and seeing it had another one basically in the exact same place. Sometimes they are visible like in the attached screenshot. That polygon should obviously have 5 sides but it has that 6th point wedged between the glass and sealants. Eventually you should be able to get it to the point where it will let you boundary the model.

To make it calculate results try:

Mesh parameter ~8. For models of this complexity, this is the mesh you are probably going to succeed at. 6 is most likely too low and 12 is too high.

I got both of your models to run and they are attached. Aside from the above, I redrew one of the glazing gaskets and deleted some unneeded geometry and then they calculated. SPLAN 16 has boundary conditions on the glass that don't make sense to me but I put some boundaries on the frame just to make it run. You'll need to look at the glass situation.

[Rheen Mendoza]

Hi Jonathan,

Thank you for your response.

I tried to open the SPAN 16A and SPLAN 10A but I'm getting this notification of "Invalid Material Properties".  Not sure of it, I tried the given choices below but still could not open the Therm files.  Is there something that I should adjust in my Therm setting?

[Jonathan Spencer]

I modified and saved these files in Therm 7.8.71. Are you on one of the older 7.8.xx versions? The files will not be backwards compatible. I would generally recommend 7.8.71 as it is more stable than 7.8.57 for example. You'll have to update to at least 7.8.71 to open these files in any case.

[Rheen Mendoza]

Thank you Jonathan.

Yeah, I think that's the reason as I'm using an older version.