I would like to know how to make a thermal connection between two objects in a Patran/Nastran 2021 heat transfer analysis.

you have to equivalence the nodes at the boundary between the left block and the right block in order to have heat flow from left to right. See attached zip file with PATRAN 2021 DB and the powerpoint,and NASTRAN bdf files.

Now if the intention is to create 2 separate thermal blocks, you can also use thermal contact to connect them as well.

This is called coupled convection in PATRAN/NASTRAN thermal preference.

 

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Here is the powerpoint for this example.

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Thanks, and what if nodes are not coincident ? is there a kind a glued thermal "contact" available ?

Regards

Yes, you can use thermal glue contact if the nodes are not coincident. In PATRAN you can create contact bodies and body pairs automatically using tools-Modeling- contact bodies pairs. (see slide 2) of the attached powerpoint, and you can set the contact detection (ERROR)=0.1, which is the the distance separated by 2 contact bodies, and you can activate HGLUE=1 for thermal glue contact.(see slide 3 and 4)

I am including the PATRAN DB 2021 in the zip file, and also the NASTRAN SOL 400 test deck.

 

In addition you can use Near Thermal contact (DQNEAR=0.1) to use thermal contact coefficient instead of glue thermal contact. The differences between the glue thermal contact and near thermal contact is that there is no thermal resistance between contact body 1 and 2 with glue thermal contact, whereas the DQNEAR option you can specify thermal contact coefficient (thermal resistance) between 2 parts such as thermal grease or adhesive between 2 parts.

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Just for completeness here is the example of using DQNEAR and also instead of thermal contact, you can use coupled convection to create connection between the 2 parts, so that you can use SOL 153 and SOL 159 to create thermal contact as well. The coupled convection feature is supported in SOL 153,SOL 159, and SOL 400.

Here include the zip file for cases of DQNEAR and coupled convection, and powerpoint.

 

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Thanks. very interesting... so to sum-up... thermal glue (as off-the-shelf Card, etc..) is only available in SOL400 ?

not in SOL153/159 (except some tricks) ?

Dealing with thermal analyses capacities what are the things we can do in SOL153/159 that we can not do in SOL400 ? (and vice-versa) ?

Regards

 

Thanks @Daniel_Chu_Thermal.

I was able to tell the temperature of what the nodes match.

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But I can't in the case of glueing.

I turned on HGLUE but it did not convey the temperature.

How can I convey it? I put up a file.

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Please tell me more about coupled as well. I was able to analyze, but I cannot set Spatial Fields for Input Date. Do I need to set it up?

Thermal contact using glue and near contact is only available in SOL 400. However, you can use coupled convection in SOL 153 or SOL 159 to simulate contact, but the user has to select which face of the solid or elements and the companion regions where the contact occurs. In SOL 400, the thermal contact is based on the real gap distance and you can specify just the contact bodies, and MSC/NASTRAN will find the contact for you within these tolerance.

SOL 400 has all the thermal capabilities of SOL 153/SOL159 such as fast hemicube view factor modules ,thermal radiation, coupled advection 1D fluid stream coupled to 2D or 3D structures, transient thermal analysis with heater, thermostat controllers, and convection.

In addition, the SOL 400 has 2D thermal thick shell elements can have temperatures on top ,middle and bottom so that the user can use a shell element to have thermal gradients across the thickness. It also has composite 2D elements with multiple layers, and each layer can have thermal material properties as well as structure material. The SOL 400 also can do multi-physic from nonlinear steady state thermal coupling with nonlinear static analysis or nonlinear Transient thermal analysis coupling with nonlinear static analysis without thermal mapping into structural analysis. This means the at each increment, the temperature at node are pass to the structural analysis to compute thermal displacement automatically. In SOL 400 you can also have a coarse thermal model, and using the NASTRAN RESTART capabilities you can map the temperature into a refined structure model given a tolerance.

 

There is a thermal webinar that I gave:

You can find that at following web page.

 

 

SimAcademy Webinar: MSC Nastran Thermal Capabilities as Compared to Sinda Thermal Solver

 

 

 

https://simcompanion.hexagon.com/customers/s/article/SimAcademy-Webinar-MSC-Nastran-Thermal-Capabilities-as-Compared-to-MSC-SINDA-Thermal-Solver

 

Here is a detailed list of SOL 400 thermal capabilities spreadsheet.

Many thanks Daniel

Very interesting summary... I will have a lot of reading for the week-end :-)

Regards

Lionel

Dealing with "hemicube" view factor calculation method, in which manual is it described ?