Temperature input as a function of two variables

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  • Last Post 27 September 2018
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malay_shankar posted this 21 September 2018

can we input temperature as a function of two variables like (radius and angle)?

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rwoolhou posted this 24 September 2018

Can you elaborate on what you're trying to do, and with which solver?  Simple answer is yes, probably, it depends. 

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malay_shankar posted this 24 September 2018

Hi, i am trying to give a temperature to the attached geometry (parasolid  file) as function of radius and angle. The attached geometry is 1/8th of the full circular model.

i am using static structural module as i am currently interested in 2D steady state conduction.

Also, i need to know how to model or which connection to give between the contact surfaces of the upper and lower plates.  I  have updated the attachment as triangular geometry

peteroznewman posted this 24 September 2018

Shankar, the ANSYS members on this site don't open attachments like Parasolid, but independent members like me do open attachments.  You can't attach a Parasolid directly, but you can put any file type into a zip file and you can attach that as long as it is < 120 MB in size.

To get the best help from all members, it is better to use the Insert Image button and select an image file that you have saved on the disk from a screen capture program like Snipping Tool. If you paste the geometry into Powerpoint, you can annotate the image with some text and point to relevant features, then do another screen capture of the Powerpoint page, save that file then Insert that image into your next post.

 

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malay_shankar posted this 24 September 2018

Thanks for the feedback. I will quickly follow this

malay_shankar posted this 24 September 2018

Hi, please find the image to better understand the geometry

peteroznewman posted this 24 September 2018

Shankar, that is a good description of the geometry and the contact/gap conditions along the interface.

What boundary conditions to you want to apply to the edges in the 2D or faces in the 3D model? For example the top edge/face of the Top plate and the bottom edge/face of the Lower plate.

Are the boundary conditions such that they have no dependence on the angle of the slice and so you can have an axisymmetric model?

Is the Gap filled with air or another fluid?

Is there any flow of fluid in that gap or is it stagnant?

Do you have any data on the thermal resistance at the faces that are in Physical contact?  ANSYS assumes perfect thermal contact, but the thermal resistance can be included in the contact definition.

Regards,

Peter

 

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malay_shankar posted this 25 September 2018

Hi Peter,

Please refer to the images above for the boundary conditions.

In the 3D slice geometry case the temperature is dependent on the angle, so we can not take it as axisymmetric model.

Yes, there is a fluid flow from top but due to O-rings and gaskets installed the gaps will be insulated.

I do not have any data on thermal resistance, so kindly suggest me the ways in which I can model the thermal contact. If that data is needed to model, i will try to get it.

 

Thanks.

malay_shankar posted this 26 September 2018

For a thermal contact between the two put a thermal conductance value. Is this correct?

I will try to get thermal resistance data and input it.

Regarding temperature input  i am still struggling to find out a way to enter temperature as function of two variables. (radius and angle)

 

peteroznewman posted this 26 September 2018

Shankar,

Create a Bonded Contact on the edges that touch in the 2D model (or on the faces that touch in the 3D model).

When you do that you can override the Thermal Conductance setting and type in a value of Thermal Conductance at that interface. When you leave it Program Controlled, it assumes there is no additional thermal resistance at the contact interface. You can instrument a prototype and measure the contact resistance. I don't know if there is a good generic value.

Any edges that don't have a Boundary Condition are assigned an Insulated BC in the solver, so you don't need to apply that manually.

It's not credible that there is no heat transfer across that thin gap, because it is so thin. If there is stagnant air in that gap, that can still conduct some heat. I recommend you add a body to fill that gap and assign the thermal conductivity of air to that thin rectangle.

Can you attach a zip file with an example of the distribution of the convective film coefficient, h, as a function of radius and angle?  You show h in the diagram, but you mention a distribution of temperature. You can provide a temperature map also. I know there is a way to import a temperature map, I don't know how to create a field variable for h.

Regards,

Peter

 

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malay_shankar posted this 26 September 2018

Hi Peter, 

Yes you are right, value of 'h' will be constant. Sorry for putting it wrongly in the image, my bad.

I have solved the 2D geometry and got the desired results. But, i need to solve the same with 3D slice geometry, and input temperature as a function of radius and angle.

Kindly help me on what is a temperature map and how it can be provided onto the model?

 

Thanks & Regards

Malay

 

 

peteroznewman posted this 26 September 2018

Malay,

Can you attach a zip file with an example of the distribution of temperature as a function of radius and angle?

If you specify a Temperature Boundary Condition on the top surface, then you can't specify a Convective Boundary Condition on that surface also. You have to choose one or the other.

Regards,

Peter

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malay_shankar posted this 26 September 2018

Peter,

I do not have any zip file for that. Please refer to the image. I hope this will make you understand better.

peteroznewman posted this 27 September 2018

The "External Data" module is a convenient way to import external data and map it into the workbench module.
Check the following video for the format that is required:

Mapping by External Data system

Regard,

Peter

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