Learning Forum

[Rama]

Hi All,

I am trying to introduce a Phase Change Material in the bottom surface of a Solar Panel to mitigate its excess operating temperature. For that I saw one tutorial showing:

1) How to perform solidification and Melting in Fluent

2) Sharing the load data from fluent to steady state thermal.

but some how the results are not consistent. they are changing depending on the temperature I provide in the boundary conditions. Please refer to the archive file in the link: https://drive.google.com/open?id=1E3RWVB-M29IXm-_kzpPEHU4NVdtms_7a

and suggest me a tutorial/process to execute it perfectly.

P.S: It would be great if anyone can suggest the perfect boundary condition for the Fluid Solid Interface in FLUENT.

Thanks,

Rama Annamraju

[Karthik Remella]

Hello Rama,

Apologies for a delayed response. Could you please point us to the tutorial you are referring to? Could you also elaborate on which boundary condition you are talking about?

Unfortunately, we will not be able to download the files from your google drive. Please post some screenshots to help us understand the issue better.

Regarding your other question related to 'loading data from fluent to steady state thermal' - are you trying to couple the two tools? Could you please elaborate your workflow so we can help you better?

Thank you.

Best Regards,

Karthik

[Rama]

Hi Karthik,

Thanks for your response.

1. Here is the link for the tutorial:

&t=1655s

2. In fluent I have not defined any inlet or outlet for the PCM as there is none. However the FSI temperature is derived from the Panel(Simulated in Steady State Thermal). These temperatures, we enter in the boundary conditions tab of the fluent module. I need help in defining those boundary conditions.

3. I am not using coupling both the tools. I just shared the load data from the fluent module to the steady state thermal module and imported the temperature load data from fluent module.

To give you a gist of the project. I need to obtain the temperature distribution inside a PV panel.

a) I have modeled a standard PV panel in Steady State Thermal and applied predetermined load to obtain the initial results.

b) then I have modeled a Phase Change Material with solidification & melting in fluent and applied the FSI temperature obtained from the thermal simulation

c) Once the Fluent simulation is done, the load data is exported into the steady state thermal module for integration.

The problem is, in Ansys Fluent when I go to Tree -> boundary condition -> fsi (wall, id=5) and open the edit window to change the temperature value. My total simulation results are changing accordingly (which is not supposed to happen)

Ansys Archive file for reference: https://drive.google.com/file/d/1E3RWVB-M29IXm-_kzpPEHU4NVdtms_7a/view

Do let me know if any additional screenshots are needed.

Please let me know the shortcomings in this process.

Thanks,

Rama

[Karthik Remella]

Hello Rama,

Thank you for your elaborate response. If I understand your model, you are looking to pass thermal data (temperature) from 'Steady State Thermal' into 'Fluent' on you 'fsi' face zone. You should be able to do this using the option 'via System Coupling' from the 'Thermal' tab on your fsi face zone. You should be able to write out the data from Steady state thermal and when you set up the problem using 'System coupling', Fluent will use this temperature data and impose it on this face zone. 

Please have a look at the following video and let me know if this is what you are looking for.

https://www.youtube.com/watch?v=wSWlUitNas0&list=PL0lZXwHtV6OmedTRo0xU5AFxCrtsSsHda&index=25&t=0s

Thanks.

Best,

Karthik

[Rama]

Hi Karthik,

Thanks for the prompt response. I actually came across this tutorial.

Below is the result if I used this tutorial. However it was not what I was looking for.

I need the Temperature distribution inside the various components of the PV panel which can be obtained precisely using steady state thermal. I was transferring the load data from Fluent to Thermal for the same reason. See Picture below

In any case the solidification and melting of the PCM is not happening. PCM is supposed to absorb the temperature for the PV panel and melt thus reducing the PV panel temperature. But I am unable to achieve it. Please let me know if my simulation in FLUENT is wrong. Also please note that there is no Inlet or Outlet in the PCM simulation as it is an enclosed body.

I would really appreciate if you can point me out any alternate tutorial or changes in the Fluent settings so the I can simulate the solidification and melting properly and then export them to Thermal.

Thanks,

Rama.

[Karthik Remella]

Hello Rama,

If you are attempting to solve a conjugate heat transfer problem (with PCM phase change), I'd strongly recommend doing it all in one single tool. In your current strategy, you are solving a transient problem thermal and phase change problem in ANSYS Fluent and a steady state problem in ANSYS Steady State Thermal. You are passing data back and forth between these solvers. Instead, you could solve your entire problem in ANSYS Fluent directly (both heat transfer in the PV panel and phase change), if I understand your problem correctly. This way you do not need to worry about any manual data transfer. Fluent will take care of this for you. Is there a reason why you are attempting to do this separately? I might be missing something here.

Here are some video which might help (unless you have gone through them already). I understand that the Fluent version is old and they have flow in their model. However, attempting to reproduce these models at your end will help you understand the modeling process better. This will help you with your modeling. I'd strongly recommend attempting to replicate the tutorial at your end and then attempting to solve your model. I hope this helps.

https://www.youtube.com/watch?v=4qTnt0B3dOY

https://www.youtube.com/watch?v=4ZgxnS78dw8

Thank you.

Best Regards,

Karthik

[Rama]

Hi Karthik,

Thanks for the suggestion, I will try modeling the whole setup in ANSYS Fluent. Can you clarify the below concern.

The Top Glass surface in the PV panel receives Solar Heat Flux and there is some convection heat loss in the same surface. How do I setup Convection and Solar Heat Flux on a single surface in ANSYS Fluent. I see no such option in Fluent.

Thanks,

Rama

 

[Karthik Remella]

Hello,

I'm assuming that your glass region is a volume (cell zone in Fluent). You could define an effective volumetric heat source (convert your surface heat flux [W/m^2] into volumetric heat source [W/m^3]). This will be applied to the entire volume (similar to an internal heat generation source). You should then be able to apply a convective boundary condition on the outer surface to model convective heat loss.

Thanks.

Best,

Karthik

[Aditya]

Hello Rama,
Even i am working on same project. Intinially i tried to import PCM temperature load from flut to mechanial workbench. So, I am facing the same isssue. May i know how you have solved this issue. It would to very much helpfull for me to complete my project if assist me a bit.

Thanks