Learning Forum

[omaralali]

Hello all,

I am trying to model flow a thermal energy storage system with a reservoir of Aluminum and supercrtical CO2 flowing in a pipe to charge/discharge the reservoir of Aluminum. 

 

When selecting the fluid from the Ansys database. I see that there are 2 options for CO2, CO2 and CO2- . I was wondering if Ansys will acknowledge that it is in supercritical phase if I set a temperature and pressure above the critical point. Or do I have to specify somewhere that this is a real gas and not an ideal gas. 

I have tried to follow something online to use real gases from the NIST REFROP but that disables the built in database in Ansys and I was no longer able to select the Aluminum (which is built into Ansys database).

 

I have attached a picture of my model. The big cylinder will house the Aluminum and the small cylinder/pipe will have sCO2 flowing through it to charge/discharge the Aluminum.

 

Any help would greatly be appreciated. 

Thank you,

Omar

[DrAmine]

You should use a cubic equation State or NIST or RGP Table. Just assign the metal material to any solid zone before activating NIST if appropriate.

[omaralali]

Hello Abenhadj,

I am actually assigning the "solid metal" to a fluid body. If I assign it first and then activate the NIST REFROP real gas properties. Will Ansys read both?
I am unfamiliar with the cubic equation state or RGP table. Is one of them preferred over the others?

Also, does the energy equation only solve the conduction problem? For example, if I decide to have a liquid metal, will Ansys fluent be able to handle the free convection that will most likely arise in the metal fluid body?

Kind regards,
Omar

[DrAmine]

Yes it handles all modi of heat transfer with exception of radiation which requires additional model or source terms.

All real gas approaches are fine for supercritical gases. I prefer working with RGP.

[omaralali]

I do not need any radiation now. If it handles real gases in supercritical phases. Why do you prefer to work with RGP? 

 

Also, I am unfamiliar on how to use RGP. Any help would be greatly appreciated.

[DrAmine]

Check the manual (especially the beta features) if you want to know more about RGP in Ansys Fluent. I will stick at first to Cubic EOS.

[zwong32]

Hi, 

I'm new to ANSYS and I'm trying to use SCO2 as my material. My application is flow through a nozzle, which reached a converged solution for air as an ideal gas. I switched to SCO2 as my fluid material, whereby I use the NIST real gas model instead of an ideal gas model. However I get the following error message:

 

I'm fairly certain my boundary conditions (mass flow rate inlet, pressure outlet) are correct but I'm not sure what else could be contributing to my error. Does anybody have experience with this? Thank you so much in advance