Learning Forum

[F123rooq]

Hello,

Firstly, I wanted to know is it possible to have Supercritical CO2 in ansys?

Secondly, I wanted to simulate a flow in a body that is rotating with a hole in the middle of it for the fluid to go though. I want it to spray out of the other end like a jet. I want to do this in 2D, not 3D.

I have a box which has a little tube sticking of it, and I pass the fluid through the tube, and I want to go into the box which is representing an open space, so I want it to go into the open space as a jet. But, I also want the tube sticking out, to rotate, but not the other big box, because that is meant to be the room and a room doesn't spin.

At the moment I am using the Transition SST model (should I be using any other?)

At the moment I can simulate a flow in the geometry but steady, and also I cannot rotate one bit of the geometry as I need it to. Can you help me please with a step by step guide, as I am completely new to CFD, and this might be the first and last time I do it, because it is so annoying.

Thank You

[Rob]

I'd suggest starting with the tutorials that come with the documentation. Modelling supercritical CO2 is hard, even for experienced users so start with the basics. 

[F123rooq]

Can you give me a little guide to rotating bodies. Where do I start to read up on. What is needed?

[DrAmine]

Yes you can model supercritical CO2 either as cubic eos or using RIP or using nist refoprop

[Rob]

Check the tutorials: there are two (reference frame) that are useful. 

[F123rooq]

Thank you all

[F123rooq]

Can you please walk me through setting up my 2D geometry for supercritical co2. I have a box, with 2 pipes sticking out of it. The two pipes will have ScCO2 coming to the box which has air in it, and mixing.

[F123rooq]

I had typed in a code that I found online into ansys, and it gave me the option to use the NIST, so I selected co2.fld file, then it said that calculations will be performed for the vapour phase. I have selected multiphase, and then Volume of Fluid. I have read someone did a similar study, and they used VOF to simulate the stream of jet that I want too.

[F123rooq]

I have chosen my inlets, my outlets, and walls

[F123rooq]

I have two phases, one is air, and other real gas co2 from the refprop etc. The problem is that my box, and the two pipes have 2 phases in the cell zone conditions. But I only need phase 1 (air) in the box, and phase 1 and 2 in the pipes together, because they open to the atmosphere, so air would already be mixed in the pipes I presume, I don't expect it to be 100% ScCO2 in the pipes. But if having one phase (ScCO2) in the pipes makes the setup easier, then I am happy with that for the time being.

[F123rooq]

And regarding the rotation, its fine, if you can help me set it up stationary, that is amazing.