Navier-Stokes Module Maturity for sCO2 Application

[LP1012]

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Question

Hello All!

I am a newer user to MOOSE, and I am looking to model heat tranasfer through a radioisotope-heated core. For this system, supercritical carbon dioxide (sCO2) was selected as the working fluid. Previously, I had been looking into using established CFD solvers like OpenFOAM or NekRS to solve for the fluid flow, outlet temperature, pressure drop, and surface temperature. Before jumping into these other codes, I wanted to see whether MOOSE's Navier-Stokes module could handle a case like this. I will include more technical specs in the Additional information section below. The biggest issues I foresee are turbulence and compressibility. To be clear: I am not inquiring as to MOOSE's capabilities of modeling radiation, only on the thermal hydraulics.

TLDR: Can the Navier-Stokes module accurately simulate sCO2 to medium fidelity (or higher) for steady-state operation?

Thank you very much in advance!

Additional information

Mesh size and type:
Reynolds number: ~20,000
Discretization (finite element CG/DG, finite volume, etc): Finite Volume is preferred based on information from MOOSE's documentation
Models (turbulence, porous media, etc): Turbulent
Solver method (fully coupled, segregated, multiapps, etc): Unknown
Base input you started from: N/A
Operating Pressure: 15 MPa
Inlet Temperature: 320 K
Outlet Temperature (approximate): 600 K

[GiudGiud]

hello

As long as you are not modeling a de-pressurization accident, you should be able to use the weakly compressible formulation to just model the coolant behavior.
The new linear finite volume solver should be able to handle several million dofs. How big is the system? and how many elements do you plan to use to mesh it?
For heat transfer, you ll be able to use correlations to compute the heat flux. Support for conjugate heat transfer will come later this year

Note that we have fluid properties for CO2 in the carbon_dioxide optional submodule of the fluid properties module of MOOSE. I have not tested them in the supercritical regime.

Guillaume

[joshuahansel]

Sorry, I don't have a good idea on the transition point of when a weakly compressible model becomes acceptable, and I also don't know whether our CO2 properties handle supercritical CO2. I would guess we only have properties in the two-phase regime. We have CarbonDioxide(Liquid|Vapor|TwoPhase)FluidProperties, so I don't know where supercritical would fit in those.

[LP1012]

Based on this documentation, it appears that MOOSE fluid properties can handle through supercritical. The equation of state given by Span and Wagner (which is what your code is based on) has a very wide range of validity.

If CFD analysis is not yet possible in MOOSE for what I need (which seems likely), would a coarser solver, say from the Thermal Hydraulics module, be able to just give surface and outlet temperatures (and maybe pressure drop)?

[joshuahansel]

Ah ok thanks, I see this CO2FluidProperties now. That one is actually documented a little! I was referring to the ones in the modules/fluid_properties/contrib/carbon_dioxide module, which are not documented (and those might be applicable too, just don't know where the supercritical regime goes).

THM can be used if your flow is 1D, but we do not have a turbulence model for its flow model though. We would just need to ensure that your fluid properties class has all the necessary interfaces, but the class could be extended with the necessary interfaces if it doesn't already have them.

Also note that there is a fully compressible NS solver, but as I understand it, it's just not actively developed (focus is mainly on weakly compressible formulation). Also I think it may not have turbulence support. @GiudGiud @grmnptr can you comment?

I think would suggest just going for it with NS and doing a small sample problem in the supercritical regime, and then try out different formulations.

[GiudGiud]

THM can be used if your flow is 1D, but we do not have a turbulence model for its flow model though

you could likely add a custom closure to add the effect of turbulence

Also note that there is a fully compressible NS solver, but as I understand it, it's just not actively developed (focus is mainly on weakly compressible formulation).

It does not have turbulence support but you could add a mixing length model to it. The accuracy of the solver would likely suffer, it's intended for advection-dominated problems.

I think would suggest just going for it with NS and doing a small sample problem in the supercritical regime, and then try out different formulations.

I agree with that. Set up the problem in a number of ways and examine with simple verification cases whether it works as intended

[LP1012]

Sounds good, thanks. I think because I am on a bit of a time crunch, I will explore using Cardinal for NekRS/OpenMC coupling. If I am able to get a good solution for this, I will see if I can replicate in MOOSE's NS solver maybe somewhere down the road.