Comments (15)
Depends on which of my proposals get funded. :)
In seriousness though, a number of designs in the open moltres issues (some of which my current graduate students are pursuing) as well as MSRE itself (as noted in the review of our paper) could be expected to reach near turbulent regimes during design basis accident transients.
from moltres.
Yes, @lcarasik , particularly someone with your expertise!
@gridley Not classified. I said 'near turbulent regimes during design basis accident transients' not 'turbulent in a steady state scenario.' In any case, there are plenty of examples of potentially laminar-to-turbulent even in not-far-off-normal MSRE experience. To quote the following about the MSRE experience.... "The regular pattern of the graphite support grid is discontinued near the centerline of the core where the control rods and the surveillance specimin holder are located. This allows greater salt velocities past these components for cooling.... The reynolds number of these channels is in the order of 3000 and is therefore in the transitional region." (http://moltensalt.org/references/static/downloads/pdf/ORNL-TM-3229.pdf) I'm not sure our published model took into account these larger central channels, as many don't.
Additionally, not to let any cats out of any bags, but some atypical dynamic operation of some of these reactors (intentional or otherwise) might be constrained by the impact of rapid power oscillations on the stability of the velocity field. All of that is to say I don't think we can ignore near-turbulent behavior for interesting transients.
Anyway, the geometry varies all over the place among the proposed designs. Some have pipes, some grids, some plates, some pools. The tool shouldn't be constrained to laminar regimes.
from moltres.
@smpark7 let's chat in person about your question:
May I inquire how much has been completed and where I should start?
from moltres.
What's y'all intended purpose here for the k-e model? (Natural circulation or convective flows?)
from moltres.
Thanks for your interest @lcarasik ! Ideally, this tool should as generally as possible support turbulent or near-turbulent flow regimes in liquid fueled MSRs. This k-epsilon feature is not intended for a specific problem, but rather to support realistic simulation of the broad class of liquid fueled MSRs. Natural convection is a significant component of the flow in MSRs. But for ordinary operation, the flow is driven primarily by the pumps. To us, k-epsilon seemed the simplest appropriate model for this scenario, but any advice is welcome!
from moltres.
I like the approach but I would warn you against trying to use it in transitional regimes. It might be worth looking into transitional RANS modeling if you get close.
Is this 2-D? Or 3-D?
Also, for finer tooth simulations where buoyancy is a big contributor to turbulence, y'all will want to look into how you handle the contributions of it in the k and e equations.
from moltres.
from moltres.
Hey Gavin,
I assume y'all are just using N-S (no RANS) for the MSRE work?
It is still worth pointing out that if you get into transitional regimes (anything below 3000 for internal flows), you're going to see issues with standard RANS approaches.
Turbulence and transitional behavior is inherently 3-D phenomena. You won't capture a lot in 2-D that you will in 3-D. Though it may not be important for y'all's work.
from moltres.
Just for the record, this is false:
I don’t think there’s a particular application of the TH in mind at the moment.
:)
from moltres.
from moltres.
It really sounds like you'd want someone to take a look at transition RANS after implementation of k-e!
from moltres.
Oh haha, nice! Out of curiosity, if it's not classified info, how could the MSRE go turbulent? The only thing I can imagine would be somehow blocking half of the channels. Aside from that, the reviewer's claim of near turbulence didn't agree with @lindsayad's calculation at all (which I trust more). The pump ran at 80% power since the heat transfer calcs were slightly off, which led them to not run at the full 10 MW(th). So Re could max out around 1200, neglecting half of the channels being blocked.
from moltres.
from moltres.
I'm working towards implementing and demonstrating this model for MSFRs modeling. I noticed that @lindsayad had already coded much of the work in the INSMomentumKEpsilon
and INSK
kernels (although INSK
had been moved out of Moltres in a previous commit). May I inquire how much has been completed and where I should start?
from moltres.
Just a quick drop in comment, please make sure the flow is fully turbulent if you apply it! If it isn't fully turbulent, you'll applying the turbulence model outside of it's applicability.
from moltres.
Related Issues (20)
- Replace the Nt action with a more intuitive name
- Tutorial issues
- Add additional installation instructions HOT 1
- Remove deprecated MOOSE code HOT 7
- moltres_xs.py maybe not compatiable with the newest version of OpenMC
- Removing unused params
- Replace deprecated NodalMaxValue
- Fix removal cross section generation in moltres_xs.py from OpenMC data
- where is the k-eff definition? HOT 1
- Add postprocessor for calculating neutron leakage
- CIVET: 'Mirror scheduled' failure
- Make PrecursorAction compatible with velocity vector variables derived from INSAD
- Welcome to Moltres Discussions! HOT 8
- Create a CI test for building documentation HOT 1
- Rename convoluted object names for clarity
- Extend PrecursorAction to support modeling with higher order precursor variables
- Add documentation on neutron diffusion theory on the Moltres website
- Compilation issue on MacOS with clang HOT 2
- Add override keyword to computeQpOffDiagJacobian in INSBoussinesqBodyForce
- Allow users to choose among Marshak, Mark, and Milne vacuum boundary conditions
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from moltres.