Hello,
I want to simulate a falling water-particle case with MFIX-DEM. Picture a closed box with no inlet and outlet, and water-particles mixture is just falling down from the upper region.
I know how to create particles but not sure about water. How it can be done?
Do you want to resolve the free surface between water and gas?
Then you need to use methods like front-tracking or Volume-of-Fluid.
Oh, sorry. I am not planning to resolve the free surface now, but eventually. Then the cube should be filled with water and only particles fall down. Currently, I am confused about settings in the Fluid tab, it has general settings and settings for species. How do I initialize the domain with water?
In the “Fluid” pane, “Enable species equations” (requires Energy equations in Model setup)
Click the “+” to add a species. The Species popup will appear.
Search for “Water”
Select “H20(L)” which is liquid H2O
Click “Import from database”
Click “Ok”
Now water is defined as a species. You can set species fractions in the Initial Conditions (IC) tab.
This is covered in the MFiX User Guide which you may find helpful.
Note that if you want to call it something other than H2O_L you can set a different alias in the species popup. You can also override any of the other properties defined in the database.
How do you set up the Initial Conditions? I get an error that the mass fraction does not sum 1.
I have two regions: 1. Background IC(whole domain) and 2. Solids(upper region of the cube).
If we have both liquid and solid phases in the domain, the mass fraction of the liquid phase in the Background IC cannot be 1. If I did not know the volume of the cube, how would I determine the mass fraction of water?
Water and particles cannot have any chemical reaction. There is no energy exchange. I do not add solids as species, only define their density and diameter.
Is there any need to add solids and water as species or I can just modify default property values in the Fluid pane?
If there is no chemistry and you are specifying constant density, thermal conductivity, etc, then you do not need to define species and you can set bulk properties for the entire Fluid pane.
We are happy to provide help here but I encourage you to take a “try it and see” approach since we can’t always answer questions right away.
– Charles
Thank you very much for your help.
I was checking different combinations of “try and see” but they are taking a lot of time to simulate and I was unsure if I was doing things correctly. Sorry about that.
No worries. Please do not hesitate to ask questions, we will provide as much help as possible.
