3.6. Three-dimensional DEM hopper¶
This tutorial shows how to create a three dimensional granular flow DEM simulation. The model setup is:
Property |
Value |
---|---|
geometry |
5 cm diameter hopper |
mesh |
10 x 25 x 10 |
solid diameter |
0.003 m |
solid density |
2500 kg/m2 |
gas velocity |
NA |
temperature |
298 K |
pressure |
NA |
3.6.1. Create a new project¶
On the main menu, select
New project
Create a new project by double-clicking on “Blank” template.
Enter a project name and browse to a location for the new project.
When prompted to enable SMS workflow, answer No, we will use the standard workflow for this tutorial.
3.6.2. Select model parameters¶
On the
Model
pane, enter a descriptive text in theDescription
fieldSelect “Discrete Element Model (MFiX-DEM)” in the
Solver
drop-down menuCheck the
Disable Fluid Solver (Pure Granular Flow)
checkbox.
3.6.3. Enter the geometry¶
On the Geometry
pane:
3.6.4. Enter the mesh¶
On the Mesh
pane, Background
sub-pane:
Enter
10
for the x cell valueEnter
25
for the y cell valueEnter
10
for the z cell value
On the Mesh
pane, Mesher
sub-pane:
Enter
0.0
in theFacet Angle Tolerance
3.6.5. Create regions for initial and boundary condition specification¶
Select the Regions
pane. By default, a region that covers the
entire domain is already defined.
A region for the hopper walls (STL) is needed to apply a wall boundary condition to:
Click the button to create a region that encompasses the entire domain
change the name of the region to a descriptive
name
such as “walls”Check the
Select facets (STL)
checkbox to turn the region into a STL region. The facets of the hopper should now be selected.
In order to allow the particles to leave the domain through the bottom, the facets at the bottom of the hopper need to be deselected. There are three ways to accomplish this:
Change the
Y Min
domain extent value on the geometry pane by a small amount so that those facets fall outside the simulation domain (for example, change the value to-0.0974
).Change the
Y From
region extent value on the regions pane for this STL region by a small amount so that those facets fall outside the region (for example, change the value toymin+0.0001
)Or, use the
Filter facets based on normals
option on the region pane.
For this example, use option 3 to filter the facets that have normals pointed in
the Y
direction by:
Select
box
from theSelection method
drop-down.Uncheck
Slice facets
.Check the
Filter facets based on normals
checkboxEnter a vector pointed in the positive
Y
direction by entering0
,1
, and0
in the x, y, z fields, respectivelyCheck the
Include equilibrant vector
to include facets with normals in the opposite direction of the vector (-x, -y, -z)Enter an angle of
10
in theangle
field to include facets with normals within 10 degrees of the filter vectorCheck the
Invert Selection
check box to de-select facets that fall along the filter vector and select all the other facets
All the facets, except for the facets at the top and bottom, of the hopper should now be selected.
Create a region to apply a pressure outlet boundary condition to allow particles to leave the domain:
Finally, create a region to initialize the solids:
3.6.6. Create a solid¶
On the Solids
pane
Enter a descriptive name in the
Name
field (“solids”)Keep the model as “Discrete Element Model (MFiX-DEM)”)
Enter the particle diameter of
0.003
m in theDiameter
fieldEnter the particle density of
2500
kg/m2 in theDensity
field
In the DEM
sub-pane, check Enable automatic particle generation
checkbox
3.6.7. Create Initial Conditions¶
On the Initial conditions
pane
3.6.8. Create Boundary Conditions¶
Select the Boundary conditions
pane and create a wall boundary condition for
the hopper by:
On the
Select region
dialog, select “No Slip Wall” from theBoundary type
drop-down menuSelect the “walls” region and click
OK
Finally, create a pressure outlet boundary condition by:
3.6.9. Select output options¶
Select the
Output
paneOn the
Basic
sub-pane, check theWrite VTK output files (VTU/VTP)
checkbox
Select the
VTK
sub-paneOn the “select region” dialog, select “particle data” from the
output type
drop-down menuSelect the “Background IC” region from the list to save particle data over the entire domain
Click
OK
to create the outputChange the
Write interval
to0.01
secondsSelect the
Diameter
andTranslational velocity
checkboxes
3.6.10. Change run parameters¶
On the Run
pane:
Change
Stop time
to2.0
secondsChange
Time step
to1e-3
secondsChange
Maximum time step
to1e-2
seconds
3.6.11. Run the project¶
3.6.12. View results¶
Results can be viewed, and plotted, while the simulation is running.