Hello and Welcome!
In this workshop we will demonstrate
how to use the Ansys Fluent Meshing Watertight Geometry Workflow
to generate a simulation-ready mesh
that can be used to perform the conjugate heat transfer analysis
of the battery module.
Specifically, we will focus on creating linear mesh patterns
of a battery unit to create a battery module
and also demonstrate how to perform share topology
to facilitate the generation of conformal Polyhedra mesh.
Let’s get started!
Launch Ansys Fluent in meshing mode.
For this demonstration, double precision is enabled,
and 4 processes are engaged for meshing.
Once Fluent Meshing launches,
select Watertight Geometry workflow.
In the Import Geometry task,
leave all the settings to default
and load the provided geometry file.
The model we have here is that of a battery unit
which consists of two cells separated by a rectangular cooling fin,
with a foam spacer on one side of the unit.
The opposite terminals of the cells are connected with the help of the connector, as can be seen here.
Let’s start with the workflow.
We will not be adding any local sizing.
Next, in the ‘Generate the Surface Mesh’ task,
set minimum size to 0.5 mm
and maximum size to 5 mm.
As the parts are thin,
to ensure the presence of an appropriate number of cells in the gaps
between the geometrical features,
set the Cells Per Gap to 2.
Click on Generate the Surface Mesh.
Once the surface mesh has been generated,
right click on the ‘Generate the Surface Mesh’ task
to access its task-specific context menu
and select ‘Add Linear Mesh Pattern’ task from the ‘Insert Next Task’ menu.
Note that it is important to add the task here before executing
the ‘Describe Geometry’ task.
In the ‘Add Linear Mesh Pattern’ task,
you first need to choose the part that you would like to pattern.
Go ahead and pick all the parts
as we have to create patterns of the complete battery unit.
Next, you have the option to let Ansys Fluent automatically estimate
the axis and pitch for the pattern.
The default setting is Pitch only.
We will change this option to ‘no’ to avoid any automatic estimation.
Next, for the Axis Direction,
we want the battery unit to be patterned in the negative x-direction
and hence will specify the X-component as -1
and set Y and Z components to 0.
Now, we need to specify the Pitch, or displacement factor,
that defines the spacing between the components of the pattern,
which is 24 mm in this case.
This value is very critical and can be determined at the CAD level.
Incorrect value will result in misalignment of the patterned parts
and will lead to failure while performing share topology.
In the ‘Total number of units’, enter 10
as we need a total of 10 battery units,
including the original unit, in the module.
You can now preview the pattern by clicking the ‘Preview Pattern’ button.
Change the ‘Highlight Unit Alignment?’ option to ‘yes’,
to highlight the interfaces between the pattern units
or the pattern and any other geometry it is attached to.
The highlights are visible once the task is executed.
Once you are satisfied with the inputs,
hit the ‘Add Linear Mesh Pattern’ button.
Ansys Fluent will now make linear patterns of the selected parts
based on these inputs.
Notice how the intersection between the parts are highlighted.
In the ‘Describe Geometry’ task, set ‘Geometry Type’ to
‘The geometry contains only solid regions’.
We will not be extracting any fluid regions
and also there is no need to create internal fluid-fluid boundaries,
as there are no fluid regions in the model.
Make sure that ‘Do you need to apply Share Topology’
is set to ‘Yes’.
Share topology operation will not only ensure
the connection of parts within a battery unit,
but also between the patterned battery units.
Once you execute this task,
you will be taken to the ‘Apply Share Topology’ task.
The Max Gap Distance and the Share Topology Method
can be left unchanged.
Click the ‘Apply Share Topology’ button.
Once this is done, the linear mesh pattern is fully created,
and the geometry overlaps have been successfully handled
Next, in the create regions task,
keep the number of estimated fluid regions to zero
and move to the update regions task.
In this task, make sure that all the regions
are assigned with ‘solid’ region type
and execute the task.
Next is the ‘Add Boundary Layers’ task.
Boundary Layer mesh can be considered in solids
for better prediction of temperature gradients
on the interfaces
but for this workshop we won’t be adding any boundary layers.
Click on update to move to the ‘Generate the Volume Mesh’ task.
In this workshop, we will use the ‘polyhedra’ Fill With method,
which is the default, to generate a conformal poly mesh
throughout the battery module.
Leave all the inputs to their default settings.
Make sure that the ‘Mesh Solid Regions’ option
is ticked before executing the task.
Hit the Generate the Volume Mesh button to create the volume mesh.
The generated mesh has a total of approximately 1.9 million cells
with a mesh quality of 0.2.
Hence, we have generated a good quality conformal poly mesh,
as can be seen from this sectional image,
which can be used for performing conjugate heat transfer analysis of the battery module.
That brings us to the end of this workshop.