Tutorial: Hex-dominant parametric – Valve Geometry
- In this tutorial, the meshing process for a valve geometry is carried out using the “Hex-dominant parametric” approach.
- The “Hex-dominant parametric” is the semi-automatic meshing option that uses hexahedral cells and allows full flexibility in meshing parameters with all type of refinements options.
Import tutorial project into workbench
- As a first step we need to create a new simulation. To create a simulation left click under the Geometries and then on Create Simulation.
Note: the STL geometry is pre-split to separate the faces for meshing and later assignment of boundary conditions.
- The Valve cane seen by hiding all the faces except face-3
Back Ground Mesh Box
- An important parameter is the size of the base box, which serves as the bounding coordinates for the mesh.
- To change the size of the box click on Back Ground Mesh Box expand geometry primitives under Mesh and change the coordinates of Base mesh Box as shown below
- Now we create additional Geometry Primitives, to be used later for region refinements.
- Click Geometry primitives and ‘add new primitive’ of type Cylinder as shown in figures below.
- Specify the name ‘Cylinder-Valve’ and following values, then save to get the shown cylinder region.
- Similarly create 4 more primitives of ‘Type: Cylinder’ as detailed in the table below:
- These will be later used to refine the up/down stream regions, the opening gap between the valve and pipe, and hinge areas.
- The figure below illustrates the created primitives:
- Here we will add the necessary refinements for the surfaces, edges and regions to generate a fine mesh of optimum size.
- The refinement levels given are relative to the ‘baseMesh’ cell size with each level reducing the size to half.
- see Hex-dominant parametric documentation for details.
- In order to have a finer mesh over the surface of the body, we add surface refinement.
- Click on Refinements to add a new refinement and select surface refinement.
- Re-name it to ‘Surf-pipe-inlet-outlet’ and select a Type ‘Surface refinement’ to specify the parameters as shown in figure below.
- This will refine the pipe, inlet and outlet surfaces. Select the shown faces and click save.
- Select the minimum and maximum level surface refinement as 2 and 3 respectively
This refinement is important to resolve the feature edges of the geometry and produce a fine mesh at the edges.
Region refinements will refine the volume mesh cells based on the given refinement level. These are important to get a fine volume mesh in the vicinity, upstream and downstream of the valve.
To generate a mesh of optimum quality, make sure the advance settings are set as shown in the figures below.
- For ‘Castellated mesh’ and ‘Span’ controls:
- For ‘Mesh Quality control’: