In this tutorial, we use Adaptive Meshing to conduct a mesh-sensitivity study of an automotive EGR valve. We will enable the option to keep each adaptation cycle, and then compare the results from each cycle to understand the effect of successively refining the mesh.
The analysis geometry consists of three parts: the outer pipe wall, the poppet, and the air:
Adaptive Meshing uses solution results to progressively improve the mesh definition. The simulation is run several times. Each time the results from the previous cycle are used to improve the mesh in the next cycle. Ideally, the result is a mesh-independent solution that is optimized for the particular simulation. The mesh is fine where it needs to be, and coarser elsewhere.
We will observe the effect of refining the mesh on the flow results. The process consists of four meshes. The first is the default defined by Automatic Mesh Sizing. Each subsequent cycle contains mesh refinements based on the previous results field. When complete, we use the Design Review Center to compare the mesh and the flow distribution. We also use Summary Planes to compare the pressure drop from the different meshes.
Note: In this tutorial, we run four cycles of this simulation, each with a finer mesh. The total simulation time for this exercise is approximately 1 hour.
Key Topics
- Mesh Adaptation of a three-dimensional flow simulation
- Decision Center
- Critical Values
- Design Review Center
- Comparing results with multiple viewports
Goals
- Use Mesh Adaptation to arrive at a mesh-independent solution.
- Use the Design Review Center to compare the flow produced by each mesh.
- Use the Critical Values table to assess the effect of mesh refinement on the overall pressure drop.