This post is for a collaborative project started by SimScale user @tgulbinas
- Internal turbulent flow
- Fan RPM = 20,000.
- Analysis Type: Incompressible turbulent steady state with rotation effect (MRF)
Two .step files for fan and housing were provided and first we need to make a single geometry file by importing fan into the housing geometry and placing it in proper position.
For the MRF mesh we need to make a cylindrical domain around the fan. This part will mimic the rotational effect of the fan.
Since in original fan housing, the gap between the outer and inner wall is very small. For the testing purposes we increased this gap a bit. For actual run geometry with original gap can be used
Now this single geometry, having three parts, can be used to make the MRF mesh.
- Meshed the geometry using Hex-dominant parametric (only CFD)
- Surface refinements are used for fan and housing with different mesh refinement levels
- To create MRF zone(this zone will act as rotating part) another surface refinement is added with Create cellZone marked as true
- Other refinements are, Surface refinement for the thin housing walls and for outlets’ base wall
- Layers addition for better flow resolution near boundary
- Feature refinement to capture the geometry details near edges
- To further resolve the mesh at the MRF zone interface Region refinement is added which will resolve the mesh in both sides of interface
- Final mesh have around 4.5 million cells
- Mesh quality can be inspected by creating mesh clips at critical areas
- Rotating zone boundaries are resolved properly
- Housing thin walls have adequate cells to resolve the flow
- Fan is also properly meshed
The link to this project can be found here
For the simulation setup, parameters like the boundary conditions, inlet flow velocity or mas flow rate (corresponding to given RPM) are required. Once we have all these parameters we will proceed to the simulation.