Design of an Axial Fan using Ansys TurboSystem - Meshing
Introduction
Hello, let's continue our journey of designing an axial fan. Up to now, we have defined a single blade design for an axial fan using ANSYS tools. The next step is conducting a detailed realistic flow analysis.
Purpose of Flow Analysis
We perform flow analysis to identify regions of flow separation, which can be eliminated by improving our design.
Pre-processing for CFD Analysis
In this step, we will start pre-processing for the CFD analysis using a feature called TurboGrid. TurboGrid is a specialized meshing tool known for generating high-quality automated hex mesh.
TurboGrid Overview
- Shows the flow domain, including:
- Inlet domain
- Upstream of the blade
- Blade domain
- Outlet domain
Meshing Process
To proceed with meshing, unsuspend the object updates. This indicates that the geometry is ready for automatic meshing.
Key Features of TurboGrid Meshing
- Automated meshing system generating high-quality hex elements.
- Finer mesh concentration near the blade region and walls to resolve boundary layer flow.
- No need for expertise in mesh generation to use this tool effectively.
Mesh Analysis
Upon checking, a red mesh analysis error may appear, often as a warning. In this case, the edge length ratio is slightly out of range for about 1% of the cells. However, CFX is robust and can handle some mesh quality issues.
Strategy
Proceed with the current mesh, monitoring for any convergence problems. If necessary, adjustments can be made by experienced meshers.
Advanced Mesh Controls
By turning on the mesh data, advanced controls become available, allowing for:
- Global mesh size control
- Boundary layer adjustments
- Mesh resolution control in:
- Hub
- Shroud
- Inlet
- Outlet
Conclusion
After inspecting the mesh, we are content with the default settings and may proceed. This concludes the meshing process for the axial fan design.
Note: If the word sounds like Ozen, it refers to Ozen Engineering, Inc.
Hello, let's continue our journey of designing an axial fan. So far, we have defined a single blade design for an axial fan using ANSYS tools. The next step is performing a detailed, realistic flow analysis.
We want to see if there are any regions with flow separation, so we can eliminate them by improving our design. In this step, we will start pre-processing for the CFD analysis. We will use a specialized meshing tool called TurboGrid, which generates high-quality automated hex meshes.
When the TurboGrid window comes up, it shows our flow domain, including the inlet domain (upstream of the blade), the blade domain, and the outlet domain. To proceed with meshing, all we need to do is unsuspend the object updates.
Once unchecked, the geometry is ready, and we can automatically mesh this model. This is an automated meshing system, generating high-quality hex elements, which is a rarity and offers great advantages. As you can see, the mesh gets finer near the blade region, particularly very near the walls.
This resolves the boundary layer flow. We have not played with any settings at this time. You don't have to be an expert in mesh generation to use this tool. We see a red mesh analysis error, which is mostly a warning.
The edge length ratio is a little out of range, but it's only for about 1% of the cells. CFX is a robust and forgiving tool with mesh quality issues. Our strategy will be to go forward with this mesh and check for trouble in CFX.
If you are a good mesher and want to improve your mesh, you have that option. Let's turn on the mesh data and check our mesh in detail. We can select components to view different regions, such as the periodic, hub level, inlet mesh, and trailing edge region.
If the user feels the mesh is stretching too rapidly in the spanwise direction, numerical controls allow for a finer mesh in the midspan. After inspecting the mesh, we can see more information about the mesh in the data section. We are content with the default settings, so we can move forward.
