Mastering ANSYS Mesh for Turbine Cooling Simulations

 Meshing the fluid domain for a turbine cooling simulation in ANSYS involves capturing the complex geometry of the turbine blade and the cooling passages. Here's a breakdown of the key steps:

1. Geometry Preparation:

• Ensure your turbine blade geometry is watertight. Small gaps or holes can cause meshing issues.

2. Mesh Sizing:

• Define a global element size for the bulk of the fluid domain.
• Set a finer local sizing for the boundary layer regions near the blade walls and around the cooling holes. This is crucial for capturing the flow behavior accurately. You can define separate sizing for the cooling passages themselves.

3. Mesh Type Selection:

• For complex geometries like turbine blades, unstructured meshes are often preferred. They offer greater flexibility in conforming to intricate shapes.
• However, if the flow is primarily axial or radial through the blade passages, a hybrid mesh with a structured core and unstructured boundary layers might be suitable.

4. Boundary Layer Meshing:

• Apply a refined mesh near the blade walls to capture the viscous effects in the boundary layer. Aim for a minimum of 5-10 high-quality elements within the boundary layer thickness.

5. Cooling Hole Meshing:

• There are two main approaches for meshing cooling holes:
  • Resolved Mesh: Capture the actual geometry of the holes with fine mesh elements. This is the most accurate approach but can be computationally expensive.
  • Surface Injection: Use a virtual inlet at the cooling hole location to inject coolant mass flow without explicitly meshing the holes. This is less computationally expensive but may require validation with the resolved mesh approach.

6. Mesh Generation:

• Use ANSYS Meshing tools to generate the mesh. Popular methods include:
  • Polyhedral Mesh: Creates a mix of hexahedral and pyramid elements for the bulk of the fluid domain.
  • Prism Mesh: Creates prism elements near the walls for the boundary layer.

7. Mesh Quality Check:

• Ensure the generated mesh has good quality. Check for highly skewed or elongated elements that can affect simulation accuracy.

Additional Tips:

• Utilize ANSYS meshing tutorials specifically focused on turbine blade cooling [ANSYS Fluent Modeling Film Cooling in Turbine Blade Design].
• Consider using symmetry planes to reduce the computational cost if the geometry is symmetrical.
• Explore advanced meshing techniques like automatic adaptation during the simulation to improve mesh quality in critical regions.

By following these steps and considering the specific requirements of your turbine cooling simulation, you can generate a high-quality mesh for accurate and efficient CFD analysis in ANSYS.