Ansys Fluent Meshing

• The behavior of real gases can be reproduced by using Vista TF’ data warehouse of gas property tables. The methodology often employed consists of a local fitting of gas data to provide the thermodynamic property required by the solver in each solution step.
• This system produces several characteristics which make it attractive as a design simulation software for industrial applications.
• First, the method functionality in the solver is simple and straightforward, as it doesn’t necessitate applicable changes in the solver structure. Additionally, it is centered on a low-computational-cost algorithm, which mitigates considerable increases in the overall computational time, and company operating costs.
• Lastly, the methodology is extensive in terms of utility, but generalized in terms of its application of industry, since the software allows engineers to handle any type of gas, gas mixture or steam over a wide operative range.

• Visualize blade loading charts, circumferentially averaged meridional vector and contour plots and machine performance quantities.
• Ansys Vista TF software was specifically designed to enable an effective CFD postprocessing of rotating machinery.
• Vista TF contains a unique slew of plugins for all kinds of rotating machinery, including both radial and axial machines.
• In addition, Vista TF is not reliant on other software and pairs well in compatibility with many Open-Source plug-ins.

Meshing Optimization in Turbomachinery

• Vista TF Turbomachinery CFD (core meshing software) enables a quick and efficient design optimization of turbomachinery components.
• SimuTech Group also provides full technical support for the package, and the SimuTrain info-sessions are maintained and regularly updated.
• In fact, our engineers are currently working on supplementary software modules and extensions covering connectivity limitations with 3^rd party applications.

Types of Meshing Methods: Tetrahedral vs. Hexahedral

There are two main types of meshing methods. For these purposes, we are referring to 3D models:

• Tetrahedal element meshing or “tet”
• Hexahedral element meshing or “hex”

Hex or “brick” elements generally result in more accurate results at lower element counts than tet elements. If it is a complex geometry, tet elements may be the best choice. These default or automatic meshing methods may be enough to get you where you need to go, however, there are additional methods that can give you more mesh control.

 

Advanced Meshing Software

Mesh morphing involves the adaption of a computational grid modified for computer aided engineering (CAE). For example, the solid or shell mesh of a structural component ready to be processed by an FEA solver, or the volume mesh complete with boundary provisions for a CFD solver, can take on a new shape by merely updating nodal positions.

This indicates that the topology of the mesh (connectivity, nodes count, cells count, etc.) stays the same. Just the x,y,z coordinates of the nodes in the section of the model undertaking a shape modification are updated during this process.

Mesh morphing can be used for critical purposes:

• Creating shape parameters → Change in length or altering of an angle’s thickness
• Swap onto a new known shape → As manufactured and/or as designed by CAD
• Move onto a shape predicted by the CAE solution → automatic shape optimization with adjoint or BGM
• Multiphysics Support →  Moving CFD mesh according to the evolution of the FEM-connected one, enable erosion/deposition.

Meshing Optimization

Another advantage of Mesh Morphing is speed.  Typically, mesh morphing is quicker than remeshing for a number of reasons:

• The process avoids “remeshing noise” or having the same mesh adapted, means the effect of a parameter is not confused with the effect of a new mesh structure. Therefore, variation effects can be assessed even with a coarser mesh.  This is fundamental in meshing optimization.
• The CAE model can be updated on the background keeping all the original settings (boundary conditions).
• The revision of nodal positions entails less computational efforts vs a full mesh regeneration.
• Designing shape parameters with mesh morphing is faster than constructing a parametric CAD model.

Relationship between Meshing Optimization and Aerodynamic Performance

Go from a single passage up to multi-stage machines to obtain excellent aerodynamic performance.

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• Vista TF provides a data warehouse, and corresponding solutions sets for 3D CFD based models of the time-averaged flow field within axial flow multistage turbomachines.
• Software emphasis has been placed on models that are compatible with the industrial design environment and those models that offer the capability of providing credible results at both design and off-design operating environments.
• The demand to develop models free of aerodynamic input from semi-empirical design systems is stressed. The precision of such models has often been shown as dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery.
• The relevant flow physics connected with unsteady flow processes produce in axial flow multistage machinery are offered along with procedures that can be used to account for such anomalies in 3D CFD simulations.
• Pre-Design sample simulations are produced for both axial flow compressors and axial flow turbines that help to illustrate to engineers the enhanced predictive capabilities afforded to their workflow by including these procedures in 3D CFD simulations.

For more information on why Meshing is Important for FEA Fluid Meshing.