As computer aided design (CAD) geometry has become more detailed, developing a finite element model to capture these features has required an increasing amount of time and experience. A tetrahedral mesh is often chosen because of its speed and robustness to discretize heavily featured geometry (e.g. hundreds of fillets). However, for structural analysis, tetrahedral elements can produce “stiff” results with an unacceptable percent error. For example, a modal analysis can produce higher than expected frequencies. To overcome this, mesh refinement and higher order tetrahedral elements can be used but this costs increased solve times and computational resources.

Another well-known approach to discretizing a model is “map meshing”, also known as solid meshing and hex meshing. For a given element size, its formulation does not have the issue of stiffness, it has faster solve times, and can produce results with less percent error. For all the advancements in processing automation, map meshing has not reached the level of automation like tet meshing has, leaving a large part of it to remain an art that is heavily dependent on user experience.

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By Aditya Jayanthi, Thermal Solutions Product Manager, Altair. GE’s Flow Simulator is a part of the Altair Partner Alliance.

In the Turbomachinery industry, Thermo fluid system design is a creative process undertaken to solve new or existing problems that are often complicated because of the complex nature of fluid flow, and of heat and mass transfer mechanisms that govern the system. It is an extremely important task because it leads to new and improved designs. It often involves an open-ended solution with multiple possibilities, and is contrasted against analysis, which gives rise to unique, well-defined, closed-ended results. Thus, Thermo fluid system design generally involves considering many different solutions, and finding an acceptable result that satisfies the given problem. Synthesis brings several different analyses and types of information together, thus forming an important facet in system design. Figure 1 below outlines the common practice adopted by Turbomachinery companies for efficient automation, control and optimization of Thermo fluid systems applications.

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