A comparison between different moving grid techniques for the analysis of the TCC engine under motored conditions 2019-01-0218
The accurate representation of Internal Combustion Engines (ICEs) flows via CFD is an extremely complex task since it strongly depends on a combination of highly impacting factors, such as grid resolution, both local and global, choice of the turbulent model, numerics and mesh motion technique.
In order to avoid excessive computational cost and numerical difficulties arising from the combination of fine computational grids, high-order numerics and geometrical complexity typical of internal combustion engines a well-founded choice must be made. Therefore, the paper focuses on the comparison between different grid strategies and mesh motion technologies, namely layer addition and removal, morphing and remapping and overset grids.
The performance of each grid strategy and mesh technology is evaluated in terms of computational efficiency (stability, scalability, robustness) and accuracy. In particular, a detailed comparison against detailed PIV flow measurements of the well-known "TCC Engine III" (Transparent Combustion Chamber Engine III) available at the University of Michigan. Since many research groups are simultaneously working on the TCC engine using different CFD codes and meshing approaches such engine constitutes a perfect playground for scientific cooperation between High-Level Institutions.
A motored engine condition is chosen and the flow evolution throughout the engine cycle is evaluated on four different section planes. Pros and cons of each grid strategy as well as mesh motion technique are highlighted and motivated.