A whole engine optimization based on medial object transformations

摘要

This paper presents, for the first time, an automated process to optimize a whole engine assembly model using medial object transformations. Five new techniques have been developed to accelerate the generation and assembly of medial meshes. Firstly, geometry surfaces leading to medial mesh branches are automatically identified and removed. This branch-reduced medial mesh takes less time to calculate and represents the original geometry more accurately. Secondly, mesh coarsening technique is developed to reduce the medial mesh element count by up to 90%. Thirdly, new methods which permit the splitting of the original CAD geometry and the rejoining of medial mesh sections are developed. This permits the medial mesh generation to be parallelized by taking advantage of symmetric and axisymmetric features within the geometry. Fourthly, the joints between multiple engine components are created automatically from a database of medial meshes and full fidelity 3D meshes thereby enabling the seamless generation of mixed fidelity (2D and 3D element) models. Finally, boundary conditions are automatically mapped from the CAD geometry onto both medial and 3D meshes. Together these developments make the structural optimization of a whole engine possible at the preliminary design stage. The presented optimization work has been focused on the compressor tip clearance control based on Kriging model but the developed process can be easily applied to other part of the engine and adopting other optimization algorithms.