다충실 최적화 홴 설계기법에 대한 연구

초록

In the research we develop and implement a multi-fidelity strategy for generating fan blade geometry in the design space and developing computational tools to achieve optimal design configurations. Our approach is based on combining selected high-fidelity CFD simulations with a large number of lower-fidelity computationally inexpensive models, to achieve various targets, e.g. efficiency, volume flowrate, noise level, static pressure and its slope near an operation point. While the high-fidelity CFD will provide detailed physics of unsteady vortex flows and aero-acoustic noise generation mechanism, in most cases it will be too computationally demanding for performing optimization or uncertainty quantification (UQ) studies over the range of parameters. This is because performing optimization and/or UQ requires a large number (often in the order of 100-10,000) of simulations of the system at different configurations. In these cases, lower-fidelity models, with 1.5D mean-line design approximations, are used instead. However, these lower fidelity models approximate the underlying physics, and that leads to surface geometries within some degree of inaccuracies in the quantities of interest. It is therefore useful to develop multi-fidelity methods that combine the desirable characteristics of both high- and low-fidelity approaches. That is, they inherit the computational efficiency of the low-fidelity model, while retaining the accuracy of the high-fidelity model. The low fidelity approach involves morphing of various surfaces based on different goal functions.