Design Space Exploration of Rotor Blades Accounting for Vibratory Responses by Indirect Emulation

Abstract

Turbomachines are an integral part of society, with global trends demanding more efficient designs while staying within structural limits. Fan blade designs must be designed for both steady and vibratory structural responses. Design space exploration (DSE) of turbomachinery blades allows improved designs to be found. DSE requires samples of vibratory responses. Traditionally, analysis to obtain these samples is too computationally expensive for thorough DSE. This work develops a simplified analysis method based on Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) and harmonic mode superposition (HMS) finite element analysis (FEA). This reduces the computational cost and allows for enough samples to create surrogate models. This work also develops a surrogate method which indirectly emulates the vibratory responses to accurately handle the large spikes in vibratory stress found throughout the design space. It was found that combining these methods allows for accurate emulation of a fan blade design space while accounting for vibratory stress. The surrogates with improved accuracy allow better designs to be found while ensuring that those designs meet structural requirements.