Fluid‐structure interaction and inverse design simulations for highly flexible turbomachinery.

Abstract

Highly flexible turbomachinery offers substantial advantages for biomedical implantation but can suffer from performance losses due to blade deformations during operation. The objective of this work is to develop a method to define an impeller shape that deforms into the design shape during operation, thereby making feasible a collapsible impeller for medical implantation without incurring performance losses due to blade flexibility. A fluid‐structure interaction (FSI) solver is developed and validated for quasi‐steady operation, capable of modeling the time‐dependent deformation inherent to the impeller polymeric material. The solver is validated using experimental data for a modified NACA 66 fin at various angles of attack. Inverse design simulations are used to define blade geometry that deforms into the design shape after being subjected to quasi‐steady flow at prescribed conditions for a specified amount of time. The validated FSI solver is used to confirm performance of the inverse design shape. Evaluation of the FSI solver convergence shows the fluid and structure are nearly fully converged after only a few sub‐iterations for these quasi‐steady simulations. Performance studies show that the flow solver consumes most of the processing time, with the mesh motion and structure solutions requiring a much smaller fraction of the total processing time.