Computational fluid–structure interaction analysis of passive adaptive blades in turbomachinery applications

This chapter presents three applications of computational fluid-structure interaction (CFSI) in the field of turbomachinery. We explore novel designs for morphing blades that adapt to changes in flow direction, focusing on small-size reversible fans and turbines. The model framework is based on the finite element formulations of fluid dynamics, structural mechanics, and mesh moving equations, while a block-iterative approach is used for the FSI coupling. We conduct first a 2D study of a reversible fan cascade made of low-stiffness material. The goal is to achieve a stable passive change in airfoil curvature in response to the aerodynamic forces. A similar design solution is then investigated for a Wells type turbine. A 2D cascade study verifies the feasibility of the concept and explores the use of different material layouts. Then, we test the 3D blade under time-dependent flow rate conditions, simulating operation of the turbine in an oscillating water column facility for sea wave energy conversion. In all cases, the results show that using CFSI provides useful insight into the functioning of these devices.