Alternate Passage Divergence of Aeroengine Fan Blades

The project will investigate the influence of aerodynamic loads on the deformation of structures with the aim to improve the understanding of strong fluid-structure coupling in rotating machinery. In bladed systems, such as gas and wind turbines, time-varying aerodynamic loads cannot only cause vibration issues but also lead to a quasi-static or transient deformation of the blades, which varies from blade to blade due to manufacturing difference or in-service wear. This resulting non-uniformity, also known as alternate passage divergence, has adverse effects on efficiency. Modelling this behaviour is difficult due to non-linear aerodynamic and structural effects and the random uncertainty associated with manufacturing tolerances and in service wear. Currently, no reliable prediction methods or counter measures exists.
Considering initially simplified geometries, this project will develop a numerical method which can accurately predict transient alternate passage divergence. In the first step, it will couple a non-linear unsteady Reynolds-averaged Navier-Stokes solver with a non-linear structural model and validate this on simplified geometries to assess the importance of including non-linear effects for the accurate prediction of structural deformations. In the second step, it will use uncertainty analysis methods and identify the sensitivity of resulting structural deformations to geometric changes in the input geometries. The project is expected to deliver a robust methodology for designs which exhibit strong fluid-structure coupling.