15th European Conference on Turbomachinery Fluid dynamics & Thermodynamics

Paper ID:

ETC2023-177

Main Topic:

Axial Turbines

https://doi.org/10.29008/ETC2023-177

Authors

Valerio Francesco Barnabei  - Sapienza University of Rome
Alessio Castorrini - University of Basilicata
Alessandro Corsini - Sapienza University of Rome
Franco Rispoli - Sapienza University of Rome

Abstract

Oscillating water column (OWC) plants represent a feasible and well know technology solution to convert the kinetic energy of sea and ocean waves into electric power using a rotating device such as a Wells turbine. Wells turbines operate under alternating direction inflow conditions, provided by the consecutive rise and decline of the oscillating water column. Consequently, the blades are characterized by a symmetrical shape and high thickness, in order to allow the turbine to rotate in the same direction regardless of the flow direction. Such design is however not optimal with respect to the aerodynamic performance, as the flow angle is usually very high even under the design operating conditions. For example, a more pronounced camber of the blade for increasing flow rates and the possibility to invert the concavity of the suction side and pressure side could help improve the performance. A possible solution is to design the blades to accommodate the alternating flow direction by exploiting the passive morphing adaptivity of flexible materials. Flexible blades designed with appropriate structural constraints and materials, inspired by boat sails, could provide the turbine blades a passive adaptive camber line, and consequently a dynamic angle of attack and incidence angle. In this study, we present a fluid-structure interaction computational analysis of a preliminary design of flexible blades for a Wells turbine, from preliminary steady state considerations to unsteady simulations. The simulations are carried out using the Residual Based Variational MultiScale (RBVMS) method to solve the Navier-Stokes equations, the Total Lagrangian formulation (TL) for the structural non-linear elastic problem, and the Solid Extension Mesh Moving Technique (SEMMT) to move the mesh and avoid a continuous remeshing of the computational domain.



ETC2023-177




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