59554 - Morphing of Reversible Axial Fan Blades: A Fsi-Fem Study 

Reversible axial fan are widely used in industrial and tunnel ventilation systems, and a lot of research effort is spent in the design process of the blades shape and blades profile to achieve reasonable performances in both flow direction, but those are still below the levels of the corresponding non-reversible geometries. In this paper a possible alternative design solution for reversible axial fan is presented, by adopting flexible blades instead of the rigid ones. Such design, inspired by the boat sails, could allow the blade to modify its shape by passively adapting to the flow field, from a symmetrical blade profile to an asymmetrical blade profile, and thus reducing flow separation. Furthermore, the morphing could increase the range of flow rates where the fan operates. In the paper, a series of alternatives materials and material distributions are analysed and compared. The analysis is conducted by performing Fluid Structure Interaction simulations using stabilized Finite Elements formulations for both the fluid and the structure dynamics. Simulations are performed using the in-house built software FEMpar, which implements the Residual Based Variational MultiScale to model the Navier-Stokes equation, the Total Lagrangian formulation for the non-linear elastic solid and the Solid Extension Moving Mesh Technique to move the fluid mesh.