PSI - Issue 17

Pedro J. Sousa et al. / Procedia Structural Integrity 17 (2019) 812–821 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

817

6

The last parameter, density, was defined considering the volume of the parametric 3D model, 3292.7 mm 3 , and the weight of the physical blade, 3.71 g, obtaining a value of 1126.7 kg/m 3 . Finally, these material properties are summarized in Table 1.

Table 1. Material properties of the blade

Property

Experimental Result

Young’s Modulus

1.003 GPa

Poisson Ratio

0.4001

Density

1126.7 kg/m 3

3.2. Coupled Simulation

The displacement of the rotating blades was analyzed by means of a transient coupled simulation, implementing fluid-structure interaction (FSI) in both Computer Fluid Dynamics and Finite Element Analysis using commercial software. Thus, three computational domains were defined, Fig. 6. Two of them are fluid domains and the other is a solid domain.

Fig. 7. Boundary conditions and computational domains

The fluid domains include a stationary and a rotational domain. The stationary domain includes the inlets/outlets from which air can enter or leave the computational domain. Additionally, a rotational motion is applied to the rotational domain, as is common in the literature [11]. The angular speed was defined as 680 rpm, which was the measured speed in the DIC experiment. The solid domain consists in the rotating blades and the supporting hub. As a simplification, the rotational degrees of freedom between the two blades and the hub were not included. As such, the whole system effectively behaves as a single part. Regarding the CFD component of the simulation, the fluid was defined as air, modelled as an ideal gas with a density of 1.225 kg/m 3 and a viscosity of 1.7894×10 -5 kg/(m∙s) , and Reynolds’ Stress 7 -equation viscosity model was employed with a linear pressure-strain model, scalable wall functions and parameters: