Model forPre-Design of Darrieus wind Turbine H-Type

Resumo

This work presents a simplified fluid-structure interaction model for pre-design of a Darrieus wind turbine. The modeling of Darrieus turbine is a challenging task due to the aerodynamic complexity associated with its operation. One challenge is determining the drag and lift coefficients for each position during the circular motion of the blades, due mainly to changes in Reynolds number and angle of attack. Structural calculations are also challenging, as the blades operate in a rotating bending regime and must withstand alternating loads. For the development of the mathematical model of this work, the main geometric and operating parameters of the turbine were considered, and can be used to estimate aerodynamic forces, torque, and blade structural deflections. To characterize the profile's aerodynamic behavior, lift and drag coefficient data obtained from the airfoil-tools website, based on data from the XFOIL software, were used. The mathematical model was implemented in a Scilab code, allowing simulation of the turbine operation under different conditions. The graphs presented were generated by the developed code. It was considered that the turbine operates at constant rotational velocity. The radial and tangential forces on the blades were determined from the lift and drag components, as a function of the instantaneous angle of attack. Subsequently, the torque was calculated during the movement, allowing estimation of the available power. The blade deflections were analyzed, considering the distributed loads and the cross-sectional moment of inertia, based on a simplified modeling of a bi-supported beam. The results obtained allow a preliminary assessment of the turbine aerodynamic performance and structural integrity. The model can provide initial design support, with low computational cost and good applicability in conceptual stages.