One of the most important issues facing humanity today is the issue of energy use and dependence on fossil fuels. My senior mechanical design project focused on the design and development of a parallel and vertical axis wind turbine for use in harnessing wind energy. Methods of analysis included computational fluid dynamics (CFD) simulation, finite element analysis (FEA), and simple hand calculations. Evaluations of alternative solutions using CFD simulations showed that a turbine with four actuating airfoils is superior to that of a turbine with three actuating airfoils. The CFD analyses also showed that the turbine must be an active system, as opposed to a passive system. FEA results showed that the final design adheres to a required factor of safety of 5.0. Final fabrication of the design was never achieved due to time constraints.
The R vs. C ratio is used to describe the ratio between two distances. “R” is the distance from the center of the central fairing to the chord line of the airfoil; this is related to the arm length. “C” is the total length of the airfoil. As the distance from the center of the central fairing increases, so does the swept area. The swept area increases by the distances and the torque increases by the same distance. The assumptions made for the static study in SolidWorks Simulation included one open airfoil being hit on the drive side by a 14 m/s wall of air.
Plot of Tangential Force vs. angle of attack for various wing opening angles; attack angles of 135deg to 225deg. This was improved upon and used to determine how far the wings should be able to open to achieve optimum tangential force.
The CFD analysis for the wing opening angles was performed using Solidworks Flow simulation. A NACA 0012 type airfoil Solidworks model was modified with the addition of adjustable wings. The ngle of the wings, α (alpha), and the attack angle, θ (theta), were incremented in degrees of 10 and 30, respectively. A diagram of the model used for the CFD analysis can be seen.
Plot of Tangential Force vs. angle of attack for various wing opening angles; attack angles of 0deg – 360deg. This was used to determine how far the wings should be able to open to achieve optimum tangential force.
Mechanical engineering senior project final design concept Solidworks model.
This analysis resulted in an optimum R vs. C value of 2.25. These contour plots show the shadowing effects of a small R value vs a large R value. Pressure builds up on the side of the turbine that the air velocity is incident upon for a small R value. An increased R value shows that air is allowed to flow around to all the airfoils, thus increasing the overall torque. Contour plots of large R value (left) and small arm value (right).
