Session: 4.1.3 - Renewable Energy Systems

Paper Number: 108771

108771 - Investigations of End Plates of Various Widths on the Performance of an Optimized Airfoil 

Steady numerical simulations of an optimized airfoil [1, 2] with different-sized end plates have been performed to identify the effect of the end plates on the aerodynamic characteristics of the airfoil. Geometrical optimization and wind tunnel experiments were used previously for the development of the optimized airfoil with a power coefficient of approximately 0.35 at 10 m/sec. The airfoil has been used in the development of a high-performance vertical-axis wind turbine with round end plates. The objective of the present investigation was to investigate the impact of end plates that follow the airfoil chord shape with different widths (offsets) on the torque generated by the airfoil. Siemens Star CCM+ software was used for the simulations. Between 17 to 42 million cells were used for airfoil without and with the end plates. High-performance computing was used for the simulations. The freestream mean velocity was 10 m/sec. and the Reynolds number based on the airfoil chord length was approximately 2.0x10⁵.  The new end plates have a width of 0.5, 3,  or 5 inches. The results of the airfoil without the end plates have shown increased lift with increasing the angle of attack (AOA) with a peak lift coefficient at 20 degrees AOA. At this angle of attack, the lift coefficient was 0.79 and the lift-to-drag ratio was 2.82. The lift coefficient decreases with increasing AOA and beyond 40 degrees AOA, drag force is the only force contributing to the torque. These results are in agreement with the previous corresponding experimental results. The addition of the end plates respectively increases and decreases the lift and drag forces with 3 inches end plate being the most impactful, resulting in a nearly 10% increase and 11% decrease in the lift and drag forces respectively. For the 0.5-inch width end plates, the average increase and decrease in respectively lift and drag forces were 7.7%  and 3.8% and when the 5-inch width end plates were used these values were 7.2% and 16.7%.  For all end plates, there were no significant increases in lift force beyond 20 degrees AOA. Experimental verifications of the numerical results are underway in the CSULB-Boeing low-speed wind tunnel with a 4ftx3ft cross-section working area, 10 ft long. The wind tunnel has been previously used for the development of a high-performance vertical axis wind turbine that is being tested by the Via-Verde company in Puerto Rico, USA. All results will be included in the final technical paper.

Presenting Author: Leovigildo Torres California State University

Presenting Author Biography: Leo Torres is a Ph.D. student in Engineering and Computational Mathematics and a research assistant at the Center for Energy and Environmental Research and Services (CEERS) in the College of Engineering at California State University, Long Beach.