Experimental investigation and analysis of proposed hybrid vertical axis wind turbine design
Muhammad Ahmad, Aamer Shahzad, Syed Irtiza Ali Shah
Abstract
In this research, an experimental and computational analysis of a novel hybrid vertical axis wind turbine (VAWT) arrangement has been performed. We suggest an innovative VAWT design that has a high power coefficient and self-starting capability. The inner side of the proposed hybrid system has been integrated with the H-rotor turbine with cambered blades, which demonstrates strong self-starting capabilities at various azimuths. Three NACA0018 airfoil blades are mounted on the outside of the proposed hybrid wind turbine, while three DU 06-W-200 airfoil blades are installed on the inside. Based on a similarity analysis, a scaled-down model was developed, and performance characteristics such as the output power, power coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mspace width=".1em"/> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> </mml:math> ), dynamic torque coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> ), and static torque coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mi>t</mml:mi> <mml:mi>s</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) were determined. An existing hybrid VAWT and a typical H-rotor Darrieus design were also examined for comparison. The highest <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mspace width=".1em"/> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> </mml:math> for the proposed hybrid design was found to be 0.486 at a tip speed ratio (TSR) of 3, while the H-rotor Darrieus’ maximum value was 0.42 at a TSR of 2.62 and the existing hybrid VAWT’s value was 0.41 at a TSR of 2.5. Positive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mi>t</mml:mi> <mml:mi>s</mml:mi> </mml:mrow> </mml:msub> </mml:math> values at all azimuths demonstrate that the proposed hybrid wind turbine can start entirely on its own. In comparison to the existing H-rotor and hybrid VAWT, this novel hybrid system has shown enhanced performance parameters ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mspace width=".1em"/> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mi>C</mml:mi> <mml:mrow> <mml:mi>t</mml:mi> <mml:mi>s</mml:mi> </mml:mrow> </mml:msub> </mml:math> , output power) by around 11%–13% over a wide range of wind speeds.