| Summary: | In the past three decades, increasing attention has being put into wind turbines as a clean and green renewable energy alternative to fossil fuels. There are two main types of wind turbines, the Horizontal Axis Wind Turbine (HAWT) and Vertical Axis Wind Turbine (VAWT). Due to the advantages that the VAWT has over the HAWT in urban environments, this project serves to investigate on an experimental Delta Blade VAWT.
With a pair of leading-edge vortices on the top surface, the delta wing is able to continue generating lift at high angles of attack where conventional wing would have already experienced stall. In addition, the reverse delta wing shows similar trends. Hence, these subsonic characteristics of the delta wing were found applicable to a VAWT, incorporated into the Delta Blade VAWT.
In this project, a Delta Blade VAWT was designed and built for wind tunnel testing. Initially, the Delta Blade VAWT with standard delta blades obtained a maximum power coefficient of 0.0138. Several modifications were done to the Delta Blade VAWT to improve its performance. Eventually, with the optimal turbine blades, cropped delta blades with 45o TE deflection, the maximum power coefficient was able to improve to 0.0496 (217.93% increment). Wind tunnel testing for 360o aerodynamic data and water tunnel flow visualization were also done to justify these improvements in performance.
As a whole, the Delta Blade VAWT with optimal turbine blades is considered to be successful. It has great self-starting and self-sustaining capabilities even at low wind speeds of 4 m/s, due to its operating TSR range of 0.2 to 0.4. Hence, the Delta Blade VAWT can be said to suit a small-scale urban rooftop application.
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