Wind Winds Windmills

Overview

Objectives/Goals This project investigated various blade configurations in order to optimize wind turbine efficiency. Methods/Materials * Build a wind tunnel; assemble the Kidwind Wind Experiment Kit with a base, a tower, a nacelle with gear set and generator, and a hub for mounting blades * Modify gearbox for higher gear ratios; build rotor with twisted blades and stators with stationary blades * Vary blade shape and dimensions, blade pitches, numbers of blades, gear ratios, and wind speeds. * Record generated power on a load resistor. Results * (2.8 m/s wind/45° blade pitch/8:1 gear ratio) efficiency almost the same with 1, 2, 3, 6, and 12 blades * (2.8 m/s wind/15° blade pitch/8:1 gear ratio) efficiency increased with 1, 2, 3, and up to 6 blades, but dropped at 12 blades * (2.8 m/s wind/45° blade pitch/16:1 gear ratio) efficiency almost 3x of that of gear ratio of 8:1 * (1.2 m/s wind) Most of high gear ratio configurations did not work * (1.2 m/s wind/30° blade pitch/12 blades) 16:1 gear ratio produced lower efficiency than 8:1 gear ratio * With 15° pitch, inversed trapezoid blade with wider tip produced higher efficiency * With 45° pitch, trapezoid blade with narrower tip produced higher efficiency * (twisted blade/15° tip pitch/32:1 gear ratio) efficiency improved as the base pitch increased from 15° to 45° * (twisted blade/15° tip pitch/16:1 gear ratio) efficiency plateaued at base pitch of 30° to 45° * Highest efficiency of 12.3% reached with 32:1 gear ratio and base pitch of 45° * Front stator caused drop in efficiency; rear stator caused even higher drop * Front stator penalty much smaller in blow in configuration than that in blow out configuration; positive gain with 45° pitch Conclusions/Discussion * Drag should be minimized with lower blade pitch and torque should be maximized with higher blade pitch * Optimized blade was twisted with high blade pitch at the base to increase torque and low blade pitch at the tip to reduce drag * Stator can reduce drag by changing airflow direction, but also creates air blockage

Competition history

• CSEF 2015 Aerodynamics/ Hydrodynamics (Junior Division Only) · Entry J0104

Resources

• CSEF project summary ↗

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