Icing on a small horizontal-axis wind turbine — Part 2: Three dimensional ice and wet snow formations

Abstract

Icing on a small horizontal-axis wind turbine was monitored during winter 1990–1991 in Newfoundland. The three-dimensional form of incident glaze ice accretion on the rotor is described. Variations in ice accretion along the blade span resulted from centripetal forces, gravity, and crossflow over the blades. The dominant forces acting on impinging water droplets were centripetal forces, which caused a greater build up of ice at the blade tips and, in particular, at the leading edge towards the blade tips. Icicles formed beyond the blade tips. Wet snow also led to icing of the wind turbine rotor. The form of this accretion is described; wet snow was found to adhere only to the pressure side of the blades. The power output from the wind turbine was monitored. Icing affected the performance of the wind turbine at this site over winter 1990–1991, for a period equivalent to about 1.5% of a year.