Icing effects on a horizontal axis wind turbine

Rong, Jiequn (1991) Icing effects on a horizontal axis wind turbine. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (11MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

Freezing precipitation has extremely high incidence in parts of Atlantic Canada and this condition is expected to severely reduce the energy output from aerogenerators. This project was aimed at the evaluation of effects of freezing precipitation conditions on the output of wind turbine generators. Major achievements have included the simulation of freezing rain events, in particular, glaze icing in a cold room and in field applications; testing of a NASA LS(1)-0417 wing section in the wind tunnel under simulated icing conditions; and theoretical evaluation of performance degradation by icing on blades for two horizontal axis wind turbines, that is, a 2.5 m diameter wind turbine and a Carter-23 wind turbine, by using lifting-line theory. -- An experiment to model the form of ice accumulation on a horizontal axis rotor was done in a cold room. Ice profiles on the blade sections were recorded. Wind tunnel tests for an airfoil used typically for wind turbine blades were done with various simulated glaze and rime ice accretions attached to the leading edge of the airfoil. Lift and drag coefficient data were obtained for angles of attack from -6° to 90°. A theoretical method was used for estimation of degradation of aerodynamic performance of horizontal axis wind turbines in icing conditions. The theory used was based on marine-propeller lifting line theory that had been adapted for wind turbine use. This made use of airfoil section data obtained from wind tunnel tests. A simulated icing test on a full scale horizontal axis wind turbine was performed at the Atlantic Wind Test Site. -- The cold room icing test gave a better understanding of the blunt shaped glaze ice accretion on the leading edge of blade sections where the wind speed was relatively high. The theoretical estimations showed that icing events, associated with ambient temperatures close to freezing point and high liquid water content in the air, could destroy the performance of wind turbines completely. The wind turbine field test showed that a progressive power reduction occurred during a simulated freezing event and a complete loss of power from the wind turbine generator was encountered after a short time period of freezing precipitation. The wind tunnel tests for the airfoil with simulated ice accretions on the leading edge revealed that increase of drag coefficient and decrease of lift coefficient on the iced blade sections of a wind turbine were the main reasons that caused the power output from a wind turbine to drop.

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