Environmental Engineering Reference
In-Depth Information
Chapter 8
Monitoring Ice Accumulation and Active
De-icing Control of Wind Turbine Blades
Shervin Shajiee, Lucy Y. Pao and Robert R. McLeod
Abstract Ice accumulation on wind turbines operating in cold regions reduces
power generation by degrading aerodynamic efficiency and causes mass imbalance
and fatigue loads on the blades. Due to blade rotation and variation of the pitch
angle, different locations on the blade experience large variation of Reynolds
number, Nusselt number, heat loss, and nonuniform ice distribution. Hence,
applying different amounts of heat flux in different blade locations can provide
more effective de-icing for the same total power consumption. This large variation
of required heat flux highly motivates using distributed resistive heating with the
capability of locally adjusting thermal power as a function of location on the blade.
Under medium/severe icing conditions, active de-icing with accurate direct ice
detection is more energy efficient and effective in keeping the blade ice-free. This
chapter includes: (1) A literature study on different methods of ice detection and a
review on passive and active anti/de-icing techniques on wind turbines, (2)
Development of an optical ice sensing method for direct detection of ice on the
blade, including experimental results, (3) Development of an aero/thermodynamic
model, which predicts how much heat flux is needed locally for de-icing under
variable atmospheric conditions, (4) Experimental results showing a proof of
concept of closed-loop de-icing using distributed optical ice sensing and resistive
heating, and (5) Numerical modeling of ice melting on a blade for different dis-
tributed heater layouts and geometries in order to optimize thermal actuation
strategy,
improve
de-icing
efficiency,
and
reduce
power
consumption.
We
