Icing Detection Of Wind Turbine Blade Using Ultrasonic Guided Waves

As one of the most important clean renewable energy, wind power plays a more and more significant role in the national economy. However, the icing of wind turbine, especially the wind turbine blades, is common problem in cold climate, where the wind energy is rich, such as high latitude or high altitude. Thus, ice detection so as to de-icing is one of the most important issues for turbine blade icing solutions. Icing can be detected by a variety of methods, among which the ice detection based on the ultrasonic guided wave attract much attention as its high efficiency, non-invasive as well as low cost.In this study, ultrasonic guided waves excited by the piezoelectric wafer array are proposed to detect the icing process. The main research content is as follows:First of all, Lamb wave propagation in viscoelastic medium as well as in GFRP-ice double-layer medium are studied. The dispersion characteristic of guided ultrasonic waves change under the variation of temperature is also researched.Secondly, after the theoretical analyses of guided wave propagating on the glass fiber reinforced plastic, the initial ice detection method based on the ultrasonic guided wave is studied at first by the finite element analysis and then on a segment of wind turbine blade in the laboratory.Finally, based on the research of the segment of wind turbine blade, a full size wind turbine blade(length: 53.8m) in ice tunnel is used to demonstrate the proposed ice detection method. In this experiment, the piezoelectric wafer array is arran ged to enhance the guided wave signal, as well as to explore the attenuation of guided wave on the full size blade. Final results indicate that the proposed method is valid for ice detection of wind turbine blade. Besides, as the traditional guided wave de tection system is susceptible to temperature, a modified guided wave ice-detection system is proposed and tested here. The results show that the modified guided wave ice-detection system with high sensitivity is hardly affected by temperature.