Abstract
In order to research the law of rime ice accretion on different scaling blades surface, a new rime ice scaling method was proposed in this research. According to previous research, there are three kinds of ice types on blade surfaces: rime ice, glaze ice and mixed ice. Under the condition of rime ice, both the freezing fraction and the coefficient of heat transfer between super-cold water droplets and blade are 100%. The heat transfer model of rime ice is simpler than that of glaze ice and mixed ice. In this research, the scaling parameters including flow field, water droplets, temperature, pressure and rotating parameters were defined. The Weber number (We) based on water film thickness as an important parameter was applied in this study. The rotating parameters including rotating speed and radius had been added into the icing scaling method. To verify the effectiveness of the new rime ice scaling method, icing wind tunnel tests were carried out. The NACA0018 airfoil was used for the test blade. Two kinds of scale chord blades were selected, the chord of full-scale blade was 200 mm and of subscale blade was 100 mm. The test temperature was −15 °C. The ice accretion on different scale blades surface were captured by high-speed camera and the icing shapes of different scaling blades were obtained. To quantitatively analyze the similar degree of icing shapes on different scale blades, an evaluation method which included similar degree (Sim) was established based on the typical characteristic parameters proposed by previous research. The results show that the icing shapes of subscale blades are similar to that of full-scale blades. The similar degree is between 75.22% and 93.01%. The icing wind tunnel test indicates that the new rime ice scaling method is an effective method to study the rime ice of large scale rotating blades. This study can be used as a reference for research on anti-icing and de-icing technologies for large-scale HAWTs (Horizontal Axis Wind Turbines).
Highlights
Wind energy, as a main kind of green and renewable energy, has been greatly developed in recent years [1,2,3]
Many verification tests based on numerical simulation have been carried out and the results showed that the icing shapes of subscale blades were similar to that of full-scale models
The results show that the similar degree of icing shape accretion on subscale blade surfaces and full-scale blade surfaces is between 75.22% and 93.01%, which indicates that the icing shapes of the subscale model are similar to those of the full-scale model
Summary
As a main kind of green and renewable energy, has been greatly developed in recent years [1,2,3]. The wind turbines operating in these areas usually are threatened by ice problems [6,7]. According to the previous research, the ice mainly accretes on the blade surface of wind turbines [8,9,10]. This will affect the aerodynamic and load distribution, which will decrease the power performance and threaten the safety of wind turbines [11,12,13]. It is essential to research ice accretion on blade surfaces of wind turbines [14,15]. As early as 1940, Taylor had already researched the possible equipment and Energies 2019, 12, 627; doi:10.3390/en12040627 www.mdpi.com/journal/energies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
