Study On Dynamic Response Of Blades For Three-Floating Body Wind Power Platform In Mooring Condition

With more and more requirement of the energy consumption in the modern society,non-renewable energy sources are running out.Wind power is a new generating energy mean using wind energy,which saves coal,oil and others non-renewable fossil energy and protects environment as well,which has received extensive attentions for its efficient development and application.Due to the immaturity of the current offshore wind power platform technologies,many technical problems have not been solved.This leads to a series of platform accidents when the offshore platform becomes more and more large-scale and high-power.The damaging of blade is the prominent problem in the current development of wind power equipment,which makes it necessary to do deep research on the dynamic response of blades.In this study,the experiments on the dynamic response of the three-floating wind power platform under mooring was carried out in the key laboratory of offshore engineering technology of Zhejiang Province.The experiments focus on the dynamic response of the blades under the action of wind speed,wave height and wave length.Some conclusions have been drawn based on the results of the experimental.Firstly,the experiments carried out in the conditions of absence of wind.The results shows that values of strain change ?? at each point on the fan blade are very small,and the changes in wavelength and wave height have little effect on the changes of strains(??).The values of ?? are dominated by several main frequencies of strains change.With the increasing of the distance between the measuring point and the center of rotation,the effects of the main frequencies on the blade strain are gradually weakened.Secondly,the experiments focus on the relationship of the strain change ?? with wind speeds.In the case of cut-in wind speed of V=3m/s and an environmental wave height of 1.56m,the strain change ?? of windward face near the middle of fan blade is much higher than the other points.In the case of V>3m/s,the ?? near the mid-windward surface is lower than other points on the blade.The value ?? of leeward surface point near the middle of the blade is always lower than the value ?? of the windward surface point,while ?? of the other leeward surface points are almost equivalent to the windward surface points.Thirdly,the experiments carried out in the conditions of rated speed of 11.4m/s.The variation of the strain changes are not completely same characteristics under different wave heights and wavelengths.In most conditions,the strain change ?? in the middle of the blade is lower than other points,and the strain changes on the windward surface is larger than the leeward surface.Numerical simulations were conducted for the cut-in wind speed(3m/s)and the rated wind speed(11.4m/s)under different wave heights and wavelengths for a typical NREL 5MW wind power platform.The strain response characteristics of the fan blade are analyzed.In the last,the research work of this paper is analyzed and summarized,and the future research works are prospected.