To overcome the problems of natural decreases in power quality,and to eliminate wind speed fluctuation due to wind shear and tower shadow effect arising from wind turbine structural parameters,an improved prediction m...To overcome the problems of natural decreases in power quality,and to eliminate wind speed fluctuation due to wind shear and tower shadow effect arising from wind turbine structural parameters,an improved prediction model accounting for the dual effect of wind shear and tower shadow is,in this paper,built.Compared to the conventional prediction model,the proposed model contains a new constraint condition,which makes the disturbance term caused by the tower shadow effect always negative so that the prediction result is closer to the actual situation.Furthermore,wind turbine structural parameters such as hub height,rotor diameter,the diameter of the tower top,and rotor overhang on wind shear and tower shadow effect are also explored in detail.The results show that the wind shear effect became weaker with the increase in hub height.The hub height is independent of the tower shadow effect.The rotor diameter is positively correlated with the wind shear and tower shadow effect.The tower shadow effect is positively correlated with the diameter of the tower top and negatively correlated with the rotor overhang.展开更多
Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed ...Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed to investigate the dynamic response of an offshore wind turbine tower on the monopile foundation assembled with rotating blades in the complex ocean environment.Several environment factors like wind,wave,current,and soil resistance are taken into account.The proposed model is ana-lytically solved with the Galerkin method.Based on the numerical results,the effects of various structure parameters including the taper angle,the height and thickness of the tower,the depth,and the diameter and the cement filler of the monopile on the funda-mental natural frequency of the wind turbine tower system are investigated in detail.It is found that the fundamental natural frequency decreases with the increase in the taper angle and the height and thickness of the tower,and increases with the increase in the diameter of the monopile.Moreover,filling cement into the monopile can effectively im-prove the fundamental natural frequency of the wind turbine tower system,but there is a critical value of the amount of cement maximizing the property of the monopile.This research may be helpful in the design and safety evaluation of offshore wind turbines.展开更多
The 2MW wind turbine tower is considered as the baseline configuration for structural optimization.The design variables consist of the thickness and height located at the top tower junction.The relationships between t...The 2MW wind turbine tower is considered as the baseline configuration for structural optimization.The design variables consist of the thickness and height located at the top tower junction.The relationships between the design variables and the optimization objectives(mass,equivalent stress,top displacement and fatigue life)are mapped on the basis of uniform design and regression analysis.Subsequently,five solutions are developed by an algorithm,NSGA-III.According to their efficiency and applicability,the most suitable solution is found.This approach yields a decrease of 0.48%in the mass,a decrease of 54.48%in the equivalent stress and an increase of 8.14%in fatigue life,as compared with existing tower designs.An improved wind turbine tower is obtained for this practice.展开更多
采用有限元方法对风力发电机塔架进行模态分析,得出了不同结构参数下塔架的固有频率;然后采用支持向量机(the Support Vector Machine)建模方法,建立了塔架结构参数与固有频率之间的快速计算模型;以混沌搜索为寻优手段,对塔架结构进行...采用有限元方法对风力发电机塔架进行模态分析,得出了不同结构参数下塔架的固有频率;然后采用支持向量机(the Support Vector Machine)建模方法,建立了塔架结构参数与固有频率之间的快速计算模型;以混沌搜索为寻优手段,对塔架结构进行了优化;将优化结果和正交优化结果进行了比较,并采用有限元方法对所得塔架结构进行强度校核。研究深化了风力机的仿真设计,取得了较好的效果。展开更多
基金funded by the National Natural Science Foundation of China(51866012).
文摘To overcome the problems of natural decreases in power quality,and to eliminate wind speed fluctuation due to wind shear and tower shadow effect arising from wind turbine structural parameters,an improved prediction model accounting for the dual effect of wind shear and tower shadow is,in this paper,built.Compared to the conventional prediction model,the proposed model contains a new constraint condition,which makes the disturbance term caused by the tower shadow effect always negative so that the prediction result is closer to the actual situation.Furthermore,wind turbine structural parameters such as hub height,rotor diameter,the diameter of the tower top,and rotor overhang on wind shear and tower shadow effect are also explored in detail.The results show that the wind shear effect became weaker with the increase in hub height.The hub height is independent of the tower shadow effect.The rotor diameter is positively correlated with the wind shear and tower shadow effect.The tower shadow effect is positively correlated with the diameter of the tower top and negatively correlated with the rotor overhang.
基金Project supported by the National Natural Science Foundation of China(Nos.11872233,11727804,and 11472163)the National Key Basic Research Project of China(No.2014CB046203)the Innovation Program of Shanghai Municipal Education Commission(No.2017-01-07-00-09-E00019)。
文摘Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed to investigate the dynamic response of an offshore wind turbine tower on the monopile foundation assembled with rotating blades in the complex ocean environment.Several environment factors like wind,wave,current,and soil resistance are taken into account.The proposed model is ana-lytically solved with the Galerkin method.Based on the numerical results,the effects of various structure parameters including the taper angle,the height and thickness of the tower,the depth,and the diameter and the cement filler of the monopile on the funda-mental natural frequency of the wind turbine tower system are investigated in detail.It is found that the fundamental natural frequency decreases with the increase in the taper angle and the height and thickness of the tower,and increases with the increase in the diameter of the monopile.Moreover,filling cement into the monopile can effectively im-prove the fundamental natural frequency of the wind turbine tower system,but there is a critical value of the amount of cement maximizing the property of the monopile.This research may be helpful in the design and safety evaluation of offshore wind turbines.
基金the National Natural Science Founda-tion of China(Nos.51965034 and 51565028)LanzhouTalent Innovation and Entrepreneurship Project(No.2018-RC-25)。
文摘The 2MW wind turbine tower is considered as the baseline configuration for structural optimization.The design variables consist of the thickness and height located at the top tower junction.The relationships between the design variables and the optimization objectives(mass,equivalent stress,top displacement and fatigue life)are mapped on the basis of uniform design and regression analysis.Subsequently,five solutions are developed by an algorithm,NSGA-III.According to their efficiency and applicability,the most suitable solution is found.This approach yields a decrease of 0.48%in the mass,a decrease of 54.48%in the equivalent stress and an increase of 8.14%in fatigue life,as compared with existing tower designs.An improved wind turbine tower is obtained for this practice.
文摘采用有限元方法对风力发电机塔架进行模态分析,得出了不同结构参数下塔架的固有频率;然后采用支持向量机(the Support Vector Machine)建模方法,建立了塔架结构参数与固有频率之间的快速计算模型;以混沌搜索为寻优手段,对塔架结构进行了优化;将优化结果和正交优化结果进行了比较,并采用有限元方法对所得塔架结构进行强度校核。研究深化了风力机的仿真设计,取得了较好的效果。
