基于高频PIV的偏航对风力机叶片尾迹膨胀和叶尖涡耗散影响
|
摘要
为了揭示叶片尾迹结构随偏航角变化的响应特征,该文以直径为1.4m的水平轴风力机为模型,利用高频PIV开展了尾迹流场特征的试验测试,探究了尾迹膨胀、叶尖涡耗散与来流风速、接入负载(即叶片转速)、偏航角度间的关联性和关联规律。研究结果揭示:不偏航时,随着发电机接入负载的增加,尾迹流动向风轮外侧膨胀的趋势变大,外流场与尾迹流场间的掺混效应加剧,从而导致叶尖涡耗散速率加快;偏航时,偏航行为会使尾迹流场向风轮内侧收缩,且收缩速率会随着偏航角的增加而变大,此时外侧流场与尾迹流场间的掺混效应减弱,从而导致叶尖涡扩散速率减小。测试结果同时揭示:在叶尖涡脱落的初始阶段,涡量值存在先增大后减小的规律性变化。同时,偏航状态下,叶片转速的增加会促使最大涡量值点提前出现,且提前出现的趋势会随偏航角的增大而加剧。该文以试验测试的方法揭示了叶片的尾迹膨胀和叶尖涡耗散特征,相关成果对于叶片尾迹结构组成和输运规律的深入探究具有较重要的参考价值。
The complex spatial vortices are generated when the airflow passes through the high-speed rotating blades.The generation,growth and expansion of vortices is not only an important basis for analyzing the structural characteristics of the blade wake flow field,but also a key problem for accurately grasping the wake flow resistance,aerodynamic noise and vibration inducement of downstream wind turbines.Therefore,it is of great value to carry out relevant research work.As the junction between wake flow field and external flow field,tip vortices' propagation characteristics are an important basis for analyzing the structure of wake flow field and an important topic that researchers have always paid close attention to.However,due to the lag of research and development of high-speed flow field monitoring equipment and insufficient attention paid by previous researchers to yaw conditions,the relevant research is still in its infancy,which leads to the uncertainty of the sensitivity of blade wake expansion to tip vorticity dissipation,and the influence of yaw behavior on the structure characteristics of wake flow field is still not clear.In particular,the regularity and mechanism of its influence on the generation and dissipation of tip vortices remain to be revealed.In order to reveal the response characteristics of blade wake structure with yaw angle,an experimental test on the near wake flow field characteristics of a small horizontal axis wind turbine with a diameter of 1.4 m was carried out using the high frequency PIV flow field measurement device,which investigated the correlations and correlations between wake expansion,tip vortex dissipation and incoming wind velocity,access load(i.e.blade velocity) and yaw angle.The results showed that,in the non-yaw state,with the increase of generator load,the trend of wake flow expanding towards the outside of wind turbine became larger,and the mixing effect between the outside flow field and wake flow field intensified,which led to the acceleration of the dissipation rate of tip vortices.The yaw behavior made the wake flow field shrink to the inside of the wind turbine,and the shrinkage rate increased with the increase of yaw angle.At this time,the mixing effect between the outer flow field and the wake flow field was weakened,which led to the decrease of tip vortex diffusion rate.The test results also showed that in the initial stage of tip vortex shedding,there was a regular change of vorticity value which increases first and then decreases.The discovery provided an exact answer to the controversy that the variation of tip vorticity value obtained by numerical simulation was not the same.At the same time,in yaw condition,the increase of blade velocity would cause the maximum vorticity point to appear ahead of time,and the trend would be aggravated with the increase of yaw angle.In this paper,the characteristics of wake expansion and tip eddy dissipation of blades were revealed by means of experimental measurements.Relevant results have important reference value for the further study of the wake structure and transport law of blades.
The complex spatial vortices are generated when the airflow passes through the high-speed rotating blades.The generation,growth and expansion of vortices is not only an important basis for analyzing the structural characteristics of the blade wake flow field,but also a key problem for accurately grasping the wake flow resistance,aerodynamic noise and vibration inducement of downstream wind turbines.Therefore,it is of great value to carry out relevant research work.As the junction between wake flow field and external flow field,tip vortices' propagation characteristics are an important basis for analyzing the structure of wake flow field and an important topic that researchers have always paid close attention to.However,due to the lag of research and development of high-speed flow field monitoring equipment and insufficient attention paid by previous researchers to yaw conditions,the relevant research is still in its infancy,which leads to the uncertainty of the sensitivity of blade wake expansion to tip vorticity dissipation,and the influence of yaw behavior on the structure characteristics of wake flow field is still not clear.In particular,the regularity and mechanism of its influence on the generation and dissipation of tip vortices remain to be revealed.In order to reveal the response characteristics of blade wake structure with yaw angle,an experimental test on the near wake flow field characteristics of a small horizontal axis wind turbine with a diameter of 1.4 m was carried out using the high frequency PIV flow field measurement device,which investigated the correlations and correlations between wake expansion,tip vortex dissipation and incoming wind velocity,access load(i.e.blade velocity) and yaw angle.The results showed that,in the non-yaw state,with the increase of generator load,the trend of wake flow expanding towards the outside of wind turbine became larger,and the mixing effect between the outside flow field and wake flow field intensified,which led to the acceleration of the dissipation rate of tip vortices.The yaw behavior made the wake flow field shrink to the inside of the wind turbine,and the shrinkage rate increased with the increase of yaw angle.At this time,the mixing effect between the outer flow field and the wake flow field was weakened,which led to the decrease of tip vortex diffusion rate.The test results also showed that in the initial stage of tip vortex shedding,there was a regular change of vorticity value which increases first and then decreases.The discovery provided an exact answer to the controversy that the variation of tip vorticity value obtained by numerical simulation was not the same.At the same time,in yaw condition,the increase of blade velocity would cause the maximum vorticity point to appear ahead of time,and the trend would be aggravated with the increase of yaw angle.In this paper,the characteristics of wake expansion and tip eddy dissipation of blades were revealed by means of experimental measurements.Relevant results have important reference value for the further study of the wake structure and transport law of blades.
引文
[1]Choudhry A.Effects of wake interaction on downstream wind turbines[J].Wind Engineering,2014,38(5):535-548.
[2]Kimura K,Tanabe Y,Aoyama T,et al.CFD simulations of a wind turbine for analysis of tip vortex breakdown[C]//Journal of Physics:Conference Series,2016(749):012013.
[3]Kim K C,Kim Y K,Ji H S,et al.Aerodynamic characteristics of horizontal axis wind turbine with Archimedes spiral blade[C]//ASME 2013 International Mechanical Engineering Congress and Exposition,2013.
[4]许波峰,王同光.一种风力机气动计算的全自由涡尾迹模型[J].计算力学学报,2013,30(6):822-827.Xu Bofeng,Wang Tongguang.A full free vortex wake model for aerodynamic calculation of wind turbines[J].Journal of Computational Mechanics,2013,30(6):822-827.(in Chinese with English abstract)
[5]马兴宇,明晓.风力机叶尖涡特性及其控制[J].南京航空航天大学学报,2011,43(5):635-639.Ma Xingyu,Ming Xiao.Characteristics and control of blade tip vortex of wind turbine[J].Journal of Nanjing University of Aeronautics&Astronautics,2011,43(5):635-639.(in Chinese with English abstract)
[6]胡丹梅,杨官奎,霍能萌,等.动态来流对风力机性能的影响[J].可再生能源,2016,34(7):1058-1066.Hu Danmei,Yang Guankui,Huo Nengmeng,et al.Effect of dynamic inflow on wind turbine performance[J].Renewable energy,2016,34(7):1058-1066.(in Chinese with English abstract)
[7]陈晓明,康顺,左薇.基于Flow Vision的水平轴风力机偏航气动性能研究[J].工程热物理学报,2014,35(9):1758-1761.Chen Xiaoming,Kang Shun,Zuo Wei.Study on yaw aerodynamic performance of horizontal axis wind turbine based on flow vision[J].Journal of Engineering Thermophysics,2014,35(9):1758-1761.(in Chinese with English abstract)
[8]Parkin P,Holm R,Medici D.The application of PIV to the wake of a wind turbine in yaw[J].Fluid Mechanics&Acoustics,2001(3):155-162.
[9]Massouh F,Dobrev I.Investigation of wind turbine flow and wake[J].Journal of Fluid Science&Technology,2014,9(3):JFST0025-JFST0025.
[10]Micallef D,Ferreira C S,Sant T,et al.Experimental and numerical investigation of tip vortex generation and evolution on horizontal axis wind turbines[J].Wind Energy,2016,19(8):1485-1501.
[11]Hashemi Tari P,Siddiqui K,Hangan H.Flow characterization in the near-wake region of a horizontal axis wind turbine[J].Wind Energy,2016,19(7):1249-1267.
[12]Bastankhah M,Porté-Agel F.A new miniature wind turbine for wind tunnel experiments.Part II:Wake structure and flow dynamics[J].Energies,2017,10(7):923.
[13]Eriksen P E,Krogstad P?.Development of coherent motion in the wake of a model wind turbine[J].Renewable Energy,2017,108:449-460.
[14]Sherry M,Sheridan J,Jacono D L.Characterisation of a horizontal axis wind turbine’s tip and root vortices[J].Experiments in Fluids,2013,54(3):1417.
[15]Jackson R S,Amano R.Experimental study and simulation of a small-scale horizontal-axis wind turbine[J].Journal of Energy Resources Technology,2017,139(5).
[16]肖京平,武杰,陈立,等.风力机叶尖涡尾迹结构PIV测量研究[J].应用数学和力学,2011,32(6):683-692.Xiao Jingping,Wu Jie,Chen Li,et al.PIV measurements of tip vortex wake structure of a wind turbine[J].Applied Mathematics&Mechanics,2011,32(6):683-692.(in Chinese with English abstract)
[17]陈秋华,赖旭.基于SPIV的风力机叶尖涡与尾流流场相关性研究[J].太阳能学报,2016,37(2):297-302.Chen Qiuhua,Lai Xu.Correlation between tip vortex and wake flow field of wind turbine based on SPIV[J].Journal of Solar Energy,2016,37(2):297-302.(in Chinese with English abstract)
[18]高志鹰,汪建文,东雪青,等.水平轴风力机近尾迹流场结构的实验研究[J].太阳能学报,2011,32(6):897-900.Gao Zhiying,Wang Jianwen,Dong Xueqing,et al.Experimental study on near wake flow structure of horizontal axis wind turbine[J].Acta Solar Energy,2011,32(6):897-900.(in Chinese with English abstract)
[19]胡丹梅,田杰,杜朝辉.水平轴风力机尾迹流场PIV实验研究[J].太阳能学报,2007,28(2):200-206.Hu Danmei,Tian Jie,Du Zhaohui.PIV experimental study on wake flow field of horizontal axis wind turbine[J].Journal of Solar Energy,2007,28(2):200-206.(in Chinese with English abstract)
[20]缪维跑,李春,阳君.基于偏航的风力机尾迹偏移控制流动机理研究[J].动力工程学报,2017,37(8):655-662.Miao Weipao,Li Chun,Yang Jun.Investigation of flow mechanism of a wind farm based on yawed wind turbine using wake deflection control strategy[J].Journal of Chinese Society of Power Engineering,2017,37(8):655-662.(in Chinese with English abstract)
[21]钟伟,王同光.风力机叶尖涡的数值模拟[J].南京航空航天大学学报,2011,43(5):640-644.Zhong Wei,Wang Tongguang.Numerical analysis of the wind turbine blade-tip vortex[J].Journal of Nanjing University of Aeronautics and Astronautics,2011,43(5):640-644.(in Chinese with English abstract)
[2]Kimura K,Tanabe Y,Aoyama T,et al.CFD simulations of a wind turbine for analysis of tip vortex breakdown[C]//Journal of Physics:Conference Series,2016(749):012013.
[3]Kim K C,Kim Y K,Ji H S,et al.Aerodynamic characteristics of horizontal axis wind turbine with Archimedes spiral blade[C]//ASME 2013 International Mechanical Engineering Congress and Exposition,2013.
[4]许波峰,王同光.一种风力机气动计算的全自由涡尾迹模型[J].计算力学学报,2013,30(6):822-827.Xu Bofeng,Wang Tongguang.A full free vortex wake model for aerodynamic calculation of wind turbines[J].Journal of Computational Mechanics,2013,30(6):822-827.(in Chinese with English abstract)
[5]马兴宇,明晓.风力机叶尖涡特性及其控制[J].南京航空航天大学学报,2011,43(5):635-639.Ma Xingyu,Ming Xiao.Characteristics and control of blade tip vortex of wind turbine[J].Journal of Nanjing University of Aeronautics&Astronautics,2011,43(5):635-639.(in Chinese with English abstract)
[6]胡丹梅,杨官奎,霍能萌,等.动态来流对风力机性能的影响[J].可再生能源,2016,34(7):1058-1066.Hu Danmei,Yang Guankui,Huo Nengmeng,et al.Effect of dynamic inflow on wind turbine performance[J].Renewable energy,2016,34(7):1058-1066.(in Chinese with English abstract)
[7]陈晓明,康顺,左薇.基于Flow Vision的水平轴风力机偏航气动性能研究[J].工程热物理学报,2014,35(9):1758-1761.Chen Xiaoming,Kang Shun,Zuo Wei.Study on yaw aerodynamic performance of horizontal axis wind turbine based on flow vision[J].Journal of Engineering Thermophysics,2014,35(9):1758-1761.(in Chinese with English abstract)
[8]Parkin P,Holm R,Medici D.The application of PIV to the wake of a wind turbine in yaw[J].Fluid Mechanics&Acoustics,2001(3):155-162.
[9]Massouh F,Dobrev I.Investigation of wind turbine flow and wake[J].Journal of Fluid Science&Technology,2014,9(3):JFST0025-JFST0025.
[10]Micallef D,Ferreira C S,Sant T,et al.Experimental and numerical investigation of tip vortex generation and evolution on horizontal axis wind turbines[J].Wind Energy,2016,19(8):1485-1501.
[11]Hashemi Tari P,Siddiqui K,Hangan H.Flow characterization in the near-wake region of a horizontal axis wind turbine[J].Wind Energy,2016,19(7):1249-1267.
[12]Bastankhah M,Porté-Agel F.A new miniature wind turbine for wind tunnel experiments.Part II:Wake structure and flow dynamics[J].Energies,2017,10(7):923.
[13]Eriksen P E,Krogstad P?.Development of coherent motion in the wake of a model wind turbine[J].Renewable Energy,2017,108:449-460.
[14]Sherry M,Sheridan J,Jacono D L.Characterisation of a horizontal axis wind turbine’s tip and root vortices[J].Experiments in Fluids,2013,54(3):1417.
[15]Jackson R S,Amano R.Experimental study and simulation of a small-scale horizontal-axis wind turbine[J].Journal of Energy Resources Technology,2017,139(5).
[16]肖京平,武杰,陈立,等.风力机叶尖涡尾迹结构PIV测量研究[J].应用数学和力学,2011,32(6):683-692.Xiao Jingping,Wu Jie,Chen Li,et al.PIV measurements of tip vortex wake structure of a wind turbine[J].Applied Mathematics&Mechanics,2011,32(6):683-692.(in Chinese with English abstract)
[17]陈秋华,赖旭.基于SPIV的风力机叶尖涡与尾流流场相关性研究[J].太阳能学报,2016,37(2):297-302.Chen Qiuhua,Lai Xu.Correlation between tip vortex and wake flow field of wind turbine based on SPIV[J].Journal of Solar Energy,2016,37(2):297-302.(in Chinese with English abstract)
[18]高志鹰,汪建文,东雪青,等.水平轴风力机近尾迹流场结构的实验研究[J].太阳能学报,2011,32(6):897-900.Gao Zhiying,Wang Jianwen,Dong Xueqing,et al.Experimental study on near wake flow structure of horizontal axis wind turbine[J].Acta Solar Energy,2011,32(6):897-900.(in Chinese with English abstract)
[19]胡丹梅,田杰,杜朝辉.水平轴风力机尾迹流场PIV实验研究[J].太阳能学报,2007,28(2):200-206.Hu Danmei,Tian Jie,Du Zhaohui.PIV experimental study on wake flow field of horizontal axis wind turbine[J].Journal of Solar Energy,2007,28(2):200-206.(in Chinese with English abstract)
[20]缪维跑,李春,阳君.基于偏航的风力机尾迹偏移控制流动机理研究[J].动力工程学报,2017,37(8):655-662.Miao Weipao,Li Chun,Yang Jun.Investigation of flow mechanism of a wind farm based on yawed wind turbine using wake deflection control strategy[J].Journal of Chinese Society of Power Engineering,2017,37(8):655-662.(in Chinese with English abstract)
[21]钟伟,王同光.风力机叶尖涡的数值模拟[J].南京航空航天大学学报,2011,43(5):640-644.Zhong Wei,Wang Tongguang.Numerical analysis of the wind turbine blade-tip vortex[J].Journal of Nanjing University of Aeronautics and Astronautics,2011,43(5):640-644.(in Chinese with English abstract)