【作者】 王猛；

【导师】 汪建文；

【作者基本信息】 内蒙古工业大学 ， 动力工程及工程热物理， 2018， 硕士

【摘要】 随着风能应用面的拓宽,发展强扰动环境中建筑物顶部小型风力机的选址工作成为前沿课题。但建筑物周围的风场复杂多变,若选址不当,会影响风力机的输出功率和寿命。本文采用数值模拟和试验相结合的方法,测得呼和浩特城郊处的风速剖面和湍流剖面,通过对城郊单体复杂建筑物上方的速度特征和湍流特征的研究,根据IEC61400-2标准风力机安装高度处湍流强度TI的控制范围,确定了不同入流剖面下建筑物顶部风力机的安装高度;季节性变化(夏秋)对风力机选址的影响和适合城郊建筑物顶部风力机微观选址的入流剖面。为建筑物顶部风力机的选址提供理论指导和数据支持。首先利用ZephIR 300和测风塔上的风速计测得呼和浩特城郊某处夏季到秋季的风数据。采用目标性拟合的方法得到夏季和秋季的风速剖面和湍流强度剖面,将其作为本文数值计算的入口边界条件。通过对风向、风能、速度剖面和湍流强度剖面的分析,结果表明:城郊风场风向多变为主要特征。盛行风向与季节密切相关,夏季与秋季以三种盛行风向为主要特征,其中北风为夏秋季共有盛行风向;风能主要存在于北方和西北方且不随高度变化。秋季和夏季拟合的速度剖面和湍流剖面均服从指数函数形式,速度剖面的指数值大于规范中的建议值,湍流剖面的拟合出的函数基本符合日本规范建议式。其次在速度入流剖面相同的情况下,以System TI法、System TKE法、Friction法及试验函数法为湍流入流剖面,对呼和浩特城郊某建筑周围的湍流强度和速度进行数值模拟,结果表明:湍流边界条件是决定风力机安装高度的重要参数,而对建筑物顶部速度场的分布影响较小。风力机安装高度由高到低的排序是:Friction法>试验函数法>System TKE法>System TI法。然后在湍流入流剖面相同的情况下以夏季试验入流剖面、对数入流剖面和夏季均匀入流剖面为速度入流剖面,分别以八个方向对目标建筑物周围的湍流强度和风加速因子进行数值模拟,结果表明:风力机的安装的位置和高度受入流方向影响较大,单风向的选址结果无法实现既避开强湍流又利用建筑物顶部的风加速,要想保证风力机寿命,三种入流剖面任意来流方向下风力机的最低安装高度分别三种入流剖面任意来流方向下风力机的最低安装高度分别是2.3H,2.25H和2.75H,湍流强度最大值在[1.1-1.5]H之间。在仅考虑主风向和主风能方向时,可实现兼顾避开强湍流和利用风加速,风力机安装位置均在在建筑物前沿,高度均为2H以上;建筑物顶部各位置最大风加速因子小于1.3,所以为减少选址的工作量可不考虑风加速效应。再次通过对以夏季和秋季的试验所得剖面为入流条件进行数值计算,对比分析夏秋季典型位置处的湍流强度和风加速因子,结果表明:夏秋季入流剖面对风力机选址的影响较小,从工程角度可考虑忽略不计。最后综合考虑不同湍流剖面和不同速度剖面对建筑物顶部风力机的选址的影响,提出适合用数值模拟的方法对城郊建筑物顶部的风力机进行选址时的入流剖面。更多还原

【Abstract】 With the widening of the application area of wind power,the location of small wind turbines on the top of buildings is becoming a preface topic.But the wind field around the building is complex and changeable.If the location is improper,it will affect the output power and life of the wind turbine.By means of numerical simulation and experiment,the wind speed profiles and turbulent profiles in the outskirts of Hohhot are measured.By studying the velocity characteristics and turbulence characteristics above the complex buildings on the outskirts of the suburbs,According to the control range of turbulence intensity TI at installation height of wind turbine according to IEC61400-2 standard,the installation height of wind turbine at the top of building under different entry profile is determined.The influence of seasonal variation on the location of wind turbine and the entry section suitable for the micro location of wind turbine on the top of suburb buildings are discussed.It provides theoretical guidance and data support for the location of wind turbines on the top of buildings.Firstly,wind data from summer to autumn in a suburb of Hohhot were measured by ZephIR 300 and anemometer on the wind tower.The wind speed profile and turbulence intensity profile in summer and autumn are obtained by target fitting method,which is taken as the entry boundary condition of numerical calculation in this paper.Based on the analysis of wind direction,wind speed,velocity profile and turbulence intensity profile,the results show that the wind direction of suburban wind field is changeable.The prevailing wind direction is closely related to the season.In summer and autumn,three prevailing wind directions are the main characteristics,of which the north wind is prevailing in summer and autumn,and the wind energy is mainly in the north and northwest and does not change with the height.The velocity profile and turbulence profile in autumn and summer are all subject to exponential function.The numerical value of velocity profile is larger than that in the norm,and the function of the turbulent section is basically in accordance with the Japanese standard formula.Secondly,under the same velocity entry profile,the turbulence intensity and velocity around a building in the suburb of Hohhot are simulated by System TI,System TKE,Friction and test function method.The results show that the turbulent boundary condition is an important parameter to determine the height of the installation of the wind turbine.But it has little effect on the distribution of velocity field at the top of building.The ranking of wind turbine installation height from high to low is Friction method > test function method > System TKE method > System TI method.Then,the turbulent inflow section,the logarithmic inflow section and the summer uniform inflow section are the velocity entry sections under the same turbulent inflow profile,and the turbulence intensity and the wind acceleration factor around the target building are numerically simulated in 8 directions.The results show that the position and height of the installation of the wind turbine are loaded.The flow direction has great influence.The location results of single wind direction can not achieve the wind acceleration that both avoid strong turbulence and use the top of the building.To ensure the life of the wind turbine,the minimum installation height of the wind turbine in the direction of the three inflow profiles under arbitrary flow direction is respectively the lowest installation height of the wind turbine.It is 2.3H,2.25 H and 2.75 H,and the maximum value of turbulence intensity is between [1.1-1.5]H.When only the main wind direction and the main wind direction are taken into consideration,both the strong turbulence and the wind acceleration can be avoided.The installation position of the wind turbine is all in the front of the building,and the height is above 2H.The maximum wind speed of the top of the building is less than 1.3 times,so the wind acceleration effect is not considered to reduce the workload of the location.Through the numerical calculation of the entry flow conditions in summer and autumn,the turbulence intensity and the wind acceleration factor are analyzed.The results show that the impact of the summer and autumn section on the location of the wind turbine is less,and the neglect is considered from the engineering point of view.It is recommended that site data be selected for a quarter.Finally,considering the influence of different turbulence profiles and different velocity profiles on the location of wind turbines at the top of the building,the inflow section of the wind turbines at the top of the suburban building is put forward by numerical simulation.更多还原