The Influence Of Different Wind Profiles On The Micro Location Of Wind Turbines At The Top Of The Building

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.