Analysis Of Arrangement Mode And Its Aerodynamic Load Of Large H-Type Vertical Axis Wind Turbines

The H-type vertical axis wind turbine（VAWT）has the advantages of no opposite wind,low noise,constant force direction,and suitable for high turbulence areas,and its advantages in wind farm construction and large-scale development are gradually emerging.However,there are still some problems in wind turbines,such as large fluctuation of aerodynamic load and significant influence by wake effect in wind farm layout,which can easily reduce its service life of shaft and reduce the aerodynamic performance.In order to improve the service life and output effect of the wind turbines,this paper explores the influence of the arrangement of large vertical axis wind turbines（L-VAWTs）on their load and performance.Firstly,the aerodynamic load of a large VAWT considering tower shadow effect is simulated and calculated by using CFD numerical simulation technology.Then the optimal arrangement of the two wind turbines and the mechanism of aerodynamic load change are determined,and the simulation results are verified by physical test.Finally,the arrangement mode of three wind turbines and multi wind turbinesand and the change of velocity field are further studied,the aerodynamic performance and load change of each wind turbine are determined.The main contents and conclusions of this paper are as follows:1)CFD simulation technology is used to study the aerodynamic load of L-VAWT blade considering tower shadow effect.The research shows that the aerodynamic load will produce a small drop trough nearθ=270°.Besides,the wake area of the single wind turbine is longer and the wind speed is lower.The amplitude of the synthetic force of the main shaft is about 52.7k N,and it changes periodicity.The length of the periodicity is related to the number of blades.2)Taking the maximum torque coefficient and the minimum variation coefficient as the goal,the aerodynamic performance and load variation of double wind turbines are studied.The results show that the closer the arrangement distance of the double wind turbines is,the higher the torque coefficient is,and the lower the variation coefficient is.CFR arrangement mode is better than CBR arrangement mode.The opposite rotation mode of the double wind turbines can effectively improve the variation of main shaft.When Y=1.3D,the C_mave of the double wind turbines is 5.9%higher than that of the single wind turbine,and the CV_ave is 19.26%lower.3)Further research shows that the outer surface pressure of the blade of double wind turbines is significantly higher than that of the blade of single wind turbine,thus increasing the pressure difference between the inner and outer surface and the aerodynamic load of the blade.At the same time,the uneven load in the upper and lower wind zone of the blade is improved to some extent.Set up a double wind turbines test bench to study the voltage and power value of the load at both ends of the double wind turbines connection.The experimental results show that the closer the distance between the double wind turbines is,the greater voltage and power values at both ends of the CFR-2 load are,and are larger than the voltage and power values at both ends of the load connected by a single wind turbine.4)The aerodynamic performance and load variation of three wind turbines and multiple wind turbines are studied.The results show that the best gain effect can be obtained by the arrangement of the three wind turbines according to the“fish swarm effect”.Under the condition of tight arrangement,the C_mave of the three wind turbines arranged in the way of X=1.8D-2D,Y=1.6D and CW3 increased by 5.53%,while the CV_ave value increased by 1.27%at least.The optimal arrangement spacing of the three wind turbines with nontight arrangement is X=3D and Y=2D,the normalized coefficient of torque and variation are 1.069 and 1.001respectively for CW3.In the arrangement of the four wind turbines,the rear double wind turbines limit the wake development of the front wind turbine and reduce its aerodynamic performance;in a given area,a maximum of eight wind turbines are arranged with X=2D and Y=1.6D,with a C_mnor value of 0.81 and a CV_nor value of 1.36.