Wind Power Collection Characteristics Research On Low Speed Wind With Converging-diverging Structure

According to the current wind power generation technology,the starting wind speed of most wind turbines is above 3m/s,which makes it difficult for the low-speed wind below 3m/s to be utilized effectively.In this paper,combining with numerical simulation and experimental verification,the acceleration characteristics of converging-diverging wind accelerating duct on low-speed wind gathering is analyzed,and the influence that the inlet and outlet angle changing have on the converging-diverging wind gathering structure is studied,and the influence law of convergence acceleration capability is analyzed at the meanwhile.The main research contents are shown as follow.(1)Firstly,the paper summarizes and discusses the work of scholars at home and abroad on the acceleration characteristics of wind gathering structure.And based on the continuity equation and momentum equation,the basic principle of wind energy convergence is analyzed,which shows that the angle characteristics of the wind gathering device have an important influence on its wind gathering capacity.At the meanwhile,combined with the distribution characteristics in urban wind field that the wind speed is low and uneven,the method of weighted average is used to calculate the average wind speed,and this method is also applied in the evaluation of internal flow field in the pipeline wind gathering duct.(2)Aiming at the converging structure and the diverging structure,and basing on the method of numerical simulation,the acceleration characteristics of wind gathering under uniform low-speed wind are investigated respectively.By analyzing the law of influence that the angle characteristics have on the acceleration capacity of wind gathering with two kinds of structures,it shows that when the angles of converging structure and diverging structure are small their wind gathering capacities are remarkable.When the angle parameter of converging structure is between 19° and 30°,the inflow velocity can be increased by 6%,and the inflow velocity can be increased by 16% when the angle of diverging structure is about 15°.By analyzing the influence that the throat length have on the air gathering capacity of the converging-diverging model,it is shown that an appropriate throat length can weaken the interaction between inlet and outlet wakes and could improve the air gathering capacity of the model.(3)On the basis of the previous research above,the converging-diverging wind gathering model is constructed.And the distribution characteristics of flow field in the converging-diverging wind gathering structure under uniform low-speed wind conditions are also investigated,and the influence of the model outlet angle change have on the acceleration capacity of wind gathering is discussed.Combining with the method of experiment and numerical simulation,it shows that the converging-diverging model can increase the velocity of low wind speed inflow by 33% when the outlet angle is about 15 degrees,which is higher than the sum of the maximum acceleration ratio of the single converging structure and the single diverging structure.In this paper,the single acceleration characteristics and coupling acceleration characteristics of each segment of the converging-diverging model is analyzed,and the influence law that the inlet and outlet angle change have on the gathering capacity is studied,on this basis,a dislocation negative pressure suction model is proposed,which provides a new idea for the study of wind gathering.