Research On Power Generation Characteristic Of Vertical Axis Wind Turbine Based On The Windbreaks With Gathering Wind

The limitation of traditional fossil energy and the environmental problems caused by its use urgently need clean and sustainable new energy to replace it.Wind power generation using non-polluting,renewable and abundant wind energy has become one of the important means to solve the problem.Using the wind gathering type wind power generation technology,combined with wind gathering effect above the windbreaks and the VAWT(vertical axis wind turbine)has the advantage of low starting wind speed,no need for wind yaw device,simple structure installation and low noise,this paper puts forward an idea of installing VAWT in the suitable wind gathering position above the windbreaks for wind power generation.It can not only use wind gathering effect of windbreaks to enhance the power generation characteristics of VAWT,but also use VAWT to transform the wind energy above the windbreaks,slow down the recovery of wind speed behind the windbreaks,enhance the protection effect of the windbreaks,improve the effective protection area of the windbreaks.According to the fluid motion characteristics of VAWT and windbreaks,the Realizable 6)- model is selected as the governing model in this paper.By processing the windbreaks as the porous media model,using UDF to compile the speed at the inlet and the resistance source term of the windbreaks,the flow field of the windbreaks was established.The protection effect within the windbreaks and the wind gathering effect above the windbreaks were compared and analyzed under different width of the windbreaks.Based on the wind gathering effect of the windbreaks and the installation cost of the wind turbine,the optimal installation position of the VAWT was determined,the flow field of VAWT under the wind gathering effect in windbreaks is established by using the Moving Mesh Mode,the power generation characteristic of the VAWT under different tip speed ratio were compared and analyzed.The result shows that:(1)Under different width of the windbreaks,the wind speed variation law of the windbreaks at the same height is consistent;(2)The effective protection distance variation law at the different height of the windbreaks is consistent.The width of the windbreaks increased from 0.05 H to 2.5H,the effective protection distance of the windbreaks increased firstly,then decreased,and stabilized finally.When the windbreaks bandwidth is 1.0H,the effective protection distances of the windbreaks was the largest;(3)Under different windbreaks width,the variation law of wind speed at different height above the windbreaks is basically the same,when the height of the windbreaks increases from 1.25 H to1.75 H,the increase rate of maximum wind speed value of gathering wind above the windbreaks.Considering the installation cost of VAWT and the ratio of wind speed increase,this paper chooses the height of 1.75 H above the windbreaks to install the VAWT for wind energy generation;(4)With the increase of blade tip speed ratio,the azimuth angle of the maximum torque coefficient of a VAWT single blade increases all the time,the Cp reaches the maximum value when the blade tip speed ratio of the VAWT is 2.5;(5)Although the wind gathering effect above the windbreaks increases the wind speed,the Cp of the VAWT is higher than that of the non-windbreaks only when the width of the windbreaks is 1.5H and the blade tip speed ratio is 2.5,the Cp is lower than that of the non-windbreaks under other windbreaks bandwidth;(6)Under different windbreaks widths and blade tip speed ratio,the available generating capacity of the VAWT under the wind gathering effect of the windbreaks is significantly higher than that under the non-windbreaks.Under the parameters of VAWT in this paper,when the blade height is 500 mm and the blade tip speed ratio is 2.5,the available generating capacity under the 1.5H windbreaks width reaches 68.7W,which is 1.2 times higher than that of 31.1W under the non-windbreaks.The model and method established in this paper are helpful for the numerical simulation research of windbreaks and VAWT,it provide a new method for increasing the protection effect of windbreaks,and also provide a new application direction for the the combination of wind gathering power technology of the VAWT and natural objects.