| With the promotion of social development by industrial revolution,the environment and resources for human survival have been greatly threatened.Therefore,countries around the world are vigorously promoting renewable and clean energy.Wind energy comes from solar energy and is widely favored by people.The use of wind energy is to convert it into mechanical energy and then into electric energy.Wind turbine is the device to realize the use of wind energy,which has two kinds of horizontal axis and vertical axis.At present,the horizontal axis wind turbine power generation technology has been quite mature,but due to the disadvantages of high cost and difficult installation and maintenance,most of the related technology research has stagnated.The vertical axis wind turbine has the advantages of strong self-starting ability,simple structure,easy maintenance,strong adaptability and no need of yaw device,which is more and more welcomed by researchers.Now,countries have begun to invest more resources to explore vertical axis wind turbine power generation technology.In this paper,taking the rotary Savonius vertical axis wind turbine as the research object,the expression method of vertical axis wind turbine airfoil profile based on trigonometric function is proposed,and two new vertical axis wind turbine airfoils are designed according to the method,in order to explore the influence of blade shape on performance and obtain better blade shape to improve its wind energy utilization.Firstly,according to the main geometric data of wind turbine in reference wind tunnel test,the CFD method is used to establish the two-dimensional vertical axis wind turbine fluid calculation model,and through the comparison with wind tunnel test data and various verification work to ensure the reliability and accuracy of the simulation.Then,by studying the influence of different blade types on the ordinary Savonius vertical axis wind turbine,the mathematical model of sine trigonometric function is proposed to express the blade type,and the optimized blade type is obtained successfully,which provides a new mathematical model and new blade type for the next research on the gyratory Savonius vertical axis wind turbine.Finally,the mathematical model of the optimized blade profile is reconstructed according to the research object of this paper.The mechanical characteristics of the traditional semi-circular blade profile and the two optimized blade profiles in terms of power coefficient and torque coefficient are compared and analyzed.The flow field characteristics of the wind turbine are analyzed and discussed based on the velocity distribution,pressure distribution and vorticity distribution of the wind turbine in the process of calculation convergence.The results show that the optimized blade sin2 can effectively improve the wind energy utilization of the rotary Savonius vertical axis wind turbine.In the environment of the incoming wind speed of 14 m / s,when the tip speed ratio is 1.3,the maximum power coefficient is 0.283,an increase of 0.039,an increase of about 16%;and when the tip speed ratio is as high as 1.8,the power coefficient is still high.This study provides a reference for blade selection of vertical axis wind turbine,and has a certain theoretical research significance and engineering application value for improving the power characteristics of vertical axis wind turbine. |
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