| Wind energy is a kind of renewable clean energy,and its large-scale application technology has matured day by day,and wind power generation is one of the fastest developing and most potential new energy technology,and it is one of the most suitable clean power generation methods in line with the national conditions of energy development in China.Wind turbine is the key component of converting wind energy into electric energy in wind power generation.At present,most wind turbines used in engineering rely on the way of lifting force on their blades,capture the kinetic energy of atmospheric flow and convert it into mechanical energy,and then turn it into electric energy through generator.According to the direction of wind turbine rotating shaft,wind turbine can be divided into horizontal axis wind turbine and vertical axis wind turbine.Compared with the horizontal axis wind turbine with relatively mature technology and wide application,the research and development of large vertical axis wind turbine is relatively lagged behind,the commercialization degree is low,and the market share is small.Because the flow field structure of vertical-axis wind turbine is more complicated than that of horizontal-axis wind turbine,it is not suitable for the analysis and design of vertical-axis wind turbine by traditional theory.The theoretical and practical operation efficiency of the horizontal shaft wind turbine designed by the traditional theory is higher than that of the vertical axis.This has also become a large vertical axis wind turbine long-term development of an important reason.However,horizontal axis wind turbines,which are widely promoted in China,do not show outstanding advantages in terms of power generation costs,and power generation enterprises still need to rely on policy subsidies to survive.In order to improve the working efficiency and reduce the cost of power generation,horizontal axis wind turbines develop towards large-scale and further improvement of their functions,and at the same time gradually increase their construction,installation and maintenance costs.The cost of horizontal axis wind power generation remains high.It can be said that the relative high efficiency of horizontal axis wind power generation is at the expense of its high cost.Relative horizontal shaft wind turbine "high above","head weight","swing head upwind","variable propeller speed","gear box speed to generate electricity" and other technical features,vertical shaft wind turbine with no need to adjust the wind direction,generators,The equipment such as gearbox can be placed on the ground,which avoids many inherent defects in the structure of horizontal shaft wind turbine.The in-depth study on it is expected to significantly improve its operating efficiency and reduce the production cost and operating cost of wind turbines.Thus more economical access to the energy provided by the wind.In this paper,a wheel-rail vertical axis wind turbine based on Magnus effect is studied.On the basis of the overall scheme,the technical characteristics of the wind turbine are analyzed in detail and the feasibility study is carried out.The technical characteristics of the scheme and the horizontal axis wind turbine and the same type vertical axis wind turbine are systematically compared and analyzed.It is considered that the wind turbine is a kind of wind power generation mode which is expected to reduce the cost of power generation greatly and has great potential for development.In this paper,the key technology of wheel-rail wind turbine based on Magnus effect is studied systematically.This paper is divided into five chapters:In the first chapter,the general situation of wind power generation at home and abroad is introduced,and the basic equipment of wind power generation-wind turbine is systematically combed.A vertical-axis wind turbine based on Magnus effect,which has not been paid much attention,is studied systematically.In this paper,the performance and working characteristics of various wind turbines are compared from different classification angles.It is considered that the wheel-rail vertical axis wind turbine based on Magnus effect has unique advantages and has a good prospect for development.Starting from the principle of Magnus effect and from the point of view of the motion mechanism of vertical axis wind turbine,this paper introduces the research status of cylindrical flow around flow theory,the prediction method of aerodynamic performance of wind turbine and the general situation of research on Magnus wind turbine.Based on the rethinking of the concept of Magnus wind power generation,the engineering significance of Magnus wind turbine is analyzed and studied.It is considered that further theoretical research,numerical calculation and experimental analysis are of great theoretical value and engineering guiding significance.In the second chapter,a cylindrical thin-wall cylindrical blade airfoil is used instead of the conventional vertical axis wind turbine streamline airfoil,and the concept of the Magnus wheel-rail type wind turbine is put forward,and the mathematical model of the Magnus wind turbine is given.Based on the theory of the circular flow around the cylinder,the motion characteristics and the mechanism of the Magnus wind turbine are analyzed systematically,and the relationship between the effective driving force and the output torque and the azimuth angle in the model is derived.The variation trend of the Magnus effect of the cylindrical blade and the way to maximize the power of the Magnus are analyzed,in that system study of the self-conversion point of the cylindrical blade of the vertical axis wind turbine with the Magnus effect and its azimuth angle and its effective drive torque,In ord to achieve that maximum effective drive torque and the minimum drive energy(control blade rotation speed and acceleration)required by the cylindrical blade,the optimal operation control strategy of the cylindrical blade of the Magnus effeet wind turbine is put forward.In chapter 3,the theoretical model of Magnus wind turbine with double actuators and multi-flow tubes is presented.The model is mainly used to calculate and predict the aerodynamic load and performance of Magnus wind turbine.It is considered that the aerodynamic load and performance of the Magnus wind turbine depends on the flow field structure passing through the swept surface of the blade twice.The difference between up-wind induced velocity and downwind-induced velocity of rotor and the relationship between the difference and blade tip-speed ratio are analyzed.The difference increases with the increase of tip-speed ratio.This problem can be solved by means of double-actuating disk multi-flow tube method.The aerodynamic characteristics of vane in upwind region and downwind region are obtained by means of double actuating disk multi-flow tube model and the principle of series double actuating disk under local flow condition.According to the Reynolds number and local angle of attack,the aerodynamic characteristics of vane in upwind region and downwind region are obtained respectively.The aerodynamic load of the updraft rotor is larger than that of the downwind rotor due to the change of induced velocity.The total torque and power of the rotor are obtained by calculating the torque and power of the rotor in the upwind region and downwind region respectively.At the same time,the aerodynamic load distribution of blade with special phase is obtained,and the prediction precision of aerodynamic load and performance is improved.In chapter 4,based on the mathematical model of Magnus wind turbine proposed in chapter 2,the numerical simulation of a single cylinder blade is carried out,and the Magnus effect is verified from a virtual point of view,and the Magnus theoretical lift of a single cylindrical blade is calculated.The simulation results show that Magnus lift reaches its limit when the circumferential velocity of the cylinder reaches four times the wind speed of the incoming flow.This conclusion not only verifies the theoretical model of chapter 2,but also verifies the theoretical analysis,prediction and experimental results of Magnus lift limit made by Plant several decades ago.The simulation is in good agreement with the theoretical and experimental results.In the fifth chapter,the whole blade simulation numerical simulation is carried out according to the two-dimensional model of the whole machine.The flow field of the wind turbine is simulated from the regional motion model and the dynamic grid model,and the advantages and disadvantages of the two models are analyzed and eompared.The results show that the dynamic grid model can be closer to the actual situation of the wind turbine.From the macro point of view,we can see the difference of the output torque calculated by different models.In addition,in order to observe the actual working condition of each blade in the whole machine model,the single blade in the whole machine model is simulated by "high speed photography",and the force and torque of the blade at different special points are obtained.The motion characteristics of the whole machine are analyzed.In summary,this paper breaks through the traditional theory,combined with the existing technology,gives a new principle and method of innovative optimization design of a new vertical axis wind turbine.Combined with modem computer simulation and numerical calculation techniques,the verification of theory is carried out from two aspects of theoretical analysis and numerical simulation and computational analysis,and the research conclusions and achievements which are of great significance to engineering practice are obtained. |
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