A Study On The Improvements Of A Wind Turbine Blade Based On Magnus Effect

With the social and economic development and the improvement of people’sliving standards, demand for energy increased dramatically, leading toover-exploitation of coal, oil and other primary energy applications, mankind isabout to face the enormous pressure of environmental problems caused by theenergy consumption. Therefore, new energy issues become the focus of the strategicneeds of the world’s long-term development planning. Wind energy is the mostmature renewable energy. As a key component of the wind power generationequipment, blades’ aerodynamic has important influence to power generationefficiency. As the power of wind turbine increasing, longer wind blades were need,at the same time how to ensure that optimize loads, reduce weight, enhance theadaptability to environment friendly and transport facilitation will becomeresearching hot topic of blade technology. With the increase of unit capacity of windturbine, size increasing of the unit, the blades are getting longer and longer, and inorder to enable it to capture the wind energy well the blade torsion angle becomegreater, which not only makes the design and manufacture of the blade moredifficult but also heighten the blade’s sensitivity to the attack angle and lead to theinstability of turbine output power. What’s more, the upsizing of blades brings thegreatly inconvenience of transportation and maintenance, which makes thetraditional blades become more and more difficult to support the rapidlydevelopment of the wind turbine. In this thesis, a new type of wind turbine bladewas studied, which integrated Magnus effect theory and advantage of airfoil.The FLUENT software was used to study the flow field changes of rotatingcylinder in Magnus wind blade and it’s lift/resistance characteristic at high Reynoldsnumber, and the rule of influence by flow velocity, rotating speed and cylinderdiameter was also analyzed, which has concluded that the most importantparameters in all those affact the Magnus blades characteristic can be summarized asthe Reynolds number and thetip-speed-ratio, and the rule of influence is alsoanalyzed. Theoretical analysis of the blade lift-drag ratio effect on the performanceof the wind turbine has been investigated. The studies found the problems of the theMagnus blade when applied to a horizontal axis wind turbine.The variation of the flow field of Magnus wind blade within different Reynoldsnumber and thetip-speed-ratio was studied and the causes of the morphologicalchanges of the flow field was also analyzed; The formation mechanism of the resistance of Magnus bladess was studied and the constraints of its lift-to-drag ratioimprovement was derived; The influence law of flow field morphology to theMagnus blades lift/resistance characteristic was studied, and the variation law oflift-to-drag ratio with changes of the position of the front stagnation point and thetrailing vortex was obtained, which provides theoretical support for the the Magnusblades improvement research.Analyzed principle of resistance formation when cylinder rotated in flow field,then proposed two programs to reduce the rotating cylindrical resistance; designedtwo programs improving structure characteristic for Magnus wind blade, which wereincreasing the head structure and the tail structure.; analyzed the impact of the flowfield by different head shape structures; then, influence of aerodynamic performanceby different parameters of tail structure were investigated, according to the results,optimized parameters of the new blade; at last, variation of lift and drag coefficientof the new blade by changing flow velocity, rotating speed, attack angle peripheralspeed to flow velocity ratio, Re numbers were investigated.Designed a testing system used to measure aerodynamic performance of theMagnus type wind turbine blade, then experimental studied lift and drag coefficientof the new wind blades by the system; analyzed the experimental error according tocomparing the simulation results.An improved Magnus horizontal axis wind turbine geometric model wasdesigned based on improved Magnus blades, and mathematical calculations modelof improved Magnus horizontal axis wind turbine was studied by using bladeelement momentum while the variation law of the turbine aerodynamic performancewithin different parameters was studied based on this model. In addition, the powercharacteristics, torque characteristics and thrust characteristics of improved Magnuswind turbine were analyzed, and a comparative analysis with horizontal axis windturbine consisting of traditional airfoil NACA0018and Magnus horizontal axis windmachine was conducted, which has obtained the advantage of improved Magnuswind turbine compared to the other two wind turbine.In summary, a improvement wind turbine blade based on the Magnus effect hadbeen investigated in this thesis, the lift-to-drag ratio of the blade was exceed40,47%increased compared to the Magnus wind blade; at the same time, compared to theconventional airfoil blade, the improvement wind turbine blade had a better angle ofinsensitivity of attack. The improved Magnus wind turbine based on this windturbine blade has high wind energy utilization and better self-starting performance,and its power output is more stable, the blades can adopt the form of a straight bladeat the same time, what makes the design and production of the blade moer modular. What is more, the difficulty of blade design and manufacture as well astransportation and maintenance costs are also reduced. Horizontal axis wind turbineconstituted of the improvement bladese has a better aerodynamic performanceaccording to numerical study, it is suitable for large and medium-sized horizontalaxis wind turbine construction, and also can be applied to special wind turbinedevelopment in areas of low wind speed and poor wind energy resource.