Design And Research For Small Horizontal Axis Wind Turbine With Passive Speed Regulation

Bad effects to environment caused by using fossil fuels and the rapid running out of fossil fuels have been pushing mankind to seek clean and renewable energy resource as alternative one. Wind energy, which has been utilized by mankind for decades, has been considered the No.1 renewable energy source and receiving tremendous attentions since 1990s. Comparing to large wind turbines, the research on small wind turbine technologies have not received enough efforts, particularly small horizontal-axis wind turbines with passive speed regulation, such as passive yaw mechanism, even though it is recognized that these kinds of wind turbines have some advantages for personal family user. Based on these considerations, this paper will make a theoretical analysis and calculation for passive yaw mechanisms with tilting tail hinges and offset pivot axis, followed by a case study of a small horizontal-axis wind turbine design. Then a fluid-solid interaction simulation for blade and CFD simulation for the whole turbine will be made in the last part of this paper.This paper contains the following specific parts:(1) Background introduction. Introduction of several types of speed-regulation mechanisms for horizontal-axis wind turbines, especially for small wind turbines, and review of their latest development, which lead to the project aims and objectives.(2) Literature review. Analysis of tilting tail hinges and offset pivot axis methods as passive speed-regulation mechanisms, and their advantages against other approaches, which justify the author's choice for the case design study. A brief introduction to Computer Fluid Dynamics (CFD) and dispersing method are also reviewed due to their key role in the project.(3) Methodology (stage 1). Design of the global parameters of the case study wind turbine. Selection of aerofoil for the wind turbine blade. Theoretical analysis of the speed-regulation mechanism and synthesis of the relationship between the angles. And finally calculation of the non-linear equation and the angles in different wind speed using MATLAB.(4) Methodology (stage 2). According to the parameters and the theory of blade designing, this paper works out the point distribution of different blade sections and establishes different 3D models at various wind speeds.(5) Methodology (stage 3). Basing on the 3D models, this paper makes a fluid-solid interaction simulation and mode analyzing for blade with Workbench. These simulations prove that the designing of blade meet the requirement of the research.(6) Methodology (stage 4). This paper makes CFD simulation for wind turbines in four different wind speed situations. Through the simulation, we can get the values of aerodynamic torque and the states of air stream in different wind speeds. The correctness of design can be confirmed by comparing the simulation and the theoretical calculation.(7) Conclusion. Research of this paper proves that: the calculation method for angles and torques of tilting tail hinges & offset pivot axis system, put forward by this paper, is basically correct. The fluid-solid interaction method can simulate the working state of blade more truly. Small wind turbine designed by this paper can satisfy the design requirements of passive speed-regulation in certain range of wind speed.