The horizontal axis wind turbine (HAWT) blades rotation in the steady wind flow is considered. We discuss the problem of determining the blade twist which could guarantee the maximum value of the power coefficient. We...The horizontal axis wind turbine (HAWT) blades rotation in the steady wind flow is considered. We discuss the problem of determining the blade twist which could guarantee the maximum value of the power coefficient. We define the blade twist as the technological turn of sections of blade around its axis. This turn changes the effective pitch angle of turbine blade along its length. For description of aerodynamic load upon the blades we used the quasi-steady approach. Air velocities of centers of pressure of blade sections are represented when taking into account components induced by flow and vortex. We reduced the functional maximization problem to find the maximum of non-dimensional function. This function is given by Riemann integral depending on section pitch angle and tip speed ratio. We suggested the algorithm for solving the problem under consideration for a given blade shape.展开更多
A dynamic model for simulating behavior of a horizontal axis wind turbine (HAWT) with differential planetary gearbox is developed. The aerodynamic load applied to the wind turbine connected with the carrier is describ...A dynamic model for simulating behavior of a horizontal axis wind turbine (HAWT) with differential planetary gearbox is developed. The aerodynamic load applied to the wind turbine connected with the carrier is described using the quasi-steady approach. The control torque is assumed to be applied to the external ring of the gearbox. Steady regimes of the device are analyzed, and their stability is studied. For the case of constant control torque, power costs are estimated required for preserving constant angular speed of the generator.展开更多
Even though wind energy is a deep-rooted technology, but not yet mature and hence there are bounteous scopes for improvement to reduce the cost of wind energy. An experimental investigation has been carried out on 1:2...Even though wind energy is a deep-rooted technology, but not yet mature and hence there are bounteous scopes for improvement to reduce the cost of wind energy. An experimental investigation has been carried out on 1:25 scaled S809 aerofoil blade featuring boundary layer fence at various span wise location. Quantifying electrical power obtained by rotation of wind turbine rotor coupled with dynamic testing system. A baseline model with no flow control and an upgraded model with detachable boundary layer fence have been studied in the wind tunnel. For upgraded model, fences were placed along the location of 40% to 90% of the blade span. The rotor blades are then tested dynamically in wind tunnel at open terrain condition for 7 m/s, 9 m/s and 11 m/s velocities. In order to study the effect of boundary layer fence test has been carried out in the low speed wind tunnel having test section of size 0.9 m × 1.2 m × 2 m. Scope corder DL 750 is used to measure time varying voltage and proximity sensor with its compatible display unit is used to measure the rotor RPM. The flow behaviour was found to be considerably favourable from conventional rotor blades. Installation of fence has been found promising for increased energy extraction from air column by controlling the three dimensional span wise flow. Results demonstrate the potential of the proposed model which can obtain a maximum of about 11.8% increase in the power. In addition, the significance of the location of wing fence and blade pitch angle has been analysed.展开更多
文摘The horizontal axis wind turbine (HAWT) blades rotation in the steady wind flow is considered. We discuss the problem of determining the blade twist which could guarantee the maximum value of the power coefficient. We define the blade twist as the technological turn of sections of blade around its axis. This turn changes the effective pitch angle of turbine blade along its length. For description of aerodynamic load upon the blades we used the quasi-steady approach. Air velocities of centers of pressure of blade sections are represented when taking into account components induced by flow and vortex. We reduced the functional maximization problem to find the maximum of non-dimensional function. This function is given by Riemann integral depending on section pitch angle and tip speed ratio. We suggested the algorithm for solving the problem under consideration for a given blade shape.
文摘A dynamic model for simulating behavior of a horizontal axis wind turbine (HAWT) with differential planetary gearbox is developed. The aerodynamic load applied to the wind turbine connected with the carrier is described using the quasi-steady approach. The control torque is assumed to be applied to the external ring of the gearbox. Steady regimes of the device are analyzed, and their stability is studied. For the case of constant control torque, power costs are estimated required for preserving constant angular speed of the generator.
文摘Even though wind energy is a deep-rooted technology, but not yet mature and hence there are bounteous scopes for improvement to reduce the cost of wind energy. An experimental investigation has been carried out on 1:25 scaled S809 aerofoil blade featuring boundary layer fence at various span wise location. Quantifying electrical power obtained by rotation of wind turbine rotor coupled with dynamic testing system. A baseline model with no flow control and an upgraded model with detachable boundary layer fence have been studied in the wind tunnel. For upgraded model, fences were placed along the location of 40% to 90% of the blade span. The rotor blades are then tested dynamically in wind tunnel at open terrain condition for 7 m/s, 9 m/s and 11 m/s velocities. In order to study the effect of boundary layer fence test has been carried out in the low speed wind tunnel having test section of size 0.9 m × 1.2 m × 2 m. Scope corder DL 750 is used to measure time varying voltage and proximity sensor with its compatible display unit is used to measure the rotor RPM. The flow behaviour was found to be considerably favourable from conventional rotor blades. Installation of fence has been found promising for increased energy extraction from air column by controlling the three dimensional span wise flow. Results demonstrate the potential of the proposed model which can obtain a maximum of about 11.8% increase in the power. In addition, the significance of the location of wing fence and blade pitch angle has been analysed.
文摘水平轴风力机尾流可显著影响风场下游风力机组气动特性,但传统基于数学或致动模型的尾流分析方法难以获得风力机尾流精细涡结构特征,且忽略了真实湍流环境的影响。该文通过计算流体力学方法开展全尺寸美国可再生能源实验室(national renewable energy laboratory,NREL)5 MW风力机在湍流风场下尾流气动特性研究规律,同时考虑风力机在湍流风下的变转速控制。结果表明,风力机输出功率随湍流风的波动而变化,而适当的转速控制可更好地提取风能;湍流风有助于加速尾流速度亏损的恢复;尾流横、纵向蜿蜒与湍流风流向及垂向的波动正相关;叶尖涡的破裂可加速尾流区速度的恢复。
