A lift-type vertical axis wind turbine

Abstract

The present invention relates to a lift - type vertical - axis wind turbine, including airfoil blades. Local moving surfaces with a length of 70%c are symmetrically arranged at positions 4%c from the leading edge on the upper and lower surfaces of the airfoil blades, and the maximum speed of the moving surfaces can reach 7V ￥ , where: c is the chord length of the airfoil blade, and V ￥ is the incoming flow wind speed. The output power of the vertical - axis wind turbine with blades having local moving surfaces in the present invention has a more obvious improvement compared with that of the existing same - type wind turbines in the full tip - speed ratio range, and it can effectively enable this type of wind turbine to maintain a high wind - energy utilization efficiency with relatively small energy consumption requirements.

Description

Technical Field

[0001] The present invention relates to a wind turbine, and particularly to a lift-type vertical-axis wind turbine. Background Art

[0002] Carbon peak and carbon neutrality (referred to as "dual carbon" for short) are new development strategies adopted by human society to address global warming. The diversified utilization of renewable energy and carbon sink resources is of great significance for implementing the carbon peak and carbon neutrality strategies. Among renewable energies, wind energy is one of the most economical power generation resources, which is very environmentally friendly and clean, with rich, almost endless, and widely distributed wind energy. Developing wind power is of great significance for ensuring energy security, adjusting the energy structure, reducing environmental pollution, and achieving sustainable development.

[0003] A wind turbine converts wind energy into mechanical energy and then into electrical energy. According to the direction of the main shaft of the wind turbine, it can be divided into two types: horizontal-axis wind turbines and vertical-axis wind turbines. Horizontal-axis wind turbines have a longer development history and higher wind energy utilization efficiency. Compared with horizontal-axis wind turbines, vertical-axis wind turbines have simple processes, convenient maintenance, low noise, and do not require wind direction changes, making them more suitable for use in densely populated cities. Vertical-axis wind turbines can be further divided into lift-type vertical-axis wind turbines and drag-type wind turbines according to the working principle of the blades. A lift-type vertical-axis wind turbine (as shown in the appendix) uses the lift of the blades to do work and rotate, thereby converting wind energy into mechanical energy, and then generating electricity through a connected generator. The lift-type vertical-axis wind turbine has developed extremely rapidly and has an increasing market share, especially being widely used in cities. However, it has poor starting performance, and its wind energy utilization efficiency is still much lower than that of horizontal-axis wind turbines. Therefore, further improving the aerodynamic performance of the lift-type vertical-axis wind turbine is the key to its wider application. Figure 1 As shown in the appendix, it uses the lift of the blades to do work and rotate, thereby converting wind energy into mechanical energy, and then generating electricity through a connected generator. The lift-type vertical-axis wind turbine has developed extremely rapidly and has an increasing market share, especially being widely used in cities. However, it has poor starting performance, and its wind energy utilization efficiency is still much lower than that of horizontal-axis wind turbines. Therefore, further improving the aerodynamic performance of the lift-type vertical-axis wind turbine is the key to its wider application.

[0004] Currently, the widely adopted methods to improve the performance of vertical-axis wind turbines mostly use different means to improve the flow state on the blade surface, suppress or delay the separation of the surface boundary layer, thereby increasing the lift of the blade and reducing the drag, and enhancing the work performance of the blade. Currently, these methods can be divided into passive and active types according to whether external energy input is required. Among them, active control requires directly injecting appropriate disturbances into the flow environment to interact with the flow in the system to achieve the control purpose, such as jet flow, plasma excitation, etc. Since active control can adjust the excitation parameters according to actual needs to control the flow field, it usually has better effects than passive control technologies, and can flexibly adjust the control parameters according to environmental changes, enabling the wind turbine to maintain a relatively high wind energy conversion efficiency under different working conditions. Therefore, it has received extensive attention from researchers and engineering and technical personnel.

[0005] Most of the active control methods adopted at the present stage usually require a large amount of external energy input, so the energy consumption is high. In addition, research shows that when the blade operates at a low tip speed ratio (TSR), these methods can effectively improve the performance of the wind turbine because they can suppress the flow separation generated on the blade surface; while at a high tip speed ratio, there is no large separation state on the blade surface, and continuing to use these methods has little effect on the aerodynamic performance of the blade. Therefore, after deducting the external energy required for applying active control, the actual wind energy utilization efficiency C pnet of the wind turbine has a small increase compared with that of the traditional wind turbine, and sometimes even decreases. Summary of the Invention

[0006] In view of the defects existing in the current prior arts, the present invention proposes a new type of lift-type vertical axis wind turbine.

[0007] To achieve the above object, the technical solution of the present invention is: a lift-type vertical axis wind turbine, including airfoil blades, and local moving surfaces with a length of 70%c are symmetrically arranged at positions 4%c away from the leading edge on the upper and lower surfaces of the airfoil blades, and the maximum speed of the moving surfaces can reach 7V ￥ , where: c is the chord length of the airfoil blade, and V ￥ is the incoming flow wind speed.

[0008] Further, the left side of the moving surface is connected to a rotating roller, and the right side is connected to a tubular motor. When the tubular motor works, it directly drives the moving surface layer to generate a linear motion.

[0009] Further, the tubular motor includes an inner stator and an outer rotor. The inner stator is fixedly connected to the inside of the airfoil blade, the moving surface is wound around the periphery of the outer rotor, and the length of the outer rotor is greater than the width of the moving surface.

[0010] Further, an angle sensor is provided on the airfoil blade, and the angle sensor is connected to the tubular motor through a processor module.

[0011] Further, the angle sensor sends a signal to the processor module, and the processor module outputs a control signal to the tubular motor to control the local surface on the suction side of the airfoil blade to generate motion while keeping the moving surface on the pressure side stationary.

[0012] The beneficial effects of the present invention are:

[0013] The local surfaces on both sides of the wind turbine blade of the present invention are symmetrically arranged surface layers with a certain length that can move at a certain speed: when the blade rotates, it is ensured that the local surface on the suction side always moves in a uniform straight line at a certain speed, while the moving surface on the pressure side remains stationary. By adopting this intermittent control method, it is ensured that only the local surface on the suction side of the blade generates movement, thereby minimizing the consumption of external energy as much as possible. The form of local surface movement can directly input energy into the low-energy boundary layer near the solid wall, accelerate the flow of the fluid in the adjacent area, enhance the ability of the boundary layer to resist separation, thereby improving the lift-drag ratio of the blade, increasing its work performance, and the current research results show that the vertical-axis wind turbine with blades with local moving surfaces has a more obvious improvement in output power compared with the existing wind turbines of the same type in the full tip-speed ratio range, and can effectively achieve high wind energy utilization efficiency of this type of wind turbine with relatively small energy consumption requirements, and has broad application prospects. Description of the Drawings

[0014] Figure 1 is a schematic diagram of the impeller form of a lift-type vertical-axis wind turbine;

[0015] Figure 2 is a schematic diagram of the cross-sectional structure of the blade of a lift-type vertical-axis wind turbine with a local moving surface;

[0016] Figure 3 is a two-dimensional cross-sectional view of the impeller of a lift-type vertical-axis wind turbine with a local moving surface;

[0017] Figure 4 is the wind energy utilization rate (C pnet ) of the wind turbine of the present invention versus the tip-speed ratio (TSR) variation curve and the comparison results with wind turbines of the same type;

[0018] Figure 5 is a schematic diagram of the tubular motor structure;

[0019] Figure 6 is a schematic diagram of the control module. Detailed Embodiment

[0020] The present invention will be further described below in conjunction with the drawings and embodiments.

[0021] The present invention proposes a lift-type vertical-axis wind turbine with blades with local moving surfaces, as shown in Figure 1 , Figure 2, including an airfoil blade 1 and a rotating shaft 2. Two moving surfaces 3 with a length of 70%c (c is the chord length of the airfoil blade) are symmetrically arranged at a position 4%c from the leading edge on the upper and lower surfaces of the airfoil blade 1, and the maximum speed of the moving surface 3 reaches 7V ￥ (V ￥(is the incoming flow wind speed). The right end of the moving surface 3 is a tubular motor 4, and the left end is a rotating roller 5. The angle sensor monitors the angle through which the blade rotates. As Figure 3 shown in FIGS. 6, when the airfoil blade 1 is in the windward area, the angle sensor sends a signal to the processor module 6. The processor module 6 is directly connected to the tubular motor 4 to control the tubular motor 4 located inside the airfoil blade 1 (suction surface A) to start working. When the tubular motor 4 works, it directly drives the moving surface 3 to rotate; when the airfoil blade 1 is in the leeward area, the angle sensor transmits a signal to the processor module 6 to control the tubular motor 4 on the outside of the airfoil blade 1 (suction surface B) to start working.

[0022] As Figure 5 shown, the tubular motor 4 includes an inner stator 4-1 and an outer rotor 4-2. The inner stator 4-1 is fixedly connected to the inside of the airfoil blade 1, the moving surface 3 is wound around the periphery of the outer rotor 4-2, and the length of the outer rotor 4-2 is not less than the width of the moving surface 3.

[0023] The local surfaces on both sides of the wind turbine blade are symmetrically arranged surface layers with a certain length that can move at a certain speed (as Figure 2 shown): When the blade rotates, it is ensured that the local surface on the suction surface side always moves in a uniform straight line at a certain speed, while the moving surface on the pressure surface side remains stationary (as Figure 3 shown). By adopting this intermittent control method, it is ensured that only the local surface on the suction surface side of the blade generates motion, thereby minimizing the consumption of external energy as much as possible. The form of local surface motion can directly input energy into the low-energy boundary layer near the solid wall, accelerate the flow of the fluid in the adjacent area, enhance the ability of the boundary layer to resist separation, thereby improving the lift-drag ratio of the blade, increasing its work performance, and the current research results show that the output power of this vertical-axis wind turbine with blades with local moving surfaces is more significantly improved compared with existing wind turbines of the same type in the full tip-speed ratio range (as Figure 4 shown), and it can effectively achieve maintaining a high wind energy utilization efficiency of this type of wind turbine with relatively small energy consumption requirements, having broad application prospects.

Claims

1. A lift-type vertical axis wind turbine, comprising airfoil blades, Characterized in that: The upper and lower surfaces of the airfoil blade are symmetrically arranged with local moving surfaces of 70% c in length at a position 4% c from the leading edge, and the maximum speed of the moving surface can reach 7V ￥ , where: c is the chord length of the airfoil blade, and V ￥ is the incoming flow wind speed; when the blade rotates, the local surface on the suction surface side of the blade moves in a uniform straight line at a certain speed, while keeping the moving surface on the pressure surface side stationary, so as to reduce the consumption of external energy; the left side of the moving surface is connected to a rotating roller, and the right side is connected to a tubular motor. When the tubular motor works, it directly drives the moving surface layer to generate a linear motion; the tubular motor includes an inner stator and an outer rotor. The inner stator is fixedly connected to the inside of the airfoil blade. The moving surface is wound around the periphery of the outer rotor, and the length of the outer rotor is greater than the width of the moving surface; an angle sensor is provided on the airfoil blade, and the angle sensor is connected to the tubular motor through a processor module.

2. The lift-type vertical axis wind turbine according to claim 1, Characterized in that: The angle sensor sends a signal to the processor module, and the processor module outputs a control signal to the tubular motor to control the movement of the local surface on the suction surface side of the airfoil blade while keeping the moving surface on the pressure surface side stationary.

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