High-efficiency ring-type vertical axis wind wheel, wind turbine and wind power generation system

Abstract

The present application relates to a kind of high-efficiency ring type vertical axis wind wheel, wind turbine and wind power generation system, wind wheel includes: ring type blade, main shaft, horizontal support and base, main shaft is vertically installed on base, there are several ring type blades along the circumferential direction of main shaft and are evenly arranged, horizontal support connects main shaft and ring type blade, ring type blade, main shaft and horizontal support synchronous rotation;Ring type blade is sequentially first variable cross-section blade, equal cross-section blade and second variable cross-section blade from top to bottom, first variable cross-section blade top is connected with main shaft by flange, second variable cross-section blade bottom is connected with main shaft by flange, equal cross-section blade is arranged in parallel with main shaft, equal cross-section blade is connected with main shaft by horizontal support.In the present application, the arc blade of ring type blade adopts variable cross-section design, let wind turbine base and main shaft bear blade gravity, while saving the construction cost of vertical axis wind turbine, improve wind energy utilization coefficient of wind turbine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind power generation, in particular to a vertical axis wind power generation device, and more particularly to a high-efficiency ring-type vertical axis wind power wheel, a wind turbine and a wind power generation system. BACKGROUND

[0002] For coastal islands, grassland pastoral areas, mountainous areas, plateau areas and remote rural areas where water resources are scarce and transportation is inconvenient, it is of great significance to utilize wind power generation according to local conditions.

[0003] However, the development of distributed wind power in rural areas faces a series of key technical problems. The commonly used horizontal axis wind turbine blades have high tip speed during rotation, and a large amount of tip vortex is generated at the tip of the blade, which not only reduces the aerodynamic performance of the wind turbine, but also produces a large amount of noise. The excessive aerodynamic noise during operation of the horizontal axis wind turbine affects the life of residents, and the aerodynamic performance of the wind turbine is poor in low wind speed environment. Therefore, for the low wind speed and high turbulence environment conditions of the distributed wind field in rural areas, a new type of wind turbine with high wind power generation efficiency and low noise pollution needs to be developed.

[0004] Compared with the large number of horizontal axis wind turbines on the market, the vertical axis wind turbine has the advantages of simple structure, flexible installation, convenient maintenance, small land occupation, safety and stability, low accident rate and low operating noise, which can improve the wind energy utilization efficiency in low wind speed areas, and its high efficiency can also meet the requirements of developing wind power in population gathering areas. Therefore, the vertical axis wind turbine is particularly suitable for distributed wind power development. The application of vertical axis wind turbine is earlier than that of horizontal axis wind turbine. In addition, compared with horizontal axis wind turbine, the wake recovery speed of vertical axis wind turbine is faster, which means that more wind turbines can be arranged in the same area. In summary, the vertical axis wind turbine is the best choice for rural distributed wind field.

[0005] Vertical axis wind turbine can be divided into drag type vertical axis wind turbine and lift type vertical axis wind turbine according to working principle. The wind energy utilization coefficient of drag type vertical axis wind turbine is low, generally not more than 0.3. The wind energy utilization coefficient of lift type vertical axis wind turbine is high, but there are still some problems. Common lift type vertical axis wind turbine includes Darrieus type vertical axis wind turbine and H type vertical axis wind turbine. The blade of Darrieus type vertical axis wind turbine is oval, although its wind energy utilization coefficient is high, but its effective wind sweeping area is small, which leads to relatively small single machine power generation. The relative wind sweeping area of H type vertical axis wind turbine is large, and the overall power generation is high, but the tip vortex is generated at both ends of the straight blade, which seriously reduces the aerodynamic performance of the blade, leading to low wind energy utilization coefficient of H type vertical axis wind turbine. In addition, the H type vertical axis wind turbine connects the main shaft and the blade through the cross support, which not only makes the weight of the blade only rely on the cross support, increases the construction cost of the cross support, but also greatly reduces the aerodynamic performance of the blade.

[0006] The existing vertical axis wind turbine has its own shortcomings, so it is urgent to design a high-efficiency vertical axis wind turbine with higher wind energy utilization coefficient and good operation in low wind speed and high turbulence environment. Unlike horizontal axis wind turbine, the present application adopts ring type blade, there is no blade tip position, which can prevent the generation of tip vortex. In addition, the rated speed of the present application is small during operation, and the smaller speed also makes the noise generated in the operation process of the present application smaller. Moreover, the present application adopts ring type blade, uses the arc-shaped blade at both ends of the blade to bear the weight of the blade, reduces the load of the cross support, can effectively reduce the number and size of the cross support, saves the construction cost of the vertical axis wind turbine, and improves the wind energy utilization coefficient of the wind turbine. SUMMARY

[0007] In view of the shortcomings of the prior art, the present application provides a high-efficiency ring type vertical axis wind turbine, wind turbine and wind power generation system. The present application adopts ring type blade, uses the arc-shaped blade at both ends of the blade to bear the weight of the blade, reduces the load of the cross support, can effectively reduce the number and size of the cross support, saves the construction cost of the vertical axis wind turbine, and improves the wind energy utilization coefficient of the wind turbine.

[0008] The technical means adopted by the present application are as follows:

[0009] A high-efficiency ring type vertical axis wind turbine, comprising: a ring type blade, a main shaft, a horizontal support and a base, the main shaft is vertically installed on the base, a plurality of ring type blades are uniformly arranged along the circumference of the main shaft, the horizontal support is used for connecting the main shaft and the ring type blade, and the ring type blade, the main shaft and the horizontal support rotate synchronously.

[0010] The ring-shaped blades are sequentially arranged from top to bottom as a first variable cross-section blade, a constant cross-section blade and a second variable cross-section blade, the top of the first variable cross-section blade is connected with the main shaft through a flange, the bottom of the second variable cross-section blade is connected with the main shaft through a flange, the constant cross-section blade is arranged in parallel with the main shaft and is connected with the main shaft through a horizontal support.

[0011] Further, the horizontal support is a cross brace made of glass fiber composite material and used for connecting the main shaft and the constant cross-section blade to improve the structural stability of the wind turbine.

[0012] Further, the horizontal support is a sling, the sling is a steel cable, a lifting ring is arranged on the flange of the constant cross-section blade and the main shaft, and the two ends of the sling are connected with the lifting rings to realize the connection between the main shaft and the constant cross-section blade.

[0013] Further, the chord length of the first variable cross-section blade gradually decreases with the increase of the radius of the wind turbine, and the chord length is 1.0-1.2 times of the chord length of the previous blade height every 10% increase of the blade height; the chord length of the second variable cross-section blade gradually increases with the decrease of the radius of the wind turbine, and the chord length is 1.0-1.2 times of the chord length of the previous blade height every 10% decrease of the blade height; the ratio of the width to the chord length of the first variable cross-section blade and the second variable cross-section blade is 0.12-0.25.

[0014] Further, the chord length and the width of the constant cross-section blade are constant from top to bottom, and the ratio of the chord length to the radius of the wind turbine is less than 0.25, and the ratio of the width to the chord length of the constant cross-section blade is 1.0-3.0.

[0015] Further, the chord length is the distance between two end points of the same horizontal line of the blade, and the radius of the wind turbine is the vertical distance from the main shaft to the connecting line of the two end points of the same horizontal line of the blade.

[0016] Further, metal structural members are embedded in the inside of the first variable cross-section blade, the constant cross-section blade, the second variable cross-section blade and the cross brace for reinforcing the structural strength, connecting the flange and installing the steel cable.

[0017] Further, the main shaft comprises a connecting shaft and a transmission shaft, the upper end of the transmission shaft is connected with the lower end of the connecting shaft through a shaft end flange, the lower end of the connecting shaft is connected with the end of the second variable cross-section blade, the upper end of the connecting shaft is connected with the top end of the first variable cross-section blade, and the middle part of the connecting shaft is connected with the constant cross-section blade through a horizontal support.

[0018] Further, bearings are arranged at the two ends of the transmission shaft, the gravity of the upper end part is transmitted to the rotating base through the bearings at the connecting position between the upper end of the transmission shaft and the lower end of the connecting shaft, and the bearings resist the rotational torque generated when the wind turbine rotates.

[0019] Further, the equal cross-section blades and the main shaft are connected through horizontal supports, and the horizontal supports arranged at the same level are located on the same horizontal line, the first variable cross-section blade and the equal cross-section blade are connected through flanges, the second variable cross-section blade and the equal cross-section blade are connected through flanges, and the horizontal supports are connected with the main shaft, so as to strengthen the structure of the connection.

[0020] Further, the cross supports and the equal cross-section blades are connected through flanges, and the cross supports and the main shaft are connected through flanges.

[0021] Further, the equal cross-section blades and the main shaft are connected through a plurality of steel cables, the steel cables are connected with the main shaft and the equal cross-section blades through lifting rings, and according to the structural strength of the fan, each lifting ring is connected with 1-2 steel cables; when the number of the ring-shaped blades arranged in the circumferential direction of the main shaft is greater than 3, the equal cross-section blades are connected through steel cables.

[0022] A high-efficiency ring-shaped vertical-axis wind turbine, comprising a generator and the high-efficiency ring-shaped vertical-axis wind turbine, and the generator is located between the transmission shaft and the base.

[0023] Further, the transmission shaft is connected with the generator rotor through a shaft coupling; in operation, the ring-shaped blades, the main shaft and the horizontal supports serve as a rotor, and the generator shell serves as a stator to generate electricity.

[0024] A wind power generation system, comprising a plurality of the high-efficiency ring-shaped vertical-axis wind turbines, and the high-efficiency ring-shaped vertical-axis wind turbines are connected in parallel.

[0025] Compared with the prior art, the high-efficiency ring-shaped vertical-axis wind turbine has the following advantages:

[0026] The high-efficiency ring-shaped vertical-axis wind turbine has a large wind sweeping area, a high wind energy utilization coefficient and a high single-machine power generation capacity. In the case that the height is consistent with the diameter, the wind energy utilization coefficient of the ring-shaped vertical-axis wind turbine adopting the high-efficiency ring-shaped vertical-axis wind turbine is increased by 35% compared with that of an H-shaped vertical-axis wind turbine, wherein the wind energy utilization coefficient of the straight blade part is increased by 45%, and the wind energy utilization coefficient of the arc-shaped blade part is increased by 25%. With the increase of the height, the length of the straight blade of the ring-shaped vertical-axis wind turbine also increases, and the percentage of the increase of the wind energy utilization coefficient of the ring-shaped vertical-axis wind turbine also increases.

[0027] Meanwhile, the arc-shaped blades adopt a variable cross-section design, the gravity of the blades is transmitted to the main shaft through the upper and lower arc-shaped blades, and the main shaft bears the gravity of the blades, so that the horizontal cross supports only need to bear the centrifugal force of the blades. The use of the steel cables further reduces the load of the horizontal cross supports, so that the horizontal cross supports can be designed to be light in weight, the construction cost of the horizontal cross supports is reduced, the resistance generated by the horizontal cross supports during high-speed rotation of the fan is reduced, and the wind energy utilization coefficient of the ring-shaped vertical-axis wind turbine is further improved.

[0028] In addition, the chord length and the width of the arc-shaped blade are increased synchronously with the decrease of the distance from the main shaft, which not only improves the aerodynamic performance of the blade and the power generation efficiency of the wind turbine, but also increases the structural strength of the arc-shaped blade, so that the large-sized blade can bear its own gravity.

[0029] Based on the above reasons, the present application can be widely popularized in the technical field of wind power generation and the like. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor based on these drawings.

[0031] Figure 1 is a perspective view of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0032] Figure 2 is a partial view of the middle part of the main shaft of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0033] Figure 3 is a partial view of the connection between the variable cross-section blade and the constant cross-section blade of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0034] Figure 4 is a partial view of the top part of the main shaft of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0035] Figure 5 is a partial view of the bottom part of the main shaft of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0036] Figure 6 is a partial view of the power generation mechanism of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0037] Figure 7 is a schematic view of the pre-embedded metal structural member inside the blade of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0038] Figure 8 is a schematic view of the chord length and the radius of the wind turbine of a high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0039] Figure 9 is a schematic view of the structure of a small high-efficiency ring-type vertical-axis wind turbine according to the present application.

[0040] In the figure: 1a, top flange; 1b, bottom flange; 2a, first variable cross-section blade; 2b, constant cross-section blade; 2c, second variable cross-section blade; 3a, connecting shaft; 3b, transmission shaft; 4, cross brace; 5, steel cable; 6, generator; 7, base; 8, main shaft connecting flange; 9, cross brace-blade connecting flange; 10, blade connecting flange; 11a, top connecting flange; 11b, bottom connecting flange; 12a, upper end flange; 12b, lower end flange; 13, transmission shaft sleeve; 14, bolted pair; 15, tapered roller bearing; 16, shaft sleeve bottom end cover; 17, double-pass stud; 18, double-disk coupling; 19, embedded metal rod; 20, embedded metal plate. DETAILED DESCRIPTION

[0041] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0042] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0043] Embodiment 1

[0044] As shown in Figure 1 The present application provides a high-efficiency ring-type vertical-axis wind turbine, mainly comprising a ring-type blade, a main shaft, a cross brace 4 and a base 7, the main shaft is vertically installed on the base 7, and a plurality of ring-type blades are uniformly arranged along the circumference of the main shaft. The ring-type blade, the main shaft and the cross brace 4 rotate synchronously. Figure 1 A schematic diagram of a wind turbine with two ring-type blades.

[0045] The annular blades, from top to bottom, consist of a first variable cross-section blade 2a, a constant cross-section blade 2b, and a second variable cross-section blade 2c. The top of the first variable cross-section blade 2a is connected to the main shaft via a flange, and the bottom of the second variable cross-section blade 2c is connected to the main shaft via a flange. The constant cross-section blade 2b is arranged parallel to the main shaft and is connected to the main shaft via a cross brace 4. The cross brace 4 is used to connect the main shaft and the constant cross-section blade 2b, further improving the structural stability of the wind turbine.

[0046] The chord lengths of the first variable cross-section blade 2a and the second variable cross-section blade 2c gradually decrease as the rotor radius increases. The chord length and width of the constant cross-section blade 2b remain constant from top to bottom, and the ratio of the chord length to the rotor radius remains constant.

[0047] In operation, the specific dimensions of the first and second variable cross-section blades remain consistent within the same wind turbine rotor. The width-to-chord length ratio of the variable cross-section blades remains constant, ranging from 0.12 to 0.25. The variable cross-section blades are divided into ten segments proportionally to the rotor radius. The end with the larger rotor radius in each segment is defined as the "head," and the end with the smaller rotor radius as the "tail." The chord length of the tail of each segment is 1.0 to 1.2 times that of the head. The height of the variable cross-section blades is related to the rotor radius, ranging from 0.1 to 1.0 times the rotor radius. Within the same wind turbine rotor, the chord length of the head of the variable cross-section blade segment with the largest rotor radius is consistent with that of the constant cross-section blade, both being less than 0.25 times the rotor radius. The width-to-chord length ratio of the constant cross-section blades is consistent with that of the variable cross-section blades. Their height is related to the rotor radius, ranging from 1.0 to 3.0 times the rotor radius.

[0048] Specifically, the rotor radius of the variable cross-section blade section varies at different heights. Therefore, at the same turbine rotational speed, the tip speed ratio of the variable cross-section blade section differs at different heights. As the rotor radius decreases, the tip speed ratio also gradually decreases. With a small tip speed ratio, blades with a larger chord length can capture more energy from the wind. Therefore, as the rotor radius decreases, the blade chord length also increases. Furthermore, because the root of the variable cross-section blade needs to bear a greater load, the design of the variable cross-section blade chord length gradually increasing with the decrease of the rotor radius also results in higher root strength.

[0049] Among them, such as Figure 8 As shown, the chord length is the distance between the two ends of the same horizontal line of the blade, and the rotor radius is the perpendicular distance from the main axis to the line connecting the two ends of the same horizontal line of the blade.

[0050] Metal structural components are pre-embedded at both ends of the first variable cross-section blade 2a, the constant cross-section blade 2b, the second variable cross-section blade 2c, and the cross brace 4 to enhance structural strength, connect flanges, and install steel cables 5.

[0051] The main shaft comprises a connecting shaft 3a and a transmission shaft 3b, the upper end of the transmission shaft 3b is connected with the lower end of the connecting shaft 3a through a shaft end flange 12a, the lower end of the connecting shaft 3a is connected with the end of the second variable cross-section blade 2c, the upper end of the connecting shaft 3a is connected with the top end of the first variable cross-section blade 2a, and the middle part of the connecting shaft 3a is connected with the constant cross-section blade 2b through a cross brace 4. The cross brace mainly bears the centrifugal force generated when the wind wheel rotates at a high speed in the present application, and prevents the wind wheel from being damaged due to excessively high rotating speed. In addition, the cross brace is an effective method to increase the strength of the blade. The maximum shear stress and the maximum bending moment acting on the blade are related to the distance between the cross braces. The smaller the distance between the cross braces, the smaller the maximum shear stress and the maximum bending moment. When the distance between the cross braces is reduced by 50%, the maximum shear stress is reduced by 50%, and the maximum bending moment is reduced by 75%.

[0052] Specifically, the connecting shaft 3a is a hollow shaft, flanges are arranged at the upper end and the lower end of the connecting shaft, the upper end of the connecting shaft is connected with the top end of the first variable cross-section blade 2a, and the lower end of the connecting shaft is connected with the end of the second variable cross-section blade 2c.

[0053] The constant cross-section blade 2b is connected with the main shaft through the cross brace 4, and the cross braces 4 arranged at the same level are located on the same horizontal line. Figure 2 For the connection between the connecting shaft 3a and the cross brace 4, as shown in the figure, each cross brace 4 is bolted with the connecting shaft 3a through the main shaft connecting flange 8. Figure 3 For the connection between the cross brace 4, the variable cross-section blade and the constant cross-section blade 2b, as shown in the figure, the variable cross-section blade is bolted with the constant cross-section blade 2b through the blade connecting flange 10, and the connection between the main shaft and the blade is strengthened by the cross brace 4 to improve the structural stability. In addition, the cross brace 4 is connected with the variable cross-section blade through the variable cross-section blade connecting flange 11. Figure 1 Each constant cross-section blade 2b is connected with three cross braces 4 through the cross brace-blade connecting flange 9.

[0054] In combination with the above, Figure 3 and Figure 4 The main shaft connecting flange 8 at the middle of the connecting shaft 3a is provided with a lifting ring, and the cross brace-blade connecting flange 9 at the two ends of the constant cross-section blade is provided with a lifting ring. The two ends of the steel cable 5 are connected with the lifting rings at the two positions respectively, so as to complete the oblique steel cable fixing of the main shaft and the constant cross-section blade 2b. In addition, according to the structural strength requirement of the wind turbine, each of the above lifting rings is connected with 1-2 steel cables 5. The steel cable can convert the centrifugal force of the blade in the transverse direction into the vertical force, reduce the influence of the centrifugal force on the blade, and improve the strength of the blade.

[0055] In the specific implementation, in order to improve the strength of the cross brace 4 and thus enhance the reliability of the overall structure, as shown in the figure, Figure 7 metal plates 20 are embedded at the two ends of the cross brace 4, and a steel pipe is embedded in the cross brace 4. The two ends of the steel pipe are fixed with the embedded metal plates 20 through welding.

[0056] In practice, when the number of annular blades evenly arranged around the main shaft is greater than 3, lifting rings are installed on the flanges at the upper end, lower end and bisection point of the blade 2b with equal cross-section. Steel cables are installed on the lifting rings and are horizontally connected to the lifting rings of the adjacent blades with equal cross-section, which further improves the stability of the wind turbine.

[0057] Figure 4 , Figure 5 These figures illustrate the connections between the connecting shaft 3a and the first variable cross-section blade 2a, and between the connecting shaft 3a and the second variable cross-section blade 2c, respectively. As shown, a top connecting flange 11a is installed on the top of the first variable cross-section blade 2a, and an upper flange 12a is installed on the top of the connecting shaft 3a. The top connecting flange 11a and the upper flange 12a are connected through the top flange 1a, thus fixing the connecting shaft 3a to the first constant cross-section blade 2b. All flanges are connected to their respective components using bolts. Similarly, a bottom connecting flange 11b is installed at the bottom of the second variable cross-section blade 2c, and a lower flange 12b is installed at the bottom of the connecting shaft 3a. The bottom connecting flange 11b and the lower flange 12b are connected through the bottom flange 1b, thus fixing the connecting shaft 3a to the second constant cross-section blade 2b. All flanges are connected to their respective components using bolts.

[0058] In specific implementation, as a preferred embodiment of the present invention, all fan blades and cross braces 4 are made of glass fiber composite material, connecting shaft 3a is made of 304 stainless steel, transmission shaft 3b is made of 45 steel, all flanges and embedded structural components are made of 304 stainless steel, and the bolts connecting each flange are M8 and made of 304 stainless steel.

[0059] Example 2

[0060] This embodiment, based on Embodiment 1, proposes a high-efficiency annular vertical axis wind turbine. The annular vertical axis wind turbine includes an annular vertical axis wind turbine rotor and a generator, with the generator located between the annular blades and the base.

[0061] like Figure 6 As shown, the upper end of the drive shaft 3b is connected to the upper fan blade body via bolt connection 14. Tapered roller bearings 15 are respectively provided at the upper and lower ends of the drive shaft 3b. A bushing is provided outside the drive shaft 3b and the tapered roller bearings 15 to further effectively resist the rotational torque generated by the upper component. The lower end of the drive shaft 3b is connected to the bottom end cover 16 of the bushing, transmitting all the weight of the upper component downwards.

[0062] In order to leave enough space for the generator 6 at the bottom of the transmission shaft 3b, and to transfer the fan blade and transmission shaft 3b components to the ground by gravity, and to consider the convenience of installation, maintenance and self-locking, the base 7 is supported in the form of double through bolts 17, and a large diameter plate is provided at the bottom as a bottom plate. The generator 6 rotor shaft and the transmission shaft 3b extending upwards are connected by a double diaphragm coupling 18, and the double diaphragm coupling 18 can transmit large torque. The generator 6 is installed between the double diaphragm coupling 18 and the bottom plate, and the transmission shaft 3b is connected to the generator 6 rotor through the coupling. In operation, the ring-shaped blade, the main shaft and the cross brace 4 are designed as an integrated unit, the ring-shaped blade, the main shaft and the cross brace 4 serve as the rotor, and the generator 6 shell serves as the stator to generate electricity.

[0063] In specific implementation, as a preferred scheme of the present application, the transmission shaft 3b is locked by inserting a pin from the pin hole on the sleeve of the bottom end cover.

[0064] In specific implementation, as a preferred scheme of the present application, the engine shell is made of cast aluminum, the base 7 and the shaft sleeve bottom end cover 16 are made of 304 stainless steel, the transmission shaft 3b is made of aluminum alloy, and the tapered roller bearing 15 is made of bearing steel.

[0065] In order to further illustrate the technical scheme and technical effects of the present application, a high-efficiency ring-shaped vertical axis wind turbine of the present application is compared with existing vertical axis wind turbines. The wind turbine power generation capacity is used as the standard for evaluating the working performance of the wind turbine, and the wind turbine power generation capacity calculation formula is as follows:

[0066]

[0067] Among them, wherein P is the wind turbine power generation capacity, is the air density, A is the swept area, V is the wind speed, is the wind energy utilization coefficient.

[0068] The swept area calculation formula of the Darrieus type vertical axis wind turbine is:

[0069]

[0070] The swept area calculation formula of the H-type vertical axis wind turbine is:

[0071]

[0072] The swept area calculation formula of the U-type vertical axis wind turbine is:

[0073]

[0074] wherein, S A is the swept area of the fan, D D is the diameter of the fan wheel, R R is the radius of the fan wheel, H H is the height of the fan wheel.

[0075] In the case of a vertical axis fan with a fan wheel diameter and a fan wheel height product of 25 m^2, a wind speed of 12 m / s, and an air density of 1.225 kg / m 3 , numerical simulation is performed on three different types of vertical axis fans, namely Darrieus type, H type, and U type, and the power generation of the three types of vertical axis fans is compared according to the results of the numerical simulation. The height-to-diameter ratio of the Darrieus type and H type vertical axis fan is 1:1, and the height-to-diameter ratio of the ring type vertical axis fan is 41:18.

[0076] Table 1: Wind turbine parameters and important calculation results

[0077]

[0078] As can be seen from the table, in the case of a vertical axis fan with a fan wheel diameter and a fan wheel height product, a wind speed, and an air density remaining the same, the power generation of the ring type vertical axis fan is increased by 33.83% and 3.58% compared with the Darrieus type and H type vertical axis fans, respectively, and the wind energy utilization coefficient is increased by 3.73% and 22.13%, respectively.

[0079] Example 3

[0080] Based on Examples 1 and 2, this embodiment proposes a small high-efficiency ring type vertical axis wind turbine. The small wind turbine has a small diameter and height, resulting in a small blade chord length under a small chord diameter ratio, making it difficult for the high-efficiency ring type vertical axis wind turbine to start at low wind speed. To solve this problem, as shown in Figure 9 , the number of blades of the small high-efficiency ring type vertical axis wind turbine is increased. In the case of a single blade chord length remaining unchanged, increasing the number of blades can effectively improve the torque of the high-efficiency ring type vertical axis wind turbine at low wind speed and low speed, and greatly improve the starting ability of the high-efficiency ring type vertical axis wind turbine.

[0081] In addition, the small high-efficiency ring type vertical axis wind turbine has a small height, resulting in a small size of the ring type blade and a small centrifugal force acting on the blade, so the small high-efficiency ring type vertical axis wind turbine does not need to install a cross brace, but installs a sling instead of a cross brace. Different from Example 2, flanges are arranged at the top, end, and bisecting point of the equal-section blade and the main shaft, the flanges are provided with eye rings, and the sling is connected to the equal-section blade and the main shaft through the eye rings.

[0082] The reduction of the number of struts can not only reduce the manufacturing cost of the wind turbine, but also effectively improve the wind energy utilization coefficient of the wind turbine. Taking a double-blade vertical axis wind turbine as an example, as shown in Table 2, the wind energy utilization coefficient of a single blade of a small and efficient ring-type vertical axis wind turbine without struts is 0.2, and the total wind energy utilization coefficient is 0.4. When a set of struts is installed in the middle of the wind turbine, the wind energy utilization coefficient of a single blade of the wind turbine is reduced to 0.179, and the struts will generate negative torque during rotation, further reducing the wind energy utilization coefficient of the wind turbine, which results in that the total wind energy utilization coefficient of the wind turbine with struts is only 0.334.

[0083] Table 2 Comparison of small ring-type vertical axis wind turbines with and without struts

[0084]

[0085] Example 4

[0086] Based on Example 2 and Example 3, Example 4 gives a wind power generation system, which includes a plurality of high-efficiency ring-type vertical axis wind turbines as given in Example 2 or Example 3, and each ring-type vertical axis wind turbine is connected in parallel. For Example 4 of the present application, since its technical content corresponds to the above examples, the description is relatively simple, and the relevant similarities can be referred to the above examples, and will not be described in detail here.

[0087] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the above examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high efficiency ring type vertical axis windmill characterized in that, The application relates to a wind wheel structure. The ring-shaped blades, the main shaft and the horizontal support rotate synchronously. The ring-shaped blades are sequentially provided with a first variable cross-section blade, an equal cross-section blade and a second variable cross-section blade from top to bottom. The chord length of the first variable cross-section blade gradually decreases with the increase of the wind wheel radius. The chord length of the second variable cross-section blade gradually increases with the decrease of the wind wheel radius.

2. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The ratio of the width to the chord length of the first variable cross-section blade and the second variable cross-section blade is 0.12-0.

25.

3. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The main shaft comprises a connecting shaft and a transmission shaft.

4. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The horizontal support is a cross support made of glass fiber composite material.

5. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 or 4 wherein, The horizontal support is a sling.

6. A high efficiency ring type vertical axis wind turbine as claimed in claim 2 wherein, The chord length and the width of the equal cross-section blade are constant from top to bottom.

7. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The ratio of the chord length to the wind wheel radius is less than 0.

25.

8. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The ratio of the width to the chord length of the equal cross-section blade is 1.0-3.

0.

9. A high efficiency ring type vertical axis wind turbine as claimed in claim 2 wherein, The chord length is the distance between two end points of the same horizontal line of the ring-shaped blade. The wind wheel radius is the vertical distance from the main shaft to the connecting line of the two end points of the same horizontal line of the ring-shaped blade. The two ends of the first variable cross-section blade, the equal cross-section blade, the second variable cross-section blade and the cross support are pre-buried with metal structural members. The transmission shaft is provided with bearings at two ends. The horizontal support is connected between the equal cross-section blade and the main shaft. The cross support is connected between the equal cross-section blade and the main shaft. The cross support is connected between the equal cross-section blade and the main shaft.

10. A high efficiency ring type vertical axis wind turbine as claimed in claim 1 wherein, The equal-section blades are connected with the main shaft through a plurality of steel cables, the steel cables are connected with the main shaft and the equal-section blades through hangers, and each hanger is connected with 1-2 steel cables according to the structural strength of the fan; when the number of the ring-shaped blades arranged uniformly in the circumferential direction of the main shaft is greater than 3, the equal-section blades are connected through steel cables.

11. A high efficiency ring type vertical axis wind turbine, characterized by, The high-efficiency ring-shaped vertical-axis wind turbine according to any one of claims 1-10, and a generator located between the transmission shaft and the base.

12. A high efficiency ring type vertical axis wind turbine as claimed in claim 11 wherein, The transmission shaft is connected with a generator rotor through a shaft coupling; in operation, the ring-shaped blades, the main shaft and the horizontal support serve as a rotor, and the generator shell serves as a stator to generate electricity.

13. A wind power system characterized by The high-efficiency ring-shaped vertical-axis wind turbines according to claim 11 or claim 12 are connected in parallel.

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