A ducted wind turbine

Abstract

This utility model discloses a ducted wind turbine, belonging to the field of new energy power generation technology. It includes a blade fixing shaft, with blades evenly installed on the outer wall of the blade fixing shaft. A central rotating shaft is fixedly installed on one side of the blade fixing shaft, and a generator is fixedly installed on the other side of the central rotating shaft. A junction box is installed inside the generator, and the junction box is connected to the outside via generator wires. A flow-guiding component for constraining and guiding airflow is provided on the outer wall of the central rotating shaft. By setting the flow-guiding component, the design of the outer duct structure can concentrate airflow and increase wind energy density during wind power generation, thereby improving the power generation efficiency of the wind turbine in low wind speed environments, reducing airflow escape, and constraining and guiding the airflow to reduce turbulence losses. This avoids the problems that natural wind is usually accompanied by turbulence, which can easily lead to blade vibration, reduced efficiency, and even fatigue damage.

Description

Technical Field

[0001] This utility model relates to the field of new energy power generation technology, and more specifically, it relates to a ducted wind turbine. Background Technology

[0002] Small wind turbines are small power generation devices that convert wind energy into electrical energy. They typically consist of a wind turbine, a generator, and a control system. The wind turbine rotates under the action of wind, converting wind energy into mechanical energy, which drives the generator to produce electricity. The speed controller ensures stable operation at different wind speeds, preventing damage to the equipment due to excessively high wind speeds and keeping it at a suitable height to obtain more wind energy. Small wind turbines are easy to install and highly flexible, making them suitable for remote areas far from the power grid. They can provide electricity for local residents' daily lives and small commercial activities, and can also be used in scenic spots, communication base stations, and other places to meet some of their electricity needs, reducing dependence on traditional electricity to a certain extent. They also have the advantages of being environmentally friendly and renewable.

[0003] However, existing small wind turbines in some low-wind-speed environments suffer from several drawbacks. Firstly, the energy density of wind energy is strongly correlated with wind speed. At low wind speeds, the energy density of wind energy itself is extremely low, meaning that even if the rotor can fully capture wind energy, the convertible mechanical energy is very limited. Secondly, the startup phase requires overcoming inherent resistance. When starting a wind turbine, the blades must first rotate and reach a certain speed. Under low-wind-speed conditions, the thrust of the airflow on the blades is small, and the generated torque may be less than the total resistance, making it difficult for the blades to start and thus difficult to drive the generator to generate electricity effectively. Thirdly, a deviation of the tip speed ratio from the optimal value leads to a decrease in aerodynamic efficiency. Each blade design has a corresponding "optimal tip speed ratio" at which the wind energy utilization coefficient is highest. However, under low-wind-speed conditions, the blade speed is limited by the wind speed and often cannot reach the optimal tip speed ratio. If the speed is too low (the tip speed ratio is too small), the blades' "interception" effect on the airflow is insufficient, and a large amount of airflow escapes through the blade gaps without being effectively converted. Simultaneously, at low speeds, the airflow around the blades easily forms a "stagnant zone," further weakening lift and increasing drag, leading to a sharp drop in aerodynamic efficiency.

[0004] In summary, small wind turbines are prone to problems such as difficulty in starting or low power generation efficiency when in low wind speed environments. To solve these problems, we propose a ducted wind turbine. Utility Model Content

[0005] To address the problems mentioned in the background section, this utility model provides the following technical solution: A ducted wind turbine includes a blade fixing shaft, blades are uniformly installed on the outer wall of the blade fixing shaft, an intermediate rotating shaft is fixedly installed on one side of the blade fixing shaft, a generator is fixedly installed on the other side of the intermediate rotating shaft, a junction box is provided inside the generator, and the junction box is connected to the outside through a generator antenna. The key feature is that the outer wall of the intermediate rotating shaft is provided with a flow guiding component for constraining and guiding airflow. The flow guiding assembly includes an outer cylinder and a flow guide shroud disposed on the outer wall of the intermediate rotating shaft. The flow guide shroud is fixedly installed on one side of the blade fixing shaft. A protective component is provided on one side of the outer cylinder to prevent the outer cylinder from deforming in a strong wind environment.

[0006] Preferably, a gap is provided between the outer cylinder and the blade at the end near the central rotating shaft, and the length of the gap is between one percent and five percent of the blade length.

[0007] Preferably, the cross-sectional radius of the outer cylinder at the end furthest from the central pivot is greater than or equal to the cross-sectional radius of the outer cylinder at the end closest to the central pivot, and the ratio between the distance between the two ends of the outer cylinder and the blade length is set to between 0.5 and 2.

[0008] Preferably, the fairing is hemispherical, and the cross-section of the fairing near the blade fixing axis is the same as the cross-section of the blade fixing axis.

[0009] Preferably, the side of the blade furthest from the generator is set as an inclined surface, and the cross-sectional area of ​​the blade increases from one end near the blade's fixed axis to the other end.

[0010] Preferably, the protection component includes a generator mounting bracket disposed on one side of the outer cylinder. The generator mounting bracket consists of a first fixing surface, a second fixing surface, and a support surface. The first fixing surface is fixedly installed on one side of the outer cylinder, and the intermediate rotating shaft passes through the inner wall of the first fixing surface. The second fixing surface is fixedly installed at one end of the first fixing surface, and a generator is fixedly installed on one side of the second fixing surface. The support surface is fixedly installed at the end of the second fixing surface away from the first fixing surface, and one end of the support surface is fixedly installed on one side of the outer cylinder, so that the support surface and the second fixing surface form a triangular stable structure on one side of the outer cylinder.

[0011] In summary, this utility model has the following beneficial effects: By incorporating airflow guiding components, the design of the outer duct structure can concentrate airflow during wind power generation, thereby increasing wind energy density and improving the power generation efficiency of wind turbines in low wind speed environments. This reduces airflow escape, lowers energy waste, and constrains and guides airflow, reducing turbulence losses and avoiding the problems that natural wind is usually accompanied by turbulence, which can easily cause blades to be jolted, reduce efficiency, or even cause fatigue damage. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a cross-sectional structural diagram of the entire utility model; Figure 2 This is a structural schematic diagram from another perspective of the present invention.

[0014] In the picture: 1. Outer cylinder; 2. Intermediate shaft; 3. Blade fixing shaft; 4. Blade; 5. Draft shield; 6. Generator mounting bracket; 7. Generator; 8. Junction box; 9. Generator wires. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0016] Example: The following is in conjunction with the appendix Figure 1 and Figure 2 The present invention will be described in further detail below.

[0017] Please see Figure 1 and Figure 2 This utility model provides a technical solution: a ducted wind turbine generator, such as... Figure 1 and Figure 2 As shown, it includes a blade fixing shaft 3, blades 4 are evenly installed on the outer wall of the blade fixing shaft 3, an intermediate rotating shaft 2 is fixedly installed on one side of the blade fixing shaft 3, a generator 7 is fixedly installed on the other side of the intermediate rotating shaft 2, a junction box 8 is provided inside the generator 7, and the junction box 8 is connected to the outside through the generator antenna 9. The feature is that the outer wall of the intermediate rotating shaft 2 is provided with a flow guiding component for constraining and guiding the airflow. The airflow guiding assembly includes an outer cylinder 1 and a guide shroud 5 disposed on the outer wall of the intermediate rotating shaft 2. It should be noted that the outer cylinder 1 adopts an elongated structural design, with its axial length significantly increased compared to a conventional outer cylinder 1, forming a unique annular channel structure, i.e., a ducted structure. This ducted structure, through its unique annular encircling characteristic, can effectively constrain and guide airflow movement, reducing vortex losses at the tips of the blades 4, thereby improving wind speed conversion efficiency. Furthermore, the ducted structure can reduce noise, prevent rotating parts from contacting foreign objects, enhance safety, and optimize the airflow path, reducing... Regarding energy loss, this duct design, which integrates multiple advantages, achieves synergistic optimization of noise reduction and safety while improving energy efficiency, reflecting the advanced concept of modern fluid machinery design. Furthermore, the ratio of the distance between the two ends of the outer cylinder 1 to the length of the blade 4 is set between 0.5 and 2. If the ratio is less than 0.5, the buffer distance between the inlet end of the outer cylinder 1 and the blade 4 is insufficient. Before reaching the impeller, the airflow will prematurely undergo "airflow separation" (i.e., the airflow detaches from the surface of the guide shroud 5 to form vortices) due to the sudden contraction or interruption at the end of the guide shroud 5. These separated vortices will consume wind energy. Furthermore, this leads to uneven airflow velocity distribution entering the wind turbine (sudden drops in wind speed in some areas), significantly reducing the wind turbine's wind energy capture efficiency. If the ratio is greater than 2, the outer cylinder 1 will become too long, increasing its windward area and causing a sharp increase in air resistance (especially pressure drag). In this case, the benefits of the deflector 5 in "guiding the airflow" will be offset by the energy consumed by its own resistance, and may even lead to a decrease in overall wind energy utilization efficiency. Setting the ratio between the distance between the two ends of the outer cylinder 1 and the length of the blade 4 to between 0.5 and 2 can guide the airflow smoothly towards the wind turbine, reducing the impact of airflow separation. The uneven velocity distribution caused by (vortex) is especially important in low wind speed environments. Uniform airflow allows the blades 4 to capture wind energy more stably, avoid energy loss caused by local load fluctuations, and control drag loss, ensuring the stability and durability of the unit under different wind speeds. In addition, the cross-sectional radius of the outer cylinder 1 at the end away from the intermediate rotating shaft 2 is greater than or equal to the cross-sectional radius of the outer cylinder 1 at the end closer to the intermediate rotating shaft 2. This setting allows the inlet end of the outer cylinder 1 to gather a larger range of airflow into the interior of the outer cylinder 1, thereby increasing the airflow velocity and flow rate through the intermediate rotating shaft 2. The deflector 5 is fixedly installed on one side of the blade fixing shaft 3. The deflector 5 is hemispherical, and the cross-section of the end of the deflector 5 near the blade fixing shaft 3 is the same as the cross-section of the blade fixing shaft 3. Through the smooth streamlined design of the deflector 5, when the airflow approaches the deflector 5, the smooth shape will guide the airflow to gradually flow around it, avoiding the problem of airflow separation caused by surface abrupt changes or roughness, which would cause the airflow to detach from the blade fixing shaft 3 and the blade 4 surface and form vortices. This reduces the resistance and turbulence when the airflow enters the blade 4, and makes the airflow flow more evenly to the blade 4, improving the wind energy capture efficiency of the blade 4. A protective component is provided on one side of the outer cylinder 1 to prevent the outer cylinder 1 from deforming in strong wind environments.

[0018] Furthermore, a gap is provided between the outer cylinder 1 near the central shaft 2 and the blade 4. The gap length is between one-hundredth and five-hundredths of the blade 4 length. This design avoids a situation where, if the gap between the outer cylinder 1 near the central shaft 2 and the blade 4 is greater than five-hundredth of the blade 4 length, a large amount of airflow will flow through the gap (without doing work through the blade 4), reducing the constraint effect of the outer cylinder 1 duct structure and thus affecting the power generation efficiency of the wind turbine. Also, a larger gap can cause leakage airflow that easily interferes with the airflow on the inner wall of the outer cylinder 1 and the tip of the blade 4, forming turbulent flow. Turbulence can lead to uneven stress on the blade 4, increasing vibration during blade rotation and shortening its service life. A smaller gap helps the outer cylinder 1 duct constrain the airflow, enhancing the effect of guiding and accelerating the airflow through the blade 4. Setting the gap length to be greater than one percent of the blade length can prevent friction between the blade 4 and the inner wall of the outer cylinder 1 when the gap is less than one percent of the blade length. This can easily lead to high temperatures, wear on the blade tip, and even local melting or breakage. In addition, an excessively small gap can also cause the airflow to form a "throttling" effect similar to water flowing through a narrow gap. According to the continuity equation and Bernoulli's principle, this causes the airflow velocity to increase sharply, resulting in increased frictional resistance between the inner wall of the outer cylinder 1 and the airflow, increasing energy loss at the blade 4 and affecting the power generation efficiency of the wind turbine. In this embodiment, by setting the gap length to be greater than one percent of the blade length, a safety redundancy can be reserved to avoid mechanical expansion and increase the safety of the wind turbine.

[0019] In this embodiment, by setting up a flow-guiding component, especially the unique duct design of the outer cylinder 1, the dispersed natural wind can be gathered into the interior of the outer cylinder 1 when the airflow passes through the wind turbine, thereby effectively constraining and guiding the airflow movement. This allows the airflow to flow parallel along the inner wall of the outer cylinder 1, reducing interference from lateral airflow, thereby reducing vortex losses at the fan tip and improving wind speed conversion efficiency. At the same time, the inner wall of the outer cylinder 1 further optimizes the airflow path, smoothing out turbulent airflow, so that the airflow impacts the intermediate rotating shaft 2 at a more stable angle, thereby reducing energy loss caused by irregular airflow on the intermediate rotating shaft 2. In addition, the duct structure can also reduce noise and prevent rotating parts from contacting foreign objects, enhancing the safety of the wind turbine. This duct design, which integrates multiple advantages, achieves synergistic optimization of noise reduction and safety while improving energy efficiency, reflecting the advanced concept of modern fluid machinery design.

[0020] like Figure 1 and Figure 2As shown, the side of blade 4 away from generator 7 is set as an inclined surface, and the cross-sectional area of ​​blade 4 increases from one end near the blade fixed shaft 3 to the other end. With this design, when the airflow flows over blade 4, the shape of the inclined surface can guide the airflow, so that the airflow flows along the surface of blade 4, effectively delaying the airflow separation phenomenon, enabling the airflow to flow more smoothly over the surface of blade 4, reducing energy loss, improving the aerodynamic efficiency of blade 4, and thus improving the power generation efficiency of wind turbine.

[0021] In this embodiment, by setting the shape of the blade 4, it can cooperate with the guide shroud 5, so that the airflow can smoothly transition to the surface of the blade 4 after being guided by the guide shroud 5. This avoids the formation of vortices and separation of airflow in the root area of ​​the blade fixed shaft 3 and the blade 4, which would cause wind energy consumption. This further improves the guiding effect of the airflow, increases the flow rate and velocity of the airflow on the surface of the blade 4, and thus increases the power generation efficiency of the wind turbine. On the other hand, the blade 4 cooperates with the duct structure of the outer cylinder 1 to form a smooth transition airflow channel, which can better guide the airflow into the duct, reduce airflow leakage and interference between the duct and the blade, and further improve the constraint and guiding effect of the duct on the airflow. After the airflow enters the outer cylinder 1, it reaches one side of the blade 4 after being guided and accelerated by the outer cylinder 1. The inclined surface of the blade 4 further guides the airflow, further improving the pushing effect of the airflow on the blade 4, thereby improving the power generation efficiency of the wind turbine and enhancing the performance of the entire wind power generation device.

[0022] like Figure 1As shown, in this embodiment, the protection component includes a generator mounting bracket 6 disposed on one side of the outer cylinder 1. The generator mounting bracket 6 consists of a first fixing surface, a second fixing surface, and a supporting surface. The first fixing surface is fixedly installed on one side of the outer cylinder 1, and the intermediate rotating shaft 2 passes through the inner wall of the first fixing surface. The second fixing surface is fixedly installed at one end of the first fixing surface, and the generator 7 is fixedly installed on one side of the second fixing surface. The supporting surface is fixedly installed at the end of the second fixing surface away from the first fixing surface, and one end of the supporting surface is fixedly installed on one side of the outer cylinder 1, so that the supporting surface and the second fixing surface form a triangular stable structure on one side of the outer cylinder 1. This design not only provides protection against the generator 7 through the triangular structure formed between the generator mounting bracket 6 and the side wall of the outer cylinder 1, but also... The overall strength of the wind turbine is improved to enhance its stability, especially in strong wind environments. The connection strength between the outer cylinder 1 and the blade fixing shaft 3 is enhanced to prevent the outer cylinder 1 from vibrating significantly in strong winds, which could lead to deformation and damage. More importantly, through the positional design of the first and second fixing surfaces, the vibrations generated when the blade 4 rotates and the generator 7 operates can be transmitted to the support surface through the first and second fixing surfaces. This allows the support surface to disperse the impact to the side wall of the outer cylinder 1, avoiding stress concentration at a single connection point. This improves the stability of the wind turbine during operation, reduces the wear of various components, and thus improves the structural stability and reliability of the wind turbine during long-term operation.

[0023] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of this utility model. Various changes and modifications may be made to this utility model without departing from the spirit and scope of this utility model, and all such changes and modifications fall within the scope of this utility model as claimed.

Claims

1. A ducted wind turbine, comprising a blade fixing shaft (3), wherein blades (4) are uniformly mounted on the outer wall of the blade fixing shaft (3), an intermediate rotating shaft (2) is fixedly mounted on one side of the blade fixing shaft (3), and a generator (7) is fixedly mounted on the other side of the intermediate rotating shaft (2), wherein a junction box (8) is provided inside the generator (7), and the junction box (8) is connected to the outside via a generator antenna (9), characterized in that, The outer wall of the intermediate rotating shaft (2) is provided with a flow-guiding component for constraining and guiding the airflow; The flow guiding assembly includes an outer cylinder (1) and a flow guide (5) disposed on the outer wall of the intermediate rotating shaft (2). The flow guide (5) is fixedly installed on one side of the blade fixing shaft (3). A protective component is provided on one side of the outer cylinder (1) to prevent the outer cylinder (1) from deforming in a strong wind environment.

2. The ducted wind turbine according to claim 1, wherein A gap is provided between the outer cylinder (1) and the blade (4) at one end near the middle rotating shaft (2), and the length of the gap is between one percent and five percent of the length of the blade (4).

3. The ducted wind turbine of claim 1, wherein, The cross-sectional radius of the outer cylinder (1) at the end away from the intermediate rotating shaft (2) is greater than or equal to the cross-sectional radius of the outer cylinder (1) at the end closer to the intermediate rotating shaft (2), and the ratio between the distance between the two ends of the outer cylinder (1) and the length of the blade (4) is set to between 0.5 and 2.

4. The ducted wind turbine of claim 1, wherein, The flow guide (5) is configured as a hemispherical shape, and the cross-section of the flow guide (5) near the blade fixing shaft (3) is the same as the cross-section of the blade fixing shaft (3).

5. The ducted wind turbine of claim 1, wherein, The side of the blade (4) away from the generator (7) is set as an inclined surface, and the cross-sectional area of ​​the blade (4) increases from one end near the blade fixing shaft (3) to the other end.

6. The ducted wind turbine of claim 1, wherein, The protective component includes a generator mounting bracket (6) disposed on one side of the outer cylinder (1). The generator mounting bracket (6) consists of a first fixing surface, a second fixing surface, and a support surface. The first fixing surface is fixedly installed on one side of the outer cylinder (1), and the intermediate rotating shaft (2) passes through the inner wall of the first fixing surface. The second fixing surface is fixedly installed at one end of the first fixing surface. A generator (7) is fixedly installed on one side of the second fixing surface. The support surface is fixedly installed at the end of the second fixing surface away from the first fixing surface. One end of the support surface is fixedly installed on one side of the outer cylinder (1), so that the support surface and the second fixing surface form a triangular stable structure on one side of the outer cylinder (1).

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