A full stall wind turbine technology

Abstract

A full-block type breeze wind turbine, the wind turbine comprises a impeller body and a plurality of guide vanes, the impeller body is a breeze wind turbine structure capable of completely blocking the airflow path in the range of the impeller; the impeller body adopts a tensegrity structure design, which is composed of truss, cable and skin into an elastic whole, the cable decomposes the pressure borne by the windward surface of the impeller body, a plurality of guide vanes are arranged on the outer edge of the windward surface of the impeller body, which are a plurality of angle-variable guide vane structures, the guide vanes have a deformation function, which can adapt to different environmental meteorological conditions by using the deformation of the guide vanes, the wind turbine impeller structure of the present application can concentrate the airflow in the range of the impeller to the outer edge of the impeller and improve the airflow velocity in the range of the impeller, thereby realizing the purpose of efficient utilization of wind energy in the range of the impeller.

Description

Technical Field

[0001] This invention belongs to the discipline of fluid mechanics and the field of wind energy utilization. Specifically, it is a fully obstructed micro-wind turbine technology designed based on the ideal wind turbine concept proposed in Bates theory. This invention is a technology that uses Bernoulli's theorem and the lever effect to accelerate airflow by utilizing the pressure difference resistance between the windward and leeward sides of the impeller, and generates a diffused wake flow field behind the ideal wind turbine, thereby driving the impeller to rotate and driving the equipment to do work. Wind turbines refer to many related technologies that directly or indirectly utilize wind energy, such as wind power generation, wind-powered water lifting, wind-powered grinding, wind-driven water aeration, and wind-powered compressors. Background Technology

[0002] Wind energy is a green, environmentally friendly, and renewable new energy technology. In today's world, when wind power generation is mentioned, almost everyone will picture a wind turbine consisting of three slender blades. This type of wind turbine with three slender blades is known in academia as a horizontal axis lift wind turbine, and its design theory is based on Betz's Law.

[0003] The Bates Theory is derived from several Bates assumptions, but research has found that many of these assumptions do not conform to the objective natural laws of the real environment, and even contradict the facts.

[0004] Bates' theory posits that the ideal wind turbine rotor consists of an infinite number of blades; this rotor structure is called an "ideal wind turbine." However, if we were to replicate this bladed rotor in a real-world environment, the resulting rotor would be a solid disk. Bates' theory assumes that this solid disk does not create resistance to the wind (airflow); the airflow passes through the disk, retaining some of its kinetic energy to drive its rotation. This assumption clearly contradicts the objective laws of nature in real-world environments.

[0005] According to Newton's third law of motion, for every action, there is an equal and opposite reaction. If we consider an ideal wind turbine and the wind (airflow) as two separate objects, when the airflow exerts a force on the turbine, the turbine will necessarily exert a reaction force on the airflow in the opposite direction and with equal force. Clearly, Bates' theory only considers the force exerted by the airflow on the turbine, neglecting the reaction force exerted by the turbine on the airflow.

[0006] Refer to Figures 01 and 02;

[0007] Figure 01 is a flow field diagram of the hypothetical "ideal wind turbine" in Bates' theory.

[0008] Figure 02 is a diagram of the airflow field of a wind turbine impeller made by simulating an "ideal wind turbine" structure in a real environment.

[0009] A comparison of Figures 01 and 02 reveals that the flow field environment of the ideal wind turbine in Bates' theory is drastically different from that of a real-world "ideal wind turbine." The main difference lies in the fact that the ideal wind turbine in Bates' theory exists within a "flow tube bounded by the impeller diameter," neglecting the airflow field outside the impeller's boundaries. In reality, the airflow range influenced by an ideal wind turbine should encompass both the flow field within and outside the impeller's boundaries.

[0010] In fact, the field of modern fluid mechanics has a very mature understanding of structures similar to "ideal wind turbines," but the results of these studies have not been applied to the field of wind power generation. For example, in the book "Fluid Mechanics as I Understand It" (ISBN / ISSN: 978-7-118-09847-1) by Professor Wang Hongwei, Chapter 6, Section 6.7.1, Viscous Shear Flow (page 169), there is a detailed discussion of the behavior of structures similar to ideal wind turbines in airflow (wind).

[0011] In a real-world environment, an ideal wind turbine is essentially equivalent to a circular flat plate perpendicular to the incoming flow. Analysis shows that the pressure at the center of the flat plate facing the fluid is equal to the total pressure of the incoming flow. After the fluid is congested, it accelerates radially, its pressure decreasing accordingly. It then flows around the outer edge of the plate and, driven by the main flow outside the plate's area, resumes its flow direction. Based on the concept that "streamline pressures are equal for parallel lines," the pressure of the fluid behind the plate is approximately equal to the pressure of the fluid just past the plate. Since the velocity of the fluid passing around the plate is slightly higher than the incoming flow velocity, this pressure is less than the static pressure of the incoming flow. Therefore, for this flat plate, the pressure facing it is close to the total pressure of the incoming flow, while the pressure behind it is less than the static pressure. From this, we can determine that the resistance acting on the plate should be slightly greater than the product of the dynamic pressure of the incoming flow and the area of ​​the plate (experiments show that the plate resistance in this flow is about 1.1 times this value). In engineering, this resistance caused by pressure difference is called pressure drag or form drag. For specific flow field annotations, please refer to the book. Figure 6-3 The content shown in 0.

[0012] Figure 03 shows the assumed airflow tube range diagram (radial cross-section of the airflow field) in Bates theory.

[0013] Figure 04 shows the airflow pipe range diagram (radial cross-section diagram of airflow field) of the ideal wind turbine structure that conforms to the real environment. Among them, the area indicated by number 100 is the area within the impeller (ideal wind turbine range), the area indicated by number 1 is the airflow field range area not affected by the impeller, and the area indicated by number 2 is the airflow field area outside the impeller range that is affected by the impeller.

[0014] Figure 04 includes the airflow field inside and outside the impeller. Experiments show that the flow field structure shown in Figure 04 is more in line with objective natural laws.

[0015] Subsequent research revealed that incorrect assumptions about the airflow field range could cause discrepancies between the calculations in subsequent derivations of Bates theory and real-world conditions. In particular, after reconstructing the ideal wind turbine assumed by Bates theory in a real-world environment, experimentally measured values ​​differed from those derived from Bates theory.

[0016] The Bates Theory is derived from the Bates Hypothesis. When the Bates Hypothesis does not conform to objective natural laws, the conclusions derived from the hypothesis that does not conform to objective natural laws will inevitably fail to yield correct results that conform to objective reality.

[0017] Practice (experiment) is the sole criterion for testing truth. During the literature search, the keyword "Bates theory experiment" was used to find experimental evidence supporting the derivation process of Bates theory.

[0018] Unfortunately, more than a century has passed since Bates' theory was proposed, and while search engines have yielded numerous results detailing its derivation, they have failed to find any records or literature demonstrating experimental verification of the ideal wind turbine concept proposed by Bates' theory. In other words, Bates' theory, which has been considered the cornerstone of wind power generation for a century, is actually a theory that has not undergone extensive experimental verification.

[0019] In recent years, with the development of wind energy utilization technology, leaf element (BEM) theory has become the mainstream theory in the field of wind power generation.

[0020] The blade element (BEM) theory refers to dividing wind turbine blades into many micro-segments along their span. The blade element theory simplifies wind turbine blades into a finite number of blade elements, superimposed radially. Therefore, the three-dimensional aerodynamic characteristics of the wind turbine can be obtained by radially integrating the aerodynamic characteristics of the blade elements. As can be seen from the above, modern wind turbines are consistent with Bates' theory; their core concepts only consider the influence of airflow (wind) on the impeller, while neglecting the influence of the impeller on the airflow, and also ignoring the influence of airflow outside the impeller's range on the impeller.

[0021] The biggest drawback of wind turbines designed based on Bates' theory is their high dependence on wind conditions. A large portion of the world's landmasses has an average annual wind speed of less than 5 meters per second, and in many areas, the wind speed is only 3 meters per second for 80% of the year. These areas are considered unsuitable for wind power development. Some experts argue that wind energy at 3 meters per second has too low an energy density to be of any use. However, calculations show that wind energy, like solar energy, is a low-density energy source, and if used effectively and rationally, it can bring significant economic benefits.

[0022] It is known that the pressure drag experienced by an ideal wind turbine can be calculated by multiplying the dynamic pressure of the incoming wind by the impeller area. It is also known that under standard atmospheric pressure, one cubic meter of air weighs approximately 1.29 kg. If the impeller surface area is 1 square meter, at a wind speed of 1 meter per second, approximately 1.29 kg of air will pass through the impeller area every second. With the wind speed remaining constant, if the impeller area is increased to 2 square meters, 2.58 kg of air will pass through the impeller area every second. Furthermore, the larger the impeller surface area and the faster the wind speed, the higher the kinetic energy that the wind turbine impeller can obtain.

[0023] The table in Figure 05 shows the total mass of air passing through the impeller area per second under different wind speeds and impeller diameters (rounded to the nearest integer during the calculation).

[0024] Given the flow velocity (wind speed), fluid mass (1.29 kg / m³), and resistance range (impeller surface area).

[0025] The total kinetic energy provided by the fluid (wind power) within the impeller range to the impeller can be calculated using the dynamic pressure calculation formula.

[0026] As shown in Figure 05, taking an 8-meter diameter impeller as an example, the impeller's circumference is approximately 25 meters, and its area is approximately 50 square meters (common large freestanding outdoor billboards typically have an area of ​​6 meters × 18 meters = 108 square meters; the area of ​​an 8-meter diameter impeller is only about half that of a typical large outdoor billboard). At a wind speed of 3 meters per second (Force 2 wind), the total weight of air passing through the impeller's area per second is approximately 194 kilograms. At a wind speed of 10 meters per second (Force 5 wind), the total weight of air passing through the area per second is approximately 647 kilograms. Effectively utilizing the kinetic energy of this airflow is sufficient to drive the wind turbine.

[0027] At the same time, excessively large impellers inevitably face higher risks. Taking an 8-meter diameter wind turbine as an example, when it encounters strong winds of 30 meters per second (Force 11), the impeller area will bear a pressure of 1942 kilograms per second. Therefore, the tower and support structure of such wind turbine impeller structures must also adopt a completely new design.

[0028] In order to solve the above problems, to make effective use of breezes, and to enable low-wind-speed areas to enjoy the free energy benefits brought by wind power, the inventors have put forward this invention. Summary of the Invention

[0029] Traditional horizontal-axis lift wind turbines suffer from poor performance in low-wind-speed environments. To address these issues, this invention redesigns the wind turbine impeller structure based on the ideal wind turbine concept proposed in Bates theory, after recognizing that the ideal wind turbine flow field assumed in Bates theory is completely different from that in real-world environments.

[0030] Bates' theory states that an "ideal wind turbine" has an infinite number of blades, meaning it can "completely block" the airflow within its impeller area and change its direction. Therefore, a wind turbine developed from this "ideal wind turbine" concept can be called a "fully obstructed wind turbine." According to Bates' theory, if an ideal wind turbine can utilize 100% of the kinetic energy generated by the airflow within its impeller area, the air, having lost its kinetic energy, will stagnate behind the impeller, creating resistance to subsequent airflow. This conclusion is reached because Bates' theory neglects the influence of the impeller on the airflow and also ignores the influence of airflow outside the impeller area on the wind turbine.

[0031] As shown in Figure 06, assuming that when the airflow encounters the impeller (ideal wind turbine), the kinetic energy of the airflow is completely absorbed by the impeller, thus the airflow stagnates on the impeller surface. However, due to the pressure difference drag between the windward and leeward sides of the impeller, a pressure difference exists between the windward and leeward sides. We know that in a natural environment, air spontaneously flows from areas of higher pressure to areas of lower pressure. Therefore, this air, having lost kinetic energy, will spontaneously flow towards the leeward side of the impeller under the influence of the pressure difference.

[0032] For related knowledge, please refer to Section 6.7.1 of Chapter 6, Viscous Shear Flow (page 169), in the book "Fluid Mechanics as I Understand". Figure 6-2 9) Content related to flow resistance.

[0033] As shown in Figure 04, when the air that has lost kinetic energy flows out from the outer edge of the impeller, the location of the airflow has shifted from the airflow range affected by the impeller to the airflow range unaffected by the impeller (area shown by number 2). Projected onto the impeller boundary, this air that has lost kinetic energy has left the impeller range, mixed with the air outside the impeller range, and is carried away by the airflow outside the impeller range that is unaffected by the impeller (that has not had its kinetic energy absorbed by the impeller), thus leaving the impeller range.

[0034] As shown in Figure 06, after the airflow leaves the impeller area, it mixes with the airflow outside the impeller area and leaves the impeller area under the influence of the airflow outside the impeller area.

[0035] In Bates' theory, "all airflow" within the impeller's range is considered an ideal fluid, unaffected by the impeller, with its velocity and direction remaining constant. While this simplifies calculations, it clearly contradicts objective natural laws. As shown in Figure 06, when airflow encounters impeller obstruction, its direction and velocity inevitably change. Bates' theory, in its derivation, obviously ignores these changes and their consequences.

[0036] In this invention, to more accurately describe the influence of the impeller (ideal wind turbine) on the airflow, the airflow is specifically classified as follows:

[0037] When wind energy (airflow) flows normally in a natural environment without being affected by the impeller, for ease of description, this type of airflow is called a type of airflow;

[0038] When a type of airflow impacts the impeller surface, the airflow exerts an axial force on the impeller. Because the impeller is fixed to the tower, the axial static net force of the impeller itself (also known as structural strength) is greater than the axial force exerted by the airflow on the impeller. Therefore, the impeller exerts a continuous reaction force on the airflow impacting it, causing the airflow to stagnate. However, since wind energy (airflow) is continuous, subsequent airflows continue to exert an axial force on the airflow ahead, while the impeller exerts a continuous reaction force on the airflow. These two forces compress the airflow, causing it to flow from the impeller surface to the outer edge of the impeller (radial along the type of airflow). This compressed airflow passes through the wind turbine impeller (ideal wind turbine) described in this invention and flows out from the outer edge of the impeller. At this time, the airflow direction, airflow velocity, and air density have all changed. For ease of description, the changed airflow is referred to as type II airflow in this invention.

[0039] When the second type of airflow leaves the impeller range and interferes with, mixes with, and influences the first type of airflow outside the impeller range, the resulting airflow is referred to as the third type of airflow in this invention. The third type of airflow generates a diffused wake flow field under the influence of the guide vanes.

[0040] Experiments show that during the operation of a wind turbine, there are certain differences in airflow velocity, airflow direction, and air density among Class I, Class II, and Class III airflows. It is unreasonable and unscientific to generalize these completely different airflows as in Bates' theory.

[0041] The characteristics of an impeller structure are that the larger the impeller diameter, the larger the circumference, and the larger the impeller area. For example, when the impeller diameter is 1 meter, the impeller circumference is approximately 3.1 meters; when the impeller diameter is 2 meters, the impeller circumference is approximately 6.3 meters. Therefore, the Type II airflow, having lost kinetic energy, dissipates outside the impeller area, effectively gaining a larger space for diffusion. Simultaneously, the centrifugal force generated by the impeller rotation also affects the dissipation of the airflow.

[0042] The jet of air ejected from the gaps in the guide vanes has a high velocity. Based on Bernoulli's principle, the higher the velocity, the lower the fluid pressure. Therefore, the jet from the gaps in the guide vanes will entrain air from the outer edge of the impeller to areas far away from the impeller, similar to the principle of bladeless fans.

[0043] Traditional wind turbine structures are influenced by Bates' theory, with design principles centered on "not affecting airflow" and "increasing tip speed ratio." The core concept of this invention, however, is based on Newton's laws of motion, Bernoulli's theorem, and the lever effect. It utilizes the interaction between airflow and the impeller to convert the kinetic energy of the airflow in the impeller region (including both the area within and outside the impeller) into mechanical energy, which is then used to drive the mechanical structure to perform work.

[0044] In the book *Fluid Mechanics as I Understand*, Chapter 6, Section 6.7.1 (page 177), regarding viscous shear flow, Figure 6-3 Figure 6 shows the drag coefficients of several typical structures at common Reynolds numbers. The drag coefficient of the "zero-thickness circular plate," similar to an ideal wind turbine structure, is approximately 1.17 (consistent with experimental results). However, the drag coefficient of the inverted hemispherical shell structure reaches 1.42. This indicates that the inverted hemispherical shell structure achieves a higher drag coefficient, meaning it has a higher wind energy utilization rate. However, the inverted hemispherical shell structure cannot directly utilize wind energy. For example, the common cup anemometer uses several inverted hemispherical shell structures to form the impeller. Without proper theoretical guidance, this type of cup anemometer cannot be further developed.

[0045] Once the relationship between the ideal wind turbine structure and wind energy utilization is clarified and the correct theoretical guidance is found, we can begin to design a feasible micro-wind turbine impeller structure.

[0046] Based on the above theoretical derivation, the wind turbine of this invention should consist of two parts: an impeller structure similar to an "ideal wind turbine" and several guide vanes. The guide vanes can be placed on the ideal wind turbine impeller or can be relatively independent.

[0047] A rotor structure similar to an "ideal wind turbine" can block the flow path of all airflows within the rotor's range, forcing a type of airflow within the rotor's range to change its forward path and increase its velocity, thus generating a type of airflow.

[0048] The type II airflow generated by the impeller cannot directly provide kinetic energy to the impeller. In this case, it is necessary to add a flow guide device on the windward side and outer edge of the impeller to obtain kinetic energy by changing the airflow path. In early research, I obtained the kinetic energy of the airflow by adding a flow guide groove structure to the impeller surface and applied for a patent "Flow Guide Type Wind Turbine Blade Structure (ZL2018102308354)".

[0049] In subsequent research, I found that the concept of an ideal wind turbine proposed in Bates' theory does not conform to objective natural laws. In experiments, I repeatedly observed that the residual wind speed of impeller structures similar to ideal wind turbines was zero. Therefore, I applied for a patent for "A horizontal axis wake diffusion wind turbine technology (ZL2019113146521)".

[0050] Based on the aforementioned technology, and through extensive experimentation, I discovered several drawbacks to the helical involute guide channel structure in real-world environments. While the helical involute guide channel can effectively utilize Type II airflow, snow accumulation inside the channel can occur during freezing rain, heavy snow, or hail, significantly increasing the impeller's weight. This can negatively impact the impeller's center of gravity and structure during high-speed rotation. Furthermore, incorporating helical involute guide channels on the impeller surface presents several challenges, including relatively high manufacturing costs, stringent impeller strength requirements, a substantial increase in impeller weight, and increased maintenance complexity.

[0051] To address the aforementioned issues, I optimized the spiral involute guide vane structure into several deformable guide vanes. These vanes absorb the kinetic energy of the second type of airflow on the impeller (ideal wind turbine) surface. In rainy or snowy weather, the deformation capability of the guide vanes can mitigate the impact of rain and snow on the impeller.

[0052] More importantly, experiments have shown that if the guide vanes are arranged around the outer edge of the impeller and a certain gap is left between the guide vanes, and the total area of ​​the gap is smaller than the total area of ​​the impeller's windward surface, then according to Bernoulli's law, the second type of airflow will be accelerated.

[0053] As shown in Figure 07, the three-view diagram of the wind turbine rotor shows several guide vanes arranged along the outer edge of the ideal rotor, with several gaps between the vanes. When the airflow enters the concave surface of the rotor from the windward side, the airflow is compressed and flows out through the gaps in the guide vanes. Because the total area of ​​the windward side of the rotor is larger than the gaps in the guide vanes, according to Bernoulli's theorem, the velocity of the airflow exiting the gaps in the guide vanes will increase.

[0054] Based on the concept of "boundary layer separation", in order to make the airflow leave the impeller area quickly, the guide vanes located behind the impeller need to extend into auxiliary vanes of a certain length.

[0055] The high-speed airflow exiting the gap between the guide vanes forms a jet and provides a reaction force to the impeller, driving the impeller to rotate.

[0056] The advantages of the ideal wind turbine structure adopted in this invention are:

[0057] First, compared to traditional wind turbines, the airflow diffuses from the outer edge of the impeller, forming a diffused wake flow field behind the impeller. The diffused wake field refers to the diffused flow field generated at the rear of the impeller by the wind turbine structure described in this invention. The reason Bates' theory states that the wind energy utilization rate of a wind turbine cannot exceed 59.3% is because if the kinetic energy absorbed by the wind turbine impeller exceeds 59.3%, the air will stagnate behind the impeller, creating resistance to subsequent airflow. However, Bates' theory ignores the possibility that the airflow will bypass the impeller. As shown in Figure 06, the airflow, after being blocked by the impeller, will bypass the impeller's outer edge. When the airflow bypasses the impeller's outer edge, the fluid that loses kinetic energy within the impeller's area will be carried away by a type of airflow outside the impeller's area, thus leaving the impeller's area. This type of airflow outside the impeller's area will share its kinetic energy with the type of airflow that loses kinetic energy within the impeller's area, forming a type of airflow. Therefore, these type of airflows that have lost kinetic energy do not stagnate and do not create resistance to subsequent airflow.

[0058] Secondly, the central shaft (101) of the wind turbine impeller is located at the center (center) of the impeller. In traditional wind turbine impeller structures (small three-bladed wind turbine impellers), the airflow passes through the impeller in a straight line, and the kinetic energy generated cannot be concentrated (refer to blade element theory). However, the wind turbine impeller structure described in this invention causes "all airflow" within the impeller area to flow away from the outer edge of the impeller. Structurally, the impeller structure is actually a wheel and shaft structure. It is known that a wheel and shaft is a lever system with the axis as the fulcrum and the radius as the rod. Therefore, the wheel and shaft can change the torque, thereby changing the magnitude of the torque. Thus, the wind turbine impeller described in this invention can essentially amplify the torque of low-speed wind energy.

[0059] Wind energy is essentially a large-area, low-density, localized energy source. In real-world wind turbines, regardless of the diameter, every square centimeter within the impeller's radius experiences a force exerted by the wind every second. Traditional wind turbines excessively pursue impeller speed and tip speed ratio, neglecting the fact that low-speed, high-torque operation can also drive the wind turbine. For example, the relatively mature wind-powered water pump technology utilizes a low-speed, high-torque wind turbine impeller structure. The impeller structure (ideal wind turbine) described in this invention concentrates the kinetic energy of the airflow within the impeller's radius and amplifies the torque generated by this low-density kinetic energy using the wheel shaft, achieving high-torque, low-speed power output.

[0060] The wind turbine impeller structure described in this invention can concentrate the airflow within the impeller area to the outer edge of the impeller and increase the airflow velocity within the impeller area, thereby achieving the goal of efficiently utilizing wind energy within the impeller area. Experiments show that the wind turbine described in this invention performs better in low wind speed environments.

[0061] As described in the claim, in this invention, the angle of the guide vane is variable:

[0062] As shown in Figure 08, when the wind speed is low, the guide vanes are at a 90-degree angle to the impeller. At this time, the guide vanes are upright, turning the impeller into a concave container, and gaps exist between the guide vanes. The gap area is smaller than the total area of ​​the impeller's windward surface; based on Bernoulli's principle, the airflow velocity increases.

[0063] As shown in Figure 09, when the wind speed is high, the guide vanes deform into an arc-shaped structure under the influence of wind force. The Class II airflow within the impeller range concentrates at the outer edge of the impeller and is "squeezed out" from the gaps between the guide vanes, driving the impeller to rotate at high speed. Experiments have shown that after the guide vanes deform into an arc-shaped structure, the jet generated by the gaps between the vanes can bring greater torque to the impeller. Specific test results show that the wind turbine impeller performs extremely well at this time.

[0064] As attached Figure 10 As shown, when the wind speed is extremely high, the guide vanes fully deploy, and the gaps between the vanes widen accordingly, allowing excess airflow to escape directly through the outer edge of the impeller. Simultaneously, the centrifugal force generated by the high-speed rotation of the impeller provides additional tension to the impeller structure. Like the "handkerchief twirling" in acrobatic performance, the centrifugal force generated by the high-speed rotation of the impeller provides additional support strength, resisting the impact of strong winds on the wind turbine impeller.

[0065] When a wind turbine rotor encounters rain or snow, the guide vanes actively deploy to prevent rain and snow from accumulating in the gaps between the guide vanes, thus preventing the rotor from being subjected to additional burdens and shifting of the center of gravity.

[0066] The deformation range of the guide vanes is not limited to the vertical deformation angle. Other angles can also be used for deformation according to design requirements. The main purpose is to adjust the airflow direction and change the wind energy utilization rate of the impeller through the deformation of the guide vanes. When necessary, it can also automatically eliminate the impact of rain and snow on the impeller.

[0067] Deformation of the air guide vane by different angles, appearances, and methods does not affect the ownership of this invention.

[0068] Compared to traditional horizontal-axis lift wind turbines, the wind turbine impeller of this invention is much larger. Using rigid materials such as fiberglass or aluminum alloy to manufacture the impeller would inevitably lead to a significant increase in its weight. To effectively reduce the impeller's weight and improve its strength, the wind turbine impeller of this invention adopts a tensioned integral structure design, utilizing trusses, tension ropes, and skin structures to manufacture the impeller structure.

[0069] Tensioned monolithic structures are a technique that uses support rods and ropes to support a three-dimensional space. They are characterized by using a truss as the supporting structure, and employing ropes and a skin for tension to form a three-dimensional structure. Common folding umbrellas are typical examples of tensioned monolithic structures.

[0070] As attached Figure 11 As shown, the ideal wind turbine structure of the present invention adopts an integral tension structure on the windward side, using the impeller central shaft and truss as support (the truss is integrated with the impeller structure), and using traction ropes to provide tension to ensure the stability of the overall impeller structure.

[0071] Depending on the design requirements, the larger the impeller area, the more traction ropes are needed. The impeller itself has a symmetrical structure, and the traction ropes can distribute the pressure on the windward side of the impeller. Based on the principle of conservation of angular momentum, the high-speed rotation of the impeller acts like a gyroscope, helping to maintain its balance. The centrifugal force generated during the impeller's rotation provides additional tension, resisting the effects of strong winds.

[0072] Although the umbrella-shaped wind turbine impeller with its tensioned structure design can withstand wind speeds of 30 meters per second, it would still be devastating in the event of a hurricane of 50 meters per second. As mentioned earlier, the impeller structure described in this invention consists of a truss, ropes, and a skin structure. The structure of the wind turbine impeller is very similar to that of a folding umbrella. The central shaft of the impeller resembles the handle of an umbrella, the truss of the wind turbine resembles the frame of an umbrella, and the skin structure of the impeller resembles the fabric of an umbrella. To prevent damage to the wind turbine during a hurricane, the structure described in patent "A Micro-Wind Turbine Generator Blade Structure (ZL201510478505.3)" can be used. When a hurricane strikes, the wind turbine skin, as described in patent "A Micro-Wind Turbine Generator Blade Structure (ZL201510478505.3)," detaches from the truss and flutters in the wind like a flag. After the hurricane, the skin structure was restored to its connection with the umbrella frame, allowing it to continue to effectively utilize wind power.

[0073] Glossary

[0074] Impeller: A horizontal-axis wind turbine is a mature wind energy utilization device, characterized by a wheel-like structure composed of several blades. The impeller described in this invention is developed based on the hypothetical "ideal wind turbine" structure proposed in Bates' theory. As described in Bates' theory, the blades within the impeller range of an ideal wind turbine are infinitely numerous, and the impeller is essentially a solid disk. This solid disk should preferably be a complete solid disk structure; however, considering the technical construction difficulties, a disk structure composed of several blades or an impeller structure composed of a tensioned structure and a skin can also be used when necessary.

[0075] Wheel and axle: As the name suggests, it is a system composed of a "wheel" and an "axle". This system can rotate around a common axis, equivalent to a lever system with the axle as the fulcrum and the radius as the lever. Therefore, the wheel and axle can change the torque, thereby achieving the purpose of changing the magnitude of the torque.

[0076] Front and Rear of the Impeller: The "wind-directing" function is a fundamental feature of modern wind turbines, and the vast majority of horizontal axis wind turbines today possess this function. In the field of wind turbines, when a horizontal axis wind turbine is operating, the airflow is perpendicular to the plane of rotation of the impeller. At this time, the direction of the wind is in front of the impeller. After the wind passes through or around the impeller, the direction away from the impeller is the rear of the impeller.

[0077] Rotation direction of the impeller: In the field of wind power generation, the wind often drives the impeller to rotate, and the impeller then drives the generator to generate electricity. In most cases, the impeller rotates clockwise (or counterclockwise). During the rotation of the impeller, the direction in which the blades move forward is forward, and the direction in which they move backward is backward.

[0078] Impeller Axial and Radial Directions: In Bates' theory, the natural environment of a wind turbine is assumed to be an airflow tube structure, with the impeller diameter as the tube diameter. However, this invention discovers that the airflow field influenced by the impeller includes both within and outside the impeller's range. Therefore, the tube diameter is expanded to "all airflow ranges affected by the impeller, including both within and outside the impeller's range." Thus, the axial and radial directions of the tube described in this invention are the same as in Bates' theory. The difference between the tube described in this invention and the tube described in Bates' theory lies in whether the tube range includes the airflow field affected by the impeller outside the impeller's range.

[0079] Impeller interior and exterior: In this invention, the impeller is a disc-shaped structure. The center point (center of the circle) of the disc-shaped structure is the center of the impeller, and the line of the maximum circumference of the impeller is the outer edge of the impeller.

[0080] Front and back sides of the impeller: In this invention, the windward side of the impeller is the front side, and the leeward side of the impeller is the back side.

[0081] Blade tip and tip: In this invention, the impeller can be composed of several blades. The portion near the center of the impeller is the blade tip, and the portion near the outer edge of the impeller is the blade tip.

[0082] Airflow Classification: In Bates' theory, the airflow within the impeller area is considered a constant average, which is unscientific. In this invention, the direction and velocity of the airflow (wind) within the wind turbine's area cannot be generalized. Some areas have high airflow velocities, while others have slow velocities; some airflow intersects the impeller plane, while others propagate along the impeller surface. For ease of description, the airflow within the wind turbine's area is hereby roughly classified.

[0083] Referring to Figure 06: When the wind energy (airflow) in the natural environment where the wind turbine is located flows normally without being affected by the impeller, for ease of description, this type of airflow is called a type of airflow (represented by the number 1 in the figure).

[0084] When a type of airflow impacts the impeller surface, the airflow exerts a force on the impeller. Because the impeller is fixed to the tower, its own strength is greater than the force exerted by the airflow. Therefore, the impeller exerts a reaction force on the airflow impacting it. Since wind energy (airflow) is continuous, subsequent airflow exerts a force on the preceding airflow, while the impeller exerts a reaction force on the airflow. These two forces compress the preceding airflow, causing it to flow from the impeller surface to the outer edge of the impeller. This compressed airflow passes through the spiral involute guide grooves composed of the guide vanes described in this invention and flows out through the blade gaps or the outer edge of the blades. At this time, the airflow direction, airflow velocity, and air density all change. For ease of description, the changed airflow is referred to as type II airflow (represented by the number 2 in the figure).

[0085] When the second type of airflow and the first type of airflow interfere with each other, mix and have an effect, the resulting airflow (turbulence) is referred to as the third type of airflow in this invention (represented by the number 3 in the figure).

[0086] Bend circulation: The principle of bend circulation, also known as the bend circulation water-sediment separation principle, is commonly used in the hydrological analysis of river bends. Air and water are both Newtonian fluids, and most of their calculation formulas are similar. When a fluid encounters a bend, its own inertial force is transferred to the bend wall.

[0087] The septum effect, also known as the canyon effect, is similar to how winds are stronger in canyons than on plains. Similarly, winds are particularly strong in narrow areas between tall buildings in cities, potentially causing accidents. The septum effect typically occurs when airflow moves from a wider area into a narrower one; the narrowing of the area causes the airflow velocity to increase, resulting in higher-speed airflow. The septum effect is a concrete example of Bernoulli's theorem.

[0088] Spiral Involute Guide Slot: Early experiments showed that adding guide slots to the surface of wind turbine blades significantly increased wind energy utilization. The inventors subsequently applied for a patent, "Guide-type Wind Turbine Blade Structure (ZL2018102308354)". However, due to the lack of comprehensive theoretical guidance at the time, the guide slot was merely considered an auxiliary device on the wind turbine blade. Subsequent research further refined the relationship between the guide slot technology and airflow, as well as the relationship between the impeller and the flow field. In this invention, the early spiral involute guide slot is optimized into a structure of several variable-angle guide vanes, solving the problem of rain and snow accumulation within the spiral involute guide slot during rainy or snowy weather, which causes the impeller's center of gravity to shift.

[0089] Guide vanes: The "ideal wind turbine" structure of the wind turbine described in this invention is developed based on the concept of an ideal wind turbine proposed by the Bates hypothesis in Bates theory. An ideal wind turbine is actually a solid disk that completely blocks the airflow within its impeller range. This causes the airflow within the ideal wind turbine range to only circulate around the outer edge of the impeller. To effectively utilize this airflow, several guide vane structures are installed on the impeller. The guide vanes obtain the kinetic energy of the second type of airflow by blocking its normal flow and transfer this kinetic energy to the impeller structure to drive the impeller to rotate, thereby propelling the equipment to perform work.

[0090] Secondary flow: In fluid mechanics, secondary flow is defined as follows: If a flow along a boundary is deflected parallel to the boundary due to lateral pressure, the fluid layer closer to the boundary, due to its lower velocity, deflects more significantly than the fluid layer farther from the boundary. This results in a secondary flow superimposed on the main flow. Therefore, when airflow directly impacts the impeller (ideal wind turbine) surface, the airflow is blocked and stagnant by the impeller. However, the force of subsequent airflow and the reaction force of the impeller cause these gases, having lost kinetic energy, to continue moving and form a secondary flow. Because the impeller continues to rotate under the influence of wind force, and there is a pressure difference between the front and rear of the impeller, these stagnant airflows form a secondary flow.

[0091] Tensioned monolithic structure: A tensioned monolithic structure refers to "a self-supporting, self-stressed spatial grid structure composed of a set of continuous or discontinuous compression members and a set of continuous tension units." Its characteristic is that it uses very little material to support a large-scale three-dimensional spatial structure. Attached Figure Description

[0092] The above and other objects and features of the present invention will become clearer from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0093] Figure 01 is a hypothetical airflow field diagram in Bates theory, which can be found in all basic textbooks on Bates theory in the field of wind power generation;

[0094] Figure 02 shows the airflow field in a real environment after the airflow encounters the "ideal wind turbine" assumed by Bates theory.

[0095] Figure 03 is a cross-sectional diagram of the flow tube assumed in the Bates theory, where the annular region is the impeller swept surface. In the derivation of the Bates theory, the airflow outside the impeller swept surface is ignored.

[0096] Figure 04 is a cross-sectional diagram of the airflow tube based on the "range of airflow that can be affected" by an ideal wind turbine structure in a real environment. In the diagram, number 100 represents the impeller (ideal wind turbine), number 2 represents the second type of airflow, and number 1 represents the first type of airflow.

[0097] Figure 05 is a comparison table of impeller diameter, impeller surface area and total mass of air passing through the impeller area per unit time. The first row of the table is the impeller diameter, the second row is the impeller circumference, and the third row is the impeller area, corresponding to wind turbine impellers of different areas. Each column below is the total mass of air passing through the corresponding impeller area per second (in kilograms).

[0098] Figure 06 is a flow field diagram measured in a real environment based on an ideal wind turbine as assumed by the Bates theory. In order to classify the airflow, the location corresponding to each type of airflow is marked in detail. The number 1 represents the first type of airflow, the number 2 represents the second type of airflow, the number 3 represents the third type of airflow, the number 4 represents the negative pressure area of ​​air, and the number 100 represents the impeller.

[0099] Figure 07 is a three-view drawing of the structural model of the ideal wind turbine rotor and guide vanes described in this invention during operation. The figure shows the specific structure of the wind turbine rotor structure described in this invention during operation from different angles;

[0100] Figure 08 is a cross-sectional flow field diagram of the wind turbine impeller structure described in this invention. In the figure, 100 represents the impeller, and 206 represents the guide vane. After the airflow is blocked by the impeller and concentrated towards the outer edge of the impeller, it is "squeezed out" from the gap of the guide vane, achieving a jet effect;

[0101] Figure 09 is a cross-sectional view of the wind turbine impeller structure described in this invention after the guide vanes deform under the influence of wind force when encountering high wind speeds. The guide vanes are supported by an elastic material truss and deform into an arc surface under the influence of wind force. Type II airflow flows along the arc surface and is squeezed out from the gaps between the guide vanes to form a jet.

[0102] Appendix Figure 10 This is a cross-sectional view of the wind turbine impeller structure described in this invention after the guide vanes are fully deployed in extremely high wind speeds or rainy / snowy weather. After the impeller is deployed, the gap between the guide vanes also increases, allowing more airflow to escape through the gaps, reducing the pressure on the wind turbine impeller while ensuring its continued normal operation. When encountering extreme weather conditions such as hurricanes with extremely high wind speeds, the wind turbine impeller guide vanes are fully deployed, the impeller yaws, and the impeller is perpendicular to the wind direction. The airflow passes over the impeller surface without acting on it, thus protecting the impeller from damage by strong winds.

[0103] Appendix Figure 11 This is a schematic diagram of a wind turbine impeller tensioned integral structure, where the number 1 represents the wind direction, the number 100 represents the impeller structure, the number 101 represents the central shaft, the number 107 represents the tension rope, and the number 206 represents the guide vane.

[0104] Appendix Figure 12This is a schematic diagram of the wind turbine structure described in Specific Embodiment 1. In the figure, number 1 represents the wind direction, number 207 represents the tower structure, and the impeller is located at the rear of the tower. The wind turbine automatically aligns with the wind, and because no aligning device is needed, the manufacturing cost is reduced, which is conducive to its promotion and use in ordinary households.

[0105] Appendix Figure 13 This is a schematic diagram of the wind turbine structure described in Specific Embodiment 2. In the diagram, number 1 represents the wind direction, and number 207 represents the tower structure. The wind turbine rotor is located in front of the tower. The tower does not obstruct the airflow and affect the wind energy utilization rate of the wind turbine.

[0106] Explanation of icon numbers:

[0107] 1. Type I airflow; 2. Type II airflow; 3. Type III airflow; 4. Negative air pressure area; 100. Impeller; 101. Central shaft; 107. Pull rope; 206. Guide vane; 207. Tower; Detailed Implementation Specific Implementation Example 1:

[0109] Wind turbines can be categorized into active wind turbines and passive wind turbines based on their design requirements. Active wind turbines utilize a motor to drive the impeller to actively seek wind direction and align with the wind. In strong winds, the impeller can be yawed to resist the force of the wind. Passive wind turbines, on the other hand, rely on wind power to adjust the impeller's direction for wind alignment. Specific embodiment 1 illustrates a passive wind turbine.

[0110] Wind turbines can be categorized into small, medium, large, and super-large wind turbines based on impeller size and power output. The wind turbine described in Example 1 is a small, foldable wind turbine. The advantage of a small, foldable wind turbine lies in its impeller structure, which resembles a folding umbrella. Its simple structure and easy assembly / disassembly allow the impeller to be folded away, making it convenient to carry.

[0111] The wind turbine in Specific Embodiment 1 uses a wind turbine impeller with a diameter of 2 meters, a guide vane width of 0.4 meters, an impeller circumference of 6.3 meters, and an impeller surface area of ​​approximately 3.1 square meters.

[0112] The wind turbine described in this embodiment is a small, foldable wind turbine. It is suitable for use in various conditions such as self-driving camping, coastal residents, greenhouse growers, high-rise building rooftops, and nomadic tent homes. For example, during camping, the foldable feature of the wind turbine can be used to support a wind turbine when setting up a campsite to provide power to the camp.

[0113] As shown in Table 05 of the attached diagram, in specific embodiment 1, the wind turbine impeller carries approximately 12 kg of air per second within its rotor radius at a wind speed of 3 m / s (Force 2). At a wind speed of 10 m / s (Force 5), the air mass passing through the rotor radius per second is approximately 40 kg. At a wind speed of 30 m / s (Force 11), the air mass passing through the rotor radius per second is approximately 120 kg.

[0114] Therefore, as long as the wind turbine in this embodiment can start working at a wind speed of 3 meters per second and will not be destroyed by strong winds at a wind speed of 30 meters per second, it can meet the basic needs of users.

[0115] According to the actual measured data:

[0116] Under natural conditions with a wind speed of 3 meters per second (level 2 wind), the impeller speed is approximately 30 revolutions per minute;

[0117] In a natural environment with a wind speed of 5 meters per second (level 4 wind), the impeller speed is approximately 50-80 revolutions per minute;

[0118] Given that the impeller has a diameter of 2 meters and a radius of approximately 1 meter (1000 mm), and the impeller shaft has a diameter of 20 mm and a radius of 10 mm, the impeller torque amplification factor is approximately 100 times.

[0119] A 1:28.2 gearbox is installed behind the impeller to accelerate its rotational speed, ensuring sufficient torque output while maintaining a speed of approximately 800-2200 revolutions per minute. A custom-designed 3000W coreless disc generator is installed behind the gearbox, enabling continuous power output. A battery pack stores the wind turbine's intermittent electrical energy, which is then rectified and inverted to power electrical appliances.

[0120] In the specific experiment, the experimental tower was 2 meters high, the impeller shaft was 1.8 meters above the ground, carbon fiber rod (high-strength fishing rod material) was used as the impeller truss, and reinforced canvas was used as the wind turbine skin, thus completing the wind turbine impeller structure of this embodiment.

[0121] Appendix Figure 12 The wind turbine structure shown is a cross-sectional view of the wind turbine impeller structure of specific embodiment 1. Specific Implementation Example 2:

[0123] Specific embodiment 2 is an active wind turbine, in which the angle of the wind turbine is controlled by an electric motor to perform wind-fighting operation.

[0124] Specific embodiment 2 adopts a design with an impeller diameter of 8 meters, a guide vane width of 1.6 meters, an impeller circumference of 25 meters, and an impeller area of ​​approximately 50 square meters.

[0125] As shown in Table 05 of the attached diagram, in specific embodiment 2, the wind turbine impeller carries approximately 194 kg of air per second within its impeller radius at a wind speed of 3 m / s (Force 2). At a wind speed of 10 m / s (Force 5), the air mass passing through the impeller radius per second is approximately 647 kg. At a wind speed of 30 m / s (Force 11), the air mass passing through the impeller radius per second is approximately 1942 kg.

[0126] It is known that the area of ​​most common large freestanding outdoor billboards is 6 meters × 18 meters = 108 square meters. The area of ​​an 8-meter diameter impeller is only half that of a common large outdoor billboard. It is known that large outdoor billboards can survive under most natural wind conditions. Therefore, it can be inferred that the wind turbine impeller structure described in this specific embodiment has the same area and can also work for a long time under natural wind conditions.

[0127] As attached Figure 13 The wind turbine structure shown utilizes a wind-aligning device, allowing the impeller's windward side to automatically align with the wind, effectively utilizing wind energy. In the event of a hurricane, the wind-aligning device automatically yaws to prevent damage to the wind turbine. Specific Implementation Example 3:

[0129] The full-flow-resistance micro wind turbine technology as described in the claim is characterized in that the guide vane (206) can be fixed on the outer edge of the impeller or can be relatively independent, and the relatively independent guide vane can directly drive the equipment to do work.

[0130] In this embodiment, the guide vanes are relatively independent of the impeller (the ideal wind turbine shown in Figure 06). After the impeller blocks the airflow, a second type of airflow is formed. This second type of airflow diffuses along the impeller surface towards the outer edge of the impeller, and its velocity increases.

[0131] A bearing-like structure is set on the outer edge of the impeller, and the bearing structure is divided into an inner bearing ring and an outer bearing ring.

[0132] The outer edge of the impeller is fixed to the inner ring of the bearing, and several guide vanes are fixed to the outer ring of the bearing. At this time, when the second type of airflow pushes the guide vanes and drives the outer ring of the bearing to rotate, the inner ring of the bearing (impeller) remains relatively stationary.

[0133] A ring-shaped rack (track) is installed on the outer ring of the bearing, and one or more generators are installed on the impeller. The generators and the ring-shaped rack (track) are engaged by gears.

[0134] When the second type of airflow pushes the guide vanes, the guide vanes drive the outer ring of the bearing to rotate. The outer ring of the bearing drives the ring rack (track) to rotate, the ring rack drives the gear, and in turn drives the generator to do work. At this time, the inner ring of the bearing (impeller) is relatively stationary.

[0135] Compared to specific embodiment 2, this embodiment is applicable to large wind turbine structures.

[0136] As the impeller diameter increases, the impeller's weight also increases significantly. If the impeller as a whole is rotated as described in Specific Embodiment 2, it will cause a lot of additional burden on the impeller itself and bring huge frictional resistance to the central shaft (101).

[0137] In this embodiment, the guide vanes are relatively independent. The two types of airflow drive the guide vanes to rotate, which in turn drives the outer ring of the bearing to move rapidly, causing the mechanical structure to perform work and significantly reducing the pressure on the central shaft. Furthermore, since the impeller does not need to rotate in this technical solution, its connection to the tower can employ a more robust technical solution. For example, a technical solution similar to that used in tower cranes or radar equipment could be adopted.

[0138] When designing large or super-large wind turbines, this specific embodiment is superior to specific embodiment 2 in terms of practicality and the difficulty of implementing the technical solution.

[0139] While embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. However, it should be understood that, to those skilled in the art, these modifications and variations will still fall within the spirit and scope of the invention as defined in the claims.

Claims

1. A fully obstructed micro-wind turbine, characterized in that, The wind turbine includes an impeller body and several guide vanes. The impeller body is a micro-wind turbine structure that can completely block the airflow path within the impeller range. The impeller body adopts a tensioned integral structure design, which is composed of a truss, ropes and skin to form an elastic whole. The ropes decompose the pressure borne by the windward side of the impeller body. The plurality of guide vanes are disposed on the outer edge of the windward surface of the impeller body, and are a plurality of guide vane structures with variable angles; The guide vane has a deformation function, which can adapt to different environmental meteorological conditions by utilizing the deformation of the guide vane, thereby adapting to rain and snow weather and preventing the impeller center of gravity from shifting or the load from being increased due to snow accumulation or icing. The air guide vane forms a concave arc surface structure after deformation, and absorbs air kinetic energy while changing the airflow direction based on the principle of curved circulation. Type I airflow refers to airflow that flows normally in the natural environment without being affected by the impeller. When Type I airflow impacts the impeller surface, the airflow exerts an axial force on the impeller. Because the impeller is fixed to the tower, the axial static net force of the impeller itself is greater than the axial force exerted by the airflow on the impeller. Therefore, the impeller will exert a continuous reaction force on the airflow impacting the impeller, causing the airflow to stagnate. However, because the airflow is continuous, the subsequent airflow will continue to exert an axial force on the airflow in front, while the impeller will exert a continuous reaction force on the airflow. The two forces will compress the airflow, causing the airflow to flow from the impeller surface to the outer edge of the impeller. This compressed airflow flows out from the outer edge of the impeller after passing through the wind turbine impeller. At this time, the airflow direction, airflow velocity, and air density have all changed, and the changed airflow is called Type II airflow. When the wind speed is low, the guide vanes are at a 90-degree angle to the impeller. At this time, the guide vanes are upright, turning the impeller into a concave container. There are gaps between the guide vanes, and the area of ​​the gaps is smaller than the total area of ​​the windward surface of the impeller. When the wind speed is high, the guide vanes deform into an arc-shaped structure under the influence of the wind force, guiding the secondary airflow within the impeller range to concentrate at the outer edge of the impeller and accelerate out through the gaps between the guide vanes; When the wind speed is extremely high, the guide vanes are fully deployed, which increases the gap between the guide vanes and allows the airflow to escape from the gap between the guide vanes, thereby reducing the pressure on the wind turbine rotor. A rotary bearing structure is provided between the guide vane and the impeller body, and the rotary bearing structure includes an inner bearing ring and an outer bearing ring arranged coaxially. The inner ring of the bearing is fixedly connected to the outer edge of the impeller body. The guide vane is fixed on the outer ring of the bearing. The outer ring of the bearing is provided with an annular rack. The impeller is provided with one or more generators. The generators and the annular rack are meshed with gears. When the second type of airflow pushes the guide vane, the guide vane drives the outer ring of the bearing to rotate. The outer ring of the bearing drives the annular rack to rotate. The annular rack drives the gears, which in turn drive the generator to do work. The inner ring of the bearing remains relatively stationary.

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