A Venturi ejector + rotor lift load reduction controllable thermo-eddy current grid power generation system

Abstract

This invention provides a Venturi ejector + rotor lift-controlled temperature difference eddy current grid-connected power generation system and a wind turbine upgrade application scheme. The system utilizes a controllable temperature difference to generate rising heat flow from the chimney, which, after being enhanced by a Venturi structure, drives the horizontal rotor. The rotor relies on aerodynamic lift to achieve levitation and load reduction, coaxially driving a large-inertia grid-connected generator within the hub to generate electricity. It possesses strong grid support capabilities and all-weather operation characteristics. This technology can be used to upgrade existing horizontal-axis wind turbines, improving power generation quality and operating time, and revitalizing existing heavy assets.

Description

Technical Field

[0001] This invention relates to the field of new energy wind power generation technology, specifically to an integrated system that relies on controllable temperature difference heat flow in the chimney, Venturi ring ejector for efficiency enhancement, large-diameter horizontal rotor jet booster, rotor aerodynamic lift suspension for load reduction, and hub-concentrated large inertia grid-type power generation unit. It also relates to the application scheme of this system in the technical upgrading of existing horizontal axis wind turbine units. Background Technology

[0002] Currently, mainstream power generation methods are divided into four main categories: fossil fuel thermal power, conventional hydropower, traditional wind power, and photovoltaic power. Thermal power uses fossil fuels such as coal, oil, and natural gas as energy sources, resulting in high carbon emissions, high fuel costs, and significant challenges in environmental governance. Conventional hydropower is subject to strict site selection constraints due to hydrological conditions and topographical differences. Photovoltaics rely on sunlight, and traditional wind turbines rely on natural wind power; both types of power generation exhibit significant intermittency and volatility. Traditional wind turbines passively generate electricity using natural wind speeds, and cannot operate normally under fluctuating wind speeds, no wind, or light wind conditions, resulting in low energy utilization and limited effective power generation time. Furthermore, these units can only be connected to the grid using full-power converters, making them current sources without physical rotational inertia. They cannot achieve autonomous voltage and frequency establishment on an isolated grid, and are prone to large-scale grid disconnection during grid failures, making it difficult to guarantee continuous and stable power supply to loads in industrial parks and remote areas. In addition, the rotating bearings of wind turbines are subjected to the weight of the rotating pair and wind impacts over long periods, resulting in high frictional losses, high starting wind speed thresholds, and high subsequent operation and maintenance costs. Based on the current state of the industry, there is an urgent need to develop a new type of grid-connected power generation equipment that does not rely on natural wind power, can operate continuously with low energy consumption around the clock, has its own physical inertia, and supports black start and islanded operation. Summary of the Invention

[0003] To address the problems of existing wind turbines, such as lack of physical inertia, stringent start-up and operation conditions, high mechanical losses, poor power generation stability, and inability to operate independently in grid-connected systems, this invention provides a Venturi ejector + rotor lift load reduction controllable thermo-vortex grid-connected power generation system. This system generates rising hot airflow through a chimney effect created by a controllable heat source within the tower. This airflow is accelerated and amplified by an annular Venturi ejector structure at the top of the tower. The high-speed airflow enters the internal flow channel of a large-sized horizontal rotor and is ejected tangentially from the converging nozzle at the wingtip, using the jet thrust to drive the rotor. During rotor operation, aerodynamic lift is generated across the entire rotational pair, offsetting the weight of the entire rotating pair and allowing the bearings to operate in a quasi-suspended, low-resistance state. The rotor's main shaft coaxially drives a large-inertia, low-speed, synchronous grid-connected generator within the hub. The system combines thermal energy regulation, thermo-vortex effect, and aerodynamic energy to achieve composite work, possessing functions such as physical inertia support, primary grid frequency regulation, low-voltage ride-through, black start, and islanded grid load carrying. Meanwhile, the power working principle of this invention can be applied to the technical upgrading of existing horizontal axis wind turbine units. By adding a Venturi ejector structure, modifying the blade guide air duct and wingtip nozzle, and replacing the generator with a large inertia grid-connected generator, the traditional unit that operates inefficiently and intermittently can be transformed into a high-quality grid-connected power asset that can generate electricity stably around the clock and has grid inertia support capability.

[0004] The technical solution adopted in this invention is as follows: a Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system, characterized in that: it includes a tower base controllable heat source unit (1), a vertical chimney tower (2), an annular Venturi ejector enhancement assembly at the top of the tower (3), a large-diameter horizontal rotor assembly (4), a wingtip convergent jet booster mechanism (6), a tower top hub support assembly (7), and a central large inertia grid power generation unit (9); the tower base controllable heat source unit (1) is equipped with Located at the air inlet at the bottom of the tower, a dual-source heating structure combining solar thermal collection and industrial waste heat reuse continuously heats the air entering the tower, creating an upward airflow due to temperature difference. The chimney tower has an inner diameter of 10m and a total height of 120m, with the interior forming the main airflow channel for the chimney effect. The annular Venturi ejector enhancement assembly is seamlessly fixed to the upper outlet of the tower, forming an annular shape that completely covers the tower's flow cross-section. It consists of three parts: a tapering section, a throat section, and a micro-diffuser section. The throat section narrows... The ratio is 1.5~2.0; the length of a single blade of the horizontal rotor assembly is 40m, the overall rotation diameter of the rotor is 80m, multiple blades are evenly arranged radially along the hub, and a through-type sealed air duct (5) is opened inside each blade. The inlet of the air duct is connected to the diffuser outlet of the Venturi structure, and the end is connected to the wingtip convergent nozzle (6); the wingtip convergent jet booster mechanism is set at the rear end of each blade, and the nozzle outlet direction is arranged obliquely along the rotor rotation tangent. It relies on the reaction force generated by the high-pressure air jet to form an additional driving torque; the hub support assembly (7) is installed above the center of the Venturi structure. It is equipped with a slewing main bearing, which supports the entire rotating pair composed of the horizontal rotor and the power generation unit; the large inertia grid power generation unit (9) is integrated and installed in the hub nacelle. The generator input main shaft is rigidly coaxially connected to the rotor main shaft. The power generation unit is equipped with a grid-type PCS converter (10) and an EMS energy management and monitoring system (11). As a preferred option, the horizontal rotor (4) adopts a lifting airfoil with a convex upper part and a flat lower part. When the unit is running under rated operating conditions, the aerodynamic lift generated by the rotor itself is superimposed with the upward thermal flow lift of the tower, which can offset 70%~80% of the overall weight of the rotating pair composed of the rotor and the hub. The slewing main bearing only bears the positioning residual load, realizing a near-floating low-resistance rotation.

[0005] As a preferred option, the total effective area of ​​the wingtip nozzles of the entire system is set to 0.55 times the cross-sectional area of ​​the tower. The total nozzle area is evenly distributed to each wingtip nozzle according to the number of blades to ensure a reasonable match between airflow and jet velocity, thereby maximizing the output power of the entire machine.

[0006] As a preferred option, the Venturi throat (3) forms a low-pressure ejection zone during the airflow acceleration process. It can draw in the bottom airflow through the air inlet at the bottom of the tower and draw in the ambient air outside the tower through the air duct at the top of the tower. The multiple negative pressure flow effectively improves the overall airflow of the system. Compared with equipment without the Venturi structure, the power generation of the whole machine can be increased by 20% to 35%.

[0007] As a preferred option, the large inertia grid-connected power generation unit (9) uses a low-speed permanent magnet synchronous generator, which provides inertial support to the power grid based on the mechanical inertia of the rotor. The system's equivalent inertia constant H = 0.3~0.6s, which can achieve 50Hz power frequency stabilization, millisecond-level switching between off-grid and on-grid modes, low-frequency ride-through of grid faults, and autonomous voltage building during black start.

[0008] As a preferred option, the controllable heat source (1) of the tower base can use industrial waste gas, geothermal waste heat, or concentrated solar energy as the heating source, either alone or in combination. The operation process does not require the combustion of fossil fuels, thus achieving clean all-weather gas generation and power generation.

[0009] As a preferred option, the inner wall of the chimney tower (2), the inner wall of the internal air guide channel (5) of the blade, and the inner wall of the wingtip convergent nozzle (6) are all coated with a hydrogen-free DLC diamond-like carbon wear-resistant and corrosion-resistant coating with a thickness of not less than 5μm, so as to reduce the airflow loss along the way and delay the occurrence of cavitation and scaling problems.

[0010] As a preferred option, the integrated working mechanism of the present invention, which combines the controllable temperature difference chimney effect, Venturi ejector enhancement, wingtip jet boost, rotor lift load reduction, and large inertia grid-based power generation, can be applied to the power retrofit of existing horizontal axis wind turbine units. The retrofit process does not require modification of the main structure of the unit, but only local optimization: adding a supporting device (1) to realize the temperature difference chimney effect and a Venturi ejector structure (3), adding a guide air passage to the original blades and assembling wingtip nozzles (6), spraying a hydrogen-free DLC diamond-like carbon wear-resistant and corrosion-resistant coating with a thickness meeting the standard on the inner wall of the air passage, and replacing the original generator with a large inertia grid-based generator (9). After the retrofit, the unit has dual working modes that can be automatically switched and operated in coordination: one is the original passive wind-driven mode, which is adapted to operation under rated wind speed conditions; the other is the newly added temperature difference jet driven mode, which is put into use under no wind, light wind, and low wind speed conditions as an auxiliary power source. The two modes complement each other and operate in coordination to ensure that the unit maintains its rated full-load state under all operating conditions. The upgraded unit has broken free from the limitation of relying solely on natural wind, completely improving the original problems of large power generation fluctuations and poor grid connection quality. It has been upgraded to a voltage source with all-weather stable power generation capability and grid inertia support capability, enabling continuous full-load operation throughout the year.

[0011] Compared with existing technologies, this invention has the following beneficial effects: 1. Relying on the controllable temperature difference chimney effect, the unit's operation is not limited by natural wind speed. Through photovoltaic energy storage heating and industrial waste heat, it continuously generates rising hot airflow, achieving uninterrupted power generation around the clock, effectively solving the intermittent shutdown problem of traditional wind power. 2. The annular Venturi ejector structure set at the top of the tower can pressurize and accelerate the airflow, and enhance the ejector flow, achieving aerodynamic efficiency enhancement. Under the same temperature difference conditions, it significantly increases the intake airflow and air kinetic energy, improving the system's output power. 3. Utilizing the tangential jet at the wingtip to generate thrust and form torque, it drives the rotating pair to rotate and do work, converting mechanical energy into electrical energy. 4. The aerodynamic lift generated by the rotor rotation can offset the weight of the rotating pair, effectively reducing the load on the main bearing and mechanical friction loss, increasing the overall power generation efficiency of the unit by 8%~12%, extending bearing life by more than 30%, and significantly reducing equipment maintenance costs. 5. The generator is integrated into the central hub, relying on the rotor to generate large physical inertia. Unlike conventional inertia-free converter wind turbines, it can participate in primary grid frequency and voltage regulation, possessing resistance to grid disturbances, islanded grid load capacity, and black start capabilities. It is suitable for various application scenarios such as weak grids, islanded grids, and industrial and mining self-owned power stations. 6. The system does not require continuously operating high-energy-consuming auxiliary equipment. It mainly utilizes photovoltaic electromagnetic high-frequency heating, or uses solar heat exchange and industrial waste heat as heat sources, achieving zero carbon emissions throughout its entire life cycle, meeting development requirements. 7. The power principle of this invention can be applied to the technical upgrading of existing horizontal axis wind turbine units. Through low-cost retrofitting, traditional wind turbines with unstable output and low utilization hours can be upgraded into high-quality grid-connected power generation assets with grid inertia support capabilities, generating electricity 24 / 7. Attached Figure Description

[0012] Figure 1 This figure shows the overall elevation structure of the system of the present invention, illustrating the vertical assembly relationship of the entire system. Figure 2 Schematic diagram of the horizontal rotor's top-down planar structure. Figure 3 : Schematic diagram of blade structure and wingtip nozzle cross section. Figure 4 : Topology diagram of airflow and energy transfer in the whole system; This diagram is a topology diagram of airflow and energy transfer in the whole system, showing the entire link of medium, energy and control.

[0013] 1-Controllable heat source unit at the tower base; 2-Chimney tower; 2-1 Air inlet at the bottom of the tower; 2-2 Negative pressure drainage hole at the top of the tower; 3-Annular Venturi throat ejector assembly; 3-1 Airflow inlet at the throat; 4-Horizontal rotor assembly; 5-Buzzer-mounted air duct; 6-Wingtip convergent nozzle; 7-Hub support assembly; 8-Slewing main bearing; 9-Large inertia grid-type power generation unit; 10-PCS grid-type converter; 11-EMS energy management system; 12-Tensioned steel wire reinforcement structure; 13-Lightning protection and lightning protection device; 14-Photovoltaic + energy storage power supply device. Specific Implementation Example 1: Full-condition operation of a newly built unit

[0015] like Figures 1 to 4 As shown, this system includes a controllable heat source unit 1 at the base, a vertical chimney tower 2, an annular Venturi ejector enhancement assembly at the top of the tower 3, a large-diameter horizontal rotor assembly 4, a wingtip convergent jet booster mechanism 6, a hub support assembly at the top of the tower 7, and a central high-inertia grid-connected power generation unit 9. The tower 2 is constructed of corrosion-resistant reinforced concrete, with an inner diameter of 10m and a total height of 120m. An annular air inlet is located at the bottom, and the controllable heat source 1 at the base is installed on the outside of the air inlet. This embodiment employs a composite heating method combining industrial waste heat from the plant's smelting sector with concentrated solar energy. Room temperature air is heated to form a high-temperature airflow, which flows upwards along the interior of the tower due to the chimney's thermal buoyancy effect.

[0016] The top of the tower is seamlessly connected to the annular Venturi assembly 3, which covers the entire flow section of the tower. The throat contraction ratio of the three-section Venturi structure is set to 1.8. The airflow completes the conversion from static pressure to dynamic pressure and accelerates as it flows through the contraction section. The throat area forms a negative pressure ejection zone, which continuously draws in cold air from the bottom of the tower. Negative pressure drainage holes 2-2 are evenly opened on the wall of the section where the tower and Venturi are connected. An airflow inlet hole 3-1 is set at the upper end of the Venturi. The two structures work together to draw in ambient air from outside the tower. The multiple ejection effects effectively increase the total intake air volume. After the airflow is rectified and stabilized by the micro-diffuser section, it is evenly distributed to the guide air passages 5 at the root of each blade.

[0017] The rotor assembly 4 is equipped with 6 carbon fiber integrally molded blades, each blade is 40m long, and the rotor rotation diameter is 80m. The blades adopt an upward convex and downward flat lifting airfoil, and have a through-type sealed airflow duct 5 inside, the end of which connects to the wingtip convergent nozzle 6. The tower cross-sectional area is 78.54m², and the total cross-sectional area of ​​the wingtip nozzle is set at 0.55 times the cross-sectional area of ​​the tower, totaling about 43.2m². The nozzle area corresponding to each blade is about 7.2m². The nozzle flows out obliquely downward along the rotor rotation tangent, and the rotor rotation is driven by the reverse thrust of the airflow. Tensioned steel wire reinforcement structure 12 is added between the rotors to improve the overall rigidity and flutter resistance.

[0018] The hub support assembly 7 is located above the center of the venturi structure and is equipped with a heavy-duty slewing main bearing 8. The entire rotating pair consisting of the rotor and the power generation equipment is supported by the main bearing 8. When the unit is running, the aerodynamic lift of the rotor combined with the heat flow lifting force at the bottom can offset 82% of the weight of the rotating pair. The main bearing only bears the positioning load, realizing suspended low-friction operation and increasing the overall power generation efficiency by an additional 9.5%.

[0019] A 2.5MW high-inertia low-speed synchronous grid-connected power generation unit 9 is coaxially mounted at the hub center, with a system equivalent inertia H=0.42s. The power generation unit is equipped with a PCS grid-connected converter 10 and an EMS energy management system 11. After converting mechanical energy into electrical energy, it outputs 50Hz industrial frequency AC power, which is supplied to the plant's production load 13 and the public power grid 14. The EMS system monitors parameters such as temperature, airflow velocity, speed, and power in real time, enabling fault interlocking and remote operation and maintenance. The propeller guide air duct and the inner wall of the wingtip nozzle are coated with a hydrogen-free DLC diamond-like carbon coating with a thickness of not less than 5μm, which has the characteristics of wear resistance, cavitation resistance, and scale prevention.

[0020] After the addition of the Venturi structure, the power generation capacity of this system is increased by 31% compared with ordinary units of the same specifications. The project only requires a one-time investment in civil engineering and equipment in the early stage. During the operation phase, it utilizes industrial waste heat and solar energy, with no fossil fuel consumption. The annual power generation time can reach 8760 hours, with an average annual net power generation of about 21.6 million kWh, reducing carbon dioxide emissions by about 17,000 tons per year. It can achieve island black start operation with load and is suitable for power supply scenarios such as self-owned power stations in industrial parks and remote mining areas.

[0021] Example 2: Upgrading and Retrofitting of Existing Horizontal Axis Wind Turbine Units In this embodiment, a 2.0MW existing horizontal axis wind turbine was selected for retrofitting, and the original tower foundation and main support structure were preserved throughout the process. The specific modification procedures are as follows: First, a controllable heat source unit for the tower base is installed at the bottom of the tower, along with a waste heat recovery device for the plant area, to continuously generate rising hot airflow; Second, an annular Venturi ejector assembly matching the size of the tower body is installed at the top of the tower to achieve airflow acceleration and flow enhancement; Third, the original blades are structurally modified by opening a through-type guide air duct and installing a wingtip convergent nozzle, with the total cross-sectional area of ​​the nozzle configured to be 0.55 times the cross-sectional area of ​​the tower; Fourth, a hydrogen-free DLC diamond-like carbon wear-resistant and corrosion-resistant coating is sprayed on the inner wall of the blade guide air duct and the wingtip nozzle; Fifth, a negative pressure guide hole is added in the area where the tower and the Venturi assembly meet, and an airflow inlet hole is set at the upper end of the Venturi to improve the secondary ejector structure; Sixth, the original generator is replaced with a high-inertia grid-type low-speed synchronous generator, and a PCS grid converter and an EMS energy management system are installed.

[0022] After the upgrade, the unit can operate stably by relying on controlled temperature difference hot airflow, overcoming the limitations of solely relying on natural wind speed. The aerodynamic lift generated by the rotor can effectively share some of the rotating pair load, reducing the pressure and mechanical wear on the slewing bearing, extending the bearing maintenance cycle to three times that before the upgrade; the unit's equivalent inertia H=0.38s, possessing primary frequency regulation capability for the grid, significantly improving fault ride-through performance, and achieving an annual utilization of up to 8760 hours. This upgrade completely improves the original unit's defects of large power generation fluctuations and poor grid connection stability, upgrading it into a high-quality grid-connected power asset with stable operation and adaptability to grid requirements.

[0023] This upgrade effectively solved the problems of large power generation fluctuations and poor grid connection quality of the original units, transforming them into stable, high-performance grid-connected power assets. This invention integrates five core structures: controllable temperature difference heat generation, Venturi jet current enhancement, wingtip jet torque enhancement, rotor aerodynamic suspension for load reduction, and high-inertia grid-connected power generation. It overcomes the technical shortcomings of traditional new energy power generation from multiple dimensions, including heat source, aerodynamics, mechanics, and electrical systems. Simultaneously, it provides a low-cost, high-return technical upgrade path for existing inefficient wind turbine units, demonstrating significant industrial application value.

Claims

1. A Venturi ejector + rotor lift load reduction controllable thermodynamic eddy current grid power generation system, characterized in that: The system includes a controllable heat source unit at the base, a vertical chimney tower, an annular Venturi ejector enhancement assembly at the top of the tower, a large-diameter horizontal rotor assembly, a wingtip convergent jet booster mechanism, a hub support assembly at the top of the tower, a central high-inertia grid-connected power generation unit, an EMS energy management system, and a PCS grid-connected converter. The controllable heat source unit at the base is located at the air inlet at the bottom of the tower and is used to heat the ambient air to create an upward airflow due to the temperature difference. The chimney tower has an inner diameter of 10m and a height of 120m, and the interior of the tower forms a chimney-effect airflow channel. The annular Venturi ejector enhancement assembly is sealed and fixed at the upper outlet of the tower. The entire annular structure fully covers the flow cross section of the tower and consists of three sections: a tapering section, a throat section, and a micro-diffuser section. The throat contraction ratio is 1.5~2.

0. The effective length of each blade of the horizontal rotor is 40m, and the overall rotor rotation diameter is 80m. The blade has a through-type airflow guide channel. The airflow inlet connects to the Venturi diffuser chamber, and the airflow outlet connects to the wingtip convergent nozzle. The wingtip convergent jet booster mechanism is located at the outer end of each blade. The nozzle outlet direction is inclined along the rotor rotation tangent, and the airflow jet reaction force forms an additional driving torque. The hub support assembly is located at the center of the Venturi structure and has a built-in slewing main bearing. The slewing main bearing is used to support the entire rotating pair consisting of the horizontal rotor assembly and the power generation unit. The large inertia grid-connected power generation unit is integrated and installed inside the hub nacelle, with the generator input main shaft rigidly coaxially connected to the rotor main shaft; the power generation unit is equipped with a grid-connected PCS converter and an EMS energy management system.

2. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The horizontal rotor adopts an airfoil with an upper convex shape and a lower flat shape for lifting. When the rotor is working, it relies on the airfoil pressure difference lift and the upward heat flow from the tower to lift, which offsets 70% to 80% of the weight of the entire rotating pair. The main bearing achieves quasi-suspended operation under low load.

3. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The total effective area of ​​the wingtip nozzles of the entire system is taken as 0.55 times the cross-sectional area of ​​the tower. The total nozzle area is evenly distributed according to the number of blades to achieve the optimal power output of the whole machine.

4. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The annular venturi assembly throat forms a low-pressure ejector zone, and the negative pressure suction tower bottom intakes air, increasing the total air mass flow rate of the system. The overall power is increased by 20% to 35% compared to the structure without venturi.

5. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The large inertia grid-connected power generation unit is a low-speed permanent magnet synchronous generator with an equivalent inertia constant H of 0.3~0.6s. It has functions such as power frequency voltage and frequency stabilization, off-grid and on-grid dual-mode switching, grid fault ride-through, and black start autonomous voltage building.

6. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The inner wall of the internal airflow channel of the propeller blade and the inner wall of the wingtip nozzle are coated with a hydrogen-free DLC diamond-like carbon anti-corrosion and wear-resistant coating with a coating thickness of ≥5μm.

7. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The controllable heat source of the tower base is powered by photovoltaic and energy storage batteries. It can adjust the heater temperature in real time by collecting grid data to form negative feedback commands. The heat source can be any one or more combinations of industrial waste heat, geothermal heat source, and concentrated solar energy. The operation process does not consume fossil fuels.

8. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The upper part of the tower is provided with a negative pressure drainage hole, and the micro-diffraction section at the upper end of the Venturi ejector enhancement assembly is provided with an airflow inlet hole. The two work together; the high-speed airflow inside the tower flows through the Venturi throat and generates negative pressure in the micro-diffraction section, which draws in the ambient air in the upper part of the outer side of the tower, forming a passive ejector enhancement effect, and increasing the airflow velocity and flow rate entering the rotor channel.

9. The Venturi ejector + rotor lift load reduction controllable temperature difference eddy current grid power generation system according to claim 1, characterized in that: The working mechanism of the present invention, which integrates controllable temperature difference chimney effect, Venturi ejector enhancement, wingtip thruster, rotor lift load reduction, and large inertia grid-connected power generation, is applied to the power technology upgrade of existing horizontal axis wind turbine units. The upgraded wind turbine units are freed from dependence on natural wind and become grid-connected power units with all-weather stable power generation and grid inertia support capabilities, and can operate continuously and stably throughout the year.

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