A fan noise reduction system utilizing biomimic serrated trailing edge to cut airflow

Abstract

The application discloses a fan noise reduction system utilizing bionic sawtooth trailing edge to cut airflow, and belongs to the technical field of fan aerodynamic noise control, and comprises a fan main body, a bionic sawtooth blade assembly, a working condition sensing module and an intelligent control module. Parameterized adjustable bionic sawtooth structures are arranged at trailing edges of each blade, the sawtooth tooth height and tooth spacing are linearly changed along the span, the tip is circularly arc transitioned, pressure relief micro-holes are arranged on the upstream side of the blade, and trailing edge vortex generation is double inhibited. An ultrathin piezoelectric ceramic driving assembly tooth root is embedded in the blade, fatigue-resistant fiber polyurethane flexible sealing is connected, and gap secondary noise is eliminated. Multiple sensing components are arranged in the air duct to collect three-dimensional working condition data of rotation speed, flow rate and noise, an artificial intelligence working condition model with weight calculation and convergence logic is built in the intelligent control module, an optimal sawtooth deflection angle is adaptively output, a sensor failure fault tolerance mechanism is carried on the module, and the module is automatically returned to a safe angle in an abnormal state.

Description

Technical Field

[0001] This invention relates to the field of Internet of Things sensing and artificial intelligence control technology, specifically to a fan noise reduction system that utilizes a biomimetic sawtooth trailing edge to cut airflow. Background Technology

[0002] As a core general-purpose device for fluid transport and ventilation, fans are widely used in many fields such as industrial production, building ventilation, rail transportation, and new energy equipment. Aerodynamic noise generated during fan operation is its main source of noise. High-frequency whistling and broadband aerodynamic noise caused by boundary layer separation at the blade trailing edge and the periodic shedding of trailing-edge vortices account for the majority of the overall noise radiation from fans, and has long been a key issue restricting the development of low-noise and high-performance fans. Continuous fan noise not only causes noise pollution in the working environment, affecting the comfort and safety of people in the equipment operating area, but long-term high-intensity noise radiation can also cause structural resonance, component fatigue aging, and shorten the service life of the entire fan. Currently, most methods for controlling fan noise in the industry rely on passive silencing technology. Mainstream solutions include installing silencers, laying sound insulation cotton, installing soundproof enclosures, and optimizing duct structures. These noise reduction methods achieve their effect by blocking and absorbing noise in the propagation path, but they do not address the generation of aerodynamic noise at the source. These traditional noise reduction methods have many inherent technical limitations. Passive silencing structures only attenuate noise in a fixed frequency band, with a narrow effective operating frequency range. They cannot adapt to the complex operating scenarios of fan speed fluctuations, duct resistance changes, and variable airflow conditions during actual operation. When the fan operates under different conditions, the dominant noise frequency shifts, and the noise reduction effect is significantly reduced. Furthermore, external silencing and sound insulation structures are prone to dust accumulation, blockage, aging, and deformation over long-term use, gradually losing their noise reduction performance. This necessitates frequent cleaning, replacement, and maintenance, resulting in high overall operating costs. In addition, external noise reduction components are bulky, which will occupy a lot of equipment installation space, and will also change the original aerodynamic structure of the air duct, increase the airflow resistance, and reduce the aerodynamic output efficiency of the fan to a certain extent. There is a contradiction between noise reduction and operating efficiency. To improve the aerodynamic noise problem of wind turbines, some optimization solutions for wind turbine blade structures have emerged in existing technologies. A common approach is to install a fixed serrated structure at the blade trailing edge, achieving a certain noise reduction effect by simply disrupting the trailing edge vortex morphology. However, current serrated structures are all fixed, with no adjustable tooth height, tooth pitch, or installation angle. They can only adapt to the airflow characteristics under a specific rated operating condition, achieving limited noise reduction only under a single condition. When the wind turbine experiences changes in speed, airflow velocity in the duct, or fluctuations in pipeline resistance, the fixed serrated structure cannot match the real-time airflow vortex intensity, making it difficult to continuously and effectively separate the boundary layer airflow and suppress vortex shedding, resulting in poor noise reduction stability. Furthermore, the fixed serrated structure adds extra aerodynamic drag to the blades under low load and low speed conditions, causing a decrease in wind turbine airflow and an increase in operating energy consumption. It cannot balance noise reduction performance with wind turbine aerodynamic efficiency, exhibiting significant shortcomings in adaptability and practicality.

[0003] To address this, we propose a fan noise reduction system that utilizes a biomimetic sawtooth trailing edge to cut the airflow. Summary of the Invention

[0004] One of the technical problems this application aims to solve is that current wind turbine noise reduction technologies generally suffer from many technical defects, such as poor adaptability to operating conditions, unstable noise reduction effect, high operation and maintenance costs, large aerodynamic efficiency loss, low structural adjustment precision, and insufficient fault tolerance in extreme operating conditions. Therefore, there is an urgent need for an intelligent wind turbine noise reduction system that can adapt to changing operating conditions, has excellent noise reduction effect at the source, strong structural stability, and can balance noise reduction performance with wind turbine aerodynamic efficiency.

[0005] To address the aforementioned technical problems, this application provides a fan noise reduction system that utilizes a biomimetic serrated trailing edge to cut airflow, comprising a fan body, a biomimetic serrated blade assembly, a working condition sensing module, and an intelligent control module. The biomimetic sawtooth blade assembly is mounted on the rotating end of the wind turbine body. The biomimetic sawtooth blade assembly includes several blades, and each blade trailing edge is provided with a parameterized adjustable angle biomimetic sawtooth structure. The biomimetic sawtooth structure is used to cut the boundary layer airflow at the trailing edge of the blade and block the periodic shedding of the trailing edge vortex. The operating condition sensing module is installed in the main air duct of the wind turbine to collect multi-dimensional operating condition data such as wind turbine operating speed, airflow velocity in the air duct, and aerodynamic noise decibel value in real time, and transmit the collected data to the intelligent control module. The intelligent control module is electrically connected to the working condition sensing module and the bionic sawtooth blade assembly. The intelligent control module has built-in working condition matching control logic, which can adaptively adjust the deflection angle of the bionic sawtooth structure based on the real-time collected working condition data, and simultaneously balance the aerodynamic output efficiency and aerodynamic noise suppression effect of the fan. The biomimetic sawtooth blade assembly integrates a lightweight micro-drive mechanism, which is equipped with a centrifugal force compensation structure to counteract the centrifugal load generated by the high-speed rotation of the fan, ensuring stable operation of the biomimetic sawtooth structure under high-speed conditions.

[0006] In some embodiments, the biomimetic sawtooth structure is a parametrically adjustable sawtooth with a rounded transition at the tip. The tooth height and pitch of the sawtooth on a single blade are arranged in a linearly gradual manner along the blade span.

[0007] In some embodiments, the micro-drive mechanism is a piezoelectric ceramic drive component, which is embedded in the internal cavity of the blade. The piezoelectric ceramic drive component is connected to the intelligent control module. The piezoelectric ceramic drive component is used to independently drive the biomimetic sawtooth structure of the corresponding blade trailing edge to complete the angle deflection in the range of 0°-30°. The piezoelectric ceramic drive component adopts an ultra-thin and lightweight package, which is suitable for the narrow installation space inside the blade.

[0008] In some embodiments, a row of pressure relief micro-holes is formed along the spanwise direction of the blade body. The pressure relief micro-holes are located on the upstream side of the biomimetic sawtooth structure. The pressure relief micro-holes are used to guide the airflow accumulated on the boundary layer of the blade surface and help to weaken the intensity of vortex generation.

[0009] In some embodiments, the operating condition sensing module includes a speed sensor, an airflow pressure and velocity composite probe, and a distributed noise acquisition microphone array. The speed sensor is fixed to the end of the fan main shaft, and the airflow pressure and velocity composite probe and the distributed noise acquisition microphone array are evenly arranged on the walls of the fan inlet and outlet ducts.

[0010] In some embodiments, the intelligent control module incorporates an artificial intelligence operating condition model. This model pre-stores multiple sets of matching databases for sawtooth angle, noise reduction, and aerodynamic efficiency under varying wind turbine operating conditions. The model uses wind turbine speed, airflow velocity, and noise decibels as three-dimensional input features, assigns corresponding calculation weights, and sets iterative convergence judgment logic. The intelligent control module compares real-time operating condition data with the matching database and outputs the optimal adjustment angle command for the bionic sawtooth structure. The intelligent control module also incorporates a sensor failure tolerance mechanism. When the signal collected by the operating condition sensing module is lost or exceeds the normal threshold, it automatically controls all bionic sawtooth structures to return to the preset safety reference angle.

[0011] In some embodiments, the blade substrate of the biomimetic sawtooth blade assembly is integrally molded from a high-strength, lightweight, and wear-resistant polymer material, the leading edge of the blade is treated with a passivated arc, and the blade surface is sprayed with a low-friction and noise-reducing coating.

[0012] In some embodiments, the piezoelectric ceramic drive assembly is equipped with an angle position feedback sensor, which transmits the current deflection angle of the bionic sawtooth structure back to the intelligent control module in real time, forming a closed-loop angle adjustment control loop.

[0013] In some embodiments, the system is also equipped with a remote IoT transmission unit, which is connected to the intelligent control module. The remote IoT transmission unit is used to upload the real-time operating conditions of the wind turbine, the bionic sawtooth adjustment parameters, and the noise monitoring data to the cloud monitoring terminal, supporting remote parameter correction and operating condition early warning.

[0014] In some embodiments, the root of the biomimetic sawtooth structure is connected to the blade trailing edge using a flexible hinge sealing structure. The flexible hinge sealing structure is made of highly elastic polyurethane material with anti-fatigue reinforcing fibers added inside the material, which can withstand high-frequency reciprocating vibration without cracking or failure. The flexible hinge sealing structure is used to seal the gaps generated during the sawtooth angle adjustment process, avoiding the generation of secondary airflow noise from the gaps.

[0015] In some embodiments, the wind turbine biomimetic sawtooth adaptive noise reduction control method includes the following steps: Step 1: Real-time data acquisition of operating conditions: The operating condition sensing module synchronously acquires three-dimensional real-time operating condition data, including the fan spindle speed, airflow velocity inside the duct, and aerodynamic noise level of the entire machine, and transmits all data to the intelligent control module. Step 2: Iterative calculation of the working condition model: The intelligent control module calls the built-in artificial intelligence working condition model, assigns preset calculation weights to the three-dimensional working condition data, iterates the calculation until the convergence judgment condition is met, and outputs the bionic sawtooth target deflection angle adapted to the current working condition. Step 3, Closed-loop angle adjustment: The intelligent control module sends angle adjustment commands to the micro-drive mechanism inside each blade, driving the bionic sawtooth structure to deflect to the target angle. At the same time, the actual deflection angle is transmitted back in real time through the angle position feedback sensor, forming a closed-loop correction. Step 4, Operating Condition Fault Tolerance Monitoring: The intelligent control module continuously verifies the signals collected by the operating condition sensing module. If abnormal operating conditions such as sensor signal interruption or value exceeding limits are identified, a return command is immediately issued to adjust all biomimetic sawtooth structures to the preset safety reference angle to maintain the fan foundation noise reduction and aerodynamic performance.

[0016] This invention has at least the following beneficial effects: 1. The biomimetic sawtooth design employs a linearly varying tooth height and pitch along the blade span, with rounded tips to match the differentiated airflow velocity distribution from blade root to tip. This allows for uniform segmentation of the boundary layer airflow across the entire trailing edge, avoiding the limitation of single-specification sawtooths only locally weakening eddies. This provides continuous suppression of high-frequency whistling noise generated by the wind turbine. Combined with pressure relief micro-holes located upstream of the sawtooth, this design proactively diverts high-pressure boundary layer airflow accumulated on the blade surface, simultaneously weakening the formation conditions of large-scale eddies at two levels. The overall noise reduction effect is not limited by the noise propagation frequency band and avoids the problem of rapid decline in noise reduction effectiveness after changes in the operating conditions of passive noise reduction structures.

[0017] 2. The sawtooth deflection angle can be autonomously adjusted within the range of 0 to 30 degrees using the embedded piezoelectric ceramic drive component. The ultra-thin and lightweight packaged piezoelectric ceramic component occupies less internal space in the blades, requiring no modification to the original aerodynamic shape of the blades and avoiding the introduction of additional blade turbulence and friction noise. Each blade's drive component can independently adjust its angle to match the real-time airflow conditions of each blade. Unlike fixed sawtooth blades, which can only adapt to a single rated operating condition, this design maintains a stable vortex cutting effect in various variable operating scenarios, including changes in fan speed, duct resistance, and intake flow fluctuations. It balances noise reduction with fan aerodynamic output, alleviating the contradiction between noise reduction and airflow output that is difficult to achieve simultaneously in existing technologies. The drive structure is equipped with a centrifugal force compensation structure, which can counteract the radial centrifugal load on the drive components and sawtooth blades during high-speed rotation. Under long-term continuous operation, the actual deflection angle of the sawtooth blades will not drift, eliminating the need for frequent shutdowns to calibrate the adjustment mechanism and reducing daily maintenance workload.

[0018] 3. A high-elasticity polyurethane sealing structure, incorporating fatigue-resistant fibers, is installed at the junction of the blade trailing edge serrations and the blade body. This material can withstand long-term high-frequency reciprocating bending of the serrations and continuous blade vibration, making it less prone to cracking, elasticity loss, and other failures. It continuously seals the tiny gaps generated at the hinge position during angle adjustment, preventing airflow penetration and secondary noise generation, ensuring the overall noise reduction performance of the machine remains stable over the long term. The blades are integrally molded from high-strength, lightweight, and wear-resistant polymer materials. The blunted leading edge arc combined with a low-friction coating on the blade surface reduces the basic noise generated by airflow impact and friction. The lightweight substrate also reduces the overall weight of the blades, decreasing the rotational load on the fan shaft. This results in reduced energy consumption and component wear during long-term operation.

[0019] 4. Rotary speed sensors, airflow composite probes, and distributed microphone arrays, arranged in zones within the duct, can simultaneously collect three types of operating data: fan speed, airflow velocity, and overall noise level (decibels). This multi-dimensional data collection method fully recreates the actual operating environment of the fan, avoiding adjustment and judgment biases caused by single-point data collection. After the collected operating data is transmitted to the intelligent control module, the built-in artificial intelligence operating model uses three-dimensional feature weight calculation and iterative convergence logic, combined with a pre-stored multi-operating-condition matching database, to output the optimal sawtooth deflection angle. The adjustment process simultaneously balances noise reduction and aerodynamic efficiency loss, preventing a significant decrease in airflow caused by excessively increasing the sawtooth angle. The module has a built-in sensor failure tolerance mechanism. In the event of signal interruption, exceeding data limits, or other abnormal situations, all sawtooth angles will automatically return to the preset safety benchmark angle. Under extreme airflow disturbances or sensor component failures, the fan will not experience sudden increases in noise or sharp drops in output, improving the safety and stability of equipment operation.

[0020] 5. The piezoelectric ceramic drive component, combined with an angle position feedback sensor, forms a closed-loop adjustment circuit. This allows for real-time correction of angular deviations caused by mechanical deformation and assembly gaps, resulting in higher precision in each angle adjustment and preventing insufficient eddy current cutting due to angular deviations. The system's accompanying remote IoT transmission unit uploads all operational data to the cloud terminal. Operators can remotely view equipment noise, sawtooth adjustment parameters, and other operational information. They can also adjust the weights and control parameters within the AI ​​model online without needing to physically visit the equipment for disassembly and debugging. Simultaneously, the cloud can identify abnormal operating conditions in advance based on continuously collected data, providing early warnings of faults and making it suitable for unattended industrial ventilation applications. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the system composition of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: See Figure 1 A fan noise reduction system that utilizes a biomimetic serrated trailing edge to cut airflow includes a fan body, a biomimetic serrated blade assembly, an operating condition sensing module, and an intelligent control module. The biomimetic sawtooth blade assembly is mounted on the rotating end of the wind turbine body. The biomimetic sawtooth blade assembly includes several blades, and each blade trailing edge is provided with a parameterized adjustable angle biomimetic sawtooth structure. The biomimetic sawtooth structure is used to cut the boundary layer airflow at the trailing edge of the blade and block the periodic shedding of the trailing edge vortex. The operating condition sensing module is installed in the main air duct of the wind turbine to collect multi-dimensional operating condition data such as wind turbine operating speed, airflow velocity in the air duct, and aerodynamic noise decibel value in real time, and transmit the collected data to the intelligent control module. The intelligent control module is electrically connected to the working condition sensing module and the bionic sawtooth blade assembly. The intelligent control module has built-in working condition matching control logic, which can adaptively adjust the deflection angle of the bionic sawtooth structure based on the real-time collected working condition data, and simultaneously balance the aerodynamic output efficiency and aerodynamic noise suppression effect of the fan. The biomimetic sawtooth blade assembly integrates a lightweight micro-drive mechanism, which is equipped with a centrifugal force compensation structure to counteract the centrifugal load generated by the high-speed rotation of the fan, ensuring stable operation of the biomimetic sawtooth structure under high-speed conditions.

[0024] Specifically, the biomimetic sawtooth blade assembly is mounted on the rotating end of the fan main shaft, comprising multiple blade bodies, each blade body having a parameterized adjustable angle biomimetic sawtooth structure integrally connected to its trailing edge; the operating condition sensing module is deployed on the inner wall of the fan's inlet and outlet air ducts to collect the fan main shaft speed in real time. Airflow velocity in the duct Overall aerodynamic noise level (decibels) Three types of basic operating condition data are transmitted in real time to the intelligent control module. The intelligent control module is electrically connected to the operating condition sensing module and the piezoelectric ceramic micro-drive mechanism inside each blade. It has a built-in artificial intelligence operating condition model and can adaptively output the optimal deflection angle of the bionic sawtooth based on the real-time collected three-dimensional operating condition data. It simultaneously takes into account both the aerodynamic output efficiency of the fan and the aerodynamic noise suppression effect.

[0025] Each blade body 1 has a lightweight piezoelectric ceramic micro-drive mechanism embedded in its internal cavity. The drive mechanism is equipped with a centrifugal force compensation counterweight. The mass of the counterweight is matched with the rated maximum speed of the wind turbine to offset the radial centrifugal load generated by the piezoelectric ceramic components and biomimetic sawtooth structure when the blades rotate at high speed. This prevents the drive mechanism from shifting or jamming under high-speed conditions and ensures smooth angle adjustment of the biomimetic sawtooth structure within the range of 0°-30°. The piezoelectric ceramic drive adopts an ultra-thin stacked packaging, with an overall thickness not exceeding 2 / 3 of the width of the blade's internal cavity. This adapts to the narrow internal installation space of the blades and, unlike the traditional micro-motor gear set structure, eliminates the additional vibration and noise caused by gear transmission backlash.

[0026] A row of pressure-relief micropores is linearly formed along the spanwise direction of the blade body on the upstream side of the biomimetic sawtooth structure. The diameter of the micropores gradually decreases from the blade root to the blade tip, which can guide the airflow of the boundary layer accumulated on the blade surface, weaken the large-scale eddies formed by the concentrated shedding of the boundary layer, and help the biomimetic sawtooth structure reduce high-frequency aerodynamic noise. The blade body is made of high-strength glass fiber reinforced polyurethane integral injection molding, with a continuous passivated arc treatment on the leading edge, and the blade surface is sprayed with a low-friction polytetrafluoroethylene noise-reducing coating to reduce airflow friction noise on the blade surface.

[0027] A flexible hinged sealing structure is set between the root of the biomimetic sawtooth structure and the trailing edge of the blade body. The main sealing material is highly elastic modified polyurethane, with uniformly blended polyester fatigue-resistant short fibers inside, and the fibers are arranged along the reciprocating bending direction of the seal. After one million reciprocating bends from 0° to 30°, the deformation of this sealing material is no more than 3%, which can withstand the high-frequency vibration of the blade and the scouring of the airflow during the operation of the wind turbine without cracking or elastic failure. The flexible hinged seal completely covers the hinge gap, sealing the gap generated between the root of the tooth and the blade during the adjustment of the sawtooth angle, and eliminating the secondary aerodynamic noise caused by the airflow penetration through the gap.

[0028] The operating condition sensing module consists of a spindle speed sensor, an airflow pressure and velocity composite probe, and a distributed microphone noise array. The speed sensor is fixed at the end of the fan spindle and outputs the speed value in real time. The velocity composite probe is evenly distributed along the circumference of the air duct to collect the average airflow velocity of the cross section. The microphone array is arranged with several pickup points along the axial direction of the air duct to collect the decibel value of aerodynamic noise across the entire frequency band. The three types of sensors sample synchronously, and the sampling period is uniformly set to 50ms.

[0029] The intelligent control module is connected to an external IoT transmission unit, which uploads real-time data on rotational speed, flow rate, noise, and sawtooth adjustment angle to the cloud monitoring terminal. It supports remote modification of model weight parameters and issuance of angle adjustment commands, and simultaneously provides cloud-based early warnings for abnormal fan noise and sensor malfunctions.

[0030] The piezoelectric ceramic micro-drive mechanism is equipped with an angle and position feedback sensor 5 at its end. The sensor collects the actual deflection angle of the bionic sawtooth in real time. It is then transmitted back to the intelligent control module to form a complete closed-loop angle adjustment circuit, eliminating the adjustment deviation caused by the driving deformation error.

[0031] The entire system is built upon two fundamental theories: biomimetic fluid mechanics and closed-loop intelligent control. In nature, the trailing edge of an owl's wings naturally exhibits a finely serrated pattern. During gliding, this structure continuously segments the airflow over the wing surface at a microscale. The originally continuous downstream airflow boundary layer is broken down into multiple smaller airflow streams. The vortices formed at the end of the structure do not continuously detach according to a fixed cycle, and the originally concentrated aerodynamic noise energy is dispersed over a wider frequency band, thus reducing the noise peak value of a single frequency band. This solution transplants this natural structure to the trailing edge of a wind turbine blade. Simultaneously, it overcomes the limitation of traditional fixed-size serrations being unable to adapt to varying operating conditions. Instead, it incorporates a biomimetic serrated structure with a parameterizable angle at the blade trailing edge, allowing the intensity of the serrations' airflow segmentation effect to change synchronously with the wind turbine's operating state.

[0032] During actual operation, the fan speed does not remain constant, and the airflow velocity inside the duct continuously changes with pipeline resistance and intake air volume. The airflow separation position and vortex generation scale on the blade surface differ significantly under different operating conditions. If the sawtooth shape and angle remain fixed, optimal noise reduction can only be achieved under specific operating conditions. When the speed increases or the airflow in the duct fluctuates, the sawtooth's airflow segmentation effect decreases significantly, and it may even increase airflow friction loss on the blade surface, reducing the overall aerodynamic output capacity of the fan. By setting a biomimetic sawtooth structure with parameterizable deflection angle, the system can change the angle between the sawtooth and the blade surface according to the current actual airflow and noise conditions, thereby matching the current boundary layer airflow characteristics and maintaining a continuous dispersing effect on the trailing edge vortices, avoiding the limitation of adapting to a single operating condition.

[0033] The system is equipped with condition-sensing components. These components, located inside the air duct, continuously capture the fan's main shaft rotation speed, the airflow velocity within the duct, and the noise level radiated outwards by the entire unit. These three types of data can comprehensively reconstruct the actual operating environment of the fan. Relying on data from only one dimension cannot determine the actual degree of airflow vortex formation. Rotation speed only reflects the speed of blade rotation, airflow velocity only reflects the overall airflow level in the duct, and noise level directly reflects the intensity of current aerodynamic noise. Combining these three types of data allows for a complete determination of the degree of boundary layer airflow separation and the noise level caused by vortex shedding. This provides a complete data basis for subsequent sawtooth angle adjustments, avoiding adjustment deviations caused by relying on a single parameter to adjust the structure.

[0034] After receiving multiple sets of operating condition data collected from within the air duct, the intelligent control component calculates the sawtooth deflection angle adapted to the current operating condition based on its internally preset operating condition matching control logic. Then, it sends an adjustment command to the internal drive structure of the blade to complete the angle adjustment. The entire adjustment process forms a complete closed loop of signal acquisition, data calculation, and structural adjustment. The adjustment process simultaneously considers noise suppression and the aerodynamic output level of the fan. Simply pursuing noise reduction by continuously increasing the sawtooth deflection angle will increase the airflow resistance on the blade surface, resulting in a significant decrease in the fan's output airflow. On the other hand, simply ensuring aerodynamic efficiency by reducing the sawtooth angle will prevent the vortex from being fully separated, greatly weakening the noise suppression effect. When calculating the target angle, the control logic simultaneously balances these two performance indicators, ensuring that the fan reduces noise without significant output loss.

[0035] The blade cavity is equipped with a lightweight micro-drive structure to drive the bionic sawtooth to complete the angle deflection. The thickness of the wind turbine blade itself is limited, and the space available for the built-in installation structure is very small. Conventional drive components are too large to be embedded inside the blade. The lightweight design can reduce the overall space occupied by the drive structure and adapt to the limited cavity volume inside the blade. It will not thicken the blade or change the original aerodynamic shape of the blade due to the addition of the drive structure, and will avoid the addition of airflow friction noise after modifying the basic profile of the blade.

[0036] When the fan is in normal operation, the blades are in a state of continuous high-speed rotation. The bionic sawteeth at the trailing edge of the blades and the built-in driving structure are subjected to radial centrifugal force during the rotation process, which continuously exerts a pulling force outward. After long-time high-speed operation, the positioning of the driving structure will shift, the actual deflection angle of the sawteeth will deviate from the target angle issued by the system, and the noise reduction effect will decrease accordingly. The supporting centrifugal force compensation structure can generate a force opposite to the direction of the centrifugal force to offset the radial load on the sawteeth and the driving member, so that the driving structure can maintain a stable installation position during high-speed rotation, the actual deflection angle of the sawteeth will not drift with the increase of the rotation speed, the dividing effect of the sawteeth on the airflow can remain stable during long-time continuous operation, there is no need to stop the machine frequently to calibrate the structure angle, and the daily maintenance workload of the equipment can be reduced.

[0037] Compared with the traditional passive noise reduction method relying on sound-absorbing cotton and silencing cavities, the entire combined structure does not need to install large-volume silencing equipment outside the fan air duct, does not occupy too much on-site installation space, and will not cause noise reduction performance degradation due to long-term dust accumulation blocking the silencing channel. Passive silencing structures can only attenuate noise in a fixed frequency band. When the fan operates under variable working conditions, the main frequency of the noise shifts, and the silencing effect will decrease significantly. This solution directly destroys the conditions for the periodic shedding of vortices at the noise generation source, reduces the noise radiation intensity at the aeroacoustic noise generation link, adapts to the working scenarios of the fan with a wide range of variable rotation speeds and variable airflow, and balances noise reduction and aerodynamic efficiency by relying on adaptive angle adjustment, and is equipped with a centrifugal force compensation structure to ensure the adjustment stability under high-speed working conditions, reducing the later maintenance investment of the equipment.

[0038] Embodiment 2: Refer to Figure 1 , the bionic sawtooth structure is a parameterized adjustable sawtooth, the tip of the sawtooth adopts a circular arc transition shape, and the tooth height and tooth pitch of the sawteeth on a single blade are arranged in a linear gradient along the spanwise direction of the blade.

[0039] The micro driving mechanism is a piezoelectric ceramic driving assembly, which is embedded in the inner cavity of the blade, connected to the intelligent regulation module, and used to independently drive the corresponding bionic sawtooth structure at the trailing edge of the blade to complete angle deflection within the range of 0°-30°; the piezoelectric ceramic driving assembly adopts an ultra-thin lightweight package as a whole, which adapts to the narrow installation space inside the blade.

[0040] A row of pressure relief micropores are opened on the blade body along the spanwise direction, the pressure relief micropores are arranged on the upstream side of the bionic sawtooth structure, and the pressure relief micropores are used to guide the accumulated airflow in the boundary layer on the blade surface to assist in weakening the generation intensity of eddy currents.

[0041] The operating condition sensing module includes a speed sensor, an airflow pressure and velocity composite probe, and a distributed noise acquisition microphone array. The speed sensor is fixed to the end of the fan main shaft, and the airflow pressure and velocity composite probe and the distributed noise acquisition microphone array are evenly arranged on the walls of the fan inlet and outlet ducts.

[0042] The intelligent control module incorporates an AI operating condition model, which pre-stores a database matching multiple sets of sawtooth angle, noise reduction, and aerodynamic efficiency under varying wind turbine operating conditions. The AI ​​operating condition model uses wind turbine speed, airflow velocity, and noise decibels as three-dimensional input features, assigns corresponding calculation weights, and sets iterative convergence judgment logic. The intelligent control module compares real-time operating condition data with the matching database and outputs the optimal adjustment angle command for the bionic sawtooth structure. The intelligent control module also incorporates a sensor failure tolerance mechanism; when the operating condition sensing module loses its signal or exceeds the normal threshold, it automatically controls all bionic sawtooth structures to return to the preset safety reference angle.

[0043] The biomimetic sawtooth blade assembly uses a high-strength, lightweight, and wear-resistant polymer material as the base material for the blade, which is integrally molded. The leading edge of the blade is treated with a blunt arc, and the blade surface is sprayed with a low-friction and noise-reducing coating.

[0044] The piezoelectric ceramic drive assembly is equipped with an angle position feedback sensor, which transmits the current deflection angle of the bionic sawtooth structure back to the intelligent control module in real time, forming a closed-loop angle adjustment control circuit.

[0045] The system is also equipped with a remote IoT transmission unit, which communicates with the intelligent control module. The remote IoT transmission unit is used to upload the real-time operating conditions of the wind turbine, the bionic sawtooth adjustment parameters, and noise monitoring data to the cloud monitoring terminal, supporting remote parameter correction and operating condition early warning.

[0046] The root of the biomimetic sawtooth structure is connected to the tail edge of the blade using a flexible hinge sealing structure. The flexible hinge sealing structure is made of highly elastic polyurethane material with anti-fatigue reinforcing fibers added inside the material. It can withstand high-frequency reciprocating vibration without cracking or failure. The flexible hinge sealing structure is used to seal the gaps generated during the adjustment of the sawtooth angle, avoiding the generation of secondary airflow noise in the gaps.

[0047] Specifically, the biomimetic sawtooth structure employs a parametrically adjustable molding method, while the sawtooth tips are rounded to avoid sharp edges and corners, effectively preventing localized airflow stripping and high-frequency whistling noise generated when airflow passes over the tips. The tooth height and pitch of the sawtooth are linearly and gradually varied along the blade span, conforming to the airflow pattern from the blade root to the blade tip. The blade tip has a higher linear velocity and greater airflow vortex intensity. The gradually varied sawtooth structure can match the airflow velocity and vortex distribution at different spanwise positions, making the airflow cutting and vortex dispersion effect at the entire blade trailing edge more uniform. This avoids the problems of uneven local noise reduction and residual vortex in some areas that occur with fixed-specification sawtooths, comprehensively weakening the overall radiation noise of the trailing edge vortex.

[0048] The piezoelectric ceramic drive component inside the blade is the core actuator that enables adjustable sawtooth angles. Unlike traditional drive structures such as motors and gear sets, the piezoelectric ceramic component can achieve precise angle adjustment based on its own electro-deformation characteristics. Its overall structure is smaller and thinner, and through ultra-thin and lightweight packaging technology, it can be completely embedded within the narrow cavity reserved in the blade, without altering the external aerodynamic profile of the blade, thus preserving the original aerodynamic performance of the blade to the greatest extent. This drive component can stably drive the bionic sawtooth to complete angle deflection within the range of 0 to 30 degrees. The drive structure of each blade can work independently, matching the corresponding deflection angle according to the actual airflow conditions of each blade, adapting to the complex variable operating conditions of the wind turbine, and significantly improving the airflow control precision of the sawtooth.

[0049] On the upstream side of the biomimetic sawtooth structure, pressure-relief micropores along the spanwise direction on the blade body surface can effectively guide the airflow accumulated in the boundary layer on the blade surface. When the wind turbine is running at high speed, the airflow continuously flows along the blade surface and gradually accumulates to form a thick boundary layer. The thick boundary layer airflow is the main cause of large-scale vortex generation. The pressure-relief micropores can export and disperse the locally high-pressure accumulated airflow in advance, reduce the airflow accumulation pressure on the blade surface, weaken the basic conditions for vortex generation from the airflow source, and work together with the vortex cutting effect of the trailing edge biomimetic sawtooth to doubly weaken the aerodynamic vortex intensity, further improve the overall noise reduction effect of the machine, and at the same time alleviate the aerodynamic drag loss caused by boundary layer airflow accumulation.

[0050] Accurate data acquisition of wind turbine operating conditions is fundamental to intelligent control. The equipment is equipped with a speed sensor, a composite probe for airflow pressure and velocity, and a distributed noise acquisition microphone array, corresponding to wind turbine power operating parameters, duct airflow parameters, and overall machine noise parameters, respectively. The speed sensor is fixed to the end of the wind turbine's main shaft, accurately capturing the real-time rotation status of the main shaft and reflecting the working intensity of the blade rotation. Multiple sets of composite probes and microphone arrays are evenly distributed on the duct walls of the wind turbine's inlet and outlet sections, enabling the acquisition of airflow and noise data across the entire duct area. This avoids data deviations caused by single-point acquisition, fully reproducing the wind turbine's true, comprehensive operating environment, providing accurate and comprehensive data support for subsequent intelligent control calculations, and ensuring the fit and accuracy of angle adjustments.

[0051] The intelligent control module is equipped with an AI-powered operating condition model. Based on a massive database of variable operating conditions, it establishes a correlation between sawtooth adjustment angle, noise reduction effect, and fan aerodynamic efficiency. The model uses fan speed, airflow velocity, and noise level as core criteria, employing multi-dimensional weighted calculations to comprehensively determine the operating condition. Combined with iterative convergence logic, it continuously optimizes adjustment parameters, ultimately outputting the optimal sawtooth angle command for the current operating condition. This allows the system to dynamically adapt to various operating conditions such as fan speed fluctuations, duct resistance changes, and airflow disturbances, always balancing noise reduction and fan aerodynamic output efficiency, avoiding performance imbalances caused by adjusting a single parameter. Simultaneously, the module's built-in fault-tolerant control mechanism automatically returns all bionic sawtooths to a preset safe angle under extreme conditions such as sensor signal loss, data anomalies, or sudden airflow interference. This ensures the fan does not experience sudden noise increases or a sharp drop in aerodynamic efficiency due to control failure, significantly improving the stability and safety of equipment operation.

[0052] The blades are integrally molded from high-strength, lightweight, and wear-resistant polymer materials. This one-piece molding process eliminates gaps and stress concentration points in the spliced ​​structure, improving the overall structural strength and operational stability of the blades. The lightweight material reduces the rotating weight of the blades, decreasing the load on the wind turbine shaft and reducing energy consumption and rotational wear. The blunted arc treatment on the leading edge of the blades weakens the turbulence and impact noise generated by the frontal impact of the airflow, optimizing the airflow conformity. The low-friction noise-reducing coating sprayed on the blade surface reduces the frictional resistance between the airflow and the blade surface, reducing frictional noise while improving blade smoothness, slowing down dust accumulation and wear, extending blade life, and maintaining stable aerodynamic and noise reduction performance over the long term.

[0053] The integrated angle and position feedback sensors can collect the actual deflection angle of the bionic sawtooth in real time and continuously transmit it back to the intelligent control module, forming a complete closed-loop regulation and control circuit. During high-speed operation of the fan, deformation errors and mechanical clearance errors of the drive components will cause slight deviations between the target angle and the actual angle. The closed-loop feedback mechanism can capture the deviation value in real time and complete angle compensation through system correction commands, ensuring the accuracy of each angle adjustment. This allows the sawtooth to always participate in airflow regulation in the optimal state, avoiding the decrease in noise reduction effect and aerodynamic efficiency loss caused by angle deviation.

[0054] The system's remote IoT transmission unit enables real-time cloud uploads of wind turbine operating conditions, sawtooth adjustment parameters, and real-time noise data, breaking the limitations of traditional local equipment control. Staff can monitor the equipment's operating status in real time via the cloud terminal and remotely adjust model parameters and adjustment logic based on changes in on-site conditions, eliminating the need for on-site disassembly and debugging, significantly reducing equipment maintenance complexity. Simultaneously, the cloud can identify potential faults such as abnormal noise and operating condition deviations based on real-time data, providing early warnings and ensuring long-term stable equipment operation, thus meeting the needs of unattended and remote maintenance in industrial scenarios.

[0055] The connection between the biomimetic sawtooth and the blade trailing edge utilizes a flexible hinged sealing structure made of highly elastic polyurethane material, with fatigue-resistant reinforcing fibers incorporated within the material. This design is adapted to the high-frequency reciprocating angle adjustment of the sawtooth during operation. During continuous wind turbine operation, the sawtooth repeatedly deflects, airflow continuously erodes, and the blades vibrate at high frequencies. Conventional sealing structures are prone to aging, cracking, and elasticity failure, leading to air leakage and secondary noise. The modified polyurethane material combined with reinforcing fibers possesses excellent bending, vibration, and aging resistance properties. It can withstand high-frequency reciprocating deformation and airflow erosion for extended periods, maintaining excellent sealing performance. This completely seals the minute gaps at the sawtooth hinge, preventing secondary aerodynamic noise generated by airflow penetration through these gaps. This further improves the overall noise reduction system, ensuring the long-term noise reduction stability of the equipment.

[0056] The weight calculation and convergence logic of the artificial intelligence working condition model are as follows: The intelligent control module has a built-in artificial intelligence operating condition model, with the wind turbine main shaft speed as the input dimension. Airflow velocity in the duct Overall aerodynamic noise level (decibels) The output is the deflection angle of the biomimetic sawtooth target. The entire calculation logic is divided into three layers: weighted summation, iterative convergence of the loss function, and fault tolerance determination. The complete algorithm logic is as follows: 2.1 Weighted Calculation of Three-Dimensional Working Condition Features First, the three types of raw collected data are normalized to eliminate differences in units: Speed ​​normalization: Flow rate normalization: Noise normalization: In the formula: , This refers to the minimum and maximum rated operating speed of the fan; , This represents the maximum airflow velocity in the duct. , These are the upper and lower limits of the noise level of the fan under no-load and full-load conditions in decibels.

[0057] Set three sets of fixed weight coefficients for different operating conditions. , , The weighting coefficients are preset according to the noise reduction priority: when noise suppression is the priority condition, the weighting coefficients are set to... When aerodynamic efficiency is the priority, take The weight values ​​can be modified remotely via the Internet of Things (IoT) cloud.

[0058] Weighted composite working condition characteristic value calculation formula: 2.2 Sawtooth Angle Mapping Curve Function Comprehensive eigenvalues The piecewise quadratic polynomial is mapped to the basic deflection angle of the biomimetic sawtooth. The mapping function is: The function curve is an upward convex quadratic curve. Under low comprehensive operating conditions, the angle is adjusted slightly, and under high operating conditions, the sawtooth deflection amplitude is rapidly increased to match the variation law of airflow vortex intensity. The basic angle value range is 0°-30°, which matches the adjustment range of piezoelectric ceramic drive.

[0059] 2.3 Iterative Convergence Judgment Logic (Loss Function Convergence) The model introduces a loss function. The loss function is used to characterize the combined deviation between the noise reduction effect and aerodynamic efficiency at the current angle. Its expression is: In the formula: The difference in decibels between real-time noise and target noise reduction; To preset the target aerodynamic efficiency; The measured aerodynamic efficiency of the current wind turbine; , These are the noise and efficiency loss balance coefficients, respectively.

[0060] Iterative convergence criteria: 1. Limitation on step size per iteration Each iteration only slightly adjusts the sawtooth angle; 2. Change in loss function over 5 consecutive iterations Once the model has converged, stop iterating and output the current angle as the target adjustment angle. ; 3. The maximum number of iterations is set to 20. If the convergence fails to occur after reaching the maximum, the angle corresponding to the minimum value of the loss function in the 20 iterations is taken as the target angle to avoid infinite iteration consuming the controller's computing power.

[0061] 2.4 Fault-Tolerant Control Logic for Extreme Operating Conditions The model verifies the signals collected by the operating condition sensing module in real time and sets up a dual anomaly detection mechanism: 1. Signal interruption determination: If any sensor of speed, flow rate, or noise fails to transmit data for three consecutive sampling cycles, the sensor is determined to be faulty. 2. Value exceeding the limit judgment: after normalization , , Any value less than 0 or greater than 1.2 indicates an extreme interference condition such as sudden airflow impact or sensor drift. Upon triggering any type of anomaly detection, the model immediately outputs a safety baseline angle. The system issues a command to control the piezoelectric ceramic drive mechanism to uniformly return all the bionic saw teeth to a 10° reference angle. This reference angle takes into account both the basic noise reduction effect and the stable aerodynamic performance of the fan, avoiding the problems of efficiency drop and noise increase caused by saw tooth angle deviation under extreme working conditions. After the sensor signal returns to normal and the values ​​stabilize for 10 consecutive sampling cycles, the model restarts the weighted iterative calculation and resumes adaptive angle adjustment.

[0062] Example 3: In this example, the piezoelectric ceramic micro-drive mechanism is defined as a stacked piezoelectric ceramic stack structure with an overall height of 12mm and a width of 8mm. It incorporates a micro temperature sensor to prevent the piezoelectric ceramic deformation accuracy from decreasing due to high-speed blade rotation and temperature rise. The matching centrifugal force compensation counterweight is a low-density carbon fiber sheet, which is attached to the side of the piezoelectric ceramic component facing away from the sawtooth. The counterweight mass is linearly matched according to the rated speed of the fan. The counterweight mass is 0.8g at the rated speed of 1500r / min and 1.6g at the rated speed of 3000r / min. The centrifugal tensile load of the sawtooth and drive component is offset by the reverse radial force, ensuring the positioning accuracy of the drive mechanism during high-speed blade rotation and preventing angular drift.

[0063] The biomimetic sawtooth structure features parametric gradient sawtooths. Along the blade span, the tooth height linearly decreases from 5mm at the blade root to 2mm at the blade tip, while the tooth pitch decreases simultaneously from 8mm at the blade root to 4mm at the blade tip. All sawtooth tips are transitioned with an R0.8 arc to eliminate local airflow separation and whistling caused by sharp edges. The sawtooths and blade body are separately molded and connected by a flexible hinge sealing structure. The sealing polyurethane material is 1.2mm thick, and the internal polyester fibers are 15μm in diameter, which are evenly distributed to improve resistance to bending fatigue.

[0064] Example 4: The adaptive noise reduction control method corresponding to the product system in this example has the following steps: Step 1: Multi-dimensional synchronous acquisition of operating conditions: The operating condition sensing module synchronously acquires the fan spindle speed at a period of 50ms. Airflow velocity in the duct Overall aerodynamic noise level (decibels) The three types of raw data are transmitted to the intelligent control module in real time; Step 2, Data Normalization and 3D Weighted Calculation: The intelligent control module calls the artificial intelligence working condition model to normalize the three types of raw data and read the preset weights. , , Calculate the comprehensive working condition characteristic value $X$, and obtain the deflection angle of the sawtooth foundation through a piecewise quadratic polynomial. ; Step 3: Iterative optimization and convergence of the loss function: The model makes small adjustments to the base angle with a single adjustment step size of 0.5°, and calculates the comprehensive loss function after each iteration. The system continuously compares the loss difference between adjacent iterations. When the loss change is less than 0.02 for 5 consecutive iterations or when 20 iterations have been performed, the converged target deflection angle is output. ; Step 4, Closed-loop angle drive adjustment: The intelligent control module sends the target angle command to each piezoelectric ceramic drive mechanism of the blades, driving the bionic sawtooth deflection, and the angle position feedback sensor transmits the actual angle back in real time. Model comparison and The difference is used to issue a compensation and adjustment command to eliminate mechanical deformation error; Step 5: Real-time fault-tolerant monitoring under extreme conditions: The model continuously verifies the sensor sampling signals. After identifying abnormal conditions such as sensor failure or severe airflow impact, it immediately controls all bionic saw teeth to return to the 10° safety reference angle. After the operating conditions return to stability, the weighted iterative adjustment process is restarted.

[0065] A control experimental platform was built to test the noise reduction decibels and aerodynamic efficiency of the three schemes at three rotational speeds of 1000 r / min, 2000 r / min, and 3000 r / min. Control group 1: Ordinary fan blades without serrations; Control group 2: Fixed non-adjustable bionic serrated blades (serrations fixed at 15°); Experimental group: The parametric adaptive adjustable bionic serrated blade of this invention (artificial intelligence model adaptively adjusts the angle). Experimental data shows that at the same rotational speed, compared with blades without serrations, fixed serrations reduce noise by an average of 3.2-4.8 dB, but reduce the aerodynamic efficiency of the fan by 2.1%-3.5%. The adaptive serrations of this invention reduce noise by an average of 5.7-7.3 dB, while controlling the aerodynamic efficiency reduction to 0.8%-1.4%. Under sudden airflow disturbance at high speed of 3000 r / min, the peak noise of fixed serrations increases by 6.1 dB, while this invention, relying on the model's fault-tolerant return mechanism, only increases the peak noise by 1.9 dB, balancing noise reduction performance and fan aerodynamic efficiency. This demonstrates that the adaptive weighted convergence model and parameterized adjustable serration structure of this invention have outstanding technical advantages.

[0066] The piezoelectric ceramic micro-drive mechanism of this invention adopts an ultra-thin and lightweight stacked packaging structure, with an overall volume only 1 / 4 of that of a traditional micro-motor gear set, significantly reducing the total weight of the rotating blades. At the same time, the matching centrifugal force compensation counterweight is arranged coaxially with the drive component. The reverse centrifugal force generated by the counterweight can offset the radial offset force of the saw teeth and drive components. Combined with the buffering and shock absorption characteristics of the flexible hinge seal, after the fan has been running continuously at a rated maximum of 3000 r / min for 2000 hours, the saw tooth angle adjustment error is still less than 0.3°, with no jamming, deformation, or seal cracking faults. This solves the technical defects of the existing technology where the blade built-in drive fails to adjust due to high-speed centrifugal force and the seal is prone to fatigue and damage.

[0067] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A fan noise reduction system that utilizes a biomimetic serrated tail edge to cut airflow, characterized in that: Includes the main body of the wind turbine, the biomimetic sawtooth blade assembly, the operating condition sensing module, and the intelligent control module; The biomimetic sawtooth blade assembly is mounted on the rotating end of the wind turbine body. The biomimetic sawtooth blade assembly includes several blades, and each blade has a parameterized adjustable angle biomimetic sawtooth structure at its trailing edge. The biomimetic sawtooth structure is used to cut the boundary layer airflow at the trailing edge of the blade and block the periodic shedding of the trailing edge vortex. The operating condition sensing module is installed in the main air duct of the wind turbine to collect multi-dimensional operating condition data such as wind turbine operating speed, airflow velocity in the air duct, and aerodynamic noise decibel value in real time, and transmits the collected data to the intelligent control module. The intelligent control module is electrically connected to the working condition sensing module and the bionic sawtooth blade assembly. The intelligent control module has built-in working condition matching control logic, which can adaptively adjust the deflection angle of the bionic sawtooth structure based on the real-time collected working condition data, and simultaneously balance the aerodynamic output efficiency and aerodynamic noise suppression effect of the fan. The biomimetic sawtooth blade assembly integrates a lightweight micro-drive mechanism, which is equipped with a centrifugal force compensation structure to counteract the centrifugal load generated by the high-speed rotation of the fan, ensuring stable operation of the biomimetic sawtooth structure under high-speed conditions.

2. The fan noise reduction system according to claim 1, which utilizes a biomimetic serrated tail edge to cut airflow, is characterized in that: The biomimetic sawtooth structure is a parametric adjustable sawtooth with a rounded transition at the tip. The tooth height and pitch of the sawtooth on a single blade are arranged in a linearly gradual manner along the blade span.

3. A fan noise reduction system for cutting airflow using a biomimetic serrated tail edge, as described in claim 2, is characterized in that: The micro-drive mechanism is a piezoelectric ceramic drive component, which is embedded in the cavity inside the blade. The piezoelectric ceramic drive component is connected to the intelligent control module. The piezoelectric ceramic drive component is used to independently drive the biomimetic sawtooth structure at the trailing edge of the corresponding blade to complete the angle deflection within the range of 0°-30°. The piezoelectric ceramic drive component adopts an ultra-thin and lightweight package, which is suitable for the narrow installation space inside the blade.

4. A fan noise reduction system for cutting airflow using a biomimetic serrated tail edge, as described in claim 1, is characterized in that: The blade body has a row of pressure relief micro-holes along its span. The pressure relief micro-holes are located on the upstream side of the biomimetic sawtooth structure. The pressure relief micro-holes are used to guide the airflow accumulated in the boundary layer on the blade surface and help weaken the intensity of vortex generation.

5. A fan noise reduction system according to claim 1, characterized in that: The operating condition sensing module includes a speed sensor, an airflow pressure and velocity composite probe, and a distributed noise acquisition microphone array. The speed sensor is fixed to the end of the fan main shaft, and the airflow pressure and velocity composite probe and the distributed noise acquisition microphone array are evenly arranged on the walls of the fan inlet and outlet ducts.

6. A fan noise reduction system according to claim 1, characterized in that: The intelligent control module incorporates an artificial intelligence operating condition model, which pre-stores multiple sets of matching databases for sawtooth angle, noise reduction, and aerodynamic efficiency under varying wind turbine operating conditions. The model uses wind turbine speed, airflow velocity, and noise decibels as three-dimensional input features, assigns corresponding calculation weights, and sets iterative convergence judgment logic. The intelligent control module compares real-time operating condition data with the matching database and outputs the optimal adjustment angle command for the bionic sawtooth structure. The intelligent control module also incorporates a sensor failure tolerance mechanism; when the operating condition sensing module loses its signal or exceeds a normal threshold, it automatically controls all bionic sawtooth structures to return to a preset safety reference angle.

7. A fan noise reduction system according to claim 1, characterized in that: The biomimetic sawtooth blade assembly has a blade substrate made of high-strength, lightweight, and wear-resistant polymer material, which is integrally molded. The leading edge of the blade is treated with a blunt arc, and the blade surface is sprayed with a low-friction and noise-reducing coating.

8. A fan noise reduction system for cutting airflow using a biomimetic serrated tail edge, as described in claim 3, is characterized in that: The piezoelectric ceramic drive assembly is equipped with an angle position feedback sensor, which transmits the current deflection angle of the bionic sawtooth structure back to the intelligent control module in real time, forming a closed-loop angle adjustment control loop.

9. A fan noise reduction system according to claim 1, characterized in that: The system is also equipped with a remote IoT transmission unit, which communicates with the intelligent control module. The remote IoT transmission unit is used to upload the real-time operating conditions of the wind turbine, the bionic sawtooth adjustment parameters, and noise monitoring data to the cloud monitoring terminal, supporting remote parameter correction and operating condition early warning.

10. A fan noise reduction system for cutting airflow using a biomimetic serrated tail edge, as described in claim 1, is characterized in that: The root of the biomimetic sawtooth structure is connected to the blade trailing edge by a flexible hinge sealing structure. The flexible hinge sealing structure is made of highly elastic polyurethane material with anti-fatigue reinforcing fibers added inside the material. It can withstand high-frequency reciprocating vibration without cracking or failure. The flexible hinge sealing structure is used to seal the gaps generated during the sawtooth angle adjustment process to avoid the generation of secondary airflow noise in the gaps.

11. A wind turbine biomimetic sawtooth adaptive noise reduction control method based on the system according to any one of claims 1 to 10, characterized in that: Includes the following steps: Step 1: Real-time data acquisition of operating conditions: The operating condition sensing module synchronously acquires three-dimensional real-time operating condition data, including the fan spindle speed, airflow velocity inside the duct, and aerodynamic noise level of the entire machine, and transmits all data to the intelligent control module. Step 2: Iterative calculation of the working condition model: The intelligent control module calls the built-in artificial intelligence working condition model, assigns preset calculation weights to the three-dimensional working condition data, iterates the calculation until the convergence judgment condition is met, and outputs the bionic sawtooth target deflection angle adapted to the current working condition. Step 3, Closed-loop angle adjustment: The intelligent control module sends angle adjustment commands to the micro-drive mechanism inside each blade, driving the bionic sawtooth structure to deflect to the target angle. At the same time, the actual deflection angle is transmitted back in real time through the angle position feedback sensor, forming a closed-loop correction. Step 4, Operating Condition Fault Tolerance Monitoring: The intelligent control module continuously verifies the signals collected by the operating condition sensing module. If abnormal operating conditions such as sensor signal interruption or value exceeding limits are identified, a return command is immediately issued to adjust all biomimetic sawtooth structures to the preset safety reference angle to maintain the fan foundation noise reduction and aerodynamic performance.

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