Adjustable low wind resistance fan air inlet guide mechanism

Abstract

The application discloses an adjustable low-wind-resistance fan air inlet guide mechanism and relates to the technical field of fan air inlet aerodynamic adjustment. The guide mechanism comprises an air inlet shell, a single-row circumferential adjustable guide vane group, a main linkage driving assembly, a segmented profile maintaining guide lip ring, a partitioned differential compensation assembly, a state sensing assembly and a control assembly. Each circular arc guide section is movably connected with the air inlet shell through a guide groove and is connected with an adjacent guide vane connecting shaft through a differential linkage member to form linkage cooperation, so that the displacement of the circular arc guide section is coupled with the rotation state of the adjacent guide vane to produce a cooperative change; the control assembly constructs an inlet low-resistance profile maintaining analysis point and a circumferential inlet flow uniformity and stability analysis point based on state sensing data to form joint modulation quantity driven bottom state machine boundary modulation, so as to realize the cooperative evolution of the whole-circle guide vane, the circular arc guide section and the compensation quantity of each circumferential sector. The application can reduce additional pressure loss and improve the aerodynamic performance and operation stability under complex working conditions.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic adjustment technology for fan inlet, and more specifically, to an adjustable low-resistance fan inlet guide mechanism. Background Technology

[0002] With the widespread application of ventilation equipment, HVAC systems, and industrial air supply and exhaust systems, the aerodynamic stability and energy efficiency of axial flow fans and their inlet structures under various operating conditions are receiving increasing attention. Especially in practical applications with pre-filters, space-constrained installations, or inflow disturbances, the impact of the inlet structure on the overall performance of the fan becomes increasingly significant.

[0003] In existing technologies, to achieve airflow regulation or adapt to different operating conditions, a guide vane adjustment mechanism is usually installed on the air inlet side of the fan. The airflow and flow direction are adjusted by changing the guide vane opening. Typical solutions often use single or multiple rows of adjustable guide vanes, and a linkage transmission mechanism is used to achieve synchronous rotation of the entire guide vane circle, thereby changing the velocity distribution and flow direction of the fluid before entering the impeller.

[0004] For example, CN113700675B discloses a guide vane adjustment structure set on the air inlet side of a fan. The guide vane opening is adjusted synchronously with the transmission mechanism to improve the airflow state. This type of technical solution can achieve a certain degree of air volume adjustment and airflow guidance, but its adjustment method mainly relies on the synchronous movement of the entire circle of guide vanes, and its structure is still mainly based on a single adjustment dimension.

[0005] However, existing technologies still have shortcomings in application. Under intermediate opening or non-design conditions, guide vane adjustment can easily cause discontinuous local contraction of the air inlet and abrupt changes in the inlet flow channel profile, resulting in increased additional pressure loss and reduced fan efficiency. When there is local blockage, filter dust accumulation, or biased incoming flow on the air inlet side, synchronous adjustment of the entire guide vane is difficult to effectively correct circumferential uneven flow, which can easily lead to local flow deviation, vortex and flow separation, further deteriorating aerodynamic performance. While some existing improvement schemes improve the flow field through guide vane structure improvements or simple zonal adjustments, they mostly focus on improving a single aerodynamic index and lack coordinated control over the continuity of the inlet profile and the balance of the circumferential flow field. Moreover, the control methods are mostly fixed rules or single threshold triggers, making it difficult to achieve a smooth, stable, and engineering-feasible dynamic adjustment process under complex operating conditions.

[0006] Therefore, it is still necessary to provide an adjustable low-resistance fan inlet guide mechanism to maintain the low-resistance profile at the inlet and control the uniform circumferential inflow during the guide vane adjustment process, thereby improving the fan's operational stability and aerodynamic performance under complex operating conditions. Summary of the Invention

[0007] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide an adjustable low-resistance fan inlet guide mechanism. This mechanism achieves continuous compensation of the inlet profile during the guide vane adjustment process through the linkage between a segmented profile-maintaining guide lip ring and a single-row circumferentially adjustable guide vane group. It corrects local circumferential flow field imbalances through a zoned micro-differential compensation component and achieves coordinated adjustment by combining a state sensing component and a control component, thereby solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: An adjustable low-resistance fan inlet guide mechanism includes an inlet housing, a single-row circumferentially adjustable guide vane assembly, a main linkage drive component, a segmented contour-maintaining guide lip ring, a zoned differential compensation component, a status sensing component, and a control component. The single-row circumferentially adjustable guide vane assembly is disposed at the air inlet of the inlet housing. The main linkage drive component is used to drive the entire circle of guide vanes to adjust synchronously. The segmented contour-maintaining guide lip ring includes multiple circumferentially spliced ​​arc guide segments, each of which is movably connected to the inlet housing via a guide groove and connected to adjacent guide vanes via a differential linkage component. The shafts are linked together, causing the displacement of each arc guide section to change synergistically due to the coupling effect of the rotation state of adjacent guide vanes; the partitioned differential compensation component is used to apply additional compensation to different circumferential sectors on the basis of synchronous adjustment of the entire guide vane; the state sensing component is used to collect the operating state of the mechanism and the inlet flow state; the control component is used to receive the sampling data of the state sensing component and coordinate the control of the main linkage drive component and the partitioned differential compensation component, so that the differential compensation of the entire guide vane, the arc guide section and each circumferential sector evolves synergistically under unified boundary constraints.

[0009] In a preferred embodiment, the air inlet housing is a cylindrical or near-cylindrical structure, with the air inlet formed at its front end and its rear end connected to the wind tunnel or main housing of the fan impeller; the inner circumferential surface of the air inlet housing is provided with multiple guide vane mounting positions along the circumferential direction; the single-row circumferentially adjustable guide vane group includes multiple guide vanes and guide vane connecting shafts corresponding to each guide vane, and each guide vane is rotatably mounted on the air inlet housing through the guide vane connecting shafts.

[0010] In a preferred embodiment, the main linkage drive assembly includes an actuator motor, a reduction mechanism, a main drive gear, a linkage gear ring, and multiple driven gears; each driven gear is fixed to the outer end of the corresponding guide vane connecting shaft, the linkage gear ring meshes with the multiple driven gears, the actuator motor drives the main drive gear through the reduction mechanism, and the main drive gear drives the linkage gear ring to move circumferentially, thereby driving the entire guide vane to rotate synchronously.

[0011] In a preferred embodiment, the inner sides of each of the arc-shaped guide sections together form the inlet transition profile of the air inlet; each of the arc-shaped guide sections slides with the air inlet housing through a guide groove and is connected to the adjacent guide vane connecting shaft through the differential linkage component.

[0012] In a preferred embodiment, adjacent arc guide sections are connected by an overlapping, interlocking, or shielding structure; the differential linkage is a rocker arm linkage, a slanted cam structure, an offset slider structure, or an elastic floating tie rod structure; the displacement of each arc guide section is axial displacement, radial micro-displacement, or a composite displacement formed by the superposition of axial and radial micro-displacements.

[0013] In a preferred embodiment, the partitioned differential compensation component divides the entire guide vane into 3 to 6 circumferential sectors, each circumferential sector including 2 to 6 guide vanes; each circumferential sector is provided with a set of differential compensation units, the differential compensation units being disposed between the main linkage drive component and the guide vanes of the corresponding circumferential sector; each differential compensation unit is equipped with a mechanical limiting component.

[0014] In a preferred embodiment, the state sensing component includes a circumferential static pressure sampling unit, a guide vane front and rear pressure difference sampling unit, a guide vane angle sampling unit, a guide lip ring displacement sampling unit, and an actuator load sampling unit.

[0015] In a preferred embodiment, the circumferential static pressure sampling unit includes a plurality of static pressure sampling holes distributed circumferentially along the air inlet; the guide vane angle sampling unit is used to obtain the reference rotation angle of the entire guide vane and the differential compensation amount of each circumferential sector; the guide lip ring displacement sampling unit is used to obtain the real-time displacement of the key arc guide section; and the actuator load sampling unit is used to obtain the current, torque or equivalent load changes of the actuator motor and each of the differential compensation units.

[0016] In a preferred embodiment, the control component has a built-in preset geometric mapping table. The geometric mapping table stores the reference angle of the entire guide vane, the differential compensation amount of each circumferential sector, and the minimum effective flow area, inlet equivalent transition rate, and reference pressure difference before and after the guide vane corresponding to the displacement of each circular arc guide segment under different discrete node combinations. The control component calls the geometric mapping table according to the currently acquired guide vane angle, sector compensation amount, and guide lip displacement, and performs interpolation calculations to construct an inlet low-resistance profile maintenance analysis point. It also combines the circumferential static pressure and load data acquired by the state sensing component to construct a circumferential inflow uniform and stable analysis point, thereby forming a joint modulation quantity.

[0017] In a preferred embodiment, the control component establishes a flow-guiding adjustment underlying state machine; the flow-guiding adjustment underlying state machine includes a low-resistance maintenance state, a smooth transition state, a limited compensation state, and a stable recovery state; the control component internally presets a first threshold and a second threshold arranged from small to large, and combines local static pressure deviation, local differential pressure deviation, and a holding time window to jointly determine state switching; the specific boundary parameters of each state are preset through a boundary table, the boundary parameters include the allowable target angle range of the entire guide vane, the upper limit of the angular velocity of the entire guide vane, the micro-differential compensation range of each circumferential sector, the upper limit of the micro-differential compensation change rate of each circumferential sector, the allowable displacement range of the arc guide section, and the state switching holding time window; the control component reads or interpolates the corresponding boundary parameters from the boundary table according to the state range corresponding to the joint modulation amount, and drives the main linkage drive component, the partitioned micro-differential compensation component, and the segmented contour-maintaining guide lip ring to coordinate their actions within the boundary range.

[0018] The technical effects and advantages of the adjustable low-resistance fan inlet guide mechanism of this invention are as follows: This invention achieves adaptive and continuous compensation of the inlet leading edge profile by using a segmented profile to maintain the linkage between the guide lip ring and the single-row circumferentially adjustable guide vane assembly. During the guide vane adjustment process, it transforms the inlet flow channel from a local abrupt state to a smooth transition state, effectively reducing the intermediate opening of the guide vanes and the additional pressure loss under non-design conditions, thereby improving the overall aerodynamic efficiency of the fan. This invention introduces a limited additional adjustment capability of circumferential partitions by setting up a partitioned micro-differential compensation component, which, on the basis of synchronous adjustment of the whole circle of guide vanes, enables each sector to make differentiated corrections for working conditions such as local blockage, filter dust accumulation, or biased incoming flow, effectively suppressing local flow deviation, vortex and flow separation phenomena, and improving the circumferential uniformity and operational stability of the inlet airflow field. This invention constructs a collaborative adjustment mechanism between state sensing components and control components, which unifies the characterization of inlet profile continuity and circumferential flow field equilibrium, and realizes the collaborative evolution of guide vane adjustment, differential compensation and guide lip displacement under the boundary constraints of the underlying state machine. This enables the system to maintain a smooth and controllable adjustment process under complex operating conditions, thereby improving control stability and engineering adaptability. The overall structure of this invention adopts a combination of a single row of guide vanes and a segmented guide lip ring, which is compact, has low modification cost, and is easy to integrate with existing wind turbine systems. At the same time, it reduces the control calculation burden by combining offline calibration and online calling, and has good engineering feasibility and promotion application value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the adjustable low-resistance fan inlet guide mechanism of the present invention.

[0020] Figure 2This is a schematic diagram of the spatial layout of the state sensing component and the main drive system of the present invention.

[0021] Figure 3 This is an enlarged schematic diagram of a partial structure of the differential compensation unit of the present invention.

[0022] Figure 4 This is a collaborative block diagram of the state perception and control component of the present invention.

[0023] Figure 5 This is a schematic diagram of the state machine boundary modulation logic driven by the joint modulation amount of the present invention.

[0024] Figure 6 This is a control flowchart of the adjustable low-resistance fan inlet guide mechanism of the present invention.

[0025] Figure 7 This is a schematic diagram illustrating the parameter calibration and mapping relationship and aerodynamic effects of the present invention.

[0026] 100. Adjustable low-resistance fan inlet guide mechanism; 110. Inlet housing; 111. Guide vane mounting position; 200. Single-row circumferentially adjustable guide vane assembly; 210. Guide vane; 220. Guide vane connecting shaft; 300. Main linkage drive assembly; 310. Actuator motor; 320. Reduction mechanism; 330. Main drive gear; 340. Linkage gear ring; 350. Driven gear; 400. Segmented contour retaining guide lip ring; 410. Arc guide section; 420. Guide groove; 430. Differential linkage component; 50 0. Zoned differential compensation component; 510. Circumferential sector; 520. Differential compensation unit; 530. Mechanical limit component; 600. State sensing component; 610. Circumferential static pressure sampling unit; 611. Static pressure sampling hole; 620. Guide vane front and rear pressure difference sampling unit; 630. Guide vane angle sampling unit; 640. Guide lip ring displacement sampling unit; 650. Actuator load sampling unit; 700. Control component; 710. Geometric mapping table; 720. Boundary table; 730. Guide adjustment underlying state machine. Detailed Implementation

[0027] 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.

[0028] Example 1: This example provides an adjustable low-resistance fan inlet guide mechanism 100, such as... Figure 1 and Figure 2 As shown, it includes an air inlet housing 110, a single-row circumferentially adjustable guide vane assembly 200, a main linkage drive assembly 300, a segmented contour-maintaining guide lip ring 400, a zoned micro-differential compensation assembly 500, a status sensing assembly 600, and a control assembly 700.

[0029] The air inlet housing 110 is preferably cylindrical or near-cylindrical, with an air inlet at its front end and its rear end connected to the air duct or main housing of the fan impeller. Multiple guide vane mounting positions 111 are arranged circumferentially on the inner circumferential surface of the air inlet housing 110. These guide vane mounting positions 111 can be evenly distributed or non-uniformly distributed depending on the overall fan installation environment, the layout of front-end obstacles, or the filter zoning method.

[0030] The single-row circumferentially adjustable guide vane assembly 200 includes multiple guide vanes 210 and guide vane connecting shafts 220 corresponding to each guide vane 210. Each guide vane 210 is rotatably mounted on the air inlet housing 110 via the guide vane connecting shaft 220 to form a single-row circumferentially adjustable airflow guiding unit on the front side of the air inlet. The guide vanes 210 preferably have an airfoil cross-section structure, with a rounded leading edge and a converging trailing edge, and the thickness gradually decreases along the chord direction. The number of guide vanes 210 is preferably 8 to 24, more preferably 10 to 16. The adjustment range of the guide vanes 210 is preferably relative to a reference installation angle. to More preferably to .

[0031] The main linkage drive assembly 300 is used to drive the entire circle of guide vanes 210 to rotate synchronously. The main linkage drive assembly 300 preferably includes an actuator motor 310, a reduction mechanism 320, a main drive gear 330, a linkage gear ring 340, and multiple driven gears 350. The multiple driven gears 350 are respectively fixed to the outer end of the corresponding guide vane connecting shaft 220. The linkage gear ring 340 meshes with the multiple driven gears 350. The actuator motor 310 drives the main drive gear 330 through the reduction mechanism 320. The main drive gear 330 drives the linkage gear ring 340 to move circumferentially, so that the entire circle of guide vanes 210 rotates synchronously. The linkage gear ring 340 preferably adopts a split type or an open type structure.

[0032] The segmented profile retaining guide lip ring 400 is disposed at the leading edge of the air inlet and includes multiple arc guide sections 410 spliced ​​together along the circumference; the inner side of each arc guide section 410 constitutes the inlet transition profile of the air inlet, which is used to maintain a relatively smooth low-resistance contraction surface during the adjustment of the guide vane 210; the adjacent arc guide sections 410 preferably adopt an overlapping, interlocking or shielding connection structure to reduce the interference of inter-segment steps and gaps on the flow continuity.

[0033] Each arc-shaped guide section 410 slides with the air inlet housing 110 via a guide groove 420 and is connected to the adjacent guide vane connecting shaft 220 via a differential linkage 430. The differential linkage 430 can be a rocker arm linkage structure, a slanted cam structure, an offset slider structure, or an elastic floating tie rod structure. Through the differential transmission relationship of the differential linkage 430, the displacement of each arc-shaped guide section 410 is not independently driven by a single guide vane 210, but is formed by the combined effect of the rotational states of multiple adjacent guide vanes 210. When adjacent guide vanes 210 rotate synchronously or asynchronously, each arc-shaped guide section 410 generates a corresponding coupled displacement under guiding constraints, thereby causing the inlet profile to change continuously and coordinately along the circumference. The preferred displacement mode of the arc-shaped guide section 410 is axial displacement, radial micro-displacement, or a composite displacement formed by the superposition of both, with the displacement amount preferably from 0.3 mm to 6 mm, more preferably from 0.8 mm to 4 mm.

[0034] Furthermore, the differential linkage 430 structurally transmits the relative rotational difference between adjacent guide vanes 210, enabling the displacement response of the arc guide section 410 to incorporate both the overall opening change information and the local differential change information of the guide vane 210. This achieves overall tracking of the inlet profile during the synchronous adjustment of the entire guide vane 210, and enables local adaptive compensation when there is uneven circumferential adjustment. Through this differential coupling mechanism, the inlet profile no longer undergoes segmented abrupt changes, but instead forms a continuous transition surface in the circumferential direction. To improve the displacement transmission stability of the differential linkage 430 and reduce the risk of jamming during long-term operation, a self-lubricating wear-resistant liner is preferably provided inside the guide groove 420 or on the sliding contact surface of the arc guide section 410, and an elastic pre-tightening compensation component is used to compensate for the transmission gap. The overlapping edges of adjacent arc guide sections 410 preferably adopt a labyrinth-type or shielded leak-proof structure to reduce the impact of leakage during the guide vane 210 adjustment period and step disturbances on the continuity of the inlet profile.

[0035] The partitioned differential compensation component 500 is used to apply limited, small-amplitude additional compensation to different circumferential sectors 510 based on the synchronous adjustment of the entire guide vane 210, to adapt to conditions such as partial blockage, offset installation, lateral flow, or local disturbance. Preferably, the entire guide vane 210 is divided into 3 to 6 circumferential sectors 510, each sector including 2 to 6 guide vanes 210. Each sector is equipped with a set of differential compensation units 520, such as... Figure 3As shown, the differential compensation unit 520 is disposed between the main linkage drive assembly 300 and the guide vane 210 of the corresponding circumferential sector 510. In a preferred embodiment, it can be disposed between the linkage gear ring 340 and the driven gear 350 of the corresponding sector, or between the guide vane connecting shaft 220 and the guide vane 210, to generate a limited additional deflection of the guide vane 210 of the corresponding sector based on the full-circumference reference angle. Each differential compensation unit 520 can be implemented by means of a micro actuator, differential elastic element, magnetorheological damping biasing element, or small-stroke biasing cam, etc. In a preferred embodiment, the differential compensation unit 520 can be a micro actuator, whose fixed end is installed on the mounting base of the main linkage drive assembly 300 or the support part adjacent to the linkage gear ring 340, and the power output end is connected to the transmission component of the corresponding circumferential sector 510 through spline connection, coupling connection, or slider connection, so as to superimpose the additional compensation amount onto the reference angle of the guide vane 210 of the corresponding sector. Preferably, the additional deflection amount in each sector is limited to to More preferably, it is limited to to Each differential compensation unit 520 is preferably equipped with a mechanical limiter 530 to avoid overcompensation in local sectors.

[0036] The state sensing component 600 is used to collect the operating status of the mechanism and the inlet flow status. For example... Figure 2 and Figure 4 As shown, the state sensing component 600 includes at least a circumferential static pressure sampling unit 610, a guide vane front-to-back pressure difference sampling unit 620, a guide vane angle sampling unit 630, a guide lip ring displacement sampling unit 640, and an actuator load sampling unit 650. The circumferential static pressure sampling unit 610 includes multiple static pressure sampling holes 611 distributed circumferentially along the air inlet, preferably 6 to 16 in number. To improve the accuracy of circumferential static pressure sampling and reduce dynamic pressure interference, the aperture of the static pressure sampling holes 611 is preferably 2mm to 4mm, and the inner edge of the hole is preferably flush with the inner wall of the air inlet housing 110; each static pressure sampling hole 611 is preferably distributed at equal angles along the circumferential direction of the air inlet, or arranged according to the boundary and center area of ​​each circumferential sector 510; the pressure sensor is preferably a piezoresistive differential pressure sensor, and its measurement accuracy is preferably not less than 0.25%. The guide vane front-to-back pressure difference sampling unit 620 is used to obtain the pressure difference change between the front and rear sides of the guide vane 210. The guide vane angle sampling unit 630 is used to acquire the reference rotation angle of the entire guide vane 210 and the differential compensation amount of each sector. The guide lip ring displacement sampling unit 640 is used to acquire the real-time displacement of the key arc guide section 410. The actuator load sampling unit 650 is used to acquire the current, torque or equivalent load changes of the actuator motor 310 and each differential compensation unit 520.

[0037] The control component 700 is used to receive the sampled data from the state sensing component 600. In order to suppress transient pulsation interference in the fan inlet flow field and prevent control signal oscillation, the control component 700 preferably performs moving average filtering, first-order low-pass filtering, or median filtering preprocessing on the circumferential static pressure signal and the pressure difference signal before and after the guide vane 210. Subsequently, the control component 700 coordinates the control of the main linkage drive component 300 and the partition differential compensation component 500 according to the preset geometric mapping relationship, analysis model, and boundary modulation strategy, so that the entire guide vane 210, the arc guide section 410, and the differential compensation amount of each sector evolve collaboratively under unified boundary constraints. Preferably, the guide vane 210 and the arc-shaped guide section 410 can be made of reinforced nylon, polybutylene terephthalate, aluminum alloy, stainless steel thin-walled parts, or composite materials, depending on the fan specifications. For small and medium power fans, engineering plastics or aluminum alloy thin-walled parts are preferred to reduce inertia and cost. For large-size or high-pressure fans, a metal frame with engineering plastic covering structure is preferred to balance rigidity and manufacturability. Each arc-shaped guide section 410 preferably adopts a detachable installation structure. The differential linkage 430 is preferably connected to the guide vane connecting shaft 220 by a pin, snap-fit, or screw quick-release method. The micro-differential compensation unit 520 preferably adopts a modular installation method to improve maintenance convenience.

[0038] In Example 2, in order to reduce the real-time computing load of the control component 700 and improve the calibration efficiency and feasibility of the project at the engineering site, this example adopts a parameter modeling method of offline calibration plus online calling.

[0039] During the prototype development phase, a geometric mapping table 710 is first established. Specifically, the reference angle of the entire guide vane 210, the differential compensation amount of each sector, and the displacement of each arc guide section 410 are discretely obtained according to preset nodes. Through 3D modeling, prototype scanning, or bench calibration, the minimum effective flow area, inlet equivalent transition rate, reference pressure difference before and after the guide vane 210, and reference load of each sector are obtained under different combinations. Figure 4 and Figure 6 As shown, the control component 700 does not need to perform complex real-time fluid calculations during operation. It only needs to obtain the corresponding geometric parameters by looking up tables and interpolation based on the currently acquired guide vane 210 angle, sector compensation amount, and guide lip ring displacement, thereby improving the real-time performance of control and engineering feasibility.

[0040] The reference angle of the full circle guide vane 210 is preferably [missing information]. or To ensure discrete value selection at intervals, the micro-differential compensation amount for each sector is preferably set at... or For discrete value taking, the displacement of each arc guide segment 410 is preferably discretely taken at intervals of 0.5 mm or 1 mm; the data obtained from offline calibration can be stored as a two-dimensional table, a three-dimensional table, or a piecewise function table, preferably called using piecewise linear interpolation or trilinear interpolation; the inlet equivalent transition rate is used to characterize the smoothness of the inlet profile between the leading edge of the air inlet and the leading edge of the guide vane 210, and is preferably determined comprehensively based on the average contraction change within the reference axial length, the continuity of the surface slope, and the splicing continuity of adjacent arc guide segments 410. During the prototype calibration stage, the inlet profile under different combinations of full-circle guide vane 210 reference angles, different sector differential compensation amounts, and different arc guide segment 410 displacements can be discretely sampled, and the corresponding inlet equivalent transition rate can be calculated according to the preset evaluation rules, and then written into the geometric mapping table 710 so that the control component 700 can directly call it during operation. It should be noted that the displacement range of the aforementioned arc guide section 410 and the compensation angle range of each sector are preferably determined by a comprehensive comparison of the pressure loss changes under the adjustment conditions of the prototype bench test, the inlet profile geometric scan, and the guide vane 210.

[0041] To facilitate unified judgment of different operating conditions by the control component 700, this embodiment constructs two parallel comprehensive analysis points: the inlet low-resistivity profile maintenance analysis point and the circumferential inflow uniform and stable analysis point.

[0042] The preferred analysis point for maintaining the low-resistivity profile at the inlet is calculated using the following formula: ; Where: L is the inlet low-resistivity profile preservation analysis point; The area shrinkage rate represents the degree of shrinkage of the current minimum effective circulation area relative to the effective circulation area under the baseline operating conditions. The profile deviation rate represents the degree of deviation of the current inlet equivalent transition rate from the reference inlet equivalent transition rate. The pressure difference deviation rate indicates the degree of deviation of the current pressure difference before and after guide vane 210 from the reference pressure difference before and after guide vane 210 under the reference operating condition. , , For the corresponding weight coefficients, and The area shrinkage rate can be obtained by comparing the current minimum effective flow area with the effective flow area under the reference operating condition; the profile deviation rate can be obtained by comparing the current inlet equivalent transition rate with the reference inlet equivalent transition rate; the pressure difference deviation rate can be obtained by comparing the current pressure difference before and after the guide vane 210 with the reference pressure difference before and after the guide vane 210 under the reference operating condition. In a preferred embodiment, Take a value between 0.35 and 0.55. Take a value between 0.20 and 0.35. Take a value between 0.15 and 0.30. When the fan is more sensitive to inlet contraction, it is preferable to increase the value. When the fan is more sensitive to the smoothness of the inlet profile, it is preferable to improve... When operating conditions fluctuate significantly and differential pressure changes better reflect the trend of additional losses, it is preferable to increase the pressure. .

[0043] The preferred circumferential inflow uniform and stable analysis point is calculated using the following formula: ; Where U is the circumferential inflow uniform and stable analysis point; Circumferential static pressure dispersion rate represents the degree of dispersion of pressure values ​​at each circumferential static pressure sampling point; The sector pressure difference dispersion rate represents the degree of dispersion of the pressure difference before and after guide vane 210 in each sector. To implement the load dispersion rate, it represents the degree of dispersion of the output current or equivalent load signal of each sector differential compensation unit 520; , , For the corresponding weight coefficients, and The circumferential static pressure dispersion rate can be determined by the standard deviation and average value of the pressure values ​​at each circumferential static pressure sampling point; the sector pressure difference dispersion rate can be determined by the standard deviation and average value of the pressure difference before and after each sector guide vane 210; the execution load dispersion rate can be determined by the standard deviation of the output current or equivalent load signal of each sector differential compensation unit 520 and the reference load. In a preferred embodiment, Take a value between 0.40 and 0.60. Take a value between 0.20 and 0.35. Use a value between 0.15 and 0.25. When localized clogging, lateral disturbances, or differences in filter zones are more pronounced, it is preferable to increase the value. When sector pressure differential fluctuations better reflect the degree of flow deviation, it is preferable to increase... When the execution amount of micro-error compensation better reflects the trend of circumferential imbalance, it is preferable to increase... .

[0044] To reflect the combined effect of the two comprehensive analysis points on the final control output, this implementation further constructs a joint modulation quantity. The joint modulation quantity is preferably calculated using the following formula: ; Where M is the joint modulation amount used to update the boundary of the underlying state machine; The uniform stability gain coefficient; This represents the linkage coupling coefficient. In a preferred embodiment, Take a value between 0.6 and 1.4. The value is set to 0.1 to 0.8. The control component 700 preferably limits M to fall between 0 and 1. The larger M is, the higher the risk of the superposition of inlet profile deterioration and circumferential inlet imbalance; the product term in the formula reflects the linkage enhancement effect, so that when inlet low-resistance profile deterioration and circumferential imbalance occur simultaneously, the control boundary can be tightened more quickly.

[0045] To avoid abrupt changes and vulnerabilities caused by simple rule tree control, the control component 700 preferably adopts a low-level state machine boundary modulation method for control. (See also...) Figure 5 and Figure 6 The control component 700 establishes a flow regulation underlying state machine 730, which includes at least a low resistance maintenance state, a smooth transition state, a restricted compensation state, and a stable recovery state.

[0046] To accurately define the trigger and hold boundaries of each state in the underlying state machine 730 of the flow guidance regulation, the control component 700 internally presets a first threshold and a second threshold arranged from smallest to largest, and combines them with local static pressure deviation, local differential pressure deviation, and hold time window to jointly determine state switching. The specific modulation logic is as follows: When the combined modulation amount is less than the first threshold, the system is in a low resistance maintenance state. At this time, the control component 700 allows the entire guide vane 210 to be adjusted in a small range at a low rate of change. The differential compensation amount of each sector is kept within a small range, and the displacement of the arc guide section 410 is controlled within a small working range to maintain the continuity of the inlet profile and the balance of circumferential air intake. The first threshold is preferably 0.25 to 0.35. In a preferred embodiment, the upper limit of the 210° angular velocity of the guide vane throughout the entire revolution in the low-drag maintenance state is preferably... to The optimal limit for micro-differential compensation in each sector is within a certain range. Within this range, the displacement of a single arc guide section 410 is preferably limited to 0.5 mm to 1.5 mm.

[0047] When the combined modulation amount is not less than the first threshold and less than the second threshold, the system enters a smooth transition state. At this time, the control component 700 allows the full circle guide vane 210 to continuously adjust towards the target working condition, while simultaneously increasing the displacement of the arc guide section 410 to maintain the smoothness of the inlet profile during the adjustment process of the guide vane 210. The micro-differential compensation components of each sector begin to participate in micro-correction. The second threshold is preferably taken as 0.50 to 0.65. In a preferred embodiment, the upper limit of the 210° angular velocity of the guide vane throughout the entire rotation under smooth transition is preferably... to The optimal limit for micro-differential compensation in each sector is within a certain range. to The displacement of a single arc guide section 410 is preferably limited to 1.0 mm to 3.0 mm.

[0048] When the joint modulation amount is not less than the second threshold, or when the local static pressure deviation or local differential pressure deviation of a certain sector continuously exceeds the preset holding time window, the system enters the restricted compensation state. At this time, the control component 700 prioritizes tightening the entire circle guide vane 210 to further increase the opening boundary and increases the response weight of the corresponding sector differential compensation component. At the same time, it drives the arc guide section 410 adjacent to the sector into a larger displacement range to alleviate the local contraction and deflection trend. The holding time window is preferably one hundred milliseconds to one thousand milliseconds. In a preferred embodiment, the upper limit of the 210° angular velocity of the guide vane in the constrained compensation state is preferably... to The optimal limit for micro-differential compensation in each sector is within a certain range. to The displacement of a single arc guide section 410 is preferably limited to 2.0 mm to 4.5 mm.

[0049] When the system is in the limited compensation state, if the joint modulation amount decreases in multiple consecutive sampling cycles, and the static pressure deviation and differential pressure deviation of the corresponding sector fall back to below the recovery threshold, the system switches to the stable recovery state. At this time, the control component 700 gradually releases the differential compensation amount of each sector and the displacement amount of the arc guide section 410 according to the preset recovery slope, so that the entire guide vane 210 and the inlet profile gradually return to the vicinity of the target working condition. The number of consecutive sampling cycles is preferably three to twenty. In a preferred embodiment, the upper limit of the angular velocity of the guide vane in the steady recovery state is preferably 210°. to The differential compensation amount for each sector can be calculated according to each sampling period. to The proportion decreases.

[0050] To ensure the smoothness, determinism, and consistency of boundary execution during state machine transitions under complex operating conditions, the specific boundary parameters for each state are preferably pre-set using a boundary table 720. These boundary parameters include at least the allowable target angle range for the entire guide vane 210, the upper limit of the angular velocity of the entire guide vane 210, the differential compensation range for each sector, the upper limit of the differential compensation rate of change for each sector, the allowable displacement range for the circular guide section 410, and the state transition holding time window. During operation, the control component 700 reads or interpolates the corresponding boundary parameters from the boundary table 720 based on the state range corresponding to the joint modulation amount, and drives the coordinated actions of each execution component within this boundary range.

[0051] Preferably, the control component 700 performs state acquisition, analysis point update, joint modulation calculation and boundary refresh once with a control cycle of 20ms to 200ms, so as to balance response speed, computational load and execution stability. Combination Figure 6The control flow diagram shown below, in a preferred application mode, illustrates the system's operation steps, typical application scenarios, and fault-tolerant maintenance methods as follows: Step 1: Power on the control component 700, read the geometric mapping table 710, boundary table 720 and reference operating condition parameters, and initialize and perform self-test on the actuator motor 310, each differential compensation unit 520 and the state sensing component 600.

[0052] Step 2: The status sensing component 600 collects the current reference angle of the full circle guide vane 210, the micro-differential compensation amount of each sector, the displacement of each key circular arc guide section 410, the circumferential static pressure distribution, the pressure difference before and after the guide vane 210, and the load information of the actuator.

[0053] Step 3: The control component 700 calls the geometric mapping table 710 based on the current reference angle of the full circle guide vane 210, the differential compensation amount of each sector, and the displacement of each key circular arc guide section 410 to obtain geometric parameters such as the current minimum effective flow area and the inlet equivalent transition rate, and calculates the inlet low resistance profile maintenance analysis point in combination with the pressure difference before and after the guide vane 210.

[0054] Step 4: The control component 700 calculates the circumferential inflow uniform and stable analysis point based on the circumferential static pressure distribution, the pressure difference distribution of each sector, and the load distribution of the actuator.

[0055] Step 5: The control component 700 calculates the joint modulation amount based on the inlet low-resistivity profile maintaining analysis point and the circumferential inflow uniform and stable analysis point, and updates the state of the underlying state machine and the corresponding boundary parameters based on the joint modulation amount.

[0056] Step six: The main linkage drive component 300, the partition micro-differential compensation component 500 and the segmented contour-maintaining guide lip ring 400 work together within the updated boundary range to make the entire guide vane 210, the micro-differential compensation amount of each sector and the displacement amount of the arc guide section 410 evolve synchronously.

[0057] Step 7: If a local sensor abnormality, guide lip ring jamming, guide vane 210 loss of synchronization, sector compensation failure, or actuator load abnormality is detected, the control component 700 triggers a degraded operation strategy to return the entire guide vane 210 to the preset safe angle, the micro-differential compensation of each sector is reduced to zero or returned to the minimum value, and the arc guide section 410 returns to the neutral position to ensure that the fan maintains basic air supply or exhaust capacity.

[0058] The preferred reference operating condition is the medium guide vane 210 opening at the rated speed of the fan. Preferably, the reference operating condition is set at 90% to 100% of the rated speed, with a reference angle of 8 to 15 degrees for the entire guide vane 210 circumference, zero degree differential compensation for each sector, and the initial median displacement of each arc guide section 410. Under this condition, the effective flow area, inlet equivalent transition rate, reference pressure difference before and after the guide vane 210, and reference current or reference load are obtained through offline modeling or bench testing.

[0059] The weighting coefficients and boundary table 720 are preferably determined through bench tests. Specifically, under different reference angles of the full-circle guide vanes 210, different local blockage rates, different filter dust accumulation states, different lateral inflows, and different installation offsets, total pressure loss, circumferential static pressure deviation, sector pressure difference deviation, and actuator load changes are collected. Then, with the goal of minimizing the increase in total pressure loss, minimizing the circumferential static pressure deviation, and stabilizing the change in actuation quantity, multiple sets of samples are fitted or empirically corrected to obtain the optimal parameters suitable for the corresponding fan model. For low-noise silent fans, it is preferable to lower the first and second thresholds and appropriately tighten the angular velocity boundaries in each state; for high-volume fans, it is preferable to appropriately relax the angular velocity boundaries in the smooth transition state and increase the upper limit of the sector differential compensation in the constrained compensation state; for application scenarios with a high probability of biased inflow or pre-filter blockage risk, it is preferable to increase the response weight of each sector differential compensation unit 520, while appropriately increasing the upper limit of the displacement of the arc guide section 410.

[0060] Combination Figure 7 Taking an axial flow fan with a pre-filter as an example, the adjustable low-resistance fan inlet guide mechanism 100 of this invention is installed on the front side of the fan. Twelve guide vanes 210 are arranged around the entire circumference. The segmented contour-maintaining guide lip ring 400 has eight arc-shaped guide sections 410. The zoned differential compensation component 500 divides the entire circumference into four sectors, each sector containing three guide vanes 210. Eight circumferential static pressure sampling holes 611 are provided, four sets of guide vane front-and-back pressure difference sampling units 620 are provided, four sets of guide lip ring displacement sampling units 640 are provided, and four sets of differential compensation units 520 are provided.

[0061] After prolonged operation of the fan, dust accumulates locally on one side of the filter, causing an increase in the inlet resistance on that side. The state sensing component 600 detects a decrease in static pressure, an increase in differential pressure, and an increase in the load on the compensation unit in that sector. Based on the aforementioned model, the control component 700 calculates that both the inlet low-resistance profile maintenance analysis point and the circumferential inflow uniform stability analysis point have significantly increased, and the combined modulation amount exceeds the second threshold. The system transitions from a smooth transition state to a restricted compensation state. At this time, the control component 700 tightens the boundary of the entire guide vane 210 to further increase its opening, in order to avoid increasing the overall opening of the guide vane 210 and exacerbating local constriction. At the same time, restricted differential compensation is applied to the sector with high local resistance, and the displacement of the arc guide section 410 corresponding to that sector is increased, making the local profile of the air inlet smoother. As the impact of localized dust accumulation is mitigated or restored to normal after maintenance, static pressure deviation and differential pressure deviation gradually decrease, joint modulation amount continuously decreases, the system enters a stable recovery state, and the differential compensation amount of each sector and the displacement amount of the 410 arc guide section are gradually released according to the predetermined slope, so that the mechanism returns to a more balanced working state.

[0062] When the control component 700 determines that a static pressure sampling point has failed, it can make a short-term estimate of the failed sampling point based on the average value of the adjacent static pressure sampling points and the pressure difference change trend before and after the guide vane 210 of the corresponding sector, and simultaneously reduce the micro-differential compensation weight of the sector. If the guide lip ring displacement sampling unit 640 fails, the control component 700 can estimate the position of the arc guide section 410 based on the correspondence between the actuator feedback position and the geometric mapping table 710; when the estimation error continuously exceeds the threshold, the system enters a degraded operation mode.

[0063] In degraded operation mode, the entire guide vane 210 is preferably returned to the safe median angle of eight to fifteen degrees, the micro-differential compensation of each sector returns to zero degrees or remains within the minimum compensation range, and each arc guide section 410 returns to the middle position. At this time, the fan can still maintain basic air supply or exhaust capacity and provide a stable operating window for subsequent manual maintenance. To improve maintenance convenience, the control component 700 can also record the number of differential compensation actions in each sector, the number of displacements of the arc guide section 410, and the peak load of the actuator, which can be used to generate maintenance prompts. When a sector is in a high load compensation state for a long time, or when the displacement response of an arc guide section 410 is continuously lagging, the control component 700 can output maintenance prompts so that maintenance personnel can handle them in a timely manner.

[0064] In summary, this invention, through a single-row circumferentially adjustable guide vane assembly 200, a segmented profile-maintaining guide lip ring 400, a zoned differential compensation component 500, and boundary modulation control based on a bottom-level state machine at two integrated analysis points, enables the low-resistance profile maintenance at the inlet of the guide vane 210 and the uniform circumferential inflow control to form a synergistic relationship. This solution has a clear structural hierarchy, well-defined parameter sources, reproducible modeling paths, a concise number of formulas, and strong engineering feasibility. It can balance completeness, practicality, and inventiveness while satisfying the requirement of sufficient disclosure.

[0065] It should be noted that, for the sake of brevity, the foregoing method embodiments are described as a series of actions, but this does not mean that the application limits the order of the steps. Based on the ideas of this application, some steps can be executed in different orders or in parallel without affecting the functional implementation. Secondly, those skilled in the art should also understand that the specific embodiments described in the specification are preferred embodiments of the technical solutions of this application, and not limitations on the scope of protection of this application. All equivalent improvements or substitutions made within the spirit and principles of this application should be covered within the scope of protection of this application.

[0066] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adjustable low-resistance fan inlet air guiding mechanism, characterized in that, It includes an air inlet housing, a single-row circumferentially adjustable guide vane assembly, a main linkage drive assembly, a segmented contour-maintaining guide lip ring, a zoned micro-differential compensation assembly, a status sensing assembly, and a control assembly. The single-row circumferentially adjustable guide vane assembly is located at the air inlet of the air inlet casing; The main linkage drive component is used to drive the synchronous adjustment of the guide vane throughout the entire circle. The segmented contour-maintaining guide lip ring includes multiple arc-shaped guide segments arranged circumferentially. Each arc-shaped guide segment is movably connected to the air inlet shell through a guide groove, and forms a linkage with the adjacent guide vane connecting shaft through a differential linkage component, so that the displacement of each arc-shaped guide segment is affected by the coupling effect of the rotation state of the adjacent guide vanes and produces a coordinated change. The partitioned differential compensation component is used to apply additional compensation to different circumferential sectors on the basis of synchronous adjustment of the entire guide vane. The state sensing component is used to collect the operating status of the mechanism and the inlet flow status; The control component is used to receive the sampling data from the state sensing component and to coordinate the control of the main linkage drive component and the partition differential compensation component, so that the differential compensation of the entire guide vane, the arc guide section and each circumferential sector evolves collaboratively under unified boundary constraints.

2. The adjustable low-resistance fan inlet guide mechanism according to claim 1, characterized in that, The air inlet casing is a cylindrical or near-cylindrical structure, with the air inlet formed at its front end and its rear end connected to the air duct where the fan impeller is located or the main casing of the fan. The inner circumferential surface of the air inlet casing is provided with multiple guide vane mounting positions along the circumferential direction; The single-row circumferentially adjustable guide vane assembly includes multiple guide vanes and guide vane connecting shafts corresponding to each guide vane. Each guide vane is rotatably mounted on the air inlet housing via the guide vane connecting shafts.

3. The adjustable low-resistance fan inlet guide mechanism according to claim 2, characterized in that, The main linkage drive assembly includes an actuator motor, a reduction mechanism, a main drive gear, a linkage gear ring, and multiple driven gears; Each of the driven gears is fixed to the outer end of the corresponding guide vane connecting shaft. The linkage gear ring meshes with multiple driven gears. The actuator motor drives the main drive gear through the reduction mechanism. The main drive gear drives the linkage gear ring to move circumferentially, thereby driving the entire guide vane to rotate synchronously.

4. The adjustable low-resistance fan inlet guide mechanism according to claim 2, characterized in that, The inner sides of each of the aforementioned arc-shaped guide sections together form the inlet transition profile of the air inlet; Each of the arc-shaped guide sections slides into the air inlet housing via a guide groove and is connected to the adjacent guide vane connecting shaft via the differential linkage component.

5. The adjustable low-resistance fan inlet guide mechanism according to claim 4, characterized in that, The adjacent arc-shaped guide sections are connected by an overlapping structure, an interlocking structure, or a shielding structure. The differential linkage component is a rocker arm linkage structure, a slanted cam structure, an offset slider structure, or an elastic floating tie rod structure. The displacement mode of each of the circular arc guide sections is axial displacement, radial micro-displacement, or a composite displacement formed by the superposition of axial displacement and radial micro-displacement.

6. The adjustable low-resistance fan inlet guide mechanism according to claim 1, characterized in that, The partitioned differential compensation component divides the entire guide vane into 3 to 6 circumferential sectors, each of which includes 2 to 6 guide vanes; Each of the circumferential sectors is provided with a set of differential compensation units, which are located between the main linkage drive component and the guide vane of the corresponding circumferential sector; Each of the aforementioned differential compensation units is equipped with a mechanical limiting component.

7. The adjustable low-resistance fan inlet guide mechanism according to claim 1, characterized in that, The state sensing component includes a circumferential static pressure sampling unit, a guide vane front and rear pressure difference sampling unit, a guide vane angle sampling unit, a guide lip ring displacement sampling unit, and an actuator load sampling unit.

8. The adjustable low-resistance fan inlet guide mechanism according to claim 7, characterized in that, The circumferential static pressure sampling unit includes a plurality of static pressure sampling holes distributed circumferentially along the air inlet; The guide vane angle sampling unit is used to obtain the reference rotation angle of the entire guide vane and the micro-differential compensation amount of each circumferential sector. The flow guide lip ring displacement sampling unit is used to obtain the real-time displacement of the key circular arc flow guide section; The actuator load sampling unit is used to obtain the current, torque or equivalent load changes of the actuator motor and each of the differential compensation units.

9. The adjustable low-resistance fan inlet guide mechanism according to claim 1, characterized in that, The control component has a built-in preset geometric mapping table; the geometric mapping table stores the reference angle of the entire guide vane, the differential compensation amount of each circumferential sector, and the minimum effective flow area, inlet equivalent transition rate, and reference pressure difference before and after the guide vane under different discrete node combinations for each arc guide section displacement. The control component calls the geometric mapping table based on the currently acquired guide vane angle, sector compensation amount, and guide lip ring displacement, and performs interpolation calculations to construct an inlet low-resistance profile maintenance analysis point. It also combines the circumferential static pressure and load data acquired by the state sensing component to construct a circumferential inflow uniform and stable analysis point, thereby forming a joint modulation amount.

10. The adjustable low-resistance fan inlet guide mechanism according to claim 9, characterized in that, The control component establishes a flow-guiding and regulating underlying state machine; The underlying state machine for flow regulation includes a low-resistance maintenance state, a smooth transition state, a constrained compensation state, and a stable recovery state. The control component internally presets a first threshold and a second threshold arranged from small to large, and combines local static pressure deviation, local differential pressure deviation and holding time window to jointly determine state switching; The specific boundary parameters for each state are preset through a boundary table. The boundary parameters include the allowable target angle range of the entire guide vane, the upper limit of the angular velocity of the entire guide vane, the micro-differential compensation range of each circumferential sector, the upper limit of the micro-differential compensation change rate of each circumferential sector, the allowable displacement range of the circular arc guide section, and the state switching holding time window. The control component reads or interpolates the corresponding boundary parameters from the boundary table according to the state interval corresponding to the joint modulation amount, and drives the main linkage drive component, the partition differential compensation component and the segmented contour maintaining guide lip ring to work together within the boundary range.

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