A performance simulation and testing mechanism for multi-condition adjustable centrifugal fans

Abstract

This invention relates to the field of fan performance testing technology and provides a multi-condition adjustable centrifugal fan performance simulation testing mechanism, including an air inlet section, a condition adjustment unit, a fan installation section, and an air outlet section. The condition adjustment unit consists of a condition adjustment duct, a large-diameter cylinder, a small-diameter cylinder, two conical components, a drive mechanism, a speed reduction transmission mechanism, and a diameter changing mechanism. Each conical component consists of a conical sleeve, a spring frame, and an arc-shaped clamp. The drive mechanism not only performs synchronous axial extension and retraction of the two conical sleeves but also changes the effective flow cross-sectional area of ​​the airflow through the speed reduction transmission mechanism and the diameter changing mechanism. This achieves synchronous linkage control of the conical sleeve shape adjustment and the throat airflow channel cross-sectional area adjustment, generating a superimposed effect of wind resistance adjustment. This significantly reduces the wind resistance adjustment time of a single condition adjustment unit, accurately reproduces typical resistance characteristics in various actual pipe networks, and covers the entire operating condition range from low-resistance ventilation to extremely high-resistance induced draft.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine performance testing technology, and in particular relates to a multi-condition adjustable centrifugal fan performance simulation testing mechanism. Background Technology

[0002] Centrifugal fans, as a type of general-purpose fluid machinery, are widely used in various sectors of the national economy. Their performance parameters are directly related to the operating efficiency and energy consumption level of the entire system. In order to ensure the product quality and operational reliability of centrifugal fans, comprehensive performance tests must be conducted on them before they leave the factory to simulate their working state in the actual pipeline network and measure their key performance parameters such as flow rate, pressure, power and efficiency.

[0003] The existing centrifugal fan performance simulation testing mechanism includes a test duct, a wind pressure detection device, and a wind resistance adjustment device. The test duct is connected to the fan outlet via a connecting duct. The wind resistance adjustment device adopts a multi-blade throttling valve structure. By driving a motor to rotate the blades, the effective cross-sectional area of ​​the airflow channel is changed, thereby adjusting the system resistance. When the blades rotate, the cross-sectional area of ​​the airflow channel decreases, and the system resistance increases; when the blades rotate in the opposite direction, the cross-sectional area increases, and the system resistance decreases.

[0004] However, existing testing institutions still have certain technical shortcomings in practical applications: existing testing institutions can only adjust the system resistance by changing the cross-sectional area of ​​the airflow channel, and cannot independently adjust the local resistance coefficient. As a result, they can only simulate simple linear resistance conditions and cannot accurately reproduce various typical resistance characteristics in actual engineering, such as friction resistance along long pipelines, resistance of large-angle bends, or throttling resistance of valves. The test results deviate significantly from the operating performance of the fan in the real pipeline network.

[0005] Therefore, in view of the above situation, there is an urgent need to develop a multi-condition adjustable centrifugal fan performance simulation and testing mechanism to overcome the shortcomings in current practical applications. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a multi-condition adjustable centrifugal fan performance simulation and testing mechanism to solve the problems in the background technology.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A performance simulation and testing mechanism for a multi-condition adjustable centrifugal fan includes an air inlet section coaxially fixed and interconnected on a steel base, at least three independent condition adjustment units connected in series, a fan installation section, and an air outlet section. Each condition adjustment unit consists of a condition adjustment duct, two symmetrically arranged large-diameter cylinders, a small-diameter cylinder coaxially disposed between the two large-diameter cylinders, two conical components, a drive mechanism, a speed reduction transmission mechanism, and a diameter changing mechanism. The condition adjustment duct, large-diameter cylinders, conical components, and small-diameter cylinders are all coaxially arranged. One end of the drive mechanism is installed on the outer wall of the condition adjustment duct, and the other end of the drive mechanism extends into the condition adjustment duct and is connected to the outer walls of the two large-diameter cylinders and the speed reduction transmission mechanism, respectively. The speed reduction transmission mechanism is installed on the inner wall of the condition adjustment duct and located outside the small-diameter cylinder. Both ends of the inner wall of the small-diameter cylinder are provided with diameter changing mechanisms, and the power input end of the diameter changing mechanism is connected to the power output end of the speed reduction transmission mechanism. Both conical sleeves consist of a conical sleeve, a spring frame, and an arc-shaped clamp. The large-diameter end of the conical sleeve is sealed and fixed to the end flange of the large-diameter cylinder through the arc-shaped clamp, and the small-diameter end of the conical sleeve is sealed and fixed to the end flange of the small-diameter cylinder through the arc-shaped clamp. Both conical sleeves adopt a flexible sealing structure with a continuous smooth inner wall and foldable design. The outer wall of the conical sleeve is spirally nested with a spring frame. The two conical sleeves and the small-diameter cylinder in the middle together form a complete Venturi airflow channel.

[0008] As a further technical solution of the present invention, the arc-shaped clamp adopts a semi-circular arc-shaped plate structure with an axial cross section of L, and the inner arc of the arc-shaped clamp is adapted to the outer wall arc of the large-diameter cylinder and the small-diameter cylinder.

[0009] As a further technical solution of the present invention, the outer walls of the ends of the large-diameter cylinder and the small-diameter cylinder near the tapered sleeve are circumferentially distributed with lower pressure strips at equal intervals, and the inner arc surface of the arc-shaped clamp is circumferentially distributed with upper pressure strips at equal intervals, and the upper pressure strips and lower pressure strips are staggered and interlocked.

[0010] As a further technical solution of the present invention, the driving mechanism includes a drive motor, a transmission component one, a bidirectional trapezoidal screw, and a sliding sleeve. The drive motor is fixed on the outer wall of the working condition regulating duct. The output end of the drive motor is coaxially and fixedly connected to one end of the transmission component one. The other end of the transmission component one extends into the working condition regulating duct and is coaxially and fixedly connected to the middle part of the bidirectional trapezoidal screw. The bidirectional trapezoidal screw is axially and rotatably mounted on the inner wall of the working condition regulating duct. Sliding sleeves are screwed to both ends of the bidirectional trapezoidal screw. The two sliding sleeves are respectively fixedly connected to the outer walls of two large-diameter cylinders. The middle part of the bidirectional trapezoidal screw is connected to the power input end of the speed reduction transmission mechanism through the transmission component two.

[0011] As a further technical solution of the present invention, the speed reduction transmission mechanism includes a speed reduction component and a transmission component. Both the speed reduction component and the transmission component are rotatably installed on the inner wall of the middle part of the working condition regulating air duct. One end of the speed reduction component is connected to the second transmission component, and the other end of the speed reduction component is coaxially connected to one end of the transmission component. The other end of the transmission component is located inside a small diameter cylinder and is coaxially connected to the diameter changing mechanism.

[0012] As a further technical solution of the present invention, the speed reduction component includes a synchronous shaft, a shift block, a speed reduction disc, and a shift lever. The synchronous shaft is rotatably installed on the inner wall of the middle part of the working condition regulating air duct. One end of the synchronous shaft is coaxially fixed to the transmission component 2, and the other end of the synchronous shaft is fixed with a clover-shaped shift block. The speed reduction disc is coaxially fixed to one end of the transmission component. Shift levers are circumferentially distributed at equal intervals on the end face of the speed reduction disc near the shift block. The three blades on the clover-shaped shift block engage with the shift levers in sequence for transmission.

[0013] As a further technical solution of the present invention, the transmission assembly includes a transmission shaft, a transmission gear, and a transmission gear ring. The transmission shaft is rotatably mounted on the inner wall of the middle part of the working condition regulating air duct. The two ends of the transmission shaft are coaxially and symmetrically fixed with transmission gears. One side of one of the transmission gears is coaxially fixed with a speed reduction disc. One side of both transmission gears extends into a small-diameter cylinder and meshes with the transmission gear rings coaxially mounted on two diameter-changing mechanisms, respectively.

[0014] As a further technical solution of the present invention, the diameter changing mechanism includes a fixed sleeve, a T-shaped rotating block, and a diameter changing assembly. The fixed sleeve is coaxially fixed on the inner walls of both ends of the small-diameter cylinder. The T-shaped rotating block is coaxially rotatably mounted on the inner wall of the fixed sleeve via bearings. A transmission gear ring is coaxially fixed on the outer wall of the T-shaped rotating block. A through-type airflow hole is opened at the center position of both the fixed sleeve and the T-shaped rotating block. A number of eccentric guide grooves are circumferentially equidistantly opened on the end face of the fixed sleeve near the tapered sleeve. An equilateral guide groove is opened on the end face of the T-shaped rotating block near the fixed tapered sleeve. The number of sides of the equilateral guide groove is the same as the number of eccentric guide grooves. The diameter changing assembly is located between the fixed sleeve and the T-shaped rotating block and slides with the eccentric guide grooves and the equilateral guide grooves respectively.

[0015] As a further technical solution of the present invention, the variable diameter assembly includes a variable diameter block, a slider, and a sliding column. The variable diameter blocks are circumferentially distributed between the T-shaped rotating block and the fixed sleeve. The two sides of the variable diameter block are respectively fixed with a sliding column that slides in cooperation with the eccentric guide groove and a slider that slides in cooperation with the equilateral guide groove. The inner contour dimension formed by the multiple variable diameter blocks is larger than the inner diameter of the airflow hole.

[0016] As a further technical solution of the present invention, a sealing flange is coaxially fixed at the end of the large-diameter cylinder away from the small-diameter cylinder. The outer diameter of the sealing flange is smaller than the inner diameter of the operating condition regulating air duct, and an annular baffle is embedded in the circumferential sidewall of the sealing flange. The edge sidewall of the annular baffle is tightly attached to the inner wall of the operating condition regulating air duct. The annular baffle adopts a lip-shaped self-sealing structure made of graphite-filled polytetrafluoroethylene material.

[0017] Compared with the prior art, the beneficial effects of the present invention are: On the one hand, the drive mechanism can drive two large-diameter cylinders to move axially within the working condition regulating air duct, and cooperate with the small-diameter cylinder that is always stationary and the spring frame to complete the synchronous axial stretching or contraction of the two conical sleeves. On the other hand, the power is transmitted to the diameter changing mechanism through the speed reduction transmission mechanism, so that the two diameter changing mechanisms located at both ends of the inner wall of the small-diameter cylinder can change the effective flow cross-sectional area of ​​the airflow. This not only achieves synchronous linkage control between the adjustment of the conical sleeve shape and the adjustment of the throat airflow channel cross-sectional area, but also changes the local resistance coefficient of the airflow channel and the effective flow section of the throat in a single continuous adjustment action, generating a superimposed effect of wind resistance adjustment. This significantly reduces the wind resistance adjustment time of a single operating condition adjustment unit, greatly improves the overall efficiency of multi-condition performance testing of centrifugal fans, and accurately reproduces typical resistance characteristics in various actual pipe networks, such as friction resistance along long pipelines, resistance at large angle bends, and valve throttling resistance. It can simulate not only conventional linear resistance conditions, but also nonlinear resistance conditions and multi-level combined resistance conditions, covering the entire operating condition range from low-resistance ventilation to extremely high-resistance induced draft. This meets the diverse needs of multi-condition performance testing of centrifugal fans in different industries and application scenarios, and significantly improves the flexibility of operating condition switching and the adaptability of multi-specification fans in the testing organization.

[0018] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the operating condition adjustment unit in the centrifugal fan performance simulation test mechanism provided in an embodiment of the present invention.

[0020] Figure 2 for Figure 1 Front view of the cross-section of the medium-load adjustment unit.

[0021] Figure 3 for Figure 2 A schematic diagram of the internal structure of the medium-load adjustment unit.

[0022] Figure 4 for Figure 3Assembly diagram of medium and large diameter cylinders, small diameter cylinders, and conical components.

[0023] Figure 5 for Figure 4 Exploded views of the structures of medium and large diameter cylinders, small diameter cylinders, and conical components.

[0024] Figure 6 for Figure 4 Front view of the radial section of medium and large diameter cylinders, small diameter cylinders, and tapered components.

[0025] Figure 7 for Figure 3 Schematic diagram of the structure of small and medium diameter cylinders, drive mechanism, speed reduction transmission mechanism and diameter changing mechanism.

[0026] Figure 8 for Figure 7 A side view of the structure of small and medium diameter cylinders, drive mechanism, speed reduction transmission mechanism and diameter changing mechanism.

[0027] Figure 9 for Figure 7 A schematic diagram of the medium-speed reduction transmission mechanism.

[0028] Figure 10 for Figure 8 Exploded view of the intermediate diameter changing mechanism and transmission components.

[0029] Figure 11 for Figure 10 An exploded side view of the intermediate diameter change mechanism and transmission assembly.

[0030] Figure reference numerals: 100-Adjustable duct, 200-Drive mechanism, 210-Drive motor, 220-Transmission component one, 230-Double-direction trapezoidal screw, 240-Sliding threaded sleeve, 300-Large diameter cylinder, 310-Sealing flange, 320-Annular baffle, 400-Transmission component two, 500-Small diameter cylinder, 600-Conical assembly, 610-Conical sleeve, 620-Spring skeleton, 630-Arc-shaped clamp, 640-Upper pressure bar, 650-Lower pressure bar, 700-Speed ​​reduction transmission Drive mechanism, 710-Speed ​​reduction assembly, 711-Synchronous shaft, 712-Pulley block, 713-Speed ​​reduction disc, 714-Pulley lever, 720-Transmission assembly, 721-Transmission shaft, 722-Transmission gear, 723-Transmission gear ring, 800-Diameter changing mechanism, 810-Fixed sleeve, 811-Eccentric guide groove, 820-T-shaped rotating block, 821-Bearing, 822-Equilateral guide groove, 830-Diameter changing assembly, 831-Diameter changing block, 832-Slider, 833-Sliding column, 840-Airflow hole. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0033] like Figures 1 to 11 As shown, an embodiment of the present invention provides a multi-condition adjustable centrifugal fan performance simulation test mechanism, comprising an air inlet section coaxially fixed to and interconnected on a steel base, at least three independent series-connected condition adjustment units, a fan mounting section, and an air outlet section. Each condition adjustment unit consists of a condition adjustment duct 100, two symmetrically arranged large-diameter cylinders 300, a small-diameter cylinder 500 coaxially disposed between the two large-diameter cylinders 300, two conical components 600, a drive mechanism 200, a speed reduction transmission mechanism 700, and a diameter changing mechanism 800. The condition adjustment duct 100, the large-diameter cylinders 300, the conical components 600, the drive mechanism 200, the speed reduction transmission mechanism 700, and the diameter changing mechanism 800 are described. The kit 600 and the small-diameter cylinder 500 are coaxially arranged. One end of the drive mechanism 200 is installed on the outer wall of the working condition regulating duct 100, and the other end of the drive mechanism 200 extends into the working condition regulating duct 100 and is connected to the outer walls of the two large-diameter cylinders 300 and the speed reduction transmission mechanism 700 respectively. The speed reduction transmission mechanism 700 is installed on the inner wall of the working condition regulating duct 100 and is located outside the small-diameter cylinder 500. Both ends of the inner wall of the small-diameter cylinder 500 are provided with a diameter changing mechanism 800. The power input end of the diameter changing mechanism 800 is connected to the power output end of the speed reduction transmission mechanism 700. Both conical sleeves 600 are composed of a conical sleeve 610, a spring skeleton 620, and an arc-shaped clamp 630. The large-diameter end of the conical sleeve 610 is sealed and fixed to the end flange of the large-diameter cylinder 300 through the arc-shaped clamp 630, and the small-diameter end of the conical sleeve 610 is sealed and fixed to the end flange of the small-diameter cylinder 500 through the arc-shaped clamp 630. Both conical sleeves 610 preferably adopt a flexible sealing structure with a continuous smooth inner wall and foldable structure. The spring skeleton 620 is spirally nested on the outer wall of the conical sleeve 610. The two conical sleeves 610 and the small-diameter cylinder 500 in the middle together form a complete Venturi airflow channel. When different pipeline resistance conditions need to be simulated, the drive mechanism 200 works. On the one hand, it can drive two large-diameter cylinders 300 to move axially within the condition-adjusting air duct 100. In conjunction with the small-diameter cylinder 500, which is always stationary, and the spring frame 620, it can complete the synchronous axial stretching or contraction of the two tapered sleeves 610. On the other hand, it transmits power to the diameter-changing mechanism 800 through the speed-reducing transmission mechanism 700. This allows the two diameter-changing mechanisms 800 located at both ends of the inner wall of the small-diameter cylinder 500 to change the effective flow cross-sectional area of ​​the airflow. The two work together to achieve synchronous linkage between the shape adjustment of the tapered sleeve 610 and the cross-sectional area adjustment of the throat airflow channel, thereby completing the rapid adjustment of the local resistance coefficient of the airflow channel and meeting the diverse needs of the testing institution for simulating long pipeline friction resistance, large-angle bend resistance, and other conditions. When the two large-diameter cylinders 300 move away from each other, they can axially stretch the tapered sleeve 610, causing the cone angle of the tapered sleeve 610 to decrease and its length to increase, thus reducing the local resistance coefficient of the airflow channel. At the same time, the speed reduction transmission mechanism 700 can drive the diameter changing mechanism 800 to synchronously increase the effective flow cross-sectional area of ​​the small-diameter cylinder 500 for airflow, thereby achieving a rapid reduction in wind resistance. When the two large-diameter cylinders 300 move closer to each other, they can cooperate with the spring frame 620 to drive the tapered sleeve 610 to axially contract, causing the cone angle of the tapered sleeve 610 to increase and its length to decrease, thus increasing the local resistance coefficient of the airflow channel. At the same time, the speed reduction transmission mechanism 700 can drive the diameter changing mechanism 800 to synchronously reduce the effective flow cross-sectional area of ​​the small-diameter cylinder 500 for airflow, thereby achieving a rapid increase in wind resistance. This not only achieves synchronous linkage control between the morphological adjustment of the conical sleeve 610 and the cross-sectional area adjustment of the throat airflow channel, but also changes the local resistance coefficient of the airflow channel and the effective flow section of the throat in a single continuous adjustment action, generating a superimposed effect of wind resistance adjustment. This significantly reduces the wind resistance adjustment time of a single-condition adjustment unit, greatly improves the overall efficiency of multi-condition performance testing of centrifugal fans, and accurately reproduces typical resistance characteristics in various actual pipe networks, such as friction resistance along long pipelines, resistance at large-angle bends, and valve throttling resistance. It can simulate not only conventional linear resistance conditions, but also nonlinear resistance conditions and multi-level combined resistance conditions, covering the entire range of conditions from low-resistance ventilation to extremely high-resistance induced draft. This meets the diverse needs of multi-condition performance testing of centrifugal fans in different industries and application scenarios, and significantly improves the flexibility of condition switching and the adaptability of multi-specification fans in the testing organization.

[0034] In a preferred embodiment, the tapered sleeve is preferably integrally formed from flexible polytetrafluoroethylene material, and its inner wall is mirror-polished. The spring skeleton 620 is preferably formed by spiral winding of stainless steel spring wire with a pitch of 10-20mm, which is used to ensure that the tapered sleeve 610 always maintains a circular cross-section during axial expansion and contraction.

[0035] like Figures 3 to 6 As shown, in a preferred embodiment of the present invention, the arc-shaped clamp 630 preferably adopts a semi-circular arc-shaped plate structure with an L-shaped axial cross section. The inner curvature of the arc-shaped clamp 630 is adapted to the outer wall curvature of the large-diameter cylinder 300 and the small-diameter cylinder 500. Lower pressure strips 650 are circumferentially distributed at equal intervals on the outer wall of the large-diameter cylinder 300 and the small-diameter cylinder 500 near the end of the tapered sleeve 610. Upper pressure strips 640 are circumferentially distributed at equal intervals on the inner arc surface of the arc-shaped clamp 630. The upper pressure strips 640 and the lower pressure strips 650 are staggered and interlocked. This not only allows the staggered interlocking and pressing of the upper pressure strips 640 and the lower pressure strips 650 to form a labyrinthine sealing barrier with multiple continuous bends at the end of the tapered sleeve 610, but also... The dual-pressure structure of the end face and radial side of the arc-shaped clamp 630 blocks radial and axial leakage paths. The uniform compression of multiple pressure strips can adaptively compensate for creep deformation and temperature deformation caused by long-term use of flexible materials, avoiding the degradation of sealing performance due to material aging and thermal expansion and contraction, and keeping the sealing reliability stable throughout the entire life cycle. The staggered pressure strips can also significantly increase the contact area and mechanical interlocking force between the arc-shaped clamp 630 and the end of the tapered sleeve 610, effectively resisting the axial tension, radial shear force and torsional force generated by the tapered sleeve 610 under frequent axial expansion and contraction deformation and alternating wind pressure. This eliminates the problems of sleeve loosening, falling off and axial movement that are prone to occur in traditional bolt connections, and significantly extends the maintenance cycle and overall service life of the adjustment unit.

[0036] like Figures 2 to 8 As shown, in a preferred embodiment of the present invention, the drive mechanism 200 includes a drive motor 210, a transmission component 220, a bidirectional trapezoidal screw 230, and a sliding sleeve 240. The drive motor 210 is fixed on the outer wall of the operating condition regulating duct 100. The output end of the drive motor 210 is coaxially fixed to one end of the transmission component 220. The other end of the transmission component 220 extends into the operating condition regulating duct 100 and is coaxially fixed to the middle part of the bidirectional trapezoidal screw 230. The bidirectional trapezoidal screw 230 is axially rotatably mounted on the inner wall of the operating condition regulating duct 100. Sliding sleeves 240 are screwed to both ends of the bidirectional trapezoidal screw 230. The two sliding sleeves 240 are respectively fixed to the outer walls of two large-diameter cylinders 300. The middle part of the bidirectional trapezoidal screw 230 is connected to the power input end of the speed reduction transmission mechanism 700 through the transmission component 200.

[0037] When the drive motor 210 drives the bidirectional trapezoidal screw 230 to rotate in the forward direction through the transmission component 220, the bidirectional trapezoidal screw 230 drives the two large-diameter cylinders 300 to move away from each other through the two sliding sleeves 240, so that it axially stretches the tapered sleeve 610, reducing the cone angle and increasing the length of the tapered sleeve 610, and reducing the local resistance coefficient of the airflow channel; at the same time, the bidirectional trapezoidal screw 230 transmits power synchronously to the speed reduction transmission mechanism 700 through the transmission component 400, which in turn drives the two diameter changing mechanisms 800 to synchronously increase the effective flow cross-sectional area of ​​the small-diameter cylinder 500, thereby achieving a rapid and significant reduction in wind resistance; When the drive motor 210 drives the bidirectional trapezoidal screw 230 to rotate in the opposite direction through the transmission component 220, the bidirectional trapezoidal screw 230 drives the two large-diameter cylinders 300 to move closer to each other through the two sliding sleeves 240. In conjunction with the spring frame 620, the tapered sleeve 610 is axially contracted, which increases the cone angle and decreases the length of the tapered sleeve 610, thereby increasing the local resistance coefficient of the airflow channel. At the same time, the variable diameter mechanism 800 simultaneously reduces the effective flow cross-sectional area of ​​the throat, achieving a rapid and significant increase in wind resistance. This meets the diverse needs of multi-condition performance testing of centrifugal fans in different industries and application scenarios, and significantly improves the flexibility of the testing mechanism in switching between operating conditions and the adaptability of multi-specification fans.

[0038] like Figures 2 to 9 As shown, in a preferred embodiment of the present invention, the speed reduction transmission mechanism 700 includes a speed reduction component 710 and a transmission component 720. Both the speed reduction component 710 and the transmission component 720 are rotatably mounted on the inner wall of the middle part of the working condition regulating air duct 100. One end of the speed reduction component 710 is connected to the transmission component 400, and the other end of the speed reduction component 710 is coaxially connected to one end of the transmission component 720. The other end of the transmission component 720 is located inside the small diameter cylinder 500 and is coaxially connected to the diameter changing mechanism 800.

[0039] The speed reduction assembly 710 includes a synchronous shaft 711, a shift block 712, a speed reduction disc 713, and a lever 714. The synchronous shaft 711 is rotatably mounted on the inner wall of the middle part of the working condition regulating air duct 100. One end of the synchronous shaft 711 is coaxially fixed to the transmission component 400, and the other end of the synchronous shaft 711 is fixed with a clover-shaped shift block 712. The speed reduction disc 713 is coaxially fixed to one end of the transmission assembly 720. Levers 714 are circumferentially distributed at equal intervals on the end face of the speed reduction disc 713 near the shift block 712. The three blades on the clover-shaped shift block 712 engage with the levers 714 in sequence for transmission.

[0040] The transmission assembly 720 includes a transmission shaft 721, a transmission gear 722, and a transmission gear ring 723. The transmission shaft 721 is rotatably mounted on the inner wall of the middle part of the working condition regulating air duct 100. The two ends of the transmission shaft 721 are coaxially and symmetrically fixed with transmission gears 722. One side of one of the transmission gears 722 is coaxially fixed with a speed reduction disc 713. One side of both transmission gears 722 extends into the small diameter cylinder 500 and meshes with the transmission gear rings 723 coaxially mounted on the two diameter changing mechanisms 800, respectively.

[0041] When the bidirectional trapezoidal screw 230 rotates, its transmission component 400 drives the synchronous shaft 711 to rotate synchronously. The synchronous shaft 711 drives the lever 712 to rotate. The lever 712, through intermittent meshing with multiple levers 714, can drive the speed reduction disk 713 to rotate at a reduced speed. This achieves a precise fixed transmission ratio match between the rotation of the bidirectional trapezoidal screw 230 and the action of the variable diameter mechanism 800, ensuring that the change of the cone angle of the tapered sleeve 610 and the change of the throat cross-sectional area always maintain the optimal synchronous ratio relationship. This makes the wind resistance adjustment process smooth and continuous, avoiding airflow fluctuations and test data distortion caused by parameter mismatch. The speed-reducing disc 713 can drive one of the transmission gears 722 to rotate at a reduced speed. This transmission gear 722 drives the other transmission gear 722 to rotate at a reduced speed synchronously via the transmission shaft 721. The two transmission gears 722 can drive the two diameter-changing mechanisms 800 at both ends of the inner wall of the small-diameter cylinder 500 to work synchronously, ensuring that the adjustment of the effective flow cross-sectional area of ​​the throat always maintains perfect axial symmetry, eliminating airflow distortion and flow deviation problems caused by unilateral adjustment, and reducing the repeatability error of test data.

[0042] In a preferred embodiment, both the first transmission component 220 and the second transmission component 400 preferably adopt a belt drive structure consisting of a synchronous belt and a synchronous pulley.

[0043] like Figures 2 to 11As shown, in a preferred embodiment of the present invention, the diameter-changing mechanism 800 includes a fixed sleeve 810, a T-shaped rotating block 820, and a diameter-changing assembly 830. The fixed sleeve 810 is coaxially fixed to the inner walls at both ends of the small-diameter cylinder 500. The T-shaped rotating block 820 is coaxially rotatably mounted on the inner wall of the fixed sleeve 810 via a bearing 821. A transmission gear ring 723 is coaxially fixed to the outer wall of the T-shaped rotating block 820. A through-hole is formed at the center of both the fixed sleeve 810 and the T-shaped rotating block 820. The airflow hole 840 is of the general type. The fixed sleeve 810 has a number of eccentric guide grooves 811 circumferentially equidistantly formed on one end face near the tapered sleeve 610. The T-shaped rotating block 820 has an equilateral guide groove 822 formed on one end face near the fixed tapered sleeve 610. The number of sides of the equilateral guide groove 822 is the same as the number of eccentric guide grooves 811. The variable diameter assembly 830 is located between the fixed sleeve 810 and the T-shaped rotating block 820 and slides with the eccentric guide grooves 811 and the equilateral guide grooves 822 respectively.

[0044] The variable diameter assembly 830 includes a variable diameter block 831, a slider 832, and a sliding column 833. The variable diameter blocks 831 are circumferentially distributed between the T-shaped rotating block 820 and the fixed sleeve 810. The two sides of the variable diameter blocks 831 are respectively fixed with a sliding column 833 that slides in cooperation with the eccentric guide groove 811 and a slider 832 that slides in cooperation with the equilateral guide groove 822. The inner contour dimension formed by the multiple variable diameter blocks 831 is larger than the inner diameter of the airflow hole 840.

[0045] When simulating different pipeline resistance conditions, the transmission gear 722 drives the T-shaped rotating block 820 to rotate within the fixed sleeve 810 via the transmission gear ring 723. The T-shaped rotating block 820, through the trajectory constraint of the eccentric guide groove 811 and the equilateral guide groove 822, can drive multiple variable diameter blocks 831 to deflect synchronously, thereby changing the effective flow cross-sectional area of ​​the airflow channel and keeping the ratio of the cross-sectional area change to the shape change of the tapered sleeve 610 constant. The wind resistance superposition adjustment effect is stable and controllable, which can accurately replicate the resistance change law of various actual pipelines, further enhance the equipment's ability to simulate complex working conditions, and adapt to the performance testing needs of various types of centrifugal fans.

[0046] like Figures 1 to 5As shown, in a preferred embodiment of the present invention, a sealing flange 310 is coaxially fixed to the end of the large-diameter cylinder 300 away from the small-diameter cylinder 500. The outer diameter of the sealing flange 310 is smaller than the inner diameter of the operating condition regulating duct 100, and an annular baffle 320 is embedded in the circumferential sidewall of the sealing flange 310. The edge sidewall of the annular baffle 320 is tightly fitted to the inner wall of the operating condition regulating duct 100. The annular baffle 320 preferably adopts a lip-shaped self-sealing structure made of graphite-filled polytetrafluoroethylene material. By cooperating with the sealing flange 310, it can not only prevent the large-diameter cylinder 300 from contacting the operating condition regulating duct 100, but also prevent the operation of the duct. A reliable radial sliding seal is formed between the regulating ducts 100, blocking airflow leakage from the annular gap between them. Combined with the overall static sealing structure of the tapered sleeve 610, this reduces the system leakage of the entire operating condition regulating unit and significantly improves the accuracy of test data. It can also act as a pre-rectifier and guide for the airflow entering the large-diameter cylinder 300, eliminating the eddies and turbulence formed between the outer wall of the large-diameter cylinder 300 and the inner wall of the operating condition regulating duct 100. This makes the airflow entering the Venturi airflow channel more uniform and stable, further reducing the repeatability error of test data and comprehensively improving the overall test accuracy of the testing mechanism.

[0047] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-condition adjustable centrifugal fan performance simulation and testing mechanism, comprising an air inlet section coaxially fixed and interconnected on a steel base, at least three independent series-connected condition adjustment units, a fan mounting section, and an air outlet section, characterized in that, Each of the aforementioned operating condition adjustment units comprises an operating condition adjustment duct, two symmetrically arranged large-diameter cylinders, a small-diameter cylinder coaxially disposed between the two large-diameter cylinders, two conical components, a drive mechanism, a speed reduction transmission mechanism, and a diameter changing mechanism. The operating condition adjustment duct, large-diameter cylinders, conical components, and small-diameter cylinders are all coaxially arranged. One end of the drive mechanism is installed on the outer wall of the operating condition adjustment duct, and the other end of the drive mechanism extends into the operating condition adjustment duct and is connected to the outer walls of the two large-diameter cylinders and the speed reduction transmission mechanism, respectively. The speed reduction transmission mechanism is installed on the inner wall of the operating condition adjustment duct and is located outside the small-diameter cylinder. Both ends of the inner wall of the small-diameter cylinder are provided with diameter changing mechanisms, and the power input end of the diameter changing mechanism is connected to the power output end of the speed reduction transmission mechanism. Both conical sleeves consist of a conical sleeve, a spring frame, and an arc-shaped clamp. The large-diameter end of the conical sleeve is sealed and fixed to the end flange of the large-diameter cylinder through the arc-shaped clamp, and the small-diameter end of the conical sleeve is sealed and fixed to the end flange of the small-diameter cylinder through the arc-shaped clamp. Both conical sleeves adopt a flexible sealing structure with a continuous smooth inner wall and foldable design. The outer wall of the conical sleeve is spirally nested with a spring frame. The two conical sleeves and the small-diameter cylinder in the middle together form a complete Venturi airflow channel.

2. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 1, characterized in that, The arc-shaped clamp adopts a semi-circular arc-shaped plate structure with an L-shaped axial cross section, and the inner arc of the arc-shaped clamp is adapted to the outer wall arc of the large-diameter cylinder and the small-diameter cylinder.

3. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 2, characterized in that, Both the large-diameter cylinder and the small-diameter cylinder have circumferentially equidistantly distributed lower pressure strips on the outer wall of their ends near the tapered sleeve. The inner arc surface of the arc-shaped clamp has circumferentially equidistantly distributed upper pressure strips, and the upper and lower pressure strips are staggered and interlocked.

4. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 1, characterized in that, The drive mechanism includes a drive motor, a transmission component one, a double-sided trapezoidal screw, and a sliding sleeve. The drive motor is fixed to the outer wall of the operating condition regulating duct. The output end of the drive motor is coaxially and fixedly connected to one end of the transmission component one. The other end of the transmission component one extends into the operating condition regulating duct and is coaxially and fixedly connected to the middle part of the double-sided trapezoidal screw. The double-sided trapezoidal screw is axially and rotatably mounted on the inner wall of the operating condition regulating duct. Sliding sleeves are screwed to both ends of the double-sided trapezoidal screw. The two sliding sleeves are respectively fixedly connected to the outer walls of two large-diameter cylinders. The middle part of the double-sided trapezoidal screw is connected to the power input end of the speed reduction transmission mechanism through the transmission component two.

5. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 4, characterized in that, The speed reduction transmission mechanism includes a speed reduction component and a transmission component. Both the speed reduction component and the transmission component are rotatably mounted on the inner wall of the middle part of the working condition regulating air duct. One end of the speed reduction component is connected to the second transmission component, and the other end of the speed reduction component is coaxially connected to one end of the transmission component. The other end of the transmission component is located inside a small-diameter cylinder and is coaxially connected to the diameter changing mechanism.

6. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 5, characterized in that, The speed reduction assembly includes a synchronous shaft, a shift block, a speed reduction disc, and shift levers. The synchronous shaft is rotatably mounted on the inner wall of the middle part of the working condition regulating air duct. One end of the synchronous shaft is coaxially fixed to the transmission component 2, and the other end of the synchronous shaft is fixed with a clover-shaped shift block. The speed reduction disc is coaxially fixed to one end of the transmission component. Shift levers are circumferentially distributed at equal intervals on the end face of the speed reduction disc near the shift block. The three blades on the clover-shaped shift block engage with the shift levers in sequence for transmission.

7. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 6, characterized in that, The transmission assembly includes a transmission shaft, transmission gears, and transmission gear rings. The transmission shaft is rotatably mounted on the inner wall of the middle part of the working condition regulating air duct. Transmission gears are coaxially and symmetrically fixed at both ends of the transmission shaft. A speed reduction disc is coaxially fixed on one side of one of the transmission gears. One side of each of the two transmission gears extends into a small-diameter cylinder and meshes with transmission gear rings coaxially mounted on two diameter-changing mechanisms.

8. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 7, characterized in that, The diameter-changing mechanism includes a fixed sleeve, a T-shaped rotating block, and a diameter-changing assembly. The fixed sleeve is coaxially fixed to the inner walls of both ends of the small-diameter cylinder. The T-shaped rotating block is coaxially rotatably mounted on the inner wall of the fixed sleeve via bearings. A transmission gear ring is coaxially fixed to the outer wall of the T-shaped rotating block. Both the fixed sleeve and the T-shaped rotating block have through-holes at their center. The fixed sleeve has a number of eccentric guide grooves circumferentially spaced at equal intervals on one end face near the tapered sleeve. The T-shaped rotating block has equilateral guide grooves on one end face near the fixed tapered sleeve, with the number of sides of the equilateral guide grooves matching the number of eccentric guide grooves. The diameter-changing assembly is located between the fixed sleeve and the T-shaped rotating block and slides with the eccentric guide grooves and the equilateral guide grooves, respectively.

9. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 8, characterized in that, The variable diameter assembly includes a variable diameter block, a slider, and a sliding column. The variable diameter blocks are circumferentially distributed between the T-shaped rotating block and the fixed sleeve. On both sides of the variable diameter block, there are sliding columns that slide in cooperation with the eccentric guide groove and sliders that slide in cooperation with the equilateral guide groove. The inner contour dimension formed by the multiple variable diameter blocks is larger than the inner diameter of the airflow hole.

10. The multi-condition adjustable centrifugal fan performance simulation and testing mechanism according to claim 1, characterized in that, A sealing flange is coaxially fixed to the end of the large-diameter cylinder away from the small-diameter cylinder. The outer diameter of the sealing flange is smaller than the inner diameter of the operating condition regulating air duct, and an annular baffle is embedded in the circumferential sidewall of the sealing flange. The edge sidewall of the annular baffle is tightly attached to the inner wall of the operating condition regulating air duct. The annular baffle adopts a lip-shaped self-sealing structure made of graphite-filled polytetrafluoroethylene material.

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