A guide vane system for use in a cloth testing tunnel and a method of testing thereof

Abstract

The present application relates to the field of wind tunnel experiment and textile carding technology, and discloses a guide vane system for testing a carding machine in a wind tunnel and a testing method thereof, the system comprising a mounting clamp, a guide vane, a driving mechanism and a tail airflow measurement and analysis system; the guide vane is located in the wind tunnel and forms a sealed structure with the inner wall of the test section of the wind tunnel, and is continuously moved along the direction perpendicular to the test airflow by the driving mechanism; the wind tunnel is 200-1000mm long, 10-150mm high and 50-250mm wide; the guide vane is provided with continuously arranged static pressure measuring points; a carding machine is arranged below the guide vane and is arranged on the mounting clamp; the mounting clamp is arranged on the bottom surface of the wind tunnel; an airflow measurement and analysis system is arranged behind the guide vane and is arranged on the bottom surface of the wind tunnel. The present application simulates the actual carding process in the textile industry, determines the optimal values of the gauge, the needle shape and the carding airflow and the like in the experiment, and improves the testing accuracy of the wind tunnel.

Description

Technical Field

[0001] This invention relates to the fields of wind tunnel testing and textile combing technology, specifically to a deflector system and its testing method used in a wind tunnel for testing carded fabric. Background Technology

[0002] In the field of textile machinery, carding cloth is the core component of a carding machine, having a decisive impact on the carding quality of fibers. The working principle of carding cloth is based on its numerous needle-like teeth on its surface. During the carding process, the fiber raw material is fed into the carding machine, and the needles of the carding cloth interact with the fibers. The needles first grasp the fibers; due to the shape, angle, and arrangement of the needles, the fibers can be effectively held. As the carding machine components move, the carding cloths move relative to each other or to other components, and the fibers held by the needles are transferred and carded between different needles. In this process, the entanglement between fibers is gradually broken, impurities are removed, and the fibers are gradually carded into a single fiber state and arranged neatly in a certain direction, laying a good foundation for subsequent textile processing steps such as drawing and spinning.

[0003] The performance of card fabric is closely related to the flow characteristics of the airflow around it. Factors such as airflow velocity distribution, flow direction changes, and turbulence intensity all affect the combing, transfer, and condensation of fibers on the card fabric surface. Therefore, accurately testing the airflow characteristics around the card fabric is a crucial step in in-depth research and optimization of card fabric design. In 1975, due to limited resources, Hosokawa Nakashigezo conducted velocity distribution tests using water flow as a substitute for airflow, confirming that the method of using wind tunnel tests to study the airflow around the card fabric is feasible and can indeed have a significant impact on card fabric design. However, in actual textile processes, the real situation between the cylinder and the movable cover plate is difficult to simulate, and research on the card fabric in the airflow is lacking, especially airflow testing in wind tunnels, which presents many difficulties. For example, Kanai in Japan conducted research on internal airflow channels, revealing the characteristics of airflow after air movement. Currently, there are some patents related to wind tunnel guide plates, such as a deformable guide plate and its preparation and working method with patent publication number CN116872570A and a corner guide device for a super-large wind tunnel with publication number CN118730466A. These patents all belong to the field of guide plates for large wind tunnels and are not applicable to simulating the actual situation of textile needle cloth, so they cannot accurately simulate the airflow on the surface of the needle cloth.

[0004] Therefore, only by establishing a dedicated wind tunnel testing platform system for carded fabric can accurate turbulence model parameters of the carded fabric product flow channel be obtained, allowing for the upgrading of the carded fabric simulation calculation model and its application in more complex combing environments. In wind tunnel testing, deflectors are key components used to adjust airflow direction, velocity, and pressure. In micro-wind tunnels, the space is typically very small, making it difficult not only to arrange measuring elements but also significantly increasing the manufacturing complexity. Especially in carded fabric testing environments where the channel width is within 0.2mm, any testing element used will significantly impact the original flow field due to geometric issues, making proper wind tunnel calibration and effective testing of the airflow on the carded fabric surface impossible.

[0005] Furthermore, with the continuous development of textile technology and the ever-increasing demands on the performance of carding cloth, wind tunnel carding cloth airflow testing faces greater challenges in terms of accuracy and efficiency. Therefore, developing an adjustable wind tunnel carding cloth airflow measurement guide plate system that simulates the actual carding process has extremely important practical significance and application value. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a guide plate system for measuring the combing airflow in wind tunnel card fabric experiments, which simulates the actual combing process in the textile industry, realizes the optimal value determination of characteristics such as spacing, needle shape and combing airflow in the experiment, and improves the accuracy of wind tunnel testing.

[0007] To address the above technical problems, this invention provides a guide plate system for use in a wind tunnel for testing needle cloth, comprising a mounting fixture, a guide plate, a drive mechanism, and a tail airflow measurement and analysis system. The guide plate is located inside the wind tunnel where the airflow inlet and outlet are connected, forming a sealed structure with the inner wall of the test section of the wind tunnel, and is continuously moved and controlled by the drive mechanism along the direction perpendicular to the test airflow. The wind tunnel is 200-1000mm long, 10-150mm high, and 50-250mm wide. The guide plate has continuously arranged static pressure measurement points. Needle cloth is placed below the guide plate and mounted on the mounting fixture. The mounting fixture is located on the bottom surface of the wind tunnel. An airflow measurement and analysis system is configured behind the guide plate to detect the average airflow velocity in the test section, and the airflow measurement and analysis system is mounted on the bottom surface of the wind tunnel.

[0008] By adopting the above technical solution, a vertically movable guide plate and mounting fixture are installed in a wind tunnel with a length of 200-1000mm, a width of 50-250mm, and a height of 10-150mm. The guide plate has continuously arranged static pressure measurement points, and the mounting fixture for the carding cloth is installed below the guide plate. Using the guide plate structure, the actual carding process in the textile industry is simulated. Measurement is achieved by distributing the airflow, keeping the overall size of the wind tunnel relatively large. This allows for the determination of optimal values ​​for characteristics such as spacing, needle shape, and carding airflow in the experiment, thereby improving the testing accuracy of the wind tunnel.

[0009] Preferably, the static pressure measurement points are located on the upper surface of the guide plate and are symmetrically distributed on both sides of the center line of the guide plate. Pressure measuring tubes are installed on the static pressure points and connected to the external pressure sensor of the wind tunnel.

[0010] Preferably, the longitudinal length A of the deflector is 300-800mm, the transverse width B of the deflector is 80-200mm, and the total height H of the deflector from the lower edge to the outer edge of the upper edge is 2-10mm.

[0011] By adopting the above technical solutions, the rational design of the longitudinal length, lateral width, and total height of the deflector can reduce the resistance of airflow when passing through it. Compared with some deflectors that are too large or have unreasonable shapes, this design allows airflow to pass through more smoothly, reducing energy consumption during wind tunnel operation.

[0012] Preferably, the deflector has a wedge-shaped structure at both the front and rear. The horizontal length L1 of the front slope is 25.5 mm, and the two slopes at the rear are symmetrical with a horizontal length L2 of 20 mm.

[0013] By adopting the above technical solution, the front wedge disperses the direct impact force of the airflow on the guide plate, and the rear wedge acts like two balanced channels, ensuring that the airflow is more evenly distributed in the lateral direction, reducing the concentration or sparseness of airflow in local areas, creating a more stable and uniform airflow environment for needle cloth testing, and reducing measurement errors caused by airflow instability.

[0014] Preferably, the front trapezoidal height H of the deflector is 0.5mm, the angle a between the inclined surface and the horizontal line is 5-15°, and the angle b between the rear inclined surface and the horizontal line is 2-10°.

[0015] By adopting the above technical solution, the coordinated design of the front and rear inclined surfaces of the guide vane helps to distribute the airflow more evenly within the test section. The front inclined surface guides the airflow to initially adjust its direction, while the rear inclined surface further optimizes the airflow distribution. This allows more airflow energy to be used for needle cloth testing, rather than being consumed in the wind tunnel or on the guide vane, thus improving the energy utilization efficiency of the wind tunnel.

[0016] Preferably, the guide vane has an arc-shaped warped structure, and the ratio of its height H1:H2 from the inner wall of the wind tunnel is 5:1-0.5:1.

[0017] By adopting the above technical solutions, the curved warp structure and appropriate height ratio can reduce the resistance of airflow when passing through the guide plate. When the airflow flows along the curved warp structure, friction and collision with the guide plate surface are reduced, thus reducing energy loss. Moreover, the curved design can stabilize the airflow direction. In needle cloth testing, stable airflow can ensure uniform stress on the needle cloth surface, and the pressure value measured by the pressure test hole can accurately reflect the effect of airflow on the needle cloth, reducing measurement errors caused by airflow instability.

[0018] Preferably, brushes are provided on both sides of the guide plate, and the part of the guide plate that contacts the wind tunnel is sealed by the brushes.

[0019] By adopting the above technical solutions, it is ensured that the airflow will not leak from the edge of the guide plate, thus guaranteeing the airtightness and control precision of the airflow inside the wind tunnel.

[0020] Preferably, the material of the deflector is aluminum, PVC, steel, or fiber composite material.

[0021] Preferably, guide pillars are installed on the guide plate by fasteners, the guide pillars extend out of the wind tunnel, wall holes are opened in the side wall of the wind tunnel, and wall plates are installed on the wall holes; the guide pillars are connected to the drive mechanism through the mounting plate, and the drive mechanism is fixed on the drive base.

[0022] A testing method for a deflector system used in a wind tunnel for testing needle cloth includes the following steps: Step 1: Fix the mounting fixture containing the needle cloth and determine the position of the guide plate. Set the distance between the highest point of the needle cloth and the guide plate to 0.25mm. Step 2: Turn on the wind tunnel fan and wait for it to stabilize. Set the test wind speed to 5 m / s. Step 3: After stable operation, measure the pressure drop of the needle cloth test section, and the static pressure measurement point is located on the guide plate; Step 4: Test and measure the total pressure and static pressure on the rake, calculate the dynamic pressure, and estimate the average flow velocity in the test section; Step 5: The above result constitutes one measurement point; Step 6: Change the wind speed, measure multiple measurement points, and plot the pressure versus velocity curve to estimate the transition Reynolds number; Step 7: After testing, turn off the fan.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a wind tunnel with dimensions of 200-1000mm in length, 50-250mm in width, and 10-150mm in height, equipped with a vertically movable guide plate and mounting fixtures. The guide plate has continuously arranged static pressure measurement points, and the mounting fixtures for the carding cloth are installed below the guide plate. By using the guide plate structure, the actual carding process in the textile industry is simulated. Measurement is achieved through airflow distribution, keeping the overall size of the wind tunnel relatively large. This allows for the determination of optimal values ​​for characteristics such as spacing, needle shape, and carding airflow in experiments, thereby improving the testing accuracy of the wind tunnel.

[0024] 2. The longitudinal length A of the guide vane of this invention is 300-800mm, the transverse width B is 80-200mm, and the total height H from the lower edge to the outer edge of the upper edge is 2-10mm. The rational design of the longitudinal length, transverse width, and total height reduces airflow resistance when passing through the guide vane. Compared with some guide vanes that are too large or have unreasonable shapes, this design allows airflow to pass more smoothly, reducing energy consumption during wind tunnel operation.

[0025] 3. The guide plate of this invention has a wedge-shaped structure at both the front and rear. The horizontal length L1 of the front inclined surface is 25.5 mm, and the two inclined surfaces at the rear are symmetrical, with a horizontal length L2 of 20 mm. The wedge shape at the front disperses the direct impact force of the airflow on the guide plate, while the wedge shape at the rear acts like two balanced channels, ensuring a more uniform distribution of airflow in the lateral direction. This reduces the concentration or thinning of airflow in local areas, creating a more stable and uniform airflow environment for needle cloth testing and reducing measurement errors caused by airflow instability.

[0026] 4. The front trapezoidal height H of the guide plate in this invention is 0.5mm, the angle α between the inclined surface and the horizontal line is 5-15°, and the angle b between the rear inclined surface and the horizontal line is 2-10°. The front and rear inclined surface designs work together to help distribute the airflow through the guide plate more evenly within the test section. The front inclined surface guides the airflow to initially adjust its direction, while the rear inclined surface further optimizes the airflow distribution. This allows more airflow energy to be used for needle cloth testing, rather than being consumed in the wind tunnel or on the guide plate, thereby improving the energy utilization efficiency of the wind tunnel. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the mounting fixture structure of the present invention; Figure 3 This is a schematic diagram showing the static pressure measurement point set on the guide plate of the present invention; Figure 4 This is a cross-sectional view of the guide plate of the present invention; Figure 5 A schematic diagram showing brushes arranged on both sides of the guide plate of the present invention; Figure 6 This is a schematic diagram of the flow guide plate used in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the arc-shaped warped structure of the guide plate of the present invention; Figure 8 This is a schematic diagram of the air guide plate of the present invention being adjusted to its highest position; Figure 9 This is a schematic diagram of the wind tunnel upper wall panel of the present invention; Figure 10 A schematic diagram showing the fan installed in front of the wind tunnel for this invention.

[0028] Drawing numbers: 1. Wind tunnel, 2. Mounting fixture, 3. Guide plate, 4. Drive mechanism, 5. Airflow measurement and analysis system, 6. Test section, 7. Needle cloth, 8. Pressure measuring tube, 9. Guide column, 10. Mounting plate, 11. Static pressure measuring point, 12. Wall panel, 13. Base, 14. Adjusting block, 15. Edge strip, 16. Magnetic guide block, 17. Magnetic guide platform, 18. Fan, 19. Drive base, 20. Brush. Detailed Implementation

[0029] In the field of textile machinery engineering, accurate testing of carding cloth performance is crucial for improving the working efficiency of carding machines. This invention focuses on a guide vane system for wind tunnel carding airflow testing, specifically a guide vane system for measuring carding airflow in wind tunnel carding experiments. It aims to simulate the actual carding process in the textile industry, achieving optimal numerical determination of characteristics such as spacing, needle shape, and carding airflow in experiments, thereby improving the testing accuracy of wind tunnels.

[0030] This application develops a guide vane system for use in a wind tunnel for testing needle cloth, including a mounting fixture 2, a guide vane 3, a drive mechanism 4, and a tail airflow measurement and analysis system 5. The guide vane 3 is installed inside a narrow wind tunnel 1, forming a sealed structure with the inner wall of the test section 6 of the wind tunnel 1, and can be continuously moved and controlled by the drive mechanism 4 in the direction perpendicular to the test airflow with an accuracy of 0.01 mm. The airflow inlet and outlet of the wind tunnel 1 are interconnected. The wind tunnel 1 is 200-1000 mm long, 50-250 mm wide, and 10-150 mm high. The guide vane 3 has continuously arranged static pressure measurement points 11. Needle cloth 7 is placed below the guide vane 3 and mounted on the mounting fixture 2. The mounting fixture 2 is located on the inner bottom surface of the wind tunnel 1. The airflow measurement and analysis system 5 is located behind the guide vane 3 to detect the average airflow velocity within the test section 6. The airflow measurement and analysis system 5 is mounted on the inner bottom surface of the wind tunnel 1 via a bracket. The drive mechanism 4 is a cylinder. By using a baffle structure to simulate the actual combing process in the textile industry, measurements are achieved through airflow distribution. This keeps the wind tunnel at a relatively large size, enabling the determination of optimal values ​​for characteristics such as spacing, needle shape, and combing airflow during experiments, thereby improving the testing accuracy of the wind tunnel.

[0031] like Figure 3 As shown, static pressure measuring points 11 are located on the end face of the guide plate 3 facing the needle cloth 7, and are symmetrically distributed on both sides of the center line of the guide plate 3. Pressure measuring tubes 8 are installed on the static pressure measuring points 11. The pressure measuring tubes 8 are connected to the external pressure sensor of the wind tunnel 1, output the static pressure value, and calculate the pressure loss inside the wind tunnel 1.

[0032] Grind the guide plate 3, and control the flatness difference between the upper and lower surfaces of the guide plate 3 to 0.01-0.02mm. The roughness of the guide plate 3 is Ra 0.2~0.4μm. After grinding, polish the surface with 800-1000 grit sandpaper to remove any possible machining marks. Example 1

[0033] like Figure 4 As shown, the longitudinal length A of the guide vane 3 is 300-800 mm, preferably 500 mm. The transverse width B of the guide vane 3 is 80-200 mm, preferably 110 mm. The total height H from the lower edge to the outer edge of the upper edge of the guide vane 3 is 2-10 mm, preferably 5 mm. The length, width, and thickness of the guide vane 3 are adapted to the dimensions of the wind tunnel 1 duct to ensure no gaps. The reasonable design of the longitudinal length, transverse width, and total height of the guide vane 3 can reduce the resistance of airflow when passing through the guide vane 3. Compared with some guide vanes 3 that are too large or have unreasonable shapes, this design allows airflow to pass more smoothly and reduces the energy consumption of the wind tunnel 1 during operation.

[0034] The guide plate 3 has a wedge-shaped structure at both the front and rear to optimize airflow characteristics. The horizontal length L1 of the front slope is 25.5 mm, and the two rear slopes are symmetrical with a horizontal length L2 of 20 mm. The wedge shape at the front disperses the direct impact force of the airflow on the guide plate 3, while the wedge shape at the rear acts like two balanced channels, ensuring a more uniform lateral distribution of airflow. This reduces the concentration or thinning of airflow in local areas, creating a more stable and uniform airflow environment for needle cloth testing and reducing measurement errors caused by airflow instability.

[0035] like Figure 4As shown, the guide vane 3 has a trapezoidal height H of 0.5mm at the front. This relatively small tip height acts as a buffer and guide when airflow enters the guide vane 3. It acts like a narrow entrance, allowing airflow to enter the guide vane 3 more concentratedly, reducing airflow diffusion and turbulence at the entrance. The angle α between the inclined plane and the horizontal line is 5-15°, preferably 10°, and the angle b between the rear inclined plane and the horizontal line is 2-10°, preferably 5.7°. The angle α between the inclined plane and the horizontal line is within the range of 5-15°. This angle range ensures that the airflow has sufficient time and space to adjust its direction when passing the front inclined plane, while preventing the inclined plane from being too gentle and resulting in poor airflow guidance. A smaller angle reduces the resistance encountered by the airflow on the inclined plane, allowing for smoother changes in flow direction; a larger angle enhances the degree of change in airflow direction but also increases airflow resistance. By reasonably selecting the angle α, the airflow guidance effect can be optimized according to specific test requirements and airflow characteristics. The front and rear inclined surfaces of the deflector 3 work together to help distribute the airflow more evenly within the test section 6. The front inclined surface guides the airflow to initially adjust its direction, while the rear inclined surface further optimizes the airflow distribution. This allows more airflow energy to be used for needle cloth testing, rather than being consumed in the wind tunnel 1 or the deflector 3, thereby improving the energy utilization efficiency of the wind tunnel 1. Example 2

[0036] like Figure 7 As shown, the guide plate 3 can be a special structure other than that of Embodiment 1. The guide plate 3 has an arc-shaped warped structure, and the ratio of its height H1:H2 from the inner wall of the wind tunnel 1 to its upper and lower parts is 5:1-0.5:1, preferably 1:1. The arc-shaped warped structure and the appropriate height ratio can reduce the resistance of the airflow when passing through the guide plate 3. When the airflow flows along the arc-shaped warped structure, the friction and collision with the surface of the guide plate 3 are reduced, thus reducing energy loss. Moreover, the arc design can stabilize the airflow direction. In the needle cloth test, the stable airflow can make the needle cloth surface uniformly stressed, and the pressure value measured by the pressure test hole can truly reflect the effect of the airflow on the needle cloth, reducing the measurement error caused by the instability of the airflow.

[0037] like Figure 5 As shown, brushes 20 are fixedly installed on both sides of the guide plate 3 with glue. The inner wall of the wall panel 12 where the guide plate 3 contacts the test section 6 is sealed with brushes 20 to ensure that the airflow will not leak from the edge of the guide plate 3, thus ensuring the airtightness and control accuracy of the airflow inside the wind tunnel 1.

[0038] The aforementioned deflector plate 3 is made of aluminum, PVC, steel, or fiber composite material, with steel being particularly preferred due to its strength and durability, making it suitable for long-term use in the wind tunnel environment 1.

[0039] The aforementioned guide plate 3 is mounted on the bottom surface of the guide column 9 by bolts (not shown in the figure). The guide column 9 extends out of the wind tunnel 1, and a sealing ring is installed between the guide column 9 and the guide column hole of the wind tunnel 1 for sealing. The guide column 9 is connected to the drive mechanism 4 via the mounting plate 10, and the drive mechanism 4 is fixed on the drive seat 19. The relative position of the guide plate 3 in the wind tunnel 1 is controlled by the drive mechanism 4 through a mechanical structure connected to it. The guide plate 3 is bolted to the guide column 9, and the guide plate 3 is a detachable structure, wherein the vertical movement control range is 0-100mm. Wall openings are provided on both side walls of the wind tunnel 1, and wall plates 12 are installed in the wall openings by screws. Figure 9 As shown, when the deflector plate 3 needs to be replaced, remove the wall panel 12, unscrew the screws on the deflector plate 3, and it can be replaced.

[0040] The drive mechanism 4 enables precise vertical position adjustment to determine the optimal spacing of the cylinder cover, with a control accuracy of 0.01mm. The drive mechanism 4 uses a cylinder and has both program control and manual control modes, improving the response speed and ease of operation of the guide vane 3 position control.

[0041] like Figure 2 As shown, the mounting fixture 2 includes a base 13, adjusting blocks 14 at both ends, side strips 15 on both sides, magnetic blocks 16, and a magnetic platform 17; all components are connected and fixed using bolts or slots. The needle cloth rack is magnetically fixed to the mounting fixture 2 by the magnetic blocks 16, which allows for convenient installation of the needle cloth and ensures that the needle cloth completely fills the test section 6. The magnetic platform 17 is mounted on the upper surface of the base 13, and the magnetic blocks 16 are fixed on the magnetic platform 17. Side strips 15 are installed on both sides of the magnetic platform 17. Adjusting blocks 14 are installed at both ends of the base 13.

[0042] like Figure 6 As shown, the guide plate 3 of Example 1 is used. This example tests a needle cloth with a special toothed back structure, which is magnetically attached to the mounting fixture 2. The height of the needle cloth 7 is 1.7 mm, and the upper edge of the mounting fixture 2 forms a gap of 0.25 mm below the guide plate 3. A drive mechanism 4 is used to connect to the upper surface of the guide plate 3 to control its up and down movement, thereby controlling the gap. The average airflow velocity through the test section 6 is controlled to be 1-30 m / s, and the surface characteristics of the needle cloth airflow are tested.

[0043] like Figure 7 As shown, the warped guide vane 3 structure of Embodiment 2 allows for sufficient airflow distribution to the test section 6. In this embodiment, the overall vibration of the wind tunnel 1 is lower, resulting in a better testing environment. However, this causes an airflow compression process when the airflow enters the test section 6, leading to local airflow instability, which is detrimental to the test results. Nevertheless, in certain special testing environments, such as with relatively large needle cloths, the accuracy of the test can be significantly improved. Figure 6A guide plate 3 structure for testing a large-size needle cloth is shown. The needle cloth is magnetically mounted on the mounting fixture 2. The total height of the needle cloth is 5.0 mm. The distance between the guide plate 3 and the needle tip of the needle cloth is controlled to test the airflow characteristics on the surface of the needle cloth. Example 3

[0044] like Figure 8 As shown, in the wind tunnel 1 testing system involved in this application, the size of wind tunnel 1 can be enlarged due to the introduction of the guide vane 3. Therefore, it is possible to test some enlarged models, and thus test the airflow details on the needle cloth surface. In this embodiment, the guide vane 3 is raised to its highest position, fitting against the upper wall of wind tunnel 1. The enlarged model is made of 3D plastic, has a test flow channel inside, is fixed in the mounting fixture 2 by a slot, and is vertically installed in the space of wind tunnel 1, thereby realizing the testing and analysis of its external flow field. This embodiment demonstrates the role of the guide vane system in expanding the functional range of wind tunnel 1.

[0045] A testing method for a deflector system used in a wind tunnel for testing needle cloth includes the following steps: Step 1: Fix the mounting clamp 2 containing the needle cloth and determine the position of the guide plate 3. Set the distance between the highest point of the needle cloth and the guide plate 3 to 0.25mm or other values. Step 2: Turn on fan 18 of wind tunnel 1, as follows: Figure 10 And wait for it to run stably, setting the test wind speed to 5m / s; Step 3: After stable operation, measure the pressure drop of the needle cloth test section 6. The static pressure measurement point 11 is located on the guide plate 3. Step 4: Test and measure the total pressure and static pressure on the rake, calculate the dynamic pressure, and estimate the average flow velocity within test section 6; Step 5: The above result constitutes one measurement point; Step 6: Change the wind speed, measure multiple measurement points, and plot the pressure versus velocity curve to estimate the transition Reynolds number; Step 7: After the test is completed, turn off fan 18 and shut down the wind tunnel test system.

[0046] The actual working principle of the deflector system in this application is as follows: (1) A guide plate 3 structure was used to divide the incoming airflow into two parts, which increased the size of the wind tunnel 1, reduced the manufacturing difficulty of the wind tunnel 1, and provided sufficient space for the measuring elements.

[0047] (2) such as Figure 1As shown, the original airflow enters from the inlet and is divided into upper and lower parts by the deflector 3. Airflow A and airflow B have different pressures and velocities, passing through the upper part of the deflector 3 in the non-test area and the lower part of the deflector 3 in the test section 6, respectively. Airflow A and airflow B eventually reach the airflow measurement and analysis system 5 located in the wake and close to the deflector 3. This airflow measurement and analysis system 5 is a typical airflow measurement rake. This airflow measurement and analysis system 5 can measure the total pressure and static pressure of the airflow at various positions of the deflector 3. After gradient correction, the difference between the total pressure and static pressure is used to obtain the dynamic pressure at each position. Then, according to the formula for calculating dynamic pressure and velocity, the airflow velocity at each position is obtained. The average velocity of the test section 6 is measured by the ratio of the integral of the velocity at each point below the deflector 3 with respect to the area to the area. The wind tunnel 1 uses airflow calibration to make this calculation and testing method more accurate. Multiple measuring holes are installed on the deflector 3 to measure the air pressure distribution on the surface of the needle cloth, such as... Figure 3 As shown. After both pressure and speed are tested, the aerodynamic characteristics related to the shape of the needle cloth can be determined.

[0048] (3) The guide plate 3 is installed on the upper wall of the duct of wind tunnel 1, and its edge adopts a wedge design with a specific gradient. This design can eliminate the periodic flow field, abnormal velocity field and intensity problems caused by high wind speed in wind tunnel 1; after the airflow passes through the guide plate 3 for a certain distance, the influence caused by the guide plate 3 itself and the step of the mounting fixture 2 is naturally eliminated, thereby effectively reducing the local resistance of the airflow. The precise adjustment of the position of the guide plate 3 is closely related to the setting of the cover plate cylinder spacing. During the test, the position of the guide plate 3 and the mounting fixture 2 on the lower wall of wind tunnel 1 is gradually adjusted by the drive mechanism 4, which can produce a corresponding change in the cover plate cylinder spacing, thereby testing the intermediate airflow state and achieving a similar match between the airflow speed, pressure and flow direction and the carding process. During this process, the airflow speed, flow direction, pressure and other parameters are monitored and analyzed in real time, thereby accurately locating the guide plate 3 to achieve the optimal airflow state. Once the optimal position is determined, the optimal spacing of the needle cloth in actual production can be derived based on the correspondence between the guide plate 3, the cover plate, and the cylinder spacing, thus clarifying the optimal value when installing different toothed needle cloths.

[0049] (4) The space formed by the lower plane of the guide plate 3 and the highest point of the carding cloth surface is used to approximate the process gap of the actual carding process. This gap is called the carding gap in the textile industry. Although the cover plate structure is not a complete planar structure, using a planar structure to replace the cover plate is an approximation. Based on relevant computational fluid dynamics results and practical experience, this approximation method is engineering-acceptable and can fully reflect the airflow characteristics of the metal carding cloth surface.

[0050] (5) The sides of the guide vane 3 are completely sealed to the walls of the wind tunnel 1, forming a closed space. The drive mechanism 4 can move up and down. The key to realizing this technology is that the inner walls of the wind tunnel 1 are made of engineering resin with a certain degree of elasticity, and the sides of the guide vane 3 have very high density fine brushes 20.

[0051] (6) The wind tunnel 1 used in this application for the guide-related needle cloth test aims to test the transition characteristics of the airflow on the needle cloth surface, thereby studying the role of turbulence in the combing process. For airflow inside the tube, it is generally considered that when Re>10 4 When Re < 10, the flow state is fully turbulent; when Re < 10, the flow state is fully turbulent. 3 When the flow is laminar, the flow is laminar. When 10 3 <Re<10 4 At this point, the flow is a transitional flow, during which the fluid transforms from laminar to turbulent flow; this process is called transition. Before and after the transition point, due to the different flow patterns, the flow resistance characteristics generated by wind tunnel 1 differ, resulting in pressure losses with different characteristics. For laminar flow inside a circular pipe, the axial velocity is twice the average velocity. When the ratio of the axial velocity to the average velocity begins to decrease, it indicates that laminar flow is beginning to transition to turbulent flow. For complex flow channel structures, this characteristic is difficult to maintain, and wind tunnel testing is usually necessary to determine the correlation coefficient, which is also the purpose of the development of the wind tunnel 1 involved in this application.

[0052] The purpose of this application's guide vane system is to achieve accurate and continuous measurement of airflow on the needle cloth surface through the guide vane 1 itself, the pressure measuring tube 8 attached to the guide vane 1, the drive mechanism 4, the downstream airflow measurement and analysis system 5, and fluid dynamics calculation methods. Compared with traditional fixed wind tunnel wall structures, its advantages are: the lower wall of the guide vane can be machined separately to obtain better flatness; the guide vane is a replaceable component, adaptable to various testing environments, and easy to maintain; the wedge-shaped structure before and after the guide vane divides the airflow, making the airflow in the main measurement area more stable; the method of dividing the airflow and calculating the average velocity using a measuring rake ensures sufficient space in the wind tunnel, avoiding the disadvantage of traditional small wind tunnel measuring elements affecting the airflow; at the same time, the larger wind tunnel cavity reduces the design and manufacturing difficulty of the wind tunnel and improves the accuracy of airflow testing; the cylinder-controlled guide vane can achieve continuous measurement at different intervals without the need for reassembly and disassembly, reducing the complexity of testing while improving the accuracy of testing.

[0053] The air guide plate involved in this application is a key component of the airflow testing device for carded card fabric surfaces. This component enables the characterization of the aerodynamic characteristics of the carded card fabric surface, providing fundamental theoretical data for the improvement of carded card fabrics, especially high-yield carded card fabrics, and guiding the direction of improvement. This is of great significance to the entire textile industry.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A deflector system for use in a wind tunnel for needle cloth testing, characterized in that: The system includes a mounting fixture (2), a guide plate (3), a drive mechanism (4), and an airflow measurement and analysis system (5). The guide plate (3) is located inside a wind tunnel (1) through which the airflow inlet and outlet pass. The guide plate (3) forms a sealed structure with the inner wall of the test section (6) of the wind tunnel (1) and is controlled to move along the direction perpendicular to the test airflow by the drive mechanism (4). The wind tunnel (1) is 200-1000mm long, 10-150mm high, and 50-250mm wide. The guide plate (3) is provided with continuously arranged static pressure measuring points (11). A needle cloth is provided below the guide plate (3) and is placed on the mounting fixture (2). The mounting fixture (2) is placed on the bottom surface of the wind tunnel (1). An airflow measurement and analysis system (5) is arranged behind the guide plate (3) to detect the average airflow velocity in the test section (6). The airflow measurement and analysis system (5) is installed on the bottom surface of the wind tunnel (1).

2. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The static pressure measuring point (11) is located on the upper plane of the guide plate (3) and is symmetrically distributed on both sides of the center line of the guide plate (3). The pressure measuring tube (8) is installed on the static pressure point and is connected to the external pressure sensor of the wind tunnel (1).

3. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The longitudinal length A of the guide plate (3) is 300-800mm, the transverse width B of the guide plate (3) is 80-200mm, and the total height H from the lower edge to the outer edge of the upper edge of the guide plate (3) is 2-10mm.

4. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The guide plate (3) has a wedge-shaped structure at both the front and rear. The horizontal length L1 of the front inclined surface is 25.5 mm, and the two inclined surfaces at the rear are symmetrical with a horizontal length L2 of 20 mm.

5. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The guide plate (3) has a front trapezoidal height H of 0.5mm, an angle a of 5-15° between the inclined surface and the horizontal line, and an angle b of 2-10° between the rear inclined surface and the horizontal line.

6. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The guide plate (3) has an arc-shaped warped structure, and the ratio of its height H1:H2 from the inner wall of the wind tunnel (1) is 5:1-0.5:

1.

7. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The guide plate (3) is provided with brushes (20) on both sides, and the part of the guide plate (3) that contacts the wind tunnel (1) is sealed by the brushes (20).

8. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: The material of the guide plate (3) is aluminum, PVC, steel, or fiber composite material.

9. A deflector system for use in a needle cloth testing wind tunnel according to claim 1, characterized in that: Guide posts (9) are installed on the guide plate (3) by fasteners. The guide posts (9) pass through the wind tunnel (1). A wall hole is opened on the side wall of the wind tunnel (1), and a wall plate (12) is installed on the wall hole. The guide posts (9) are connected to the drive mechanism (4) through the mounting plate (10), and the drive mechanism (4) is fixed on the drive seat (19).

10. A testing method for a deflector system used in a wind tunnel for needle cloth testing, based on any one of claims 1 to 9, characterized in that: Includes the following steps: Step 1: Fix the mounting fixture (2) containing the needle cloth to the guide plate (3) and determine the position. Set the distance between the highest point of the needle cloth and the guide plate (3) to 0.25mm. Step 2: Turn on the fan (18) of the wind tunnel (1) and wait for it to run stably. Set the test wind speed to 5 m / s. Step 3: After stable operation, measure the pressure drop of the needle cloth test section (6), and measure the static pressure point (11) on the guide plate (3); Step 4: Test and measure the total pressure and static pressure on the rake, calculate the dynamic pressure, and estimate the average flow velocity in the test section (6); Step 5: The above result constitutes one measurement point; Step 6: Change the wind speed, measure multiple measurement points, and plot the pressure versus velocity curve to estimate the transition Reynolds number; Step 7: After the test is completed, turn off the fan (18).

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