Fan flow guide ring, air guide equipment and air guide equipment control method

Abstract

The invention discloses a fan flow guide ring, air guide equipment and an air guide equipment control method, and belongs to the field of air flow guide. The fan flow guide ring comprises at least one telescopic unit. Each telescopic unit comprises a first section, a second section and an adjusting device. The first section and the second section are connected in a sleeved mode, the adjusting device is connected with the first section and the second section, and the adjusting device changes the length of the flow guide ring by adjusting the sleeved connection length of the sleeved connection portion of the first section and the second section. Therefore, the length of the flow guide ring can be adjusted according to different wind speeds of the fan, and noise generated by the fan can be reduced while the efficiency of the fan is improved.

Description

Technical Field

[0001] The present application relates to the technical field of air guide technology, and in particular, to a fan guide ring, an air guide device, and an air guide device control method. Background Art

[0002] In the field of air guide equipment technology, the efficiency of the outdoor unit axial flow fan blades directly affects the overall performance of the air guide equipment. The design of the guide ring of the outdoor unit fan of traditional air guide equipment is often relatively simple, and fails to fully consider its impact on the air inlet speed and angle of the axial flow fan blades, thereby affecting the efficiency of the fan and may also increase the noise of the outdoor unit. The existing fan guide ring design focuses on structural stability and cost considerations, while ignoring its potential in improving fan efficiency and reducing noise.

[0003] Even if there is a fan guide ring that can reduce noise, it is to eliminate or reduce noise by changing the shape and internal structure of the fan guide ring, rather than changing the length of the fan guide ring. Therefore, the length of the traditional fan guide ring is fixed and cannot be adjusted according to different wind speeds, which to a certain extent limits the efficiency and noise control of the fan. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present application provides a fan guide ring, an air guide device and an air guide device control method to solve the problem that the length of the traditional fan guide ring is fixed and cannot be adjusted according to different wind speeds, which to a certain extent limits the efficiency and noise control of the fan.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] In a first aspect, a fan guide ring is provided, comprising: at least one telescopic unit; the telescopic unit can change the length of the guide ring;

[0007] The telescopic unit comprises a first segment, a second segment and an adjusting device;

[0008] The first segment and the second segment are sleeved;

[0009] The adjusting device is connected to the first segment and the second segment respectively, and is used to adjust the sleeve length of the sleeve parts of the first segment and the second segment, and the sleeve length is the overlapping length of the first segment and the second segment.

[0010] Further, the adjustment device is a ball screw;

[0011] The ball screw comprises a screw, a nut, a ball and a circulator;

[0012] The screw is connected to the first segment, and the nut is connected to the second segment; the circulator drives the nut through the ball bearing, so that the nut drives the second segment to move.

[0013] Furthermore, a limit switch is provided on the screw rod, and the limit switch is used to cut off the power supply of the circulator when the sleeve length is less than a threshold value.

[0014] Furthermore, it also includes: a locking unit, which is used to fix the sleeve length of the first segment and the second segment unchanged when the adjustment device does not adjust the sleeve length.

[0015] In a second aspect, a wind guiding device is provided, comprising the above-mentioned fan guide ring.

[0016] In a third aspect, a method for controlling an air guide device is provided, the method comprising:

[0017] If the preset condition is triggered, the target length of the guide ring is determined, and the target length is the length of the guide ring when the noise is the smallest when the fan speed remains unchanged at the current fan speed;

[0018] The length of the guide ring is controlled to be the target length, wherein the length of the guide ring is adjustable.

[0019] Furthermore, the trigger preset condition includes any one of the following:

[0020] The noise changes and the fan speed changes;

[0021] Alternatively, the fan rotation speed changes.

[0022] Further, determining the target length of the guide ring includes:

[0023] Obtaining the current fan speed;

[0024] The target length is determined based on the current fan speed.

[0025] Further, determining the target length based on the current fan speed includes:

[0026] Determining a minimum preset length and a maximum preset length of the guide ring based on the current fan speed;

[0027] Controlling the guide ring to extend from the minimum preset length to the maximum preset length, and recording the noise change;

[0028] The length corresponding to the minimum noise is used as the target length.

[0029] Further, determining the target length of the guide ring includes:

[0030] Controlling the guide ring to extend from the minimum length of the guide ring to the maximum length of the guide ring, and recording the noise change;

[0031] The length corresponding to the minimum noise is used as the target length.

[0032] Beneficial effects:

[0033] The technical solution of the present application provides a fan guide ring, a wind guide device and a method for controlling the wind guide device. The fan guide ring includes at least one telescopic unit. Each telescopic unit includes a first segment and a second segment and an adjusting device. The first segment and the second segment are sleeved, and the adjusting device is respectively connected to the first segment and the second segment. The adjusting device changes the length of the guide ring by adjusting the sleeve length of the sleeved part of the first segment and the second segment. Therefore, the length of the guide ring can be adjusted according to the wind speed of the fan, so that the noise generated by the fan can be reduced while increasing the efficiency of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 This is a structural schematic diagram of the relative positions of a fan and a guide ring provided in an embodiment of the present application;

[0036] Figure 2 It is a structural schematic diagram of a guide ring provided in an embodiment of the present application;

[0037] Figure 3 This is a structural schematic diagram of a guide ring installation provided in an embodiment of the present application;

[0038] Figure 4 This is a flow chart of a method for controlling an air guide device provided in an embodiment of the present application;

[0039] Figure 5 is a flow chart of a specific air guide device control method provided in an embodiment of the present application;

[0040] Figure 6 It is a structural schematic diagram of a wind guide equipment control device provided in an embodiment of the present application;

[0041] Figure 7 It is a schematic diagram of the structure of an air guide equipment control system provided in an embodiment of the present application.

[0042] Description of reference numerals:

[0043] 100-fan, 200-guide ring, 210-first section, 220-second section, 230-adjusting device, 231-screw, 232-nut, 300-panel. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application is described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0045] The relative position of the guide ring 200 and the fan 100 is as follows: Figure 1 As shown, the rotation speed of the fan 100 determines the speed of the airflow in the fan 100 and the way of kinetic energy conversion. As the rotation speed of the fan 100 increases, it means that the fan 100 needs a stronger airflow guiding ability to effectively guide the high-speed airflow to the outlet, while reducing the vortex and fluid separation phenomenon, thereby reducing the vibration and disturbance of the air caused by these irregular airflow movements, and then reducing the generation of noise. Therefore, under normal circumstances, a high-speed fan 100 usually requires a longer fan guide ring to ensure that the stable airflow dynamics can be maintained during high-speed operation, and to maximize the conversion of the kinetic energy of the airflow into effective output power. Secondly, the situation of a low-speed fan 100 also needs to be considered. Although low speeds usually do not need to deal with atmospheric flow energy like high-speed fans 100, a fan guide ring of appropriate length is still required to avoid unnecessary energy loss and fluid dynamic failure. A short fan guide ring may cause airflow dispersion and fluid separation, reducing the efficiency and performance of the fan 100, especially when it needs to run for a long time or needs to maintain stable operation.

[0046] To solve this problem, refer to Figure 2 , the embodiment of the present application provides a fan guide ring, including: at least one telescopic unit; the telescopic unit can change the length of the guide ring 200; for the convenience of description, Figure 2 There is only one telescopic unit in the middle. In practice, multiple telescopic units can be added to increase the adjustable range of the guide ring 200 length.

[0047] The telescopic unit includes a first segment 210, a second segment 220 and an adjustment device 230;

[0048] The first segment 210 and the second segment 220 are sleeved;

[0049] The adjusting device 230 is connected to the first segment 210 and the second segment 220 respectively, and is used to adjust the sleeve length of the sleeve portion of the first segment 210 and the second segment 220, and the sleeve length is the overlapped length of the first segment 210 and the second segment 220. The adjusting device 230 of the telescopic unit can change the length of the guide ring 200 by changing the sleeve length of the sleeve portion of the first segment 210 and the second segment 220.

[0050] like Figure 2 As shown, the adjustment device 230 is a ball screw;

[0051] The ball screw includes a screw rod 231, a nut 232, balls and a circulator;

[0052] The screw rod 231 is connected to the first segment 210 , and the nut 232 is connected to the second segment 220 ; the circulator drives the nut 232 through the ball bearing, so that the nut 232 drives the second segment 220 to move.

[0053] Optionally, the adjusting device 230 may also be in the form of a motor and a transmission device, or in the form of a cylinder. As long as the adjusting device 230 can drive the first segment 210 and the second segment 220 to move, the length of the guide ring 200 can be changed. This application does not make any specific limitations on this.

[0054] As a preferred implementation of the present application, a limit switch is provided on the screw rod 231, and the limit switch is used to cut off the power supply of the circulator when the sleeve length is less than a threshold value. This can prevent the nut 232 from directly detaching from the screw rod 231, thereby ensuring the safety of the device.

[0055] In actual use, a locking unit is also included, which is used to fix the sleeve length of the first segment 210 and the second segment 220 unchanged when the adjustment device 230 does not adjust the sleeve length. Because the sleeve connection between the first segment 210 and the second segment may not be firm after some adjustment devices 230 are adjusted, a locking unit is provided to lock. It is ensured that the length of the guide ring 200 remains unchanged when the adjustment device 230 is not involved in the adjustment.

[0056] The fan guide ring provided in the embodiment of the present application includes at least one telescopic unit. Each telescopic unit includes a first segment 210, a second segment 220 and an adjusting device 230. The first segment 210 and the second segment 220 are sleeved, and the adjusting device 230 is respectively connected to the first segment 210 and the second segment 220. The adjusting device 230 changes the length of the guide ring 200 by adjusting the sleeve length of the sleeved portion of the first segment 210 and the second segment 220. Therefore, the length of the guide ring 200 can be adjusted according to the wind speed of the fan 100, so that the noise generated by the fan 100 can be reduced while increasing the efficiency of the fan 100.

[0057] Based on the same inventive concept, the present application provides an air guide device, including the fan guide ring provided in the above embodiment. The air guide device is a device including a fan 100. The air guide device includes but is not limited to an air conditioner, a fan, an atomizer, etc. Taking the air conditioner as an example, the guide ring 200 is arranged on the outdoor unit of the air conditioner, such as Figure 3 As shown, the guide ring 200 is fixed on the panel 300 .

[0058] Among them, the guide ring structure is composed of at least two retractable segments, and the two segments are connected by a rolling screw device. The guide ring is designed to be retractable, usually divided into a first segment and a second segment. The first segment is fixed on the panel, and the second segment is a movable component that can move with the change of the ball screw, thereby changing the length of the entire guide ring to form an integral retractable guide ring. The nut of the ball screw is fixed to the second segment farther from the external machine panel. The circulator in the circulation groove between the screw and the nut guides the balls in the groove to circulate and roll between the screw and the nut, providing a linear motion force for the nut, so that the nut drives the slidable second segment farther from the external machine panel to move linearly. In order to ensure the safe operation of the device, a limit switch is installed at the extreme safety position of the screw. When it runs to the extreme safety position, the limit switch will cut off the power supply of the circulator to prevent excessive extension and retraction. To ensure the stability of the structure, three ball screws are set between the first segment and the second segment to synchronously control the expansion and contraction of the guide ring. The interval between each two devices is 120 degrees, forming a stable triangular fixed support effect. Of course, in actual control, only two ball screws can be set. Or four or more ball screws can be set.

[0059] Based on the same inventive concept, Figure 4 As shown, the present application provides a method for controlling an air guide device, the method comprising:

[0060] S11: if the preset condition is triggered, determining a target length of the guide ring, wherein the target length is the length of the guide ring when the noise is the lowest when the fan speed remains unchanged at the current fan speed;

[0061] In one embodiment, the preset triggering condition is that the noise changes and the fan speed changes; that is, after the sound sensor detects the change in noise, it is determined whether the fan speed changes.

[0062] In another embodiment, the triggering preset condition is that the noise changes. At this time, if the fan speed does not change, the target length is the current length, and if the fan speed changes, the target length needs to be re-determined.

[0063] However, in actual operation, the environment and the fan speed change at the same time, resulting in no change in noise. In this case, the length of the guide ring will not be adjusted, but in fact, the noise of the air guide device can be even lower. Therefore, in another embodiment, the triggering preset condition is the change in the fan speed. That is, the noise is no longer considered, and the fan speed is directly used for judgment.

[0064] As a preferred implementation method of the embodiment of the present application, determining the target length of the guide ring includes:

[0065] The current fan speed is obtained; the actual fan speed may be detected based on the gear position or by setting a sensor.

[0066] The target length is determined based on the current fan speed.

[0067] In one embodiment, determining the target length based on the current fan speed includes: directly determining the target length corresponding to the current fan speed based on a preset correspondence or a preset table. A corresponding target length is set for each fan speed in the preset correspondence or the preset table. The preset correspondence and the preset table are obtained based on testing.

[0068] However, in actual use, the actual environmental conditions and actual working conditions may be different from those during testing, so the target length obtained in this way may not be the optimal value.

[0069] Based on this, in another embodiment, determining the target length based on the current fan speed includes:

[0070] The minimum preset length and the maximum preset length of the guide ring are determined based on the current fan speed; the minimum preset length and the maximum preset length are a range value of the fan efficiency that is set in advance for each fan speed, the lower limit of the range value is the minimum preset length, and the upper limit is the maximum preset length. That is, the embodiment of the present application reduces noise while ensuring high fan efficiency.

[0071] The guide ring is controlled to extend from the minimum preset length to the maximum preset length, and the noise change is recorded.

[0072] The length corresponding to the minimum noise is used as the target length.

[0073] As another optional implementation of the embodiment of the present application, determining the target length of the guide ring includes:

[0074] Controlling the guide ring to extend from the minimum length of the guide ring to the maximum length of the guide ring, and recording the noise change;

[0075] The length corresponding to the minimum noise is used as the target length.

[0076] That is, this embodiment does not guarantee high fan efficiency, but only guarantees minimum noise.

[0077] The two methods can be selected according to actual needs. For example, when the noise is greater than the threshold, only the minimum noise is guaranteed. When the noise is less than or equal to the threshold, the fan efficiency is guaranteed to be high while the noise is reduced.

[0078] S12: Controlling the length of the guide ring to be the target length, wherein the length of the guide ring is adjustable.

[0079] The air guide device control method provided in the embodiment of the present application determines the target length of the guide ring when the preset condition is triggered. Since the target length is the length of the guide ring when the noise is the smallest when the fan speed maintains the current fan speed unchanged, when the guide ring length is controlled to be the target length, the noise of the air guide device is the smallest. This can effectively reduce noise and improve user experience.

[0080] Because, taking the air guide device as an air conditioner as an example, the guide ring is used on the outdoor unit of the air conditioner. When the speed of the outdoor unit of the air conditioner increases, the noise can be reduced by adjusting the length of the guide ring. This is mainly based on the principles of fluid mechanics and aerodynamics. The guide ring plays a role in guiding and rectifying the airflow. The adjustment of its length can change the entry angle and flow path of the airflow, thereby affecting the noise level generated when the fan speed increases.

[0081] The specific principles are as follows:

[0082] 1. Airflow rectification: The extended guide ring can make the fast and turbulent airflow orderly and stable, and reduce the turbulence of the airflow. When the airflow passes through the guide ring, the flow direction is guided more evenly, reducing the turbulent collision between the airflow and the heat exchanger and reducing the noise.

[0083] 2. Reduce eddy currents: The optimized design of the guide ring can reduce the eddy currents formed by the airflow around the heat exchanger, which is an important source of noise. By adjusting the length of the guide ring, the distribution of the airflow can be effectively controlled, the eddy current formation can be reduced, and thus the noise caused by friction and vibration can be reduced.

[0084] 3. Wind resistance adjustment: The length of the guide ring also affects the wind resistance entering the external unit. The appropriate length can reduce the wind resistance effect caused by high-speed airflow, allowing the airflow to pass more smoothly, reducing airflow separation and turbulence caused by wind resistance, thereby reducing noise.

[0085] 4. Mechanical vibration suppression: A high-speed rotating fan without proper air flow guidance is prone to resonance due to uneven air flow resistance, increasing the vibration and noise of mechanical parts. Adjusting the length of the guide ring can help disperse or absorb these vibrations and reduce the spread of noise.

[0086] Therefore, by properly adjusting the length of the guide ring, the noise of the air conditioner outdoor unit at high speed can be effectively controlled and reduced, while maintaining or even improving the heat exchange efficiency, achieving quiet and efficient operation. Normally, the speed of the outdoor unit of a household air conditioner is within 1000rpm. Generally speaking, the role of the guide ring is to improve the airflow structure, reduce turbulence, and thus reduce noise. The following Table 1 is a simplified model based on industry experience and experimental data, which is used to illustrate the effect of the extension length of the guide ring on noise at different speeds, as well as the recommended corresponding data:

[0087] 1. When the fan speed is less than or equal to 600rpm, in order to ensure the air volume and reduce the noise, the recommended extension length of the guide ring is a1-a2mm. At this time, the noise level can be controlled at 32-41dB, which is about 1dB (A) lower than the existing outdoor unit noise level.

[0088] 2. When the fan speed is 600-800rpm, the extension length of the guide ring can be adjusted to a2-a3mm, which helps to further optimize the airflow and reduce the noise to 41-48dB, which is about 1dB (A) lower than the existing outdoor unit noise level.

[0089] 3. When the fan speed is 800-1000rpm, due to the increase in speed and air flow velocity, the extension length of the guide ring should be appropriately increased to a3-a4mm to effectively suppress the noise, so that the noise is kept within the range of 48-54dB, which is about 2dB (A) lower than the existing outdoor unit noise level.

[0090] Table 1

[0091] Fan speed rpm Length of guide ring (mm) Noise level dB Noise reduction dB ≤600 a1-a2 32-41 1 600-800 a2-a3 41-48 1 800-1000 a3-a4 48-54 2

[0092] In actual applications, factors such as fan characteristics (such as blade design, motor performance), air duct design, and installation environment will affect noise. Therefore, the above data is only used as a mapping relationship between the initial fan speed, guide ring length, and noise. The actual extension length of the guide ring needs to be dynamically adjusted through real-time monitoring of noise when the external unit is working and feedback to the system to ensure the best noise control effect.

[0093] In order to more clearly illustrate the present application scheme, a specific implementation method is provided below. Figure 5 As shown, the control method includes a sensor system installed in the outdoor unit air duct system to detect noise in the outdoor unit air duct.

[0094] Specifically, the sensor for detecting the noise of the external unit monitors the noise of the external unit once every interval ΔT and records the noise data.

[0095] When the monitored noise data changes, a signal is provided to the outdoor unit controller, and the controller will analyze and determine whether the outdoor unit speed changes between two moments.

[0096] If the speed of the outdoor unit does not change, the guide ring maintains the current state and does not change; if the speed of the outdoor unit changes, the state of the guide ring is adjusted, and the guide ring length is adjusted according to the data table of the speed, noise and guide ring length of the outdoor unit.

[0097] First, determine the external machine speed and the preset length variation range of the guide ring at the current speed.

[0098] According to the preset data table, adjust the guide ring length to the shortest length position of the guide ring length corresponding to the current speed, and start to extend the guide ring at a uniform speed of 1mm / s until it reaches the farthest distance in the current range. Δ The noise data is recorded once at a time of t=1s, and the noise data corresponding to the position of each millimeter of the guide ring extension can be obtained. According to the noise data within the adjustment range of the guide ring, the length of the guide ring is adjusted to the position with the minimum noise value, thus completing a complete guide ring length adjustment process. In the actual operation of the outdoor unit, the guide ring can adjust the length of the guide ring in real time according to the speed of the outdoor unit through the above control method, thereby controlling the noise of the outdoor unit.

[0099] The specific air guide equipment control method provided in the embodiment of the present application can control the length of the guide ring according to the real-time fan speed of the air guide equipment, thereby realizing the telescopic adjustment of the guide ring to adapt to the adjustment of the air guide equipment under different working conditions. This automated adjustment not only improves the overall performance of the fan, but also effectively reduces the noise generated during the operation of the air guide equipment.

[0100] Based on the same inventive concept, Figure 6 As shown, the present application further provides an air guide device control device 60, and the air guide device control device 60 includes:

[0101] A target length determination module 61 is used to determine the target length of the guide ring when a preset condition is triggered, wherein the target length is the length of the guide ring when the noise is the smallest when the fan speed maintains the current fan speed unchanged;

[0102] The triggering preset condition includes any one of the following:

[0103] The noise changes and the fan speed changes;

[0104] Alternatively, the fan rotation speed changes.

[0105] In one embodiment, determining the target length of the guide ring includes:

[0106] Obtaining the current fan speed;

[0107] The target length is determined based on the current fan speed.

[0108] Further, determining the target length based on the current fan speed includes:

[0109] Determining a minimum preset length and a maximum preset length of the guide ring based on the current fan speed;

[0110] Controlling the guide ring to extend from the minimum preset length to the maximum preset length, and recording the noise change;

[0111] The length corresponding to the minimum noise is used as the target length.

[0112] In another embodiment, determining a target length of the guide ring includes:

[0113] Controlling the guide ring to extend from the minimum length of the guide ring to the maximum length of the guide ring, and recording the noise change;

[0114] The length corresponding to the minimum noise is used as the target length.

[0115] The guide ring control module 62 is used to control the guide ring length to be the target length, wherein the guide ring length is adjustable.

[0116] The air guide device control device provided in the embodiment of the present application determines the target length of the guide ring when the preset condition is triggered. Since the target length is the length of the guide ring when the noise is the smallest when the fan speed maintains the current fan speed unchanged, when the guide ring length is controlled to be the target length, the noise of the air guide device is the smallest. This can effectively reduce noise and improve user experience.

[0117] Based on the same inventive concept, Figure 7 As shown, the present application also provides a wind guide device control system 70, including:

[0118] at least one processor 71 and at least one memory 72;

[0119] The memory stores executable instructions of the processor;

[0120] The processor is configured to execute the wind turbine guide ring method provided in the above embodiment.

[0121] The air guide device control system provided by the embodiment of the present application stores executable instructions of the processor in the memory. When the executable instructions are executed, the processor can determine the target length of the guide ring when the preset condition is triggered. Since the target length is the length of the guide ring when the noise is the smallest when the fan speed maintains the current fan speed unchanged, when the guide ring length is controlled to be the target length, the noise of the air guide device is the smallest. It can effectively reduce noise and improve user experience.

[0122] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0123] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

Claims

1. A fan guide ring, characterized in that: include: at least one telescopic unit; The telescopic unit can change the length of the guide ring; The telescopic unit comprises a first segment, a second segment and an adjusting device; The first segment and the second segment are sleeved; The adjusting device is connected to the first segment and the second segment respectively, and is used to adjust the sleeve length of the sleeve parts of the first segment and the second segment, and the sleeve length is the overlapping length of the first segment and the second segment.

2. The fan guide ring according to claim 1, characterized in that: The adjusting device is a ball screw; The ball screw comprises a screw, a nut, a ball and a circulator; The screw is connected to the first segment, and the nut is connected to the second segment; the circulator drives the nut through the ball bearing, so that the nut drives the second segment to move.

3. The fan guide ring according to claim 2, characterized in that: The screw rod is provided with a limit switch, and the limit switch is used to cut off the power supply of the circulator when the sleeve length is less than a threshold value.

4. The fan guide ring according to claim 1, characterized in that: Also includes: The locking unit is used to fix the sleeve length of the first segment and the second segment unchanged when the adjusting device does not adjust the sleeve length.

5. An air guide device, characterized in that: It comprises the fan guide ring as described in any one of claims 1 to 4.

6. A method for controlling an air guide device, characterized in that: The method comprises: If the preset condition is triggered, the target length of the guide ring is determined, and the target length is the length of the guide ring when the noise is the smallest when the fan speed remains unchanged at the current fan speed; The length of the guide ring is controlled to be the target length, wherein the length of the guide ring is adjustable.

7. The method according to claim 6, characterized in that: The trigger preset condition includes any one of the following: The noise changes and the fan speed changes; Alternatively, the fan rotation speed changes.

8. The method according to claim 6, characterized in that: Determining the target length of the guide ring includes: Obtaining the current fan speed; The target length is determined based on the current fan speed.

9. The method according to claim 8, characterized in that: The determining the target length based on the current fan speed includes: Determining a minimum preset length and a maximum preset length of the guide ring based on the current fan speed; Controlling the guide ring to extend from the minimum preset length to the maximum preset length, and recording the noise change; The length corresponding to the minimum noise is used as the target length.

10. The method according to claim 6, characterized in that Determining the target length of the guide ring includes: Controlling the guide ring to extend from the minimum length of the guide ring to the maximum length of the guide ring, and recording the noise change; The length corresponding to the minimum noise is used as the target length.

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