Cross-flow fan and air conditioner

Abstract

The cross-flow fan comprises a first end cover, a second end cover and at least one blade assembly, the first end cover and the second end cover are oppositely arranged in the first direction, and the blade assembly is arranged between the first end cover and the second end cover and comprises a plurality of blades. The plurality of blades are arranged at intervals in the circumferential direction of an imaginary circle; each blade is provided with a blade root close to the circle center of the imaginary circle and a blade top away from the circle center of the imaginary circle, and at least part of the contour line of each blade top is a waveform line extending in the first direction; the waveform line comprises a plurality of waveform segments arranged in the first direction, at least two waveform segments are different in shape, or at least one waveform segment is of a non-axisymmetric structure. According to the cross-flow fan provided by the embodiment of the utility model, when air flows through the blades, periodic vortex falling of the blade tops of the blades can be inhibited, flow separation and vortex intensity are reduced, and noise can be reduced under the condition of the same air volume.

Description

Technical Field

[0001] This utility model relates to the field of cross-flow fan technology, specifically to a cross-flow fan and an air conditioner. Background Technology

[0002] When a cross-flow fan rotates, the gas flows through the blades twice during the flow process, allowing the blades to do work on the gas twice, thereby obtaining a larger dynamic pressure.

[0003] However, in the cross-flow fan of the related technology, the vortex shedding generated by the airflow at the blade tip during the periodic rotation process will cause vortex noise, and the pressure pulsation of the airflow in the blade boundary layer will also cause noise, resulting in a large operating noise of the cross-flow fan. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a cross-flow fan that can reduce noise while maintaining the same airflow.

[0005] This utility model also proposes an air conditioner having the above-mentioned cross-flow fan.

[0006] A cross-flow fan according to a first aspect of the present invention includes: a first end cover and a second end cover, disposed opposite to each other in a first direction; at least one blade assembly disposed between the first end cover and the second end cover, and including a plurality of blades, the plurality of blades being arranged circumferentially at intervals in an imaginary circle; each blade having a blade root near the center of the imaginary circle and a blade tip away from the center of the imaginary circle, the outline of the blade tip being at least partially a wave line extending in the first direction; wherein the wave line includes a plurality of wave segments arranged in the first direction, at least two of the wave segments having different shapes, or at least one of the wave segments having a non-axisymmetric structure.

[0007] According to the embodiments of the present invention, the cross-flow fan, by setting the shapes of at least two waveform segments to be different, or setting at least one waveform segment to a non-axisymmetric structure, can make the waveform lines have irregular characteristics, such as making at least two waveform segments irregularly distributed, or making at least one waveform segment irregularly shaped. When the gas flows through the blades, it can suppress the periodic vortex shedding of the blade tips, reduce flow separation and vortex intensity, and reduce the noise OA value and BPF peak value under the same air volume, that is, reduce noise. On the other hand, it can improve the differentiation of the cross-flow fan and break the conventional design of the cross-flow fan.

[0008] In some embodiments, the waveform segment includes a first waveform segment, which is a sine function curve or a cosine function curve. At least two of the first waveform segments have different shapes, and at least two of the first waveform segments have at least one set of different design parameters, including amplitude, phase, vertical displacement, and frequency.

[0009] In some examples, the amplitudes of at least two of the first waveform segments are different.

[0010] In some examples, the waveform line includes n first waveform segments arranged sequentially and connected in the first direction, each first waveform segment being a sine function curve; the amplitudes of the n first waveform segments decrease sequentially from the first to the nth, and the frequencies of the n first waveform segments are equal.

[0011] In some examples, the amplitude of the first waveform segment is randomly distributed and ranges from [0.5L, 1L], where L is the chord length of the blade; the frequency of the first waveform segment is greater than or equal to 1; and the vertical displacement of the first waveform segment ranges from [0, A], where A is the amplitude.

[0012] In some embodiments, the waveform segment includes a second waveform segment, which includes a first arc and a second arc arranged and connected in the first direction. The first arc and the second arc are non-axially symmetrical about a centerline extending in a second direction, and the second direction is perpendicular to the first direction.

[0013] In some examples, at least two of the second waveform segments have different shapes, and adjacent second waveform segments are connected by an arc transition; and / or, the second waveform segment is an asymmetric airfoil function curve.

[0014] In some examples, the wavelength of the second waveform segment is 0.1H-0.18H, where H is the height of the blade; the amplitude of the second waveform segment is 0.23L-0.27L, where L is the chord length of the blade.

[0015] In some embodiments, the multiple blades in the blade assembly have identical structures and shapes; and / or, there are multiple blade assemblies arranged in the first direction, with the number of blades in two adjacent blade assemblies being equal and their positions corresponding one-to-one, and the two blades in two adjacent blade assemblies being arranged at a preset angle.

[0016] An air conditioner according to a second aspect of the present invention includes a cross-flow fan as described in the above embodiments.

[0017] According to the embodiments of the present invention, the air conditioner can reduce its operating noise by employing the aforementioned cross-flow fan.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a projection view of multiple blades of a cross-flow fan in some embodiments along a first direction;

[0021] Figure 2 A side view of the blade assembly of a cross-flow fan according to some embodiments;

[0022] Figure 3 for Figure 2 A schematic diagram of the blades of a cross-flow fan shown in the figure;

[0023] Figure 4 for Figure 3 A schematic diagram of the wavy lines of the blade shown;

[0024] Figure 5 for Figure 4 A schematic diagram of the first waveform segment of the waveform line shown;

[0025] Figure 6 for Figure 3 The diagram shows the blade parameters and gas flow direction.

[0026] Figure 7 A perspective view of a cross-flow fan according to other embodiments;

[0027] Figure 8 for Figure 7 A side view of the blade assembly of the cross-flow fan shown;

[0028] Figure 9 for Figure 8 A schematic diagram of the blades of a cross-flow fan shown in the figure;

[0029] Figure 10 for Figure 9 A schematic diagram of the waveform lines shown;

[0030] Figure 11 for Figure 9 The second waveform segment shown is a design drawing of an asymmetric airfoil;

[0031] Figure 12A schematic diagram of the asymmetric airfoil NACA3315 in some embodiments;

[0032] Figure 13 Schematic diagram of the asymmetric airfoil NACA2412 in other embodiments;

[0033] Figure 14 This is a graph showing the airflow-noise ratio of the cross-flow fan (with a wavy blade tip) of this application to a comparative cross-flow fan (with a straight blade tip).

[0034] Figure label:

[0035] Blade assembly 100;

[0036] Leaf blade 10; Leaf root 11; Leaf tip 12; Waveform line 120; Waveform segment 121; First waveform segment 1211; Second waveform segment 1212; First arc 12121; Second arc 12122; Middle arc 12123. Detailed Implementation

[0037] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0038] In the description of this utility model, it should be understood that the terms "center," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of those features. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] This application describes the structure of an air conditioner.

[0041] Before proceeding, let's introduce the structure of a common air conditioner. The most common type of air conditioner is the split-type air conditioner, which consists of an indoor unit and an outdoor unit. The indoor and outdoor units are connected by pipes to transfer refrigerant. The indoor unit includes an indoor heat exchanger and an indoor fan.

[0042] The outdoor unit includes a compressor, an outdoor heat exchanger, an outdoor fan, and a throttling device. The compressor, outdoor heat exchanger, throttling device, and indoor heat exchanger are connected in sequence to form a refrigerant circuit. The refrigerant circulates in the refrigerant circuit and exchanges heat with the air through the outdoor heat exchanger and the indoor heat exchanger, respectively, to achieve the air conditioner's cooling mode or heating mode.

[0043] The compressor is configured to compress the refrigerant so that the low-pressure refrigerant is compressed to form a high-pressure refrigerant.

[0044] The outdoor heat exchanger is configured to exchange heat between outdoor air and refrigerant transported within it. For example, in the cooling mode of the air conditioner, the outdoor heat exchanger operates as a condenser, causing the refrigerant compressed by the compressor to dissipate heat to the outdoor air and condense. In the heating mode of the air conditioner, the outdoor heat exchanger operates as an evaporator, causing the depressurized refrigerant to absorb heat from the outdoor air and evaporate.

[0045] In some embodiments, the outdoor heat exchanger further includes heat exchange fins to increase the contact area between the outdoor air and the refrigerant transported in the outdoor heat exchanger, thereby improving the heat exchange efficiency between the outdoor air and the refrigerant.

[0046] The outdoor fan is configured to draw in outside air into the outdoor unit and expel the outdoor air, which has been heated by the outdoor heat exchanger, to the outside. The outdoor fan provides power for the flow of outdoor air.

[0047] A throttling device connects the outdoor and indoor heat exchangers. It regulates the refrigerant pressure flowing through both devices, thereby controlling the refrigerant flow rate between them. The flow rate and pressure of the refrigerant between the outdoor and indoor heat exchangers affect their heat exchange performance. The throttling device can be a throttling tube, an electronic valve, etc. When the throttling device is an electronic valve, its opening is adjustable to regulate the refrigerant flow rate and pressure.

[0048] An indoor heat exchanger is configured to exchange heat between indoor air and a refrigerant transported within the indoor heat exchanger. In some embodiments, the indoor heat exchanger further includes heat exchange fins to increase the contact area between the indoor air and the refrigerant transported within the indoor heat exchanger, thereby improving the heat exchange efficiency between the indoor air and the refrigerant.

[0049] The indoor fan is configured to draw indoor air into the indoor unit and deliver the indoor air, which has been heated by the indoor heat exchanger, into the room. The indoor fan provides power for the flow of indoor air.

[0050] Indoor fans can be cross-flow fans. When a cross-flow fan rotates, gas enters radially from one side of the fan and flows radially out from the other side. In other words, the gas flows through the blades twice during its flow, allowing the blades to do work on the gas twice, resulting in greater dynamic pressure when the gas exits the fan.

[0051] The following description, with reference to the accompanying drawings, describes a cross-flow fan according to an embodiment of the present invention.

[0052] Reference Figure 1 and Figure 2 , Figure 1 This is a projection view of a plurality of blades 10 of a cross-flow fan in some embodiments along a first direction; Figure 2 This is a side view of the blade assembly 100 of a cross-flow fan according to some embodiments. The cross-flow fan according to an embodiment of the present invention includes: a first end cap (not shown), a second end cap (not shown), and at least one blade assembly 100. The first end cap and the second end cap are in a first direction (e.g., Figure 2 The blade assembly 100 is disposed between the first end cap and the second end cap, and is positioned opposite each other in the F1 direction shown.

[0053] The blade assembly 100 includes a plurality of blades 10, which are arranged circumferentially at intervals in an imaginary circle. Each blade 10 has a root 11 near the center of the imaginary circle and a tip 12 away from the center of the imaginary circle, and the outline of the tip 12 of the blade 10 is at least partially a wavy line 120 extending in a first direction.

[0054] Reference Figure 3 , Figure 3for Figure 2 The diagram shows the structure of the blade 10 of the cross-flow fan. The waveform line 120 includes multiple waveform segments 121, which are arranged in a first direction. At least two waveform segments 121 have different shapes, or at least one waveform segment 121 has a non-axisymmetric structure.

[0055] In related technologies, the blades of cross-flow fans have straight blade tips. When gas flows through the blade tips, the pressure difference creates periodically shedding Kármán vortex streets. This periodic shedding of vortices generates sound waves of specific frequencies, forming significant narrowband noise, such as whistling. Furthermore, at the straight blade tips, the gas may suddenly separate, forming large-scale turbulent structures and generating high-frequency noise. In addition, the shedding of vortices at the straight blade tips has high spatial and temporal coherence, which easily leads to the superposition of sound wave phases, enhancing the noise intensity.

[0056] In the technical solution of this application, the blade tip 12 of the blade 10 has an irregular waveform line 120, which breaks the geometric symmetry of the blade tip 12 of the blade 10, and disperses the phase and frequency of the eddy current shedding in space, thereby dispersing the concentrated narrowband noise energy into a wider frequency band and significantly reducing peak noise.

[0057] Furthermore, the waveform line 120, through changes in local curvature, causes the gas to gradually separate along the blade tip 12 of the blade 10, reducing sudden flow separation and turbulence intensity, thereby lowering broadband noise caused by turbulent pulsations. In addition, the waveform line 120 can decompose large eddies into multiple small-scale eddies and destroy their coherence. Due to the interference effect, the sound waves of these small eddies cancel each other out during propagation, thereby reducing the overall noise level.

[0058] Therefore, according to the cross-flow fan of the present invention, by setting the shapes of at least two waveform segments 121 to be different, or setting at least one waveform segment 121 to a non-axisymmetric structure, on the one hand, the waveform line 120 can have irregular characteristics, for example, at least two waveform segments 121 can be irregularly distributed, or at least one waveform segment 121 can be irregularly shaped. When the gas flows through the blade 10, the periodic vortex shedding of the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced. On the other hand, the differentiation of the cross-flow fan can be improved, breaking the conventional design of the cross-flow fan.

[0059] Please refer to this again. Figure 3 and further refer to Figure 4 , Figure 4 for Figure 3The diagram shows a schematic of the waveform line 120 of the blade 10. In some embodiments, the waveform segment 121 includes a first waveform segment 1211, which is a sine function curve or a cosine function curve.

[0060] Among them, at least two first waveform segments 1211 have different shapes. Here, "different shapes" means that the two first waveform segments 1211 do not completely overlap. The opposite statement is "same shapes", that is, "same shapes" means that the two first waveform segments 1211 completely overlap.

[0061] In other words, at least one set of design parameters differs for at least two first waveform segments 1211. These design parameters include amplitude, phase, vertical displacement, and frequency.

[0062] For example, the first waveform segment 1211 is a sine function curve, and the waveform line 120 is composed of at least two sine function curves with different design parameters. For example, the waveform line 120 is composed of two or more sine function curves with different amplitudes and vertical displacements; or, for another example, the waveform line 120 is composed of two or more sine function curves with different amplitudes and frequencies.

[0063] For example, the first waveform segment 1211 is a cosine function curve, and the waveform line 120 is composed of at least two cosine function curves with different design parameters. For example, the waveform line 120 is composed of two or more cosine function curves with different amplitudes and vertical displacements; or, for another example, the waveform line 120 is composed of two or more cosine function curves with different amplitudes and frequencies.

[0064] Therefore, by setting at least one set of design parameters of at least two waveform segments 121 to be different, when gas flows through the blade 10, the periodic vortex shedding of the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced.

[0065] In some examples, at least two first waveform segments 1211 have different amplitudes. That is, the waveform line 120 is composed of at least two sine or cosine function curves with different amplitudes, such that at least two first waveform segments 1211 are irregularly distributed.

[0066] With this configuration, at least two first waveform segments 1211 can be irregularly distributed, which can suppress the periodic vortex shedding of the blade tip 12 of the blade 10, reduce flow separation and vortex intensity, and reduce noise under the same air volume.

[0067] Please refer to this again. Figure 4 and further refer to Figure 5 , Figure 5 for Figure 4 The diagram shows a first waveform segment 1211 of the waveform line 120. In some examples, the waveform line 120 includes n first waveform segments 1211, which are arranged sequentially and connected in a first direction.

[0068] Among them, the first waveform segment 1211 is a sine function curve, and the curve function of the i-th first waveform segment 1211 is: y(t)=A i sin(2πf i t+φ i )+D i i = 1, 2, ..., n. Taking n = 3 as an example, it can be understood as follows:

[0069] The curve function of the first waveform segment 1211 is:

[0070] y(t)=A1sin(2πf1t+φ1)+D1;

[0071] The curve function for the second first waveform segment 1211 is:

[0072] y(t)=A2sin(2πf2t+φ2)+D2;

[0073] The curve function for the third first waveform segment 1211 is:

[0074] y(t)=A3sin(2πf3t+φ3)+D3;

[0075] The curve function of the nth first waveform segment 1211 is:

[0076] y(t)=A n sin(2πf n t+φ n )+D n ;

[0077] In other words, the curve function of waveform line 120 is:

[0078]

[0079] Where A is the amplitude, t is the parameter variable, θ is the phase, D is the vertical displacement, and f is the frequency. At least two sets of design parameters for the first waveform segments 1211 are different. Here, the phase θ refers to the initial offset angle of the waveform at t=0, and the vertical displacement D refers to the overall vertical translation of the waveform.

[0080] For example, waveform line 120 is composed of at least two sine function curves with different amplitudes A and different phases θ; for example, waveform line 120 is composed of at least two sine function curves with different amplitudes A and different vertical displacements D; for example, waveform line 120 is composed of at least two sine function curves with different amplitudes A and different frequencies f.

[0081] For example, waveform line 120 is composed of at least two sine function curves with different phases θ; for example, waveform line 120 is composed of at least two sine function curves with different phases θ and different frequencies f.

[0082] For example, waveform line 120 is composed of at least two sine function curves with different vertical displacements D; for example, waveform line 120 is composed of at least two sine function curves with different vertical displacements D and different frequencies f.

[0083] For example, waveform line 120 is composed of at least two sine function curves with different frequencies f.

[0084] In the above technical solution, the design parameters of the first waveform segment 1211 are set to meet the above conditions, so that it has a certain design law and conforms to a specific mathematical model. The blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0085] Reference Figure 4 In some specific examples, the amplitudes of the n first waveform segments 1211 decrease sequentially from the 1st to the nth, and the frequencies of the n first waveform segments 1211 are equal.

[0086] Taking waveform line 120 comprising three first waveform segments 1211 as an example, the amplitude of the first first waveform segment 1211 is A1, and it has a sine function curve with two periods; the amplitude of the second first waveform segment 1211 is A2, and it has a sine function curve with two periods; the amplitude of the third first waveform segment 1211 is A3, and it has a sine function curve with two periods. Wherein, A1... <A2<A3。

[0087] In the above technical solution, the amplitude and frequency of multiple first waveform segments 1211 are set to meet the above conditions, so that the blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0088] In some embodiments, the random distribution of multiple first waveform segments 1211 satisfies the discrete random variable function: P(X=x i )=p(x i); where x i These are the possible values ​​of x.

[0089] Property 1: Nonnegativity: p(x i )≥0;

[0090] Property 2: Normalization: ∑ip(x) i ) = 1;

[0091] In some examples, the parameter variable t takes values ​​in the range [0, 1].

[0092] In the above technical solution, the parameter variable t is limited to meet the above conditions, so that the waveform line 120 has a certain design law and conforms to a specific ratio range. The blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0093] In some examples, the amplitude A of the first waveform segment 1211 is randomly distributed and ranges from [0.5L, 1L], where L is the chord length of the blade 10.

[0094] For example, the waveform line 120 includes four first waveform segments 1211 arranged and connected along a first direction. The amplitude A1 of the first first waveform segment 1211 can be L, the amplitude A2 of the second first waveform segment 1211 can be 0.8L, the amplitude A3 of the third first waveform segment 1211 can be 0.6L, and the amplitude A4 of the fourth first waveform segment 1211 can be 0.5L.

[0095] In the above technical solution, by limiting the amplitude A to meet the above conditions, the waveform line 120 has a certain design law and conforms to a specific ratio range. The blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0096] In some examples, the frequency f of the first waveform segment 1211 is greater than or equal to 1. The frequency f determines the number of periods in each sine wave of the sine function curve; for example, the frequency f can be one or more.

[0097] In the above technical solution, by limiting the frequency f to meet the above conditions, the waveform line 120 has a certain design law and conforms to a specific ratio range. The blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0098] In some examples, the vertical displacement D of the first waveform segment 1211 ranges from [0, A].

[0099] Specifically, when the vertical displacement D is 0, the first waveform segment 1211 has a symmetrical waveform structure; when the vertical displacement D is greater than 0, the first waveform segment 1211 has an asymmetrical waveform structure.

[0100] It should be noted that the vertical displacement D here is based on the X-axis. That is, when the vertical displacement D is 0, the first waveform segment 1211 is a symmetrical waveform structure about the X-axis, and when the vertical displacement D is greater than 0, the first waveform segment 1211 is an asymmetrical waveform structure about the X-axis.

[0101] In the above technical solution, by limiting the vertical displacement D to meet the above conditions, the waveform line 120 has a certain design law and conforms to a specific ratio range. The blade tip 12 of the cross-flow fan blade 10 obtained by following this design law can reduce the noise OA value and eliminate the BPF rotation noise problem under the same air volume.

[0102] Please refer to this again. Figure 3 In this embodiment, waveform line 120 combines three sine function curves with different amplitudes and wavelengths. Of course, it can also be extended to sine function curves with different vertical displacements D and different period variations. Such combinations can be infinitely varied, while still adhering to specific mathematical laws, and can be adjusted according to needs.

[0103] Please refer to Figure 6 and Figure 14 , Figure 6 for Figure 3 The diagram shows the parameters of blade 10 and the gas flow direction. Figure 14 This is a comparison graph of airflow-noise ratio between the cross-flow fan (with a wavy blade tip) of this application and a comparative cross-flow fan (with a straight blade tip). K1-F2 represents the airflow-noise ratio curve of the cross-flow fan of this application, and K1-F1 represents the airflow-noise ratio curve of the comparative cross-flow fan. Verification shows that using this sine function curve to design the blade tip 12 of blade 10, compared to the cross-flow fan with a straight blade tip 12, results in a 2 dB reduction in noise OA and a 3-5 dB reduction in peak BPF at the same airflow rate.

[0104] In summary, in this embodiment of the application, by setting the outline of the blade tip 12 of the blade 10 to include a plurality of first waveform segments 1211 arranged along the first direction, the plurality of first waveform segments 1211 can be distributed in a non-single regular pattern, that is, the plurality of first waveform segments 1211 can be irregularly distributed in various combinations, such as according to a discrete random function distribution, the vortex noise caused by the vortex shedding generated by the airflow at the blade tip 12 of the blade 10 during the periodic rotation of the cross-flow fan can be suppressed. Its irregular waveform distribution can also reduce the noise caused by the pressure pulsation of the airflow in the boundary layer of the blade 10. In addition, the irregular waveform distribution can also eliminate or reduce the discrete frequency noise caused by the periodic cutting of the airflow by the blade 10.

[0105] Please refer to Figures 7-9 , Figure 7 A perspective view of a cross-flow fan according to other embodiments; Figure 8 for Figure 7 The side view of the cross-flow fan shown; Figure 9 for Figure 8 The diagram shows a schematic representation of the blades 10 of a cross-flow fan. In some embodiments, waveform segment 121 includes a second waveform segment 1212. At least one second waveform segment 1212 is non-axisymmetrically arranged about a centerline J extending along a second direction.

[0106] Please refer to Figure 10 and Figure 11 , Figure 10 for Figure 9 A schematic diagram of the waveform line 120 shown; Figure 11 for Figure 9 The second waveform segment 1212 shown is a design drawing of an asymmetric airfoil. The second waveform segment 1212 includes a first arc 12121 and a second arc 12122. The first arc 12121 and the second arc 12122 are arranged and connected in a first direction. The first arc 12121 and the second arc 12122 are non-axially symmetrical about the centerline J extending along the second direction. The second direction is perpendicular to the first direction.

[0107] In the above technical solution, by setting the second waveform segment 1212 non-axisymmetrically, when the gas flows through the blade 10, the periodic vortex shedding of the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced.

[0108] In some examples, at least two second waveform segments 1212 have different shapes, and adjacent second waveform segments 1212 are connected by an arc transition. Here, "different shapes" means that the two second waveform segments 1212 do not completely overlap. The opposite statement is "same shapes," that is, "same shapes" means that the two second waveform segments 1212 completely overlap.

[0109] That is, at least two second waveform segments 1212 have different shapes for their first arc 12121 and the same shape for their second arc 12122; or, at least two second waveform segments 1212 have the same shape for their first arc 12121 and different shapes for their second arc 12122; or, at least two second waveform segments 1212 have different shapes for their first arc 12121 and different shapes for their second arc 12122.

[0110] Therefore, by setting the shapes of at least two second waveform segments 1212 to be different, when gas flows through the blade 10, the periodic vortex shedding of the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced.

[0111] Please refer to Figure 10 and Figure 11 In some examples, the second waveform segment 1212 is an asymmetric airfoil function curve, that is, the second waveform segment 1212 satisfies the asymmetric NACA airfoil mathematical relation.

[0112] Therefore, by using the second waveform segment 1212 asymmetric airfoil function curve, when gas flows through the blade 10, the periodic vortex shedding at the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced.

[0113] Figure 11 The second waveform segment 1212 shows the key design parameters for the asymmetric airfoil function curve, and the coordinate axes are defined. The thickness distribution satisfies the following mathematical relationship based on the X and Y coordinates:

[0114] The curve function of the first arc 12121 is:

[0115] x N =xy t sinθ, y N =y m +y t cosθ;

[0116] The curve function of the second arc 12122 is:

[0117] x M =x+y t sinθ, y M =y m -y t cosθ;

[0118]

[0119] Where yt represents the thickness distribution (half thickness) and ym represents the curvature distribution.

[0120] Specifically, the main design parameters of the asymmetric airfoil function curve include the upper airfoil arc (first arc 12121), the lower airfoil arc (second arc 12122), the middle airfoil arc 12123, blade height H, blade chord length L, amplitude A, period wavelength λ, maximum thickness t, maximum camber m, and airfoil chord length l. By constraining these design parameters to meet certain design rules and conforming to specific mathematical models and proportional ranges, the blade tip 12 of the cross-flow fan blade 10, obtained by following these design rules, can reduce the noise OA value and eliminate the BPF rotational noise problem under the same airflow conditions.

[0121] In some examples, the curvature distribution is expressed using the y-coordinate. m express:

[0122]

[0123] Thickness distribution is represented by half-thickness yt:

[0124]

[0125] Where m is the maximum curvature, P is the location of the maximum curvature, and t is the maximum thickness.

[0126] Based on the above functional relationship, the asymmetric airfoil NACA3315 and the asymmetric airfoil NACA2412 can be obtained.

[0127] In some embodiments of this application, the asymmetric airfoil NACA3315 may be selected. Figure 12 The profile features of the asymmetric airfoil NACA3315 are shown in detail. Specifically, the maximum camber m is 3% of the airfoil chord length, the maximum camber position P is at 30% of the airfoil chord length, and the maximum thickness t is 15% of the airfoil chord length.

[0128] In other embodiments of this application, the asymmetric airfoil NACA2412 may be used. Figure 13 The details show the profile characteristics of the asymmetric airfoil NACA2412, specifically meaning that the maximum camber m is 2% of the airfoil chord length, the maximum camber position P is at 40% of the airfoil chord length, and the maximum thickness t is 12% of the airfoil chord length.

[0129] The waveform line 120 can consist of one airfoil array as one cycle, or it can consist of two airfoil arrays combined into one cycle, with the cycle wavelength λ and amplitude A satisfying a specific ratio range. For example, the combination of the asymmetric airfoil NACA3315 and the asymmetric airfoil NACA2412 into one wave cycle will result in richer variations, and the junctions of adjacent airfoils are connected by a circular arc transition.

[0130] In some examples, the wavelength of the second waveform segment 1212 is 0.1H-0.18H, where H is the height of the blade 10. For example, the wavelength of the second waveform segment 1212 can be 0.1H, 0.12H, 0.14H, 0.16H, 0.18H, etc.

[0131] If the wavelength λ of the second waveform segment 1212 is too small, it is difficult to obtain a relatively complete asymmetric airfoil structure, resulting in poor noise reduction effect; if the wavelength λ of the second waveform segment 1212 is too large, it is easy to lose air volume.

[0132] Therefore, in the embodiments of this application, by limiting the wavelength of the second waveform segment 1212 to the above range, the operating noise of the cross-flow fan can be reduced while ensuring that the air volume remains unchanged.

[0133] In some examples, the amplitude of the second waveform segment 1212 is 0.23L-0.27L, where L is the chord length of the blade 10. For example, the amplitude of the second waveform segment 1212 can be 0.23L, 0.25L, 0.27L, etc.

[0134] If the amplitude of the second waveform segment 1212 is too small, the waveform line 120 of the blade tip 12 of the blade 10 will not be obvious, affecting the noise reduction effect; if the amplitude of the second waveform segment 1212 is too large, the blade 10 will have a large gap, resulting in a loss of air volume.

[0135] Therefore, in the embodiments of this application, by limiting the amplitude of the second waveform segment 1212 to the above range, the operating noise of the cross-flow fan can be reduced while ensuring that the air volume remains unchanged.

[0136] It has been verified that designing the blade tip 12 of blade 10 using an asymmetric airfoil function curve, compared with a cross-flow fan with a straight blade tip 12, reduces the noise OA value by 1.5 dB and the BPF peak value by 2-3 dB under the same air volume.

[0137] In summary, in this embodiment of the application, by setting the profile of the blade tip 12 of the blade 10 to include multiple second waveform segments 1212 arranged along the first direction, and setting the second waveform segments 1212 to be asymmetric airfoil function curves, that is, the profile of the blade tip 12 of the blade 10 satisfies the asymmetric NACA airfoil mathematical relationship, and the periodic wavelength satisfies a specific proportional relationship with the blade length, and the amplitude varies with the chord length of the blade 10 according to a certain design ratio range, on the one hand, the flow separation and periodic pressure pulsation of the blade tip 12 of the blade 10 can be suppressed to a certain extent, thereby reducing eddy noise and broadband noise caused by the periodic rotation of the blade 10; on the other hand, the discrete frequency noise caused by the periodic cutting of the airflow by the blade 10 can be eliminated or reduced.

[0138] In some other embodiments, at least two waveform segments 121 include a first waveform segment 1211 and a second waveform segment 1212. The first waveform segment 1211 is a sine function curve or a cosine function curve. The second waveform segment 1212 includes a first arc 12121 and a second arc 12122 arranged and connected in a first direction. The first arc 12121 and the second arc 12122 are non-axially symmetrical about a center line J extending along a second direction. The second direction is perpendicular to the first direction.

[0139] For example, the first waveform segment 1211 is a sine function curve or a cosine function curve, and the second waveform segment 1212 is an asymmetric airfoil function curve.

[0140] In the above technical solution, by setting at least two waveform segments 121 to include a first waveform segment 1211 and a second waveform segment 1212, since the first waveform segment 1211 and the second waveform segment 1212 have different shapes, when the gas flows through the blade 10, the periodic vortex shedding of the blade tip 12 of the blade 10 can be suppressed, reducing flow separation and vortex intensity. Under the same air volume, the noise OA value and BPF peak value can be reduced, that is, the noise can be reduced.

[0141] In some specific embodiments, a plurality of first waveform segments 1211 and a plurality of second waveform segments 1212 are arranged in a first direction. For example, a plurality of first waveform segments 1211 are concentrated together and a plurality of second waveform segments 1212 are concentrated together; or, for another example, a plurality of first waveform segments 1211 and a plurality of second waveform segments 1212 are arranged alternately in a first direction.

[0142] In this embodiment, the shapes of the plurality of first waveform segments 1211 can be exactly the same, that is, the plurality of first waveform segments 1211 are all sine function curves or cosine function curves with the same design parameters; or, at least one set of design parameters of the plurality of first waveform segments 1211 are different, that is, the plurality of first waveform segments 1211 are at least one set of sine function curves or cosine function curves with different design parameters.

[0143] In this embodiment, the shapes of the multiple second waveform segments 1212 can be exactly the same, that is, the design parameters of the multiple second waveform segments 1212 are exactly the same; or, at least one set of design parameters of the multiple second waveform segments 1212 are different.

[0144] In some embodiments, the multiple blades 10 in the blade assembly 100 have identical structures and shapes.

[0145] Therefore, by setting the structure and shape of the multiple blades 10 of the blade assembly 100 to be exactly the same, on the one hand, there is no need to design different blades 10 separately, which can reduce the design difficulty of the blade assembly 100 and facilitate the mass production of blades 10, thereby improving production efficiency and reducing manufacturing costs. On the other hand, when maintenance is required, in order to ensure that the performance of the crossflow fan remains unchanged, only the blades 10 of the same specification need to be replaced, which can significantly reduce maintenance costs and time.

[0146] In some embodiments, the number of blade assemblies 100 is multiple, and the multiple blade assemblies 100 are arranged in the first direction. That is, while keeping the size of the cross-flow fan in the first direction unchanged, setting the number of blade assemblies 100 to multiple can reduce the size of a single blade 10 in the first direction. On the one hand, this can reduce the risk of deformation of the blade 10, and on the other hand, it can reduce airflow separation and reduce vortex noise.

[0147] For example, a separator is provided between two adjacent blade assemblies 100, and multiple blades 10 of the two adjacent blade assemblies 100 are connected to the separator.

[0148] In some embodiments, the number of blades 10 in two adjacent blade assemblies 100 is equal and their positions correspond one-to-one. In two adjacent blade assemblies 100, the two blades 10 corresponding to each other are arranged at a preset angle. That is, in two adjacent blade assemblies 100, the two blades 10 corresponding to each other have a phase difference.

[0149] Along the axial direction of the cross-flow fan, the gas in different regions flows through the blades 10 twice during the flow process, allowing the blades 10 to perform work on the gas twice. Since the two blades 10 corresponding to the positions of two adjacent blade assemblies 100 are set at a preset angle, on the one hand, the phase of the airflow passing through each blade assembly 100 is different, which can disperse the frequency and position of airflow disturbance and make the axial airflow distribution more uniform. On the other hand, it can avoid the generation of strong noise at a single frequency and instead disperse the noise energy to a wider frequency range, thereby reducing the noise intensity perceived by the human ear.

[0150] An air conditioner according to an embodiment of the present invention includes a cross-flow fan according to the above embodiment. Since the cross-flow fan according to the present invention has the above-described technical effects, the air conditioner according to the present invention also has the above-described technical effects, that is, by employing the above-described cross-flow fan, the operating noise of the air conditioner can be reduced.

[0151] In the description of this specification, the reference to the terms "embodiment," "example," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0152] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cross-flow fan, comprising: The first end cap and the second end cap are disposed opposite to each other in a first direction; At least one blade assembly is disposed between the first end cap and the second end cap, and includes a plurality of blades, the plurality of blades being arranged circumferentially at intervals in an imaginary circle; The characteristic feature is that each of the blades has a root near the center of the imaginary circle and a tip away from the center of the imaginary circle, and the outline of the tip is at least partially a wavy line extending in the first direction. The waveform line includes multiple waveform segments arranged in the first direction, at least two of the waveform segments have different shapes, or at least one of the waveform segments has a non-axisymmetric structure.

2. The cross-flow fan according to claim 1, characterized in that, The waveform segment includes a first waveform segment, which is a sine function curve or a cosine function curve. At least two of the first waveform segments have at least one set of different design parameters, which include amplitude, phase, vertical displacement and frequency.

3. The cross-flow fan according to claim 2, characterized in that, At least two of the first waveform segments have different amplitudes.

4. The cross-flow fan according to claim 3, characterized in that, The waveform line includes n first waveform segments that are arranged sequentially and connected in the first direction, and the first waveform segment is a sine function curve; The amplitudes of the n first waveform segments decrease sequentially from the 1st to the nth, and the frequencies of the n first waveform segments are equal.

5. The cross-flow fan according to claim 2, characterized in that, The amplitude of the first waveform segment satisfies a random distribution and takes values ​​in the range of [0.5L, 1L], where L is the chord length of the blade; The frequency of the first waveform segment is greater than or equal to 1 Hz; The vertical displacement of the first waveform segment ranges from [0, A], where A is the amplitude.

6. The cross-flow fan according to claim 1, characterized in that, The waveform segment includes a second waveform segment, which includes a first arc and a second arc arranged and connected in the first direction. The first arc and the second arc are non-axially symmetrical about a centerline extending in the second direction, and the second direction is perpendicular to the first direction.

7. The cross-flow fan according to claim 6, characterized in that, At least two of the second waveform segments have different shapes, and adjacent second waveform segments are connected by an arc transition; and / or, the second waveform segment is an asymmetric airfoil function curve.

8. The cross-flow fan according to claim 6, characterized in that, The wavelength of the second waveform segment is 0.1H-0.18H, where H is the height of the blade; the amplitude of the second waveform segment is 0.23L-0.27L, where L is the chord length of the blade.

9. The cross-flow fan according to any one of claims 1-8, characterized in that, The blades in the blade assembly have identical structures and shapes; And / or, the number of blade assemblies is multiple, the multiple blade assemblies are arranged in the first direction, the number of blades in two adjacent blade assemblies is equal and their positions correspond one-to-one, and in two adjacent blade assemblies, the two blades corresponding to each other are arranged at a preset angle.

10. An air conditioner, characterized in that, Includes the cross-flow fan according to any one of claims 1-9.

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