Heat exchange tube, heat exchanger and air conditioner

Abstract

The utility model discloses a heat exchange tube, heat exchanger and air conditioner, heat exchange tube includes: tube body, the inner circumferential wall of tube body is provided with tooth structure along the length direction of tube body spiral extension, the tooth structure is provided with a plurality of tooth structure along the circumferential direction of tube body interval arrangement, the ratio of tooth number of tooth structure to tooth height of tooth structure is 1000-2590.7, the outer diameter of the pipe body ranges from 6.8 mm to 7.5 mm. According to the heat exchange tube, the tooth structures spirally extending in the length direction of the tube body are arranged on the inner circumferential wall of the tube body, the tooth structures are arranged at intervals in the circumferential direction of the tube body, and the ratio of the tooth number of the tooth structures to the tooth height of the tooth structures is 1000-2590.7 for the heat exchange tube with the outer diameter of the tube body ranging from 6.8 mm to 7.5 mm. The pressure drop of the heat exchange tube can be reduced, the flow path can be simplified under the condition that the heat exchange performance is not changed, and the complexity of the manufacturing process is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of air treatment equipment, in particular to a heat exchange tube, a heat exchanger and an air conditioner. Background Art

[0002] In the related art, conventional refrigerants R410A and R32 are high-pressure refrigerants, insensitive to pressure, and the heat transfer coefficient increases with the increase of pressure drop, and the overall heat transfer performance is improved. However, for potential future refrigerants such as R290, compared with conventional refrigerants, the refrigerating capacity per unit volume of R290 is 50% less, the allowable charge is 60% less, and the volume flow rate is more than twice as high. On the premise of using the same heat exchange tube, the flow velocity of R290 in the system is high and the flow resistance loss is increased. To ensure the same heat transfer performance, the flow path will be relatively complex. Summary of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a heat exchange tube, which can reduce the pressure drop of the heat exchange tube, and can simplify the flow path and reduce the complexity of the manufacturing process while ensuring the same heat transfer performance.

[0004] The utility model also provides a heat exchanger, which includes the above-mentioned heat exchange tube.

[0005] The utility model also provides an air conditioner, which includes the above-mentioned heat exchanger.

[0006] The heat exchange tube according to the embodiment of the utility model includes: a tube body, and a tooth structure spirally extending along the length direction of the tube body is arranged on the inner peripheral wall of the tube body. The tooth structure is multiple and arranged at intervals along the circumferential direction of the tube body. The ratio of the number of teeth of the tooth structure to the tooth height of the tooth structure is 1000 - 2590.7, wherein the outer diameter of the tube body is 6.8 mm - 7.5 mm.

[0007] The heat exchange tube according to the embodiment of the utility model, by arranging a tooth structure spirally extending along the length direction of the tube body on the inner peripheral wall of the tube body, and the tooth structure is multiple and arranged at intervals along the circumferential direction of the tube body. For the heat exchange tube with an outer diameter of 6.8 mm - 7.5 mm of the tube body, the ratio of the number of teeth of the tooth structure to the tooth height of the tooth structure is 1000 - 2590.7, which can reduce the pressure drop of the heat exchange tube, and can simplify the flow path and reduce the complexity of the manufacturing process while ensuring the same heat transfer performance.

[0008] According to some embodiments of the utility model, the ratio of the spiral angle of the tooth structure to the number of teeth of the tooth structure is 5.33 - 12.5.

[0009] According to some embodiments of the present utility model, the ratio of the number of teeth of the tooth structure to the tooth apex angle of the tooth structure is 5.3 - 10.

[0010] According to some embodiments of the present utility model, the helix angle of the tooth structure is 8° - 15°.

[0011] According to some embodiments of the present utility model, the tooth apex angle of the tooth structure is 10° - 18°.

[0012] According to some embodiments of the present utility model, the heat exchange tube is used for filling with R290 refrigerant.

[0013] The heat exchanger according to an embodiment of the present utility model includes the above-mentioned heat exchange tube.

[0014] The heat exchanger according to an embodiment of the present utility model, by providing the above-mentioned heat exchange tube, with a tooth structure spirally extending along the length direction of the tube body provided on the inner peripheral wall of the tube body, and the tooth structure being multiple and arranged at intervals in the circumferential direction of the tube body, for a heat exchange tube with an outer diameter of 6.8 mm - 7.5 mm of the tube body, such that the ratio of the number of teeth of the tooth structure to the tooth height of the tooth structure is 1000 - 2590.7, can reduce the pressure drop of the heat exchange tube, and can achieve a simplified flow path and reduce the complexity of the manufacturing process while ensuring the same heat exchange performance.

[0015] In some embodiments of the present utility model, the heat exchanger has a heat exchange flow path, and the heat exchange flow path includes two heat exchange sub-flow paths arranged in parallel.

[0016] In some embodiments of the present utility model, the two heat exchange sub-flow paths are arranged in sequence in the height direction of the heat exchanger.

[0017] The air conditioner according to an embodiment of the present utility model includes the above-mentioned heat exchanger, wherein the heat exchanger is configured as an outdoor heat exchanger.

[0018] The air conditioner according to an embodiment of the present utility model, by providing the above-mentioned heat exchanger, the heat exchanger includes the above-mentioned heat exchange tube, with a tooth structure spirally extending along the length direction of the tube body provided on the inner peripheral wall of the tube body, and the tooth structure being multiple and arranged at intervals in the circumferential direction of the tube body, for a heat exchange tube with an outer diameter of 6.8 mm - 7.5 mm of the tube body, such that the ratio of the number of teeth of the tooth structure to the tooth height of the tooth structure is 1000 - 2590.7, can reduce the pressure drop of the heat exchange tube, and can achieve a simplified flow path and reduce the complexity of the manufacturing process while ensuring the same heat exchange performance.

[0019] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. Description of the Drawings

[0020] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 is a partial cross-sectional view of a heat exchange tube according to an embodiment of the present utility model;

[0022] Figure 2 is along Figure 1 a cross-sectional view taken along line C-C in

[0023] Figure 3 is a schematic diagram of the flow path of a heat exchanger according to an embodiment of the present utility model;

[0024] Figure 4 is a relationship curve between the comprehensive heat exchange performance of a heat exchanger and N / H according to an embodiment of the present utility model.

[0025] Reference numerals:

[0026] 100, heat exchanger;

[0027] 10, heat exchange tube;

[0028] 1, tube body; 2, tooth structure;

[0029] 20, fin;

[0030] 30, heat exchange flow path; 31, heat exchange sub-flow path. Detailed implementation manners

[0031] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where 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 the present utility model and should not be construed as a limitation of the present utility model.

[0032] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the features defined with "first", "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise stated, the meaning of "a plurality" is two or more.

[0033] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0034] The heat exchange tube 10 according to an embodiment of the present utility model will be described below with reference to the drawings.

[0035] As Figure 1 and Figure 2 shown, the heat exchange tube 10 according to an embodiment of the present utility model includes a tube body 1.

[0036] Specifically, the tube body 1 may be a circular tube structure, and the outer diameter of the tube body 1 is 6.8 mm - 7.5 mm. It can be understood that the present application is an improvement on the heat exchange tube 10 with an outer diameter of the tube body 1 being 6.8 mm - 7.5 mm.

[0037] The heat transfer coefficient K and pressure drop P inside the heat exchanger 100 both consist of two parts. One is the heat transfer coefficient K1 and pressure drop P1 corresponding to the inlet flow velocity of the heat exchange tube 10. At the same mass flow rate, the more the flow paths are divided, the lower the flow velocity, the smaller K1, and the smaller P1. Conversely, the fewer the flow paths are divided, the higher the flow velocity, the higher K1, and the higher P1. The other is the heat transfer coefficient K2 and pressure drop P2 corresponding to the tooth profile parameters inside the heat exchange tube 10. The higher K2 inside the heat exchange tube 10, the higher P2, and the lower K2, the smaller P2. It is defined that the heat transfer coefficient K of the heat exchanger 100 = K1 * K2, and P = P1 * P2. Since the pressure drop of R290 is relatively large and the existing flow paths are relatively complex, which increases the welding difficulty and manufacturing consistency, therefore, to ensure the same heat transfer coefficient and pressure drop, it is necessary to comprehensively consider the influence of the flow path and tooth profile parameters on heat transfer and pressure drop. On the basis of simplifying the flow path, to ensure that the performance remains unchanged, the tooth profile parameters inside the heat exchange tube 10 can be reasonably set to reduce the pressure drop.

[0038] In the present application, a tooth structure 2 is provided on the inner peripheral wall of the tube body 1. The tooth structure 2 is a convex structure on the inner peripheral wall of the tube body 1. The tooth structure 2 spirally extends along the length direction of the tube body 1. The tooth structure 2 is a plurality of structures arranged at intervals along the circumferential direction of the tube body 1. The ratio of the number of teeth N of the tooth structure 2 to the tooth height H of the tooth structure 2 is 1000 - 2590.7. Among them, when calculating the ratio of the number of teeth N to the tooth height H, the tooth height is calculated in millimeters.

[0039] The more the number of teeth N, the greater the processing difficulty, the greater the flow resistance inside the tube, the greater the pressure drop, and the better the heat transfer performance. Conversely, the fewer the number of teeth N, the smaller the processing difficulty, the smaller the flow resistance inside the tube, the smaller the pressure drop, and the worse the heat transfer performance. The greater the tooth height H, the greater the processing difficulty, the greater the flow resistance inside the tube, the greater the pressure drop, and the better the heat transfer performance. Conversely, the smaller the tooth height H, the smaller the processing difficulty, the smaller the flow resistance inside the tube, the smaller the pressure drop, and the worse the heat transfer performance.

[0040] As Figure 4 shown, when the tooth tip angle α, the helix angle β, and the wall thickness of the tube body 1 remain unchanged, by changing the tooth height H and the number of teeth N, the comprehensive heat transfer performance is the ratio of the heat transfer coefficient to the cube root of the pressure drop. Taking the range with a deviation within ±3% from the maximum value as the preferred range, it can achieve substantially the same heat transfer performance as the heat exchange tube of the same size in the prior art. At this time, the ratio of the number of teeth N to the tooth height H is 1000 - 2590.7, where the tooth tip angle α is 12° and the helix angle β is 10°.

[0041] Meanwhile, when the ratio of the number of teeth N to the tooth height H is within 1000 - 2590.7, it is also convenient for the processing of the heat exchange tube 10 and reduces costs, including processing costs and material costs, etc.

[0042] For example, the ratio of the number of teeth N to the tooth height H can be 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, etc.

[0043] Optionally, the heat exchange tube 10 is a copper tube, which has high structural strength and good heat exchange performance.

[0044] It should be noted that the number of teeth can be the number of tooth structures 2 in the cross-section perpendicular to the axis of the heat exchange tube 10, the tooth height can be the height by which the tooth structure 2 protrudes from the inner peripheral wall of the tube body 1, the tooth apex angle can be the angle between the two side walls of the tooth structure 2 in the height direction, and the helix angle is the angle between the extending direction of the tooth structure 2 and the axis of the heat exchange tube 10.

[0045] According to the heat exchange tube 10 of the embodiment of the present invention, by providing a tooth structure 2 that spirally extends along the length direction of the inner peripheral wall of the tube body 1, and the tooth structure 2 is a plurality of spaced along the circumferential direction of the tube body 1, for the heat exchange tube 10 with an outer diameter of 6.8 mm - 7.5 mm of the tube body 1, making the ratio of the number of teeth of the tooth structure 2 to the tooth height of the tooth structure 2 be 1000 - 2590.7, the pressure drop of the heat exchange tube 10 can be reduced, and while ensuring the heat exchange performance remains unchanged, the flow path can be simplified and the complexity of the manufacturing process can be reduced.

[0046] In some embodiments of the present invention, the ratio of the helix angle β of the tooth structure 2 to the number of teeth N of the tooth structure 2 is 5.33 - 12.5. Among them, the larger the number of teeth N and the helix angle β, the more difficult it is to process. The ratio of the helix angle β to the number of teeth N being 5.33 - 12.5 is convenient for the processing of the tooth structure 2, ensures the feasibility of forming teeth, reduces the processing cost, and at the same time can ensure the heat exchange performance of the heat exchange tube 10. For example, the ratio of the helix angle β of the tooth structure 2 to the number of teeth N of the tooth structure 2 can be 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 11.5, 12, etc.

[0047] In some embodiments of the present invention, the ratio of the number of teeth N of the tooth structure 2 to the tooth apex angle α of the tooth structure 2 is 5.3 - 10. Among them, the smaller the tooth apex angle, the smaller the tooth width when the tooth height is certain, the smaller the area of the inner peripheral wall of the tube body 1 covered by the tooth structure 2, the larger the heat exchange surface in the heat exchange tube 10, and the better the heat exchange effect, but if the tooth apex angle is too small, the teeth are prone to being inverted. Making the ratio of the number of teeth N of the tooth structure 2 to the tooth apex angle α of the tooth structure 2 be 5.3 - 10 can not only ensure the heat exchange performance, but also avoid the occurrence of inverted teeth, facilitate the processing of the tooth structure 2, and reduce the cost. For example, the ratio of the number of teeth N of the tooth structure 2 to the tooth apex angle α of the tooth structure 2 can be 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, etc.

[0048] In some embodiments of the present utility model, the helix angle β of the tooth structure 2 is 8° - 15°. For example, the helix angle β of the tooth structure 2 can be 9°, 10°, 11°, 12°, 13° or 14°, etc. In the related art, for heat exchange tubes with the same pipe diameter, in order to adapt to conventional refrigerants, the helix angle is 35°. Compared with the existing heat exchange tubes, the present application can not only reduce the flow resistance inside the heat exchange tube 10, thereby reducing the pressure drop, which is beneficial to simplifying the flow path on the premise of the same heat exchange performance and reducing the complexity of the manufacturing process, but also facilitate the processing of the heat exchange tube 10, reducing the processing cost and material cost, etc.

[0049] In some embodiments of the present utility model, the tooth apex angle α of the tooth structure 2 is 10° - 18°. For example, the tooth apex angle α of the tooth structure 2 can be 11°, 12°, 13°, 14°, 15°, 16° or 17°. The smaller the tooth apex angle, the better the heat exchange, but if the tooth apex angle is too small, the teeth are prone to being inverted. In the present application, making the tooth apex angle α of the tooth structure 2 be 10° - 18° can not only ensure the heat exchange performance, facilitate the processing of the tooth structure 2, but also avoid the teeth of the tooth structure 2 from being inverted.

[0050] In some embodiments of the present utility model, the heat exchange tube 10 is used for charging R290 refrigerant. It can be understood that the heat exchange tube 10 of the present application can be used for R290 refrigerant, which can not only reduce the flow resistance loss of R290 refrigerant, but also simplify the flow path and reduce the complexity of the manufacturing process under the condition of the same heat exchange performance.

[0051] The heat exchanger 100 according to an embodiment of the present utility model will be described below.

[0052] The heat exchanger 100 according to an embodiment of the present utility model includes the above-mentioned heat exchange tube 10. The heat exchanger 100 further includes a plurality of fins 20, and the heat exchange tube 10 is passed through the fins 20. Among them, the heat exchanger 100 can be an outdoor heat exchanger or an indoor heat exchanger; in a preferred embodiment, the heat exchanger 100 is an outdoor heat exchanger.

[0053] The heat exchanger 100 according to an embodiment of the present utility model, by providing the above-mentioned heat exchange tube 10, with a tooth structure 2 spirally extending along the length direction of the tube body 1 provided on the inner peripheral wall of the tube body 1, and the tooth structure 2 being a plurality of strips spaced along the circumferential direction of the tube body 1, for the heat exchange tube 10 with an outer diameter of the tube body 1 being 6.8 mm - 7.5 mm, making the ratio of the number of teeth of the tooth structure 2 to the tooth height of the tooth structure 2 be 1000 - 2590.7, can reduce the pressure drop of the heat exchange tube 10, and can achieve simplifying the flow path and reducing the complexity of the manufacturing process while ensuring the heat exchange performance remains unchanged.

[0054] In some embodiments of the present utility model, such as Figure 3As shown, the heat exchanger 100 has a heat exchange flow path 30, and the heat exchange flow path 30 includes two heat exchange sub-flow paths 31 arranged in parallel. The refrigerant flowing into the heat exchanger 100 is divided into two paths and flows into the two heat exchange sub-flow paths 31 respectively, and then flows out of the heat exchanger 100 from the two heat exchange sub-flow paths 31. Each heat exchange sub-flow path 31 flows through a part of the heat exchange tubes 10. Specifically, the heat exchange tubes 10 include a plurality of U-shaped tubes arranged at intervals, and the two heat exchange sub-flow paths 31 respectively flow through a part of the U-shaped tubes, and the two heat exchange sub-flow paths 31 can flow through all the U-shaped tubes. Thereby, the number of the heat exchange sub-flow paths 31 can be reduced, the flow path can be simplified, and the complexity of the manufacturing process can be reduced.

[0055] In the related art, on the basis of the existing heat exchange tubes, due to the large pressure drop of the heat exchange tubes, the flow path is relatively complex. For example, the existing heat exchange flow path includes three heat exchange sub-flow paths arranged in parallel, which is more complex than the structure of the present application. For R290, the pipe diameter D satisfies 6.8 mm ≤ D ≤ 7.5 mm; Condensation: dry bulb temperature of the working condition is 35 °C, wet bulb temperature is 24 °C, inlet temperature is 75 °C, pressure is 3100 KPa, outlet subcooling degree is 10 °C, air volume is 2500; Evaporation: dry bulb temperature of the working condition is 7 °C, wet bulb temperature is 6 °C, temperature before the valve is 30 °C, saturation temperature is 48 °C, inlet temperature is 0.5 °C. The comparison between the present application and the existing technology is shown in Table 1 below.

[0056] Table 1

[0057] Existing solution Solution of this application Pipe diameter (mm) 7 7 Tooth height (mm) 0.14 0.05 Helix angle (°) 35 10 Tooth tip angle (°) 15 12 Number of teeth (°) 58 92 Flow path 3 in 3 out 2 in 2 out Condensing capacity (W) 4700 4683 Condensing heat transfer coefficient ((W / m2·K)) 3607 3556 Condensing pressure drop (KPa) 4.5 5.8 Evaporation capacity (W) 3968 4023 Evaporation heat transfer coefficient ((W / m2·K)) 7655 7734 Evaporation pressure drop (KPa) 14.3 15.5

[0058] As can be seen from Table 1 above, for R290, the pipe diameter D satisfies 6.8 mm ≤ D ≤ 7.5 mm. Under the condition that the heat exchange performance is generally the same, the structure of the heat exchange tubes 10 of the present application is simpler, the processing is more convenient, the pressure drop inside the tubes is lower, the flow path is simpler, and the manufacturing process will be simpler.

[0059] In some embodiments of the present utility model, as Figure 3 shown, the two heat exchange sub-flow paths 31 are arranged in sequence in the height direction of the heat exchanger 100. Thereby, the arrangement of the flow path can be simplified, which is convenient for the connection between multiple U-shaped tubes. For example, in Figure 3 the example shown, the heat exchange tubes 10 include a plurality of U-shaped tubes, and the plurality of U-shaped tubes are arranged in a row in the thickness direction of the heat exchanger 100, and the plurality of U-shaped tubes are arranged at intervals in the height direction of the heat exchanger 100. One heat exchange sub-flow path 31 flows through the plurality of U-shaped tubes on one side in the height direction of the heat exchanger 100, and the other heat exchange sub-flow path 31 flows through the plurality of U-shaped tubes on the other side in the height direction of the heat exchanger 100.

[0060] Furthermore, as Figure 3As shown, the arrows indicate the refrigerant flow direction when the heat exchanger 100 functions as a condenser. The refrigerant flow directions in the two heat exchange sub-flow paths 31 are the same, both flowing from one end to the other end in the height direction of the heat exchanger 100.

[0061] The air conditioner according to an embodiment of the present invention will be described below.

[0062] The air conditioner according to an embodiment of the present invention includes the above-mentioned heat exchanger 100, wherein the heat exchanger 100 is configured as an outdoor heat exchanger.

[0063] In the air conditioner according to an embodiment of the present invention, by providing the above-mentioned heat exchanger 100, the heat exchanger 100 includes the above-mentioned heat exchange tube 10. A tooth structure 2 that spirally extends along the length direction of the tube body 1 is provided on the inner peripheral wall of the tube body 1, and the tooth structure 2 is a plurality of teeth spaced apart in the circumferential direction of the tube body 1. For the heat exchange tube 10 with an outer diameter of 6.8 mm - 7.5 mm of the tube body 1, the ratio of the number of teeth of the tooth structure 2 to the tooth height of the tooth structure 2 is 1000 - 2590.7, which can reduce the pressure drop of the heat exchange tube 10. Without changing the heat exchange performance, it is possible to simplify the flow path and reduce the complexity of the manufacturing process.

[0064] Other configurations and operations of the air conditioner according to an embodiment of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0065] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0066] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A heat exchange tube, characterized in that: include: A pipe body, wherein the inner circumferential wall of the pipe body is provided with a tooth structure extending spirally along the length direction of the pipe body, the tooth structure is a plurality of teeth arranged at intervals along the circumferential direction of the pipe body, and the ratio of the number of teeth of the tooth structure to the tooth height of the tooth structure is 1000-2590.7, Wherein, the outer diameter of the tube body is 6.8mm-7.5mm.

2. The heat exchange tube according to claim 1, characterized in that: The ratio of the helix angle of the tooth structure to the number of teeth of the tooth structure is 5.33-12.

5.

3. The heat exchange tube according to claim 1, characterized in that: The ratio of the number of teeth of the tooth structure to the tooth top angle of the tooth structure is 5.3-10.

4. The heat exchange tube according to claim 1, characterized in that: The helix angle of the tooth structure is 8°-15°.

5. The heat exchange tube according to claim 1, characterized in that: The tooth top angle of the tooth structure is 10°-18°.

6. The heat exchange tube according to claim 1, characterized in that: The heat exchange tube is used for filling R290 refrigerant.

7. A heat exchanger, characterized in that: The heat exchange tube comprises the heat exchange tube according to any one of claims 1 to 6.

8. The heat exchanger according to claim 7, characterized in that The heat exchanger has a heat exchange flow path, and the heat exchange flow path includes two heat exchange sub-flow paths arranged in parallel.

9. The heat exchanger according to claim 8, characterized in that The two heat exchange sub-flow paths are arranged sequentially in the height direction of the heat exchanger.

10. An air conditioner, characterized in that: The method comprises a heat exchanger according to any one of claims 7 to 9, wherein the heat exchanger is configured as an outdoor heat exchanger.

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