Evaporation tube for an evaporative heat exchanger

Abstract

The application relates to an evaporation tube for an evaporation heat exchanger, which comprises a tube body and outer fins formed by material on the tube body extending along the radial direction of the tube body and spirally extending on the outer surface of the tube body and integrated with the tube body, the gap between two adjacent outer fins forming a channel communicating with each other, the top end of the outer fin forming a head part extending to the front and back of the axial direction, at least one side of the waist part of the outer fin being further provided with a side fin extending to the adjacent outer fin, and two composite cavities being formed on the upper and lower sides of the side fin. Since the side fin is arranged on the side of the waist part of the outer fin, the channel space below the side fin forms a cavity, the space between the side fin above and the head part below also forms a cavity, thereby forming two composite cavities, increasing the number of cavity structures, being beneficial to increasing the number of evaporation cores, and thereby improving the heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of evaporative heat exchange tubes in air conditioning and refrigeration systems, and relates to an evaporative tube for an evaporative heat exchanger. Background Technology

[0002] Evaporative heat exchangers are essential components of central air conditioning systems, and evaporator tubes are the core components of these systems, their heat exchange performance determining the overall performance of the evaporative heat exchanger. For the heat exchanger tube manufacturing industry, improving the energy efficiency of refrigeration and air conditioning equipment is primarily achieved by improving the heat exchange efficiency of the heat exchanger tubes. Research on the boiling heat transfer mechanism shows that the boiling of a liquid requires the presence of vaporization nuclei. Under a given superheat of the heating surface, bubbles can only grow and nucleation boiling can occur when the radius of the vaporization nucleus is greater than the minimum radius required for bubble growth. The cavities formed by grooves on the heating surface are most likely to become vaporization nuclei. During boiling, after a bubble grows and leaves the cavities, due to the surface tension of the liquid, the active cavities will trap some vapor, becoming new vaporization nuclei, growing new bubbles, and thus continuing the boiling process. For full liquid evaporation, the proper arrangement of the pore structure plays a crucial role in enhancing heat transfer. The pore structure of the heat exchange tube should be conducive to the generation of bubbles and allow the bubbles to float freely and be discharged from the liquid surface, forming a continuous boiling heat exchange process, thereby improving the heat exchange performance of the heat exchange tube.

[0003] Chinese patent documents “CN217764628U”, “CN209672913U”, “CN211261912U”, “CN207050545U”, and “CN110425773A” all involve evaporator tubes. Their basic approach is to modify the outer fins and the channel structure between adjacent outer fins to form vaporization nuclei and to increase the contact area between the outer fins and the medium to improve heat exchange efficiency. However, there is still room for improvement. Summary of the Invention

[0004] The purpose of this invention is to provide an evaporation tube for an evaporative heat exchanger, which solves the problem of how to improve heat exchange efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an evaporator tube for an evaporative heat exchanger, comprising a tube body and an outer fin integrally formed by a material on the tube body extending along the radial direction of the tube body and spirally extending around the tube body on the outer surface of the tube body. The gap between two adjacent outer fins forms an interconnected channel. The top of the outer fin extends axially back and forth to form a head. At least one side of the waist of the outer fin is provided with a side fin extending to the adjacent outer fin. The side fin forms two composite cavities on the upper and lower sides.

[0006] Preferably, the lower surface of the side fin is inclined outward from the root towards the outer end of the side fin.

[0007] Preferably, the angle between the upper surface of the side fin and the outer surface of the outer fin is 60°-90°.

[0008] Preferably, the thickness of the side fins decreases from the root to the outer end.

[0009] Furthermore, the outer end of the side fin is a pointed tip.

[0010] Preferably, the outer fins are provided with side fins on both sides.

[0011] Furthermore, a gap is left between the outer ends of the side fins on the opposite sides of the adjacent outer fins.

[0012] Preferably, the top of the outer fin is provided with a connecting groove that intersects and communicates with the channel at intervals.

[0013] Preferably, the top surface of the head is provided with at least one wing-top groove.

[0014] Preferably, the outer fin side above the side fin and / or the outer fin side below the side fin and / or the bottom surface of the channel are provided with an indentation groove.

[0015] Preferably, the inner surface of the tube is provided with internal thread ribs.

[0016] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The evaporator tube of the present invention has two composite cavities. These cavities are formed by side fins on the side of the outer fin waist, creating a cavity in the channel space below the side fins and another cavity in the space between the side fins and the head. This increases the number of cavities, which is beneficial for increasing the number of vaporization nuclei. The structure also facilitates better and faster bubble growth and their rise from the liquid surface, resulting in continuous boiling heat exchange and thus improving heat exchange efficiency. Furthermore, the composite cavities contain grooves, further increasing the number of vaporization nuclei on the outer surface of the tube and maximizing the heat exchange area outside the tube, thereby further enhancing the boiling heat exchange effect outside the tube. Attached Figure Description

[0017] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1This is a partial cross-sectional view of the tube wall of the present invention, wherein the outer fins extend spirally around the axis of the evaporator tube; Figure 2 This is a cross-sectional view of the tube wall of the present invention, with the cross-section passing through the axis of the evaporator tube; Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 4 This is a diagram showing the gradual evolution of this invention; The reference numerals in the attached figures are explained as follows: 1. Pipe body; 2. Outer fins; 21. Head; 22. Wing tip groove; 3. Channel; 4. Side fins; 5. Holes and acupoints; 6. Connecting slot; 7. Grooves inside the acupoint; 8. Internal thread rib; 81. Boss. Detailed Implementation

[0018] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 The diagram shown is a partial view of the evaporator tube used in the evaporator heat exchanger, representing a section of the tube wall. Surface F passes through the centerline of the evaporator tube, while surface G is perpendicular to the centerline.

[0022] The evaporator tube in this example includes a tube body 1, external fins 2 on the outer surface of the tube body 1, and internally threaded ribs 8 on the inner surface. Both the external fins 2 and the internally threaded ribs 8 are formed by spinning tubular material. Both the external fins 2 and the internally threaded ribs 8 are formed by extending material from the tube body 1 along the radial direction of the tube body 1, and both the external fins 2 and the internally threaded ribs 8 extend spirally on the outer surface of the tube body 1. Figure 1 The image shown is a partial cut, displaying the parallel extension of the outer fins 2 (actually spiral extensions around the outer surface of the evaporator tube), extending from one end of the tube body 1 to the other. The outer fins 2 are integral with the tube body 1, thus eliminating contact thermal resistance. The gap between two adjacent outer fins 2 (i.e., axially adjacent outer fins 2, actually the same outer fin 2) forms a channel 3, which also spirally extends along the outer surface of the tube body 1 and is therefore interconnected. The tips of the outer fins 2 extend axially in a front-back direction, forming a head 21. The outer surface of the head 21 has two fin-top grooves 22 (the number is unlimited, or fin-top grooves 22 may be omitted), which increase the contact area with the external medium.

[0023] like Figure 1 , Figure 2 and Figure 3 The outer fin 2 is provided with side fins 4 on both sides of its waist. The side fins 4 extend to the adjacent outer fin 2. The side fins 4 on the opposite sides of the adjacent outer fin 2 extend towards each other, and there is a gap between the outer ends of the two side fins 4.

[0024] The space above the side fin 4 and below the head 21 forms a cavity 5, and the space below the side fin 4 forms another cavity 5. These two cavities 5 are connected by the gap between the outer ends of the side fin 4, thus forming a composite cavity 5. The composite cavity 5 increases the number of cavity structures, which is beneficial for increasing the number of vaporization nuclei.

[0025] Although in this example, the side fins 4 are arranged on both sides of the outer fin 2, they can also be arranged on only one side of the outer fin 2.

[0026] like Figure 3 The lower surface of the side fin 4 is inclined outward (away from the tube body 1) from the root to the outer end of the side fin 4, so that the top of the hole below has an outward guiding slope, which is conducive to the overflow of bubbles.

[0027] like Figure 3 The angle α between the upper surface of the side fin 4 and the outer surface of the outer fin 2 is 60°-90°. This facilitates the overflow of air bubbles from the upper cavity.

[0028] The thickness of the side fin 4 decreases from the root to the outer end, and in this example, it gradually decreases. Furthermore, in this example, the outer end of the side fin 4 is a pointed tip. In other embodiments, the tip of the side fin 4 may not be a pointed tip, but rather a curved or flat surface. The pointed tip of the side fin 4 is advantageous for piercing air bubbles.

[0029] The outer fin 2 above the side fin 4, the outer fin 2 below the side fin 4, and the bottom surface of the channel 3 are all provided with recessed grooves 7. These structures further increase the vaporization nuclei on the outer surface of the tube, while maximizing the heat exchange area outside the tube, thus effectively improving the boiling heat exchange effect outside the tube. Although recessed grooves 7 are provided in all three locations mentioned above, in other embodiments, recessed grooves 7 can be provided in only one or any two of them.

[0030] like Figure 1 The top of the outer fin 2 has intermittently formed connecting grooves 6, which extend downwards to the root of the side fin 4. The connecting grooves 6 intersect and connect with the channel 3, which is beneficial for the discharge of the external medium.

[0031] like Figure 1 The inner surface of the tube body 1 is provided with internal thread ribs 8, which helps to reduce the fluid boundary layer inside the tube. The tooth tip of the internal thread ribs 8 is provided with a sharp boss 81. The boss 81 structure can further improve the turbulence of the fluid inside the tube, reduce the thermal resistance of heat transfer inside the tube, and increase the heat transfer area inside the tube, thereby improving the heat transfer efficiency inside the tube.

[0032] like Figure 4 In this example, the evaporator heat exchanger is gradually formed using evaporator tubes through shapes B, C, and D. First, as shown in B, the shape of outer fins 2 is spun out on the outer surface of the tube body 1, and internal thread ribs 8 are spun out on the inner surface. Then, as shown in C, side fins 4 are spun out on both sides of the waist of the outer fins 2. Then, as shown in D, grooves 7 are spun out on the inner side of the outer fins 2 at the bottom of the channel 3 and above and below the side fins 4, and fin top grooves 22 are spun out on the top of the outer fins 2.

[0033] In summary, the evaporator tube in this example uses two composite cavities 5 formed above and below the side fins 4, increasing the number of cavities and thus the number of vaporization nuclei. The crisscrossing channels 3 and connecting grooves 6 on the outer surface of the tube body 1 create an active cavity structure, which facilitates better and faster bubble growth, allowing bubbles to rise and exit from the liquid surface, forming continuous boiling heat exchange and improving heat transfer performance. Furthermore, the fin-top groove 22 on the head 21 and the groove 7 within the cavities 5 further increase the number of vaporization nuclei on the outer surface of the tube, while also increasing the external heat exchange area, effectively enhancing the boiling heat exchange effect outside the tube.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An evaporator tube for an evaporative heat exchanger, comprising a tube body (1) and external fins (2) integrally formed with the tube body (1) by extending material from the tube body (1) along the radial direction of the tube body (1) and spirally extending around the tube body (1) on the outer surface of the tube body (1), wherein the gap between two adjacent external fins (2) forms interconnected channels (3), and the top of the external fins (2) extends axially back and forth to form a head (21), characterized in that: At least one side of the waist of the outer fin (2) is provided with a side fin (4) extending to the adjacent outer fin (2). The thickness of the side fin (4) decreases from the root to the outer end. The outer end of the side fin (4) is a pointed tip. Two composite cavities (5) are formed on the upper and lower sides of the side fin (4). The lower surface of the side fin (4) is inclined outward from the root to the outer end of the side fin (4). The angle between the upper surface of the side fin (4) and the outer side of the outer fin (2) is 60°-90°. The side of the outer fin (2) above the side fin (4) and / or the side of the outer fin (2) below the side fin (4) and / or the bottom surface of the channel (3) are provided with a cavity groove (7). The top of the outer fin (2) is provided with a connecting groove (6) that intersects and communicates with the channel (3) at intervals. The connecting groove (6) extends downward to the root of the side fin (4).

2. The evaporator tube for an evaporative heat exchanger according to claim 1, characterized in that: The outer fin (2) has side fins (4) on both sides.

3. The evaporator tube for an evaporative heat exchanger according to claim 2, characterized in that: A gap is left between the outer ends of the side fins (4) on the opposite sides of the adjacent outer fins (2).

4. The evaporator tube for an evaporative heat exchanger according to claim 1, characterized in that: The top surface of the head (21) is provided with at least one wing-top groove (22).

5. The evaporator tube for an evaporative heat exchanger according to claim 1, characterized in that: The inner surface of the tube (1) is provided with internal thread ribs (8).

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