Evaporating pipe
By designing spiral fins and boss structures on the inner and outer surfaces of the evaporator tube to form a cavity structure, the problem of film boiling caused by the low fin height of traditional microfin tubes is solved, thereby improving the evaporation heat transfer performance and heat transfer efficiency, and achieving energy saving and emission reduction effects.
Patent Information
- Application Number
- CN202422995413.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-12-04
AI Technical Summary
Traditional microfinned tubes have low fin height and small specific surface area, resulting in boiling heat transfer mostly occurring in the film boiling stage, which has high thermal resistance and affects heat transfer efficiency.
An evaporator tube is designed with spiral fins wound around its inner and outer surfaces. Protrusions are distributed on the outer surface, with the cross-section of the protrusions gradually decreasing to form gaps. The gap width is smaller than the width of the medium channel, forming a large number of cavitation structures to promote nucleation boiling.
Improve the performance and efficiency of evaporative heat exchange, maintain nucleation boiling conditions, enhance the heat exchange efficiency of shell-and-tube heat exchangers, reduce material consumption, and achieve heat recovery and energy conservation and emission reduction.
Smart Images
Figure CN223623458U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat exchange equipment technology, and in particular to an evaporation tube. Background Technology
[0002] Shell-and-tube heat exchangers, as a traditional and highly efficient heat exchange device, are widely used in refrigeration, heating, chemical, and power industries. The heat exchange tubes are the core heat exchange elements of a shell-and-tube heat exchanger, and their heat exchange performance directly affects the overall heat exchange efficiency of the exchanger. Improving its heat exchange efficiency can reduce energy waste, thereby achieving energy conservation and emission reduction.
[0003] Boiling heat transfer is divided into nucleation boiling and film boiling stages. To achieve high boiling heat transfer efficiency, the boiling within the evaporator must be nucleation boiling. In the nucleation boiling stage, concave cavities are fully activated to form vaporization nuclei, and numerous bubbles are generated on the wall surface and detach. In the film boiling stage, due to the fusion of numerous bubbles forming a gas film that covers the heat exchange surface, heat exchange between the liquid working fluid and the heat exchange surface must pass through this gas film. Therefore, the thermal resistance between the liquid working fluid and the heat exchange surface increases sharply, and the boiling heat transfer performance decreases accordingly. The evaporator should avoid excessive superheating on the finned tube surface to prevent the surface boiling condition from transitioning to film boiling. Traditional microfinned tubes have low fin height and small specific surface area, and their outer surface can only form a small number of vaporization nuclei. Therefore, boiling heat transfer is mostly in the film boiling stage, resulting in high thermal resistance. 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 an evaporation tube that can form a large number of concave cavities, which is beneficial to maintaining the heat exchange condition as nucleation boiling and has higher evaporation heat exchange performance.
[0005] An evaporator tube according to an embodiment of the present invention includes a tube body and a plurality of protrusions. The inner surface of the tube body is wound with a plurality of inner spiral fins, and the outer surface of the tube body is wound with a plurality of outer spiral fins to form a spiral medium channel. The plurality of protrusions are distributed on the outer surface of the outer spiral fins. The cross-section of the protrusions is leaf-shaped, and the cross-section of the protrusions gradually decreases from the outside to the inside. There is a gap between two adjacent protrusions. The width of each region of the gap is smaller than the width of the medium channel. A cavity structure is formed between the medium channel and the protrusions.
[0006] It has at least the following beneficial effects:
[0007] Because the cross-section of the protrusion gradually decreases from the outside to the inside, and there is a gap between two adjacent protrusions, the width of each region of the gap is smaller than the width of the medium channel. Therefore, a large number of cavitation structures are formed on the evaporator tube, and the cavitation structures have a large heat exchange surface. Under heat exchange conditions, the liquid working fluid boils rapidly and detaches from the heat exchange surface, which helps to maintain the heat exchange condition as nucleation boiling rather than film boiling. The evaporator tube has high evaporation heat exchange performance and efficiency, thereby improving the heat exchange efficiency of the shell-and-tube heat exchanger, increasing energy utilization, reducing the consumption of processing materials, and enabling heat recovery from the evaporator tube, reducing energy waste and achieving the effect of energy saving and emission reduction.
[0008] According to some embodiments of the present invention, the boss has two tips, which are respectively located on the outer sides of two adjacent medium channels.
[0009] According to some embodiments of the present invention, the boss has two tips, and the angle between the line connecting the two tips and the outer helical fin is 43°-47°.
[0010] According to some embodiments of the present invention, the inner bottom of the medium channel is provided with a plurality of grooves.
[0011] According to some embodiments of this utility model, the cross-section of the groove is square, prismatic, or trapezoidal.
[0012] According to some embodiments of the present invention, a plurality of the grooves are equidistantly distributed along the axial direction on the inner bottom of the medium channel, and 400-600 of the grooves are distributed on one circumference of the medium channel.
[0013] According to some embodiments of the present invention, the rotation angle of the outer helical fin is 0.2°-0.4°.
[0014] According to some embodiments of the present invention, a plurality of the bosses are equidistantly distributed along the axial direction on the outer helical fin, and 300-450 of the bosses are distributed on one circumference of the outer helical fin.
[0015] According to some embodiments of the present invention, the height of the boss is less than half the height of the outer helical fin.
[0016] 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
[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:
[0018] Figure 1This is a partial structural schematic diagram of an embodiment of the present utility model;
[0019] Figure 2 This is a partial front view structural schematic diagram of an embodiment of the present utility model;
[0020] Icon labels:
[0021] Tube body 100; inner spiral fins 110; outer spiral fins 120; boss 121; medium channel 130; groove 131. Detailed Implementation
[0022] The embodiments of this utility model are described in detail below. Examples of the 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.
[0023] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and 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 this utility model.
[0024] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.
[0025] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0026] See Figure 1 and Figure 2This utility model discloses an evaporation tube, including a tube body 100 and a plurality of protrusions 121. The inner surface of the tube body 100 is wound with a plurality of inner spiral fins 110, and the outer surface of the tube body 100 is wound with a plurality of outer spiral fins 120 to form a spiral medium channel 130. The plurality of protrusions 121 are distributed on the outer surface of the outer spiral fins 120. The cross-section of the protrusions 121 is leaf-shaped, and the cross-section of the protrusions 121 gradually decreases from the outside to the inside. There is a gap between two adjacent protrusions 121. The width of each region of the gap is smaller than the width of the medium channel 130, and a cavity structure is formed between the medium channel 130 and the protrusions 121.
[0027] The tube body 100 has a cavity that allows water to pass through it, and the tube body 100 can be immersed in the liquid working medium. The large amount of heat carried by the liquid working medium is transferred to the water through structures such as the boss 121, the outer spiral fins 120, the tube body 100, and the inner spiral fins 110. Because the cross-section of the boss 121 gradually decreases from the outside to the inside, there is a gap between two adjacent bosses 121. The width of each region of the gap is smaller than the width of the medium channel 130, so a large number of cavities are formed on the evaporator tube. The cavities have a large heat exchange surface. Under heat exchange conditions, the liquid working medium boils rapidly and detaches from the heat exchange surface, which helps to maintain the heat exchange condition as nucleation boiling rather than film boiling. The evaporator tube has high evaporation heat exchange performance and efficiency, thereby improving the heat exchange efficiency of the shell-and-tube heat exchanger, increasing energy utilization, reducing the consumption of processing materials, and enabling heat recovery from the evaporator tube, reducing energy waste and achieving energy saving and emission reduction.
[0028] It is understandable that the boss 121, the outer spiral fin 120, and the inner spiral fin 110 can be manufactured using the material of the tube body 100 itself, that is, the evaporator tube is a one-piece molded structure, and the boss 121, the outer spiral fin 120, and the inner spiral fin 110 are not easy to fall off, the structure is stable, and the outer spiral fin 120 and the inner spiral fin 110 are not easy to fall off from the tube body 100.
[0029] See Figure 1 and Figure 2 All bosses 121 have the same structural shape and all bosses 121 have the same posture, and all bosses 121 form a regular longitudinal and transverse distribution.
[0030] See Figure 2In some embodiments, the boss 121 has two tips, which are located on the outside of two adjacent medium channels 130. That is, the two tips block the outside of the medium channels 130. When the liquid working medium is about to leave the medium channel 130, the two tips create an obstruction effect on the liquid working medium. Since the gap width between any two adjacent bosses 121 is smaller than the width of the medium channel 130, it is beneficial for the liquid working medium in the medium channel 130 and the cavity structure to boil quickly and leave the heat exchange surface, maintaining the heat exchange condition as nucleation boiling.
[0031] In some embodiments, the boss 121 has two tips, and the line connecting the two tips forms an angle of 43°-47° with the outer spiral fin 120, so that the direction of the gap between any two adjacent bosses 121 forms an angle with the direction of the medium channel 130, which is beneficial to the flow and heat exchange of the liquid working fluid, and also beneficial to the two tips of the boss 121 being located on the outside of the two adjacent medium channels 130 respectively.
[0032] It is understandable that the outer surface of the boss 121 is larger in the middle and smaller at both ends, and the outer surface of the boss 121 has a central axis, which can be a straight line or an arc.
[0033] See Figure 1 and Figure 2 In some embodiments, the inner bottom of the medium channel 130 is provided with a plurality of grooves 131. Under heat exchange conditions, the arrangement of the plurality of grooves 131 can provide a plurality of vaporization nuclei. The vaporization nuclei keep the boiling heat exchange in the nucleus boiling stage, thereby further improving the evaporation heat exchange performance of the evaporation tube.
[0034] In some embodiments, the cross-section of the groove 131 is square, prismatic, or trapezoidal, which increases the heat exchange surface of the evaporator tube. Of course, the cross-section of the groove 131 can also be other shapes.
[0035] See Figure 1 In some embodiments, multiple grooves 131 are equidistantly distributed along the axial direction on the inner bottom of the medium channel 130. 400-600 grooves 131 are distributed on one circumference of the medium channel 130. The greater the number of grooves 131, the more vaporization nuclei can be formed, which is more conducive to maintaining boiling heat transfer in the nucleus boiling stage. Furthermore, the density or spacing of the grooves 131 cannot be too small, and the shape and size of the grooves 131 cannot be too small; otherwise, it will be detrimental to the formation of vaporization nuclei.
[0036] It is understandable that the inner bottom of the medium channel 130 is a flat or curved surface in its cross section.
[0037] In some embodiments, the rotation angle of the outer helical fin 120 is 0.2°-0.4°, which results in a greater number of turns in the medium channel 130 on the axis, which is beneficial for setting more bosses 121.
[0038] See Figure 1 and Figure 2 In some embodiments, multiple bosses 121 are equidistantly distributed along the axial direction on the outer helical fin 120. There are 300-450 bosses 121 distributed on one circumference of the outer helical fin 120. The number of bosses 121 and the number of gaps are moderate, which is more conducive to heat exchange and keeps the boiling heat exchange in the nucleation boiling stage.
[0039] The density or spacing of the bosses 121 should be moderate. The shape and size of the bosses 121 should not be too small, otherwise they will not be able to fully contact the liquid working fluid, which is not conducive to heat exchange. The shape and size of the bosses 121 should also not be too large, otherwise the number of gaps will be too small.
[0040] In some embodiments, the height of the boss 121 is less than half the height of the outer helical fin 120, making the volume of the medium channel 130 region larger than the volume of the gap region, which is beneficial for the formation of vaporization nuclei.
[0041] The processing method for evaporator tubes includes the following steps:
[0042] In the tube body 100, inner spiral fins 110 and outer spiral fins 120 are machined. In the axial direction, a medium channel 130 is formed between two adjacent outer spiral fins 120 or between two adjacent turns on one outer spiral fin 120.
[0043] Multiple grooves 131 are machined on the inner bottom of the medium channel 130;
[0044] Multiple notches are machined on the outer spiral fin 120 along the direction of the outer spiral fin 120. The multiple notches are equidistantly arranged on the outer spiral fin 120 so that multiple protrusions are formed on the outer spiral fin 120.
[0045] The protrusion is shaped into a boss 121.
[0046] The processing tools for the evaporator tube include a cutting blade assembly, gaskets, toothed cutters, groove cutters, extrusion cutters, threaded mandrels, and three rollers. The cutting blade assembly includes eleven cutting blades, arranged sequentially from the first to the eleventh cutting blade, with a gasket between adjacent cutting blades. The gasket thickness is 0.254 mm. The outer diameter of the first to the tenth cutting blade increases by 0.3 mm sequentially, with the outer diameter of the tenth and eleventh cutting blades being 67.2 mm.
[0047] Three parallel rollers are arranged in an equilateral triangle. There is a feed angle between the rollers and the axis of the tube 100. When the rollers rotate and act on the tube 100, the force is divided into axial and circumferential forces, allowing the tube 100 to perform a combined rotational and feed motion. A threaded mandrel is inserted into the cavity of the tube 100 to process the inner helical fins 110. The first to tenth cutting blades of the cutting blade assembly contact the outer surface of the tube 100 one by one and process the outer helical fins 120 on the outer surface of the tube 100. The eleventh cutting blade... The rolling cutter shapes the outer spiral fin 120 and the medium channel 130; the grooving cutter has protruding teeth distributed on its circumferential surface, and the protruding teeth machine grooves 131 in the inner bottom of the medium channel 130; the outer diameter of the grooving cutter is larger than that of the extrusion cutter, and the outer diameter of the grooving cutter is 66.0 mm to 66.3 mm. The grooving cutter acts on the outer spiral fin 120 to form multiple notches that are evenly distributed along the circumference, so that multiple protrusions are formed on the outer spiral fin 120; the extrusion cutter extrudes the protrusions to deform them, and finally forms bosses 121.
[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0049] Of course, this utility model is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.
Claims
1. An evaporation tube, characterized in that, include: The tube body (100) has several inner spiral fins (110) wound around its inner surface and several outer spiral fins (120) wound around its outer surface to form a spiral medium channel (130). Multiple protrusions (121) are distributed on the outer surface of the outer helical fin (120). The cross-section of each protrusion (121) is leaf-shaped and gradually decreases from the outside to the inside. There is a gap between two adjacent protrusions (121). The width of each region of the gap is smaller than the width of the medium channel (130). A cavity structure is formed between the medium channel (130) and the protrusions (121).
2. An evaporation tube according to claim 1, characterized in that: The boss (121) has two tips, which are located on the outside of two adjacent medium channels (130).
3. An evaporation tube according to claim 1 or 2, characterized in that: The boss (121) has two tips, and the line connecting the two tips forms an angle of 43°-47° with the outer helical fin (120).
4. An evaporation tube according to claim 1, characterized in that: The inner bottom of the medium channel (130) is provided with a plurality of grooves (131).
5. An evaporation tube according to claim 4, characterized in that: The cross-section of the groove (131) is square, prismatic, or trapezoidal.
6. An evaporation tube according to claim 4 or 5, characterized in that: Multiple grooves (131) are equidistantly distributed along the axial direction on the inner bottom of the medium channel (130), and 400-600 grooves (131) are distributed on one circumference of the medium channel (130).
7. An evaporation tube according to claim 1, characterized in that: The rotation angle of the outer helical fin (120) is 0.2°-0.4°.
8. An evaporation tube according to claim 1, characterized in that: Multiple bosses (121) are equidistantly distributed along the axial direction on the outer helical fin (120), and 300-450 bosses (121) are distributed on one circumference of the outer helical fin (120).
9. An evaporation tube according to claim 1, characterized in that: The height of the boss (121) is less than half the height of the outer spiral fin (120).