CN111678374A - Heat exchange tube and air conditioner - Google Patents

Heat exchange tube and air conditioner Download PDF

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Publication number
CN111678374A
CN111678374A CN202010581089.0A CN202010581089A CN111678374A CN 111678374 A CN111678374 A CN 111678374A CN 202010581089 A CN202010581089 A CN 202010581089A CN 111678374 A CN111678374 A CN 111678374A
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CN
China
Prior art keywords
fin
heat exchange
exchange tube
notch
fins
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010581089.0A
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Chinese (zh)
Inventor
武永强
胡东兵
胡海利
王小勇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gree Electric Appliances Inc of Zhuhai filed Critical Gree Electric Appliances Inc of Zhuhai
Priority to CN202010581089.0A priority Critical patent/CN111678374A/en
Publication of CN111678374A publication Critical patent/CN111678374A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/126—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element consisting of zig-zag shaped fins
    • F28F1/128—Fins with openings, e.g. louvered fins
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F25B39/04—Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2215/00—Fins
    • F28F2215/08—Fins with openings, e.g. louvers

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Geometry (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

The application provides a heat exchange tube and an air conditioner. The heat exchange tube comprises a tube body and fins arranged on the tube body. The fin is provided with a first notch and a second notch at the top, the depth of the first notch is greater than that of the second notch, the extending direction of the first notch is arranged at a positive angle relative to the circumferential direction of the fin, and the extending direction of the second notch is arranged at a negative angle relative to the circumferential direction of the fin. By applying the technical scheme of the invention, the phenomenon of liquid bridging between the fins can be weakened, more liquid can flow along with the dripping condensate between the adjacent fins, so that the condensate retention area is further reduced, the retention angle is further reduced, the heat transfer area between steam and the pipe body is increased, and the condensation heat transfer efficiency is enhanced.

Description

Heat exchange tube and air conditioner
Technical Field
The invention relates to the technical field of air conditioners, in particular to a heat exchange tube and an air conditioner.
Background
The condensation of steam outside a horizontal pipe is an important heat transfer mode, and has wide application in the industrial fields of refrigeration air conditioners, chemical industry, food processing, power plants and the like: in the heat transfer process, low-temperature fluid flows in the tube, and the heat of steam outside the tube is taken away through the tube wall to promote the steam outside the tube to condense. With the development of heat transfer equipment over the years, emphasis has been placed on developing more efficient condensing heat transfer surfaces, both in academia and in industrial applications. In the two modes of condensation, the heat exchange efficiency of bead condensation is much higher than that of film condensation, but the popularization and application of the bead condensation in the industry are hindered due to the processing cost and the maintainability of stable performance; film-like condensation has found widespread use in industry and has become the primary means of heat transfer for condensation in industrial applications because of the use of enhanced heat transfer surfaces, such as added fins.
As shown in fig. 1, a trapezoidal outer fin, generally called a 2D fin 1, which is simply extruded outside a tube and developed in the thirties of the twentieth century has been widely used in the field of heat transfer, and it can increase a heat transfer area and thus can improve heat transfer efficiency.
However, the main heat transfer resistance of film-shaped condensation is the obstruction of the contact of the condensate liquid film with steam and a pipe wall, so that in order to further improve the condensation heat transfer coefficient, the thinning of the condensate liquid film is further strengthened and the condensate is promoted to be rapidly discharged. Over decades of development, as shown in fig. 2, complex condensation surfaces have also been developed and widely used, commonly referred to as 3D fins 2. The 3D fin 2 not only can increase the heat transfer area, but also can promote the flow of condensate by reducing the liquid film under the action of the surface tension of the liquid refrigerant.
However, in the lower half part of the tube body, due to the fact that the surface tension direction of the liquid film is opposite to the gravity direction of the liquid film, a condensate retention area is formed in the lower half part of the tube body, the condensate retention area is filled in the condensate retention area, such as a phi area shown in fig. 1 and 2 and is called as a retention area, and the contact area of steam and the outer wall of the tube is reduced due to the existence of the retention area, so that the condensation heat transfer efficiency cannot be further improved.
Disclosure of Invention
The embodiment of the invention provides a heat exchange tube and an air conditioner, and aims to solve the technical problem that condensation heat transfer efficiency is limited due to a stagnation area of the heat exchange tube in the prior art.
The embodiment of the application provides a heat exchange tube, including body and the fin of setting on the body, the top of fin is formed with first incision and second incision, and the degree of depth of first incision is greater than the degree of depth of second incision, and the extending direction of first incision is positive angle setting for the circumferential direction of fin, and the extending direction of second incision is negative angle setting for the circumferential direction of fin.
In one embodiment, the first cut has a depth H1，0.1mm≤H1≤0.95mm。
In one embodiment, the second cut has a depth H2，0.005mm≤H2≤0.65mm。
In one embodiment, the direction of extension of the first cut is relative to the circumferential direction α of the fin1，5°≤α1≤90°。
In one embodiment, the direction of extension of the second cut is relative to the circumferential direction α of the fin2，-85°≤α2＜0°。
In one embodiment, the first slits and the second slits are alternately arranged in sequence on the fin.
In one embodiment, the fin is plural, and the plural fins are spirally distributed on the tube body.
In one embodiment, each fin is provided with 10-120 first notches and 10-120 second notches.
In one embodiment, the first cut has a width L1The width of the second cut is L2，0.05mm≤L1≤1mm，0.005mm≤L2≤0.5mm。
In one embodiment, the first cut has an opening angle θ1The opening angle of the second notch is theta2，10°≤θ1≤120°，0°＜θ2≤90°。
In one embodiment, the roots of the fins are perpendicular to the surface of the tube body.
The application also provides an air conditioner, which comprises the heat exchange tube, wherein the heat exchange tube is the heat exchange tube.
In the above embodiment, the first and second notches act to sharpen the tips of the fins to pierce the film of condensate and maximize the pressure of the liquid phase at the tips to increase the pressure differential between the tips and roots of the condensate fins to encourage the condensate to be drawn rapidly towards the fin roots. In addition, the first incision and the second incision with different depths can lead the liquid film to be bent through the bottom of the incision, so that the thickness of the liquid film is different, the Gregorig effect is enhanced, namely, the average thermal resistance can be reduced by the uneven distribution of the condensed liquid film. Then again, the extending direction of first incision is positive angle setting for the circumferential direction of fin, the extending direction of second incision is negative angle setting for the circumferential direction of fin, can also make full use of surface tension effect, make the flow of condensate further strengthen between adjacent fin, can weaken liquid "bridging" phenomenon between the fin, make more liquid can flow along with the drippage condensate between adjacent fin, thereby further reduce condensate detention district, further reduce the detention angle, increase the heat transfer area of steam and body, thereby reinforcing condensation heat transfer efficiency.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.
In the drawings:
fig. 1 is a front view and a cross-sectional view of a 2D finned heat exchange tube according to the prior art;
fig. 2 is a front view and a cross-sectional view of a 3D finned heat exchange tube according to the prior art;
FIG. 3 is a partial schematic structural view of an embodiment of a heat exchange tube according to the present invention;
FIG. 4 is a schematic left side view of the heat exchange tube of FIG. 3;
FIG. 5 is a schematic structural view of section A-A of the heat exchange tube of FIG. 3;
FIG. 6 is a schematic structural view of a section B-B of the heat exchange tube of FIG. 3;
FIG. 7 is a schematic structural view of a section C-C of the heat exchange tube of FIG. 3;
fig. 8 is a schematic top view of the heat exchange tube of fig. 3.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
The existing condensation heat transfer mode mainly takes film-shaped condensation as a main mode, and a liquid film formed after steam is condensed covers the outer surface of a heat transfer pipe and becomes main thermal resistance for hindering heat transfer. Therefore, in order to improve the condensation heat transfer efficiency, not only the heat transfer area needs to be increased, but also the condensate film needs to be promoted to be rapidly discharged, meanwhile, the condensate bridging among fins needs to be prevented, a detention area is formed at the lower part of the tube, namely, a larger detention angle exists, the contact between steam and the tube wall is hindered, and the condensation heat transfer coefficient cannot be further improved. With the requirements of policies such as national 'energy conservation and emission reduction' and 'green building', the improvement of the energy efficiency of the air conditioning unit also becomes a subject which must be faced by the industry, and the strength of the heat exchange capacity of the heat exchange pipe directly determines the energy efficiency of the heat exchange pipe and the whole air conditioning unit. Therefore, in the technical scheme of the invention, the structure of the fin is improved so as to further improve the condensation heat transfer efficiency.
As shown in fig. 3, 4 and 5, in the technical solution of the present invention, the heat exchange tube includes a tube body 10 and fins 20 provided on the tube body 10. A first notch 21 and a second notch 22 are formed in the top of the fin 20, the depth of the first notch 21 is greater than the depth of the second notch 22, the extending direction of the first notch 21 is set at a positive angle with respect to the circumferential direction of the fin 20, and the extending direction of the second notch 22 is set at a negative angle with respect to the circumferential direction of the fin 20.
By applying the technical scheme of the invention, the tops of the fins 20 can be sharpened under the action of the first cuts 21 and the second cuts 22, so that a condensate film can be pierced, the pressure of a liquid phase at the tops reaches the maximum value, the pressure difference between the tops and the roots of the condensate fins 20 can be increased, and the condensate can be promoted to be rapidly pulled to the roots of the fins 20. In addition, the first incision 21 and the second incision 22 with different depths can make the liquid film turn through the bottom of the incision, so that the thickness of the liquid film is different, the Gregorig effect is enhanced, namely, the average thermal resistance can be reduced by the uneven distribution of the condensed liquid film. Then, the extending direction of the first notch 21 is arranged at a positive angle relative to the circumferential direction of the fin 20, the extending direction of the second notch 22 is arranged at a negative angle relative to the circumferential direction of the fin 20, the surface tension effect can be fully utilized, the flow of condensate between the adjacent fins 20 is further strengthened, the liquid bridging phenomenon between the fins 20 can be weakened, more liquid can flow along with the dripping condensate between the adjacent fins 20, the condensate retention area is further reduced, the retention angle is further reduced, the heat transfer area between steam and the pipe body 10 is increased, and the condensation heat transfer efficiency is enhanced.
As shown in fig. 4, in the solution of the present embodiment, the roots of the fins 20 are perpendicular to the surface of the tube 10. By the formula
Pl＝Pv+2σ/rc
It can be seen that the pressure P of the liquid phase along the height of the finslPressure P in the vapour phasevAnd surface tension sigma and local radius of curvature r of the fincIt is related. According to the invention, the root of the fin is processed into a right angle, the curvature radius of the root is minimum at the moment, so that the liquid phase pressure at the root of the fin reaches the maximum value, the pressure difference between the top and the root of the fin of the condensate can be reduced, the force of the condensate pulling to the root of the fin can be weakened, the downward discharge capacity of the condensate at the lower part of the tube is enhanced, the retention angle is reduced, the condensation is continuously carried out, and the condensation heat exchange efficiency is enhanced. Meanwhile, the fin root is a right angle, the fin distance of the fin root part can be increased to the maximum extent, and the condensate flows more smoothly, so that the condensate dripping is accelerated, and the condensation heat exchange efficiency is improved.
As shown in fig. 5, in the technical solution of the present embodiment, the first notches 21 and the second notches 22 are sequentially and alternately arranged on the fin 20, so that the effect of enhancing the condensation heat transfer efficiency can be more uniformly achieved.
In the technical solution of the present embodiment, as shown in fig. 4, there are a plurality of fins 20, and the plurality of fins 20 are spirally distributed on the tube body 10. The number of the fins 20 is 5-60 per inch in the axial direction, and the helix angle is 0.2-2.5 °. Preferably, in the technical solution of the present embodiment, 10 to 120 first notches 21 and 10 to 120 second notches 22 are distributed on each fin 20.
As shown in fig. 6 and 7, optionally, in the technical solution of the present embodiment, the depth of the first cut 21 is H1，0.1mm≤H1Less than or equal to 0.95 mm. Optionally, the second cut 22 has a depth H2，0.005mm≤H2≤0.65mm。
Optionally, in the technical solution of the present embodiment, the extending direction of the first notch 21 is opposite to the circumferential direction α of the fin 201，5°≤α190 DEG or less, the second cut 22 extending in a direction α relative to the circumferential direction of the fin 202，-85°≤α2＜0°。
As shown in fig. 6 and 7, optionally, in the technical solution of the present embodiment, the width of the first notch 21 is L1The width of the second incision 22 is L2，0.05mm≤L1≤1mm，0.005mm≤L2Less than or equal to 0.5 mm. Through experiments, the opening angle of the first cut 21 is determined to be theta1The opening angle of the second slit 22 is θ2，10°≤θ1≤120°，0°＜θ2≤90°。
More preferably, in the technical solution of this embodiment, the inner cavity surface of the pipe body 10 is further provided with internal teeth in a thread shape, so as to increase the heat transfer area of the heat transfer pipe, and to enhance the turbulence of the fluid in the heat transfer pipe, so as to increase the heat exchange efficiency in the pipe. Optionally, the internal teeth of the pipe body 10 are in a thread shape, the cross section of the thread-shaped internal teeth is in a triangle shape, and the tooth crest angle range of the internal teeth is 10-120 degrees. Preferably, the included angle range of the thread inner teeth and the axis of the pipe body is 0-75 degrees, the number of the inner teeth is 6-90, and the height of the inner teeth is 0.1-0.6 mm.
In one embodiment, the nominal outer diameter of the tube 10 is 19.05mm, 44 fins 20 are provided per inch, the height of the fins 20 is 0.95mm, and the roots of the fins 20 are at right angles; the number of the first notches 21 in the circumferential direction is 60, the extending direction of the first notches 21 forms an angle of 45 DEG with respect to the circumferential direction of the fin 20, and the depth H10.35 mm; first, theThe number of the second notches 22 in the circumferential direction is 60, the extending direction of the second notches 22 forms an angle of-35 DEG with respect to the circumferential direction of the fin 20, the direction is opposite to that of the first notches 21, and the depth H2Is 0.2 mm; the height of the inner teeth in the tube is 0.4mm, the number of the inner teeth is 45, and the helix angle of the inner teeth is 45 degrees. Tests show that the heat exchange performance of the outer side of the tube type is improved by about 18 percent compared with the common 3D type finned tube with the same parameters when the refrigerant flows.
The size is limited, and for different refrigerants, the sizes of fin spacing, notch density, depth and the like can be properly adjusted according to different use working conditions so as to meet the requirement of heat exchange efficiency.
The heat transfer pipe of the invention is processed by a special machine tool, and the fin-shaped inside and outside the pipe is integrally formed, the specific processing process outside the pipe is as follows: the fin 20 is first machined on the tube 10, then the root of the fin 20 is pressed into a right angle by a fin root cutter, and then the fin 20 is cut into a first cut 21 by a knurling cutter to form a plurality of independent fins 20, and then the fin 20 is subjected to a second cut 22 by another special cutter to form a second cut 22. The rolling and spinning technology is adopted for processing without increasing the manufacturing material of the heat transfer pipe, thereby not only saving the production cost, but also increasing the strength and the heat transfer area of the heat transfer pipe.
The invention also provides an air conditioner which comprises the heat exchange tube, and the working efficiency of the air conditioner can be improved by adopting the heat exchange tube.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (12)

1. A heat exchange tube comprising a tube body (10) and a fin (20) provided on the tube body (10), characterized in that the fin (20) is formed at the top thereof with a first slit (21) and a second slit (22), the depth of the first slit (21) being greater than the depth of the second slit (22), the extending direction of the first slit (21) being set at a positive angle with respect to the circumferential direction of the fin (20), and the extending direction of the second slit (22) being set at a negative angle with respect to the circumferential direction of the fin (20).
2. A heat exchange tube according to claim 1, characterised in that the first cut (21) has a depth H1，0.1mm≤H1≤0.95mm。
3. A heat exchange tube according to claim 1, characterised in that the depth of the second cut (22) is H2，0.005mm≤H2≤0.65mm。
4. A heat exchange tube according to claim 1, characterized in that the direction of extension of the first cut (21) is relative to the circumferential direction α of the fin (20)1，5°≤α1≤90°。
5. A heat exchange tube according to claim 1, characterized in that the direction of extension of the second cut (22) is relative to the circumferential direction α of the fin (20)2，-85°≤α2＜0°。
6. The heat exchange tube according to claim 1, characterized in that the first notches (21) and the second notches (22) are arranged alternately in sequence on the fin (20).
7. A heat exchange tube according to claim 1, wherein the fin (20) is plural, and the plural fins (20) are spirally distributed on the tube body (10).
8. The heat exchange tube according to claim 7, wherein 10 to 120 first notches (21) and 10 to 120 second notches (22) are distributed on each fin (20).
9. A heat exchange tube according to claim 1, characterised in that the first cut (21)) Has a width of L1The width of the second cut (22) is L2，0.05mm≤L1≤1mm，0.005mm≤L2≤0.5mm。
10. A heat exchange tube according to claim 1, characterized in that the opening angle of the first slit (21) is θ1The opening angle of the second notch (22) is theta2，10°≤θ1≤120°，0°＜θ2≤90°。
11. A heat exchange tube according to claim 1, wherein the roots of the fins (20) are perpendicular to the surface of the tube body (10).
12. An air conditioner comprising a heat exchange tube, wherein the heat exchange tube is the heat exchange tube of any one of claims 1 to 11.
CN202010581089.0A 2020-06-23 2020-06-23 Heat exchange tube and air conditioner Pending CN111678374A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010581089.0A CN111678374A (en) 2020-06-23 2020-06-23 Heat exchange tube and air conditioner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010581089.0A CN111678374A (en) 2020-06-23 2020-06-23 Heat exchange tube and air conditioner

Publications (1)

Publication Number Publication Date
CN111678374A true CN111678374A (en) 2020-09-18

Family

ID=72437091

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010581089.0A Pending CN111678374A (en) 2020-06-23 2020-06-23 Heat exchange tube and air conditioner

Country Status (1)

Country Link
CN (1) CN111678374A (en)

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