CN212931132U - Heat exchange tube for air cooler capable of reducing flow resistance - Google Patents
Heat exchange tube for air cooler capable of reducing flow resistance Download PDFInfo
- Publication number
- CN212931132U CN212931132U CN202021213143.8U CN202021213143U CN212931132U CN 212931132 U CN212931132 U CN 212931132U CN 202021213143 U CN202021213143 U CN 202021213143U CN 212931132 U CN212931132 U CN 212931132U
- Authority
- CN
- China
- Prior art keywords
- heat exchange
- air cooler
- flow resistance
- boundary layer
- reducing flow
- 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.)
- Active
Links
Images
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The utility model discloses a heat exchange tube for an air cooler for reducing flow resistance, which comprises a base tube and a fin protruding on the base tube; a groove-shaped channel for heat exchange is formed between the adjacent fins; two side walls in the channel are smooth fin surfaces; including a plurality of dimples on the heat exchange surface between adjacent fins to form a roughened heat exchange surface; the pits are arranged along the extending direction of the channel; the concave pit comprises a multi-edge bottom surface formed by mutually splicing a plurality of unit surfaces. Under the condition of low Reynolds number, the rough surface of the base pipe can promote the fluid boundary layer to transition, and the fluid boundary layer can be developed into a turbulent flow boundary layer from a laminar flow boundary layer as soon as possible, so that the heat exchange coefficient of the evaporative cooler can be improved; under the condition of larger Reynolds number, the fluid small micro-clusters in the turbulent boundary layer fully exchange mass and momentum with the main flow, so that the fluid in the boundary layer obtains enough momentum to overcome the inverse pressure gradient, the separation position of the boundary layer extends downstream along the wall surface, the width of a wake negative pressure area is reduced, the front-back pressure difference is reduced, and the resistance is reduced.
Description
Technical Field
The utility model relates to an air cooler's heat exchange tube structure field, concretely relates to heat exchange tube for air cooler suitable for cooling/condensation heat exchanger, especially a reduce flow resistance.
Background
The air cooling/condenser has the advantages of water saving, environmental friendliness, good economical efficiency and the like. The attention of various industries has been paid for a long time, and particularly at present, along with the improvement of environmental awareness, the water is more and more commonly recycled, so that the technology of cooling the circulating water by air through an air cooler is greatly improved.
The top of the mechanical air cooler is provided with a fan, and under the suction of the fan, surrounding air can enter the air cooler through a shutter at the bottom of the air cooler, pass through the heat exchange tube bundle and then be discharged from the top. Then, the hot fluid in the heat exchange tube transfers heat to air and finally is discharged from the top, and the hot fluid in the tube achieves the cooling/condensing effect.
Because the heat exchange coefficient of the air outside the heat exchange tube is lower, in order to achieve the purpose of heat exchange enhancement, some air coolers adopt fin heat exchange tubes. The finned heat exchange tube can increase the heat exchange area outside the tube and improve the heat exchange effect. But also can increase flow resistance, increased the energy consumption, the fan at air cooler top is axial fan, can satisfy the requirement of big amount of wind, but the pressure head that can provide is limited, therefore has restricted the bank of tubes number of heat exchange tube, and then influences heat transfer area. In addition, the wind resistance is increased, so that the energy consumption of the fan is greatly improved.
To reduce flow resistance, many air coolers employ elliptical heat exchange tubes. The geometric size and manufacturing method of the elliptical heat exchange tube used in the air cooler are disclosed in the chinese patent CN 208620885. According to the theory of hydrodynamics, there are two types of flow resistance: frictional resistance and differential pressure resistance. The elliptical tube with the streamline shape can delay the separation and the separation of the boundary layer under the condition of high Reynolds number, reduce the width of the vortex trail and reduce the pressure difference resistance in front of and behind the elliptical tube. Under the condition of low Reynolds number, although the elliptical tube with the streamline shape is not easy to generate the phenomenon of pressure difference resistance caused by boundary layer separation, the elliptical heat exchange tube sometimes has the phenomenon that the resistance is larger than that of the circular tube because the flow resistance under the low Reynolds number mainly comes from the friction resistance of the solid surface, and the wet circumference area of the elliptical tube with the streamline shape is larger than that of the circular tube, so the resistance of the elliptical tube is larger than that of the circular tube. Furthermore, the method is simple. The boundary layer on the surface of the oval tube is a laminar boundary layer, and the heat exchange efficiency is low.
SUMMERY OF THE UTILITY MODEL
The utility model discloses the purpose is: the heat exchange tube for the air cooler reduces flow resistance, solves the problem of pressure difference resistance on the surface of the fin heat exchange tube, and further solves the problem of low heat exchange efficiency of a smooth surface.
The technical scheme of the utility model is that: a heat exchange tube for an air cooler with integrated fins can reduce flow resistance and improve heat exchange coefficient in a wide Reynolds number range.
When the heat exchange surface between the fins on the fin heat exchange tube adopts a pit-shaped rough surface, the pressure difference resistance of the front surface and the back surface of the fin heat exchange tube is reduced, and the heat exchange effect of the heat exchange surface of the fin heat exchange tube is improved.
Specifically, the heat exchange tube for the air cooler comprises a base tube, and the rotary surface of the base tube is a heat exchange surface. The fins are formed as protrusions on the heat exchanging surface, and there are various arrangements of fins in the art: convex in the tube length direction, convex in the direction of revolution, spirally arranged in the direction of revolution, etc. As long as the reduction pressure differential resistance that reaches and improve the heat transfer effect based on the rough surface between the fin, all should regard as the utility model discloses the protection scope who records.
The height of the protruding fins on the base tube is larger than 1.0mm, and the heat exchange effect in the size is ideal. Generally, the fins include: as the outer surface of the revolution outline of the heat exchange tube, the outer surface comprises a spiral groove to form a spiral revolution outline surface of the heat exchange tube.
A groove-shaped channel for heat exchange is formed between adjacent fins, and two side walls of the channel are smooth fin surfaces.
The heat exchange surface between adjacent fins comprises a plurality of pits to form a rough heat exchange surface, and when air flows pass through the pits, the pits cause pulsation of the flow in the laminar flow, so that transition is promoted. Meanwhile, the pits fully distributed on the surface are easy to transition into a turbulent flow boundary compared with a laminar flow boundary layer with a smooth surface, and the heat exchange efficiency of the turbulent flow boundary layer is far higher than that of the laminar flow boundary layer.
In the scheme, the shape of the pit is not limited, and a circular pit, an elliptical pit, a polygonal pit and the like can be adopted. But the consideration of the preparation of the processing mold is to reduce the mold opening cost and the mold opening difficulty. Through long-term research experiments and theoretical calculation, the pit with the multi-edge bottom surface formed by mutually splicing a plurality of unit surfaces is preferred. I.e. a pit with a regular hexagonal outline. The pit includes: the central unit surface and the boundary unit surfaces around the central unit surface are in a regular hexagon shape, and the peripheral five trapezoidal boundary unit surfaces are spliced together to form the regular hexagon.
Theoretically, the more the edges, the better the effect, but the more the edges, the more the die opening difficulty and the die opening cost are, the higher the die opening cost is. Therefore, the 'regular hexagonal pits' are the best technical means in combination with actual production requirements.
The multi-edge bottom surface of the pit is arranged in the direction of a single curved surface, namely the multi-edge bottom surface of the pit is an approximate arc surface, and the multi-edge bottom surface is gently in slope transition to a heat exchange surface, which also takes the consideration of die processing and stamping processing. Because, if the multi-edge bottom surface is concave and convex, the technical requirements on the die cutter head are higher. Although the concave-convex polygonal bottom surface has technical limitations, the protection scope of the present invention should be considered.
The arrangement of dimples is mainly arranged in the direction of extension of the channel, and in particular comprises at least one row of dimples arranged in the direction of extension of the channel on the heat exchange surface between adjacent fins. If be multiseriate pit to convenient machining is the principle, this scheme does not specifically restrict the requirement of arranging. Therefore, other arrangements should be considered as the scope of protection of the present invention.
Specific arrangement means for the pits: the depth of the pits is 0.01 to 0.25 mm.
If the pits are regular hexagonal outline pits, the side length is ensured to be 0.1-1.5 mm.
In the scheme, a preferred fin is arranged on the rotary heat exchange surface of the base pipe in an axial mode of slitting the base pipe, the number of the fins is less than 30 in the axial length of each inch on the base pipe, and the arrangement number is also the best for product preparation and heat exchange effects.
Based on the structure, the flow resistance in the fluid mechanics theory is two: frictional resistance and differential pressure resistance.
The frictional resistance is characterized in that: when fluid flows around the surface of an object, a thin boundary layer is formed on the surface of the object under the action of viscosity of the fluid, and the velocity gradient in the direction vertical to the wall surface in the boundary layer is large, so that frictional resistance is caused.
The frictional resistance is related to the wetted perimeter area (the contact area of the object with the fluid), and the greater the wetted perimeter area, the greater the frictional resistance experienced by the object.
The pressure difference resistance is characterized in that: when fluid flows through a blunt body (such as a square body, a tube, a ball, etc.), a pressure difference is generated due to the difference of pressures before and after the body, resulting in pressure difference resistance.
Differential pressure resistance requires boundary layer flow theory to understand: that is, when fluid sweeps across a smooth pipe body, the boundary layer on the surface of the pipe body is a laminar boundary layer, on the smooth surface, the laminar boundary layer is not easy to transition into turbulent flow, and the laminar boundary layer is easy to generate a flow separation phenomenon (that is, a streamline is separated from the surface of a ball) to form a vortex region on the back, so that a high-pressure region is formed on the front side of the pipe body, a large low-pressure region is formed on the back side of the pipe body, and great resistance (differential pressure resistance) is generated. When the surface of the sphere is provided with the pits, the pits cause the pulsation of the flow in the laminar flow, and the momentum exchange of fluid micelles occurs, so that transition is promoted. The turbulent flow boundary layer is not easy to generate flow separation phenomenon or the separation position extends downstream, so that the low-pressure area of the vortex area at the back of the ball body is small, and the pressure difference between the front area and the rear area is reduced.
This method of reducing the differential pressure resistance by making a rough surface was first applied to golf ball sports and is therefore also referred to as "golf". Experiments have shown that a standard golf ball with dimples on its surface may have a lower drag 4/5 than a golf ball with a smooth surface.
In addition, objects with pits distributed on the surface are easy to transition into a turbulent flow boundary compared with a laminar flow boundary layer of objects with smooth surfaces, and the heat exchange efficiency of the turbulent flow boundary layer is far higher than that of the laminar flow boundary layer.
To sum up, the utility model has the advantages that: under the condition of low wind speed, namely under the condition of low Reynolds number, the rough surface of the base pipe can promote the transition of a fluid boundary layer, and the fluid boundary layer is developed into a turbulent flow boundary layer from a laminar flow boundary layer as soon as possible, so that the heat exchange coefficient of the evaporative cooler is favorably improved; under the condition of higher wind speed, namely under the condition of larger Reynolds number, the fluid small micelles in the turbulent boundary layer fully exchange mass and momentum with the main flow, so that the fluid in the boundary layer obtains enough momentum to overcome the inverse pressure gradient, the separation position of the boundary layer extends downstream along the wall surface, the width of a wake negative pressure area is reduced, the front-back pressure difference is reduced, and the resistance is reduced.
Drawings
The invention will be further described with reference to the following drawings and examples:
FIG. 1 is a partial schematic view of a heat exchange tube for an air cooler with a double row pit arrangement;
FIG. 2 is a transverse cross-sectional view of a double row of pits;
FIG. 3 is a longitudinal cross-sectional view of a double row of pits;
FIG. 4 is a partial schematic view of a single row of heat exchange tubes for an air cooler with a dimple arrangement;
FIG. 5 is a transverse cross-sectional view of a single row of pits;
FIG. 6 is a longitudinal cross-sectional view of a single row of dimples;
wherein: 1. a base pipe; 2. a fin; 3. and (4) pits.
Detailed Description
The utility model discloses a preferred embodiment 1:
the heat exchange tube for the air cooler comprises a base tube 1, and the rotary surface of the base tube 1 is a heat exchange surface.
Raised fins 2 are formed on the heat exchange surface, a groove-shaped channel for heat exchange is formed between the adjacent fins 2, and two side walls of the channel are smooth fin surfaces.
A plurality of dimples 3 are included on the heat exchange surface between adjacent fins 2 to form a rough heat exchange surface, and when the air flow passes through, the dimples 3 cause pulsation of the flow in the laminar flow, promoting transition to occur.
Meanwhile, the pits 3 fully distributed on the surface are easy to transition into a turbulent flow boundary compared with a laminar flow boundary layer with a smooth surface, and the heat exchange efficiency of the turbulent flow boundary layer is far higher than that of the laminar flow boundary layer.
The utility model discloses a preferred embodiment 2:
an integral finned heat exchange tube comprising: the outer surface heliciform fin, fin both sides face are smooth section, and on the heat transfer surface between adjacent fin, promptly, the ditch groove bottom is provided with one row of regular hexagon pit.
The side length of the regular hexagon pit is 0.1-1.5 mm, and the depth is 0.01-0.25 mm.
The integral helical fins have a height >1.0mm and the number of fins is less than 30 fins/inch.
The fin heat exchange tube is made of copper and copper alloy.
The utility model discloses a preferred embodiment 3:
the copper material pipe is used as a base pipe, the diameter of the copper material pipe is 19.0mm, the height of fins on the base pipe is 0.9mm, 19 fins per inch are arranged, the width of a groove between every two adjacent fins is 0.8mm, two rows of hexagonal pits are arranged on the surface of the bottom of the groove, the side length of each pit is 0.25mm, and the depth of each pit is 0.15 mm.
The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical concepts of the present invention be covered by the claims of the present invention.
Claims (10)
1. A heat exchange tube for an air cooler for reducing flow resistance, comprising:
the base pipe and the fins protruding from the heat exchange surface of the base pipe;
a groove-shaped channel for heat exchange is formed between the adjacent fins;
two side walls in the channel are smooth fin surfaces;
the method is characterized in that: including a plurality of dimples on the heat exchange surface between adjacent fins to form a roughened heat exchange surface; the pits are arranged along the extending direction of the channel; the concave pit comprises a multi-edge bottom surface formed by mutually splicing a plurality of unit surfaces; the multi-edge bottom surface comprises a single curved surface direction.
2. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the concave pit comprises a multi-edge bottom surface which is formed by splicing a plurality of unit surfaces and has a regular hexagon-shaped orifice profile.
3. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the multi-edge bottom surface is in gentle slope transition to the heat exchange surface.
4. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: at least one row of said dimples is included in the heat exchange surface between adjacent fins, arranged in the direction of the extension of the channel.
5. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the depth of the pits is 0.01-0.25 mm.
6. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 2, wherein: the side length of the concave pits with the regular hexagonal outline is 0.1-1.5 mm.
7. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the height of the fins protruding on the base pipe is larger than 1.0 mm.
8. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the fins are arranged on the rotary heat exchange surface of the base pipe in an axial mode of cutting the base pipe.
9. A heat exchange tube for an air cooler for reducing flow resistance according to claim 8, wherein: the fins are less than 30 fins per inch of axial length on the base pipe.
10. A heat exchange pipe for an air cooler for reducing flow resistance according to claim 1, wherein: the fin includes: an outer surface as a heat exchange tube revolution contour; the outer surface comprises spiral grooves to form a spiral revolution outline surface of the heat exchange tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021213143.8U CN212931132U (en) | 2020-06-28 | 2020-06-28 | Heat exchange tube for air cooler capable of reducing flow resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021213143.8U CN212931132U (en) | 2020-06-28 | 2020-06-28 | Heat exchange tube for air cooler capable of reducing flow resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212931132U true CN212931132U (en) | 2021-04-09 |
Family
ID=75326862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021213143.8U Active CN212931132U (en) | 2020-06-28 | 2020-06-28 | Heat exchange tube for air cooler capable of reducing flow resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212931132U (en) |
-
2020
- 2020-06-28 CN CN202021213143.8U patent/CN212931132U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101532798B (en) | Reinforced heat transfer element of truncated cylindrical surface wing type vortex generator | |
| CN100485303C (en) | Heat-transfer pipe in use for strengthening condensation | |
| CN101338987B (en) | Heat transfer pipe for condensation | |
| JPS616595A (en) | Heat transfer pipe and manufacture thereof | |
| CN109737793B (en) | Bionic wave type fin for air conditioner heat exchanger | |
| JPH0670556B2 (en) | Heat transfer tube and manufacturing method thereof | |
| CN212931132U (en) | Heat exchange tube for air cooler capable of reducing flow resistance | |
| CN104870926A (en) | Evaporation heat transfer tube with a hollow cavity | |
| CN114353564A (en) | Slotted spindle-shaped fin printed circuit board heat exchanger core | |
| CN211715180U (en) | Turbine blade and V-shaped sunken rib structure for inner cooling channel of turbine blade | |
| CN101949662B (en) | Novel high-efficiency heat exchange pipe for condenser of electric refrigeration unit | |
| CN206362236U (en) | A kind of inside and outside fin multiple tube | |
| CN201803634U (en) | Novel efficient heat exchange tube used for condenser of electric refrigerating unit | |
| CN112944991A (en) | Heat exchange tube, heat exchanger and air conditioner | |
| CN217236589U (en) | Concave-convex heat exchange tube | |
| CN201803635U (en) | High-efficiency heat exchange tube for electrical chiller set condenser | |
| CN207688679U (en) | A kind of heat-dissipating pipe in automobile radiators | |
| CN203203301U (en) | Fin type heat exchanger | |
| CN202329345U (en) | Novel strengthening pipe for boiling heat exchange in duct | |
| CN209639584U (en) | A kind of helix tube for heat exchanger | |
| CN201141739Y (en) | Single-row finned tube radiator | |
| CN204987997U (en) | High -efficient heat transfer condenser pipe | |
| CN201803631U (en) | Highly-efficient heat exchange tube for electric refrigeration unit condenser | |
| CN211551846U (en) | Shutter-curved surface vortex generator combined type reinforced fin | |
| CN215766673U (en) | Heat exchange tube, heat exchanger and water chilling unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |