EP3995773A1 - Heat transfer tube - Google Patents
Heat transfer tube Download PDFInfo
- Publication number
- EP3995773A1 EP3995773A1 EP21207242.5A EP21207242A EP3995773A1 EP 3995773 A1 EP3995773 A1 EP 3995773A1 EP 21207242 A EP21207242 A EP 21207242A EP 3995773 A1 EP3995773 A1 EP 3995773A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- tube
- finned tube
- enhancement
- exterior surface
- fin
- 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
Links
- 239000011552 falling film Substances 0.000 abstract description 2
- 239000003507 refrigerant Substances 0.000 description 12
- 239000007788 liquid Substances 0.000 description 11
- 230000006911 nucleation Effects 0.000 description 9
- 238000010899 nucleation Methods 0.000 description 9
- 238000009835 boiling Methods 0.000 description 8
- 239000012530 fluid Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000010409 thin film Substances 0.000 description 5
- 238000001704 evaporation Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000001737 promoting effect Effects 0.000 description 4
- 239000011800 void material Substances 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 238000005057 refrigeration Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 230000012447 hatching Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 230000004941 influx Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 210000001161 mammalian embryo Anatomy 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 238000003825 pressing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
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- 230000009466 transformation Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
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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
- F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
- F28F1/422—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element with outside means integral with the tubular element and inside means integral with the tubular element
-
- 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
- F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
- F28F1/424—Means comprising outside portions integral with inside portions
- F28F1/426—Means comprising outside portions integral with inside portions the outside portions and the inside portions forming parts of complementary shape, e.g. concave and convex
-
- 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
- F28F1/24—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 and extending transversely
- F28F1/26—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 and extending transversely the means being integral with the element
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/022—Making the 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
- F25B39/02—Evaporators
-
- 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
- F28F1/34—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 and extending obliquely
- F28F1/36—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 and extending obliquely the means being helically wound fins or wire spirals
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
- F28F13/185—Heat-exchange surfaces provided with microstructures or with porous coatings
- F28F13/187—Heat-exchange surfaces provided with microstructures or with porous coatings especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites
-
- 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
- F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
- F28F2001/428—Particular methods for manufacturing outside or inside fins
-
- 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
- F28F2215/10—Secondary fins, e.g. projections or recesses on main fins
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
- F28F2255/16—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes extruded
Definitions
- the invention relates generally to heat transfer tubes in flooded heat exchangers where nucleate boiling (e.g., on the external surface of the heat transfer tubes) is the dominant mode of heat transfer.
- the invention relates to the external surface configuration of a heat transfer tube that is used for evaporating a liquid in which the tube in submerged (e.g., either completely or partially).
- Shell and tube type evaporators are used to transfer heat from one fluid to other in many air conditioning and refrigeration systems.
- a shell and tube evaporator is a heat exchanger in which multiple tubes are arranged in some patterns within a single shell.
- a coolant is passed through the multiple parallel tubes arranged along the length of the shell.
- Refrigerant flows into the shell of the heat exchanger in liquid phase and forms a refrigerant pool in the shell. Due to heat transfer from the tubes, the refrigerant undergoes phase transformation and leaves the shell as a refrigerant vapor.
- the fluid is cooled by heat transfer through the walls of the tubes.
- the heat transfer capability of such an evaporator is largely determined by the efficiency of the heat transfer surface of the individual tubes which are customized based on the thermophysical properties of the refrigerant.
- the external surface enhancement configuration along with internal enhancement of an individual tube determines the overall heat transfer characteristics of the shell and tube heat exchanger.
- Heat transfer performance of a heat transfer tube can be improved by following methods including (i) increasing the heat transfer surface area of the tube, (ii) promoting nucleate boiling on the surface of the tube that is in contact with the boiling fluid, and (iii) promoting external natural convection at the outer surface of the tube.
- nucleate boiling process initially, a small quantity of entrapped vapor, embryo bubble, in the nucleation sites grows due to the heat transferred from the heated surface. When the bubble grows, it vaporizes more liquid in contact with the solid surface and also vaporizes at the liquid-vapor interface. Heat from the solid surface and from the surrounding superheated liquid superheats the vapor in a bubble and the bubble grows in size.
- the nucleate boiling process can be enhanced by configuring the heat transfer surface so that more nucleation sites can be created and sustained on the surface of the tube that provide locations for the entrapment of vapor and promote the bubble nucleation. For example, simply roughening a heat transfer surface will provide more nucleation sites that can improve the heat transfer performance of the surface over a similar smooth surface.
- nucleation sites of the re-entrant type produce stable bubble columns, good surface heat transfer characteristics and also amount to more surface area.
- a re-entrant type nucleation site is a surface cavity in which the opening of the cavity is smaller than the subsurface volume of the cavity. An excessive influx of the surrounding liquid can flood a re-entrant type nucleation site and deactivate it.
- thin film evaporation happens when the film becomes discontinuous. This thin film evaporation contributes to the steady nucleation process.
- the heat transfer performance of the surface improved.
- new heat transfer tube configurations that can further improve heat transfer are always welcome.
- a finned tube including a tube body, and a plurality of adjacent helical fins.
- the tube body includes an interior surface and an exterior surface.
- the plurality of adjacent helical fins intermittently protrude circumferentially around the exterior surface of the tube body, at least one channel is disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel including at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall including at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- helical fins per centimeter between thirty-three (33) and seventy (70) per inch) of tube length.
- a ratio (H f /D o ) of a fin height (H f ) to an outer diameter (D o ) of the tube body is between 0.02 and 0.05.
- each respective channel enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each respective sidewall enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each fin top includes at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- each respective top enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each respective sidewall is devoid of a protruding wing.
- each respective helical fin is approximately cross-sectionally symmetrical.
- a finned tube including a tube body and a plurality of adjacent helical fins.
- the tube body includes an interior surface and an exterior surface.
- the plurality of adjacent helical fins continuously protrude circumferentially around the exterior surface of the tube body, at least one channel is disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel including at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall including at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- helical fins per centimeter between thirty-three (33) and seventy (70) per inch) of tube length.
- a ratio (H f /D o ) of a fin height (H f ) to an outer diameter (D o ) of the tube body is between 0.02 and 0.05.
- each respective channel enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each respective sidewall enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each fin top includes at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- each respective top enhancement includes a depth (D e ) between 0.05 and 0.2 of a fin height (H f ).
- each respective sidewall is devoid of a protruding wing.
- each respective helical fin is approximately cross-sectionally symmetrical.
- a finned tube with unique features that enhance its heat transfer capabilities may improve the finned tube's heat transfer capabilities by (i) increasing the heat transfer area of the tube surface (e.g., by incorporating one or more enhancements in at least one of the channels between the fins, the sidewalls of the fins, and the top surface of the fins) and (ii) promoting nucleate boiling on the surface of the tube that is in contact with the boiling fluid (e.g., by creating nucleation sites and reentrant cavities at or near the enhancements that provide locations for the entrapment of vapor and promote the formation of vapor bubbles).
- the finned tube described herein may be particularly useful in an evaporator (e.g., flooded and/or falling film type evaporators) of a vapor compression system (e.g., which may utilize one or more refrigerant to transfer heat from a working fluid, such as air, water, glycol, etc.).
- a working fluid such as air, water, glycol, etc.
- the finned tube described herein may be configured to allow the working fluid to pass through interior of the finned tube with the refrigerant located on the exterior of the finned tube, where heat is transferred from the working fluid to the refrigerant through the body of the finned tube.
- a plurality of finned tubes may be mounted in parallel and connected together to form a tube bundle within the evaporator.
- This tube bundle is typically is immersed (e.g., either completely or partially) in the refrigerant pool. It is envisioned that by utilizing the finned tube described herein the heat transfer characteristics of the evaporator may be improved.
- FIG. 1 a schematic illustration of the manufacture of an exemplary finned tube 100 using an exemplary tool arbor containing a plurality of finning disks 63, a channel marking disk 68, a flattening disk 67, and a notching disk 66 is shown in FIG. 1 .
- the finning disks 63, the channel marking disk 68, the flattening disk 67, and the notching disk 66 may be collectively referred to as the tool gang 62.
- the tube 100 may be viewed to include a tube body 110 with an exterior surface 111 and an interior surface 110.
- the finned tube 100 (e.g., as a results of the tool gang 62) includes a plurality of adjacent helical fins 120 protruding (e.g., intermittently or continuously) circumferentially around the exterior surface 111 of the tube body 110.
- At least one channel 130 may be disposed between the plurality of adjacent helical fins 120 (e.g., to separate the different rows R f (shown in FIGs. 7 and 8 ) of fins 120 from one another. It should be appreciated that each channel 130 may be viewed as a void between adjacent helical fins 120. As shown in FIGs.
- each respective helical fin 120 may be viewed to include at least one sidewall 122 and a fin top 121.
- Each channel 130 may include at least one channel enhancement 131 impressed radially into and transversely through at intervals around the circumference of the exterior surface 111 of the tube body 110 (e.g., by the channel marking disk 68). This placement of the channel enhancements 131 at intervals may enhance the heat transfer characteristics of the finned tube 100. These intervals may be generated by spacing of the surface features 70 (shown in FIGs. 2-5 ) on the channel marking disk 68.
- the finned tube 100 described herein may be readily manufactured by a rolling process. This rolling process is illustrated in FIG. 1 .
- the finning machine 60 may operate on a tube 10, made of a malleable metal such as copper or aluminum, to produce both interior ribs and exterior fins 120 on the tube 10.
- the finned tube 100 described herein may, in certain instances, be viewed to be manufactured in a rolling process where the fins 120 are created through extrusion of the metal (e.g., copper or aluminum), instead of using an applied process where the fins are applied by winding an independent metal around the tube.
- the finning machine 60 may include one or more tool arbors 61, each containing one or more tool gangs 62.
- the mandrel shaft 65 extending into the tube 100 is the mandrel shaft 65 to which the mandrel 64 is attached.
- the tube body 110 is pressed between the mandrel 64 and the finning disks 63 as the tube 100 rotates.
- the metal, of which the tube 100 is made of flows into the grooves between the finning disks 63, which forms the beginnings of the fins 120 (and the channels 130 therebetween, as shown in FIG. 2 ) on the exterior surface 111 of the tube 100.
- the tube 100 continues to rotate the tube 100 advances between the mandrel 64 and the tool gang 62 (from left to right in FIG. 1 ) resulting in a number of rows R f of helical fins being formed on the tube 100.
- FIGs. 2-5 may be viewed as cross-sectional side views of rows R f of helical fins (e.g., where each fin 120 represents a different row R f ). It should be appreciated that the number of rows R f generated may be a function of the number of finning disks 63 on the tool arbor 61 in use on the finning machine 60.
- a channel marking disk 68 which includes one or more surface features 70 (e.g., which may be configured as a star, rectangle, square, triangle, star, etc.), may be used to impress radially into and transversely through within the channels 130 so as to form the channel enhancements 131.
- the intervals at which the channel enhancements 131 are spaced within the channel 130 may be a function of the spacing of the surface features 70 on the channel marking disk 68. It is envisioned that all embodiments, as described below, include at least one channel enhancement 131 in each channel 130 (defined between adjacent helical fins 120).
- This channel enhancement 131 may contribute to the improved heat transfer characteristics of the finned tube 100 described herein.
- a flatting disk 67 may be used to flatten and spread the distal tips of the fins 120 (e.g., thereby closing the gaps 180 (shown in FIGs. 7 and 8 ), at least partially, between adjacent rows R f of fins 120.
- a notching disk 66 may be used to generate at least one top enhancement 124 (shown in FIGs. 2-5 ) on the fins 120.
- notching disk 66 may be omitted or removed from the finning machine 60 when the finned tube 100 does not include top enhancements 124.
- the notching disk may be combined with the flattening disk 67 in certain instances.
- the mandrel 64 may be configured in such a way that it will impress some type of pattern into the interior surface 112 of the tube body 110.
- a typical pattern is of one or more helical rib convolutions, which can improve the efficiency of the heat transfer between the fluid flowing through the tube 100 and the tube body 110. It should be appreciated that any pattern, or no pattern at all, may be impressed by the mandrel 64 for the finned tube 100 described herein.
- the finned tube 100 described herein may be configured in various manners.
- the finned tube 100 may include top enhancements 124, which may be absent in other embodiments. It should be appreciated that the various enhancements may be completed by modifying the finning machine 60.
- the finned tube 100 includes a plurality of adjacent helical fins 120 protruding (e.g., either intermittently or continuously) circumferentially around the exterior surface 111 of the tube body 110, where each channel 130 (e.g., disposed between adjacent fins 120) includes at least one channel enhancement 131 impressed radially into and transversely through at intervals (e.g., as compared to continuous, uninterrupted enhancements) around the exterior surface 111 of the tube body 110.
- FIG. 2 illustrates a magnified cross-sectional side view of a portion of a first embodiment of a finned tube 100.
- the finned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by a channel 130 with at least one channel enhancement 131 impressed radially into and transversely through at intervals around the exterior surface 111 of the tube body 110).
- channel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized.
- the finned tube 100 may further include a top enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of the exterior surface 111 of the tube body 110.
- each respective enhancement 131, 124 regardless of specific configuration or where located (e.g., in the channel 130 or in the fin top 121), may have a certain depth D e , which may be defined in terms of the fin height H f .
- the depth D e of the enhancement 131, 124 is between 0.05 and 0.2 of the fin height H f in certain instances.
- each fin 120 may be designed to have a certain fin height H f , which may be defined (e.g., as a ratio H f /D o ) in terms of the outer diameter D o of the tube body 110 (shown in FIG. 1 ). This ratio H f /D o may be between 0.02 and 0.05 in certain instances.
- H f the finned tube 100
- each respective helical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown in FIG. 6 ).
- FIG. 3 illustrates a magnified cross-sectional side view of a portion of a second embodiment of a finned tube 100. As shown, similar to the first embodiment (shown in
- this embodiment of the finned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by a channel 130 with at least one channel enhancement 131 impressed radially into and transversely through at intervals around the exterior surface 111 of the tube body 110).
- channel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized. In this embodiment, as with the first embodiment (shown in FIG.
- the finned tube 100 may further include a top enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of the exterior surface 111 of the tube body 110.
- the finned tube 100 may further include at least one sidewall enhancement 123 impressed radially into and transversely through (e.g., with the sidewall marking disk 69, which may be included in the finning machine 60) at intervals around the circumference of the exterior surface 111 of the tube body 110. These intervals may be generated by spacing of the surface features 71 (shown in FIGs. 3-5 ) on the sidewall marking disk 69.
- the sidewall enhancement 123 may be in any suitable configuration (e.g., rectangle, square, triangle, hatching, etc.). It is envisioned that each respective enhancement 131, 124, 123 regardless of specific configuration or where located (e.g., in the channel 130, in the fin top 121, or in the sidewall 122), may have a certain depth D e , which may be defined in terms of the fin height H f . The depth D e of the channel enhancement 131, 124, 123 is between 0.05 and 0.2 of the fin height H f in certain instances.
- each fin 120 may be designed to have a certain fin height H f , which may be defined (e.g., as a ratio H f /D o ) in terms of the outer diameter D o of the tube body 110 (shown in FIG. 1 ). This ratio H f /D o may be between 0.02 and 0.05 in certain instances.
- H f the finned tube 100, as shown in FIG. 3 , may be designed with manufacturability in mind.
- each respective helical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown in FIG. 6 ).
- FIG. 4 illustrates a magnified cross-sectional side view of a portion of a third embodiment of a finned tube 100.
- this embodiment of the finned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by a channel 130 with at least one channel enhancement 131 impressed radially into and transversely through at intervals around the exterior surface 111 of the tube body 110).
- channel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized.
- the finned tube 100 may further include a top enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of the exterior surface 111 of the tube body 110.
- the finned tube 100 may further include at least one sidewall enhancement 123 impressed radially into and transversely through (e.g., with the sidewall marking disk 69) at intervals around the circumference of the exterior surface 111 of the tube body 110.
- a single sidewall 122 may include multiple sidewall enhancements 123.
- each sidewall enhancement 123 may be in any suitable configuration (e.g., rectangle, square, triangle, hatching, etc.). It is envisioned that each respective enhancement 131, 124, 123 regardless of specific configuration or where located (e.g., in the channel 130, in the fin top 121, or in the sidewall 122), may have a certain depth D e , which may be defined in terms of the fin height H f .
- the depth D e of the channel enhancement 131, 124, 123 is between 0.05 and 0.2 of the fin height H f in certain instances.
- each fin 120 may be designed to have a certain fin height H f , which may be defined (e.g., as a ratio H f /D o ) in terms of the outer diameter D o of the tube body 110 (shown in FIG. 1 ). This ratio H f /D o may be between 0.02 and 0.05 in certain instances.
- H f the finned tube 100
- each respective helical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown in FIG. 6 ).
- FIG. 5 illustrates a magnified cross-sectional side view of a portion of a fourth embodiment of a finned tube 100.
- this embodiment of the finned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by a channel 130 with at least one channel enhancement 131 impressed radially into and transversely through at intervals around the exterior surface 111 of the tube body 110).
- the channel enhancement 131 is depicted as a triangle, which, as shown, may be formed alongside the sidewall enhancements 123 (which, as shown, may have the same triangular configuration) using a plurality of unitary enhancement disks 80 (which may be included in the finning machine 60).
- the unitary enhancement disks 80 may serve the combined functions of the finning disks 63 (by extruding the metal away from the exterior surface 111 of the tube body 110), the channel marking disk 68 (by impressing the channel enhancements 131 in the channels 130), and the sidewall marking disk 69 (by impressing the sidewall enhancements 123 in the sidewalls 122).
- the finned tube 100 may further include a top enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of the exterior surface 111 of the tube body 110.
- each respective enhancement 131, 124, 123 regardless of specific configuration or where located (e.g., in the channel 130, in the fin top 121, or in the sidewall 122) or how formed (e.g., whether through individual disks or a unitary enhancement disk 80, may have a certain depth D e , which may be defined in terms of the fin height H f .
- the depth D e of the channel enhancement 131, 124, 123 is between 0.05 and 0.2 of the fin height H f in certain instances.
- each fin 120 may be designed to have a certain fin height H f , which may be defined (e.g., as a ratio H f /D o ) in terms of the outer diameter D o of the tube body 110 (shown in FIG. 1 ). This ratio H f /D o may be between 0.02 and 0.05 in certain instances.
- H f the finned tube 100
- each respective helical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown in FIG. 6 ).
- FIG. 6 illustrates a magnified cross-sectional side view of a portion of a fifth embodiment of a finned tube 100.
- this embodiment of the finned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by a channel 130 with at least one channel enhancement 131 impressed radially into and transversely through at intervals around the exterior surface 111 of the tube body 110).
- the helical fins 120 are not symmetrical (e.g., along the vertical plane), the sidewalls 122 include protruding wings 140, and the fin tops 121 do not include enhancements.
- the lack of symmetry may be created by the configuration of the sidewall enhancements 123 shown in FIG. 6 , which may be viewed as non-uniformly distributed in the cross-section of the fin 120.
- This non-uniform distribution of the sidewall enhancement 123 may be created during manufacture. For example, as the tube 100 is rotated and advanced, the notching disk 66 with oblique notches and the flattening disk 67 may cause the top of the fin 120 to twist slightly from the base (from the exterior surface 111) to its tip (toward the fin top 121) such that the sidewall enhancement 123 has a twisted, non-uniform asymmetrical configuration.
- material while creating a notch, material will be pushed down in a perpendicular to the channel length 130 forming the wings 140.
- each of the above-described embodiments (shown in FIGs. 2-6 ) of the finned tube 100 may have a certain designed density of the helical fins 120 (e.g., which, as mentioned above, may be viewed in terms of number of fins 120 per tube 100 length).
- the finned tube 100 may have between thirteen (13) and twenty-eight (28) helical fins 120 per centimeter (between thirty-three (33) and seventy (70) helical fins 120 per inch) of tube length. It is envisioned that this density in combination with the specific enhancements may contribute to the improved heat transfer characteristics of the finned tube 100 described herein.
- each of the above-described embodiments (shown in FIGs. 2-6 ) of the finned tube 100 may be configured with the plurality of adjacent helical fins 120 being either intermittently (as shown in FIG. 7 ) or continuously (as shown in FIG. 8 ) protruding circumferentially around the exterior surface 111 of the tube body 110.
- each fin 120 within each respective row R f may be separated by a void 170 (i.e., a space).
- This void 170 may be generated by the finning machine 60 by intermittently pressing in between the fins 120 (e.g., after the fins 120 are extruded by the finning disk 63).
- each fin 120 within each respective row R f may not be separated (i.e., there is no void 170 generated by the finning machine 60).
- the finned tube 100 includes openings 180 (i.e., spaces) at the upper end of the fins 120 (e.g., between each respective helical fin 120) so as to allow refrigerant vapor to rise through the fin 120 and liquid refrigerant to go to the inner wall either in one opening 180 or alternative openings.
- these openings 180 may be viewed to align with the respective fin 120 columns C f , which are configured in a helical fashion.
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Abstract
Description
- The invention relates generally to heat transfer tubes in flooded heat exchangers where nucleate boiling (e.g., on the external surface of the heat transfer tubes) is the dominant mode of heat transfer. In particular, the invention relates to the external surface configuration of a heat transfer tube that is used for evaporating a liquid in which the tube in submerged (e.g., either completely or partially).
- Shell and tube type evaporators are used to transfer heat from one fluid to other in many air conditioning and refrigeration systems. A shell and tube evaporator is a heat exchanger in which multiple tubes are arranged in some patterns within a single shell. In refrigeration systems, typically a coolant is passed through the multiple parallel tubes arranged along the length of the shell. Refrigerant flows into the shell of the heat exchanger in liquid phase and forms a refrigerant pool in the shell. Due to heat transfer from the tubes, the refrigerant undergoes phase transformation and leaves the shell as a refrigerant vapor. The fluid is cooled by heat transfer through the walls of the tubes. The heat transfer capability of such an evaporator is largely determined by the efficiency of the heat transfer surface of the individual tubes which are customized based on the thermophysical properties of the refrigerant. The external surface enhancement configuration along with internal enhancement of an individual tube determines the overall heat transfer characteristics of the shell and tube heat exchanger.
- Heat transfer performance of a heat transfer tube can be improved by following methods including (i) increasing the heat transfer surface area of the tube, (ii) promoting nucleate boiling on the surface of the tube that is in contact with the boiling fluid, and (iii) promoting external natural convection at the outer surface of the tube. In the nucleate boiling process, initially, a small quantity of entrapped vapor, embryo bubble, in the nucleation sites grows due to the heat transferred from the heated surface. When the bubble grows, it vaporizes more liquid in contact with the solid surface and also vaporizes at the liquid-vapor interface. Heat from the solid surface and from the surrounding superheated liquid superheats the vapor in a bubble and the bubble grows in size. When the bubble size is large enough, surface tension is overcome by the buoyancy force and the bubble detaches from the surface. As the bubble leaves the surface, liquid enters the volume vacated by the bubble. The bubble departure results in a convection current in the liquid. Usually, some traces of vapor remains in the volume, and becomes a source of additional liquid to vaporize to form another bubble. The periodic formation of bubbles at the surface, the release of the bubbles from the surface, and the rewetting of the surface together with the convective effect of the vapor bubbles rising through the liquid results in an improved heat transfer rate for the heat transfer surface.
- It is generally known that the nucleate boiling process can be enhanced by configuring the heat transfer surface so that more nucleation sites can be created and sustained on the surface of the tube that provide locations for the entrapment of vapor and promote the bubble nucleation. For example, simply roughening a heat transfer surface will provide more nucleation sites that can improve the heat transfer performance of the surface over a similar smooth surface.
- In nucleate boiling including liquid refrigerants, for example, in the evaporator of an air conditioning or refrigeration system, nucleation sites of the re-entrant type produce stable bubble columns, good surface heat transfer characteristics and also amount to more surface area. A re-entrant type nucleation site is a surface cavity in which the opening of the cavity is smaller than the subsurface volume of the cavity. An excessive influx of the surrounding liquid can flood a re-entrant type nucleation site and deactivate it. In the subsurface volumes, which are mostly filled with vapor with liquid films in the neighboring wall, thin film evaporation happens when the film becomes discontinuous. This thin film evaporation contributes to the steady nucleation process. By configurating the heat transfer surface so that it has relatively large communicating subsurface channels with relatively smaller openings to the surface, and it promotes the discontinuity in the thin film, the heat transfer performance of the surface improved. There are many different configurations of heat transfer tubes, each having their own take of which features to include so as to improve heat transfer. However, new heat transfer tube configurations that can further improve heat transfer are always welcome.
- Accordingly, there remains an ongoing need for newly configured heat transfer tubes with improved heat transfer capabilities.
- According to a first aspect of the invention, a finned tube including a tube body, and a plurality of adjacent helical fins is provided. The tube body includes an interior surface and an exterior surface. The plurality of adjacent helical fins intermittently protrude circumferentially around the exterior surface of the tube body, at least one channel is disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel including at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall including at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- Optionally, there are between thirteen (13) and twenty-eight (28) helical fins per centimeter (between thirty-three (33) and seventy (70) per inch) of tube length.
- Optionally, a ratio (Hf/Do) of a fin height (Hf) to an outer diameter (Do) of the tube body is between 0.02 and 0.05.
- Optionally, each respective channel enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each respective sidewall enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each fin top includes at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- Optionally, each respective top enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each respective sidewall is devoid of a protruding wing.
- Optionally, each respective helical fin is approximately cross-sectionally symmetrical.
- According to another aspect of the disclosure, a finned tube including a tube body and a plurality of adjacent helical fins is provided. The tube body includes an interior surface and an exterior surface. The plurality of adjacent helical fins continuously protrude circumferentially around the exterior surface of the tube body, at least one channel is disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel including at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall including at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- Optionally, there are between thirteen (13) and twenty-eight (28) helical fins per centimeter (between thirty-three (33) and seventy (70) per inch) of tube length.
- Optionally, a ratio (Hf/Do) of a fin height (Hf) to an outer diameter (Do) of the tube body is between 0.02 and 0.05.
- Optionally, each respective channel enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each respective sidewall enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each fin top includes at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- Optionally, each respective top enhancement includes a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- Optionally, each respective sidewall is devoid of a protruding wing.
- Optionally, each respective helical fin is approximately cross-sectionally symmetrical.
- Certain exemplary embodiments will now be described in greater detail by way of example only. The following descriptions of the drawings should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
-
FIG. 1 is a schematic illustration of the manufacture of a finned tube using a tool arbor containing a plurality of finning disks, a channel marking disk, a flattening disk, and a notching disk. -
FIG. 2 is a cross-sectional side view of a finned tube. -
FIG. 3 is a cross-sectional side view of a finned tube. -
FIG. 4 is a cross-sectional side view of a finned tube. -
FIG. 5 is a cross-sectional side view of a finned tube. -
FIG. 6 is a cross-sectional side view of a finned tube. -
FIG. 7 is a perspective view of a section of a finned tube with the fins intermittently protruding circumferentially around the exterior surface of the tube body. -
FIG. 8 is a perspective view of a section of a finned tube with the fins continuously protruding circumferentially around the exterior surface of the tube body - As will be described below, a finned tube with unique features that enhance its heat transfer capabilities is provided. Specifically, the features of the finned tube described herein may improve the finned tube's heat transfer capabilities by (i) increasing the heat transfer area of the tube surface (e.g., by incorporating one or more enhancements in at least one of the channels between the fins, the sidewalls of the fins, and the top surface of the fins) and (ii) promoting nucleate boiling on the surface of the tube that is in contact with the boiling fluid (e.g., by creating nucleation sites and reentrant cavities at or near the enhancements that provide locations for the entrapment of vapor and promote the formation of vapor bubbles). In addition, promoting thin film evaporation of the thin film entrapped in the channel marks as will be described. The finned tube described herein may be particularly useful in an evaporator (e.g., flooded and/or falling film type evaporators) of a vapor compression system (e.g., which may utilize one or more refrigerant to transfer heat from a working fluid, such as air, water, glycol, etc.). For example, the finned tube described herein may be configured to allow the working fluid to pass through interior of the finned tube with the refrigerant located on the exterior of the finned tube, where heat is transferred from the working fluid to the refrigerant through the body of the finned tube. Although described as an independent tube, it should be appreciated that typically a plurality of finned tubes may be mounted in parallel and connected together to form a tube bundle within the evaporator. This tube bundle is typically is immersed (e.g., either completely or partially) in the refrigerant pool. It is envisioned that by utilizing the finned tube described herein the heat transfer characteristics of the evaporator may be improved.
- With reference now to the Figures, a schematic illustration of the manufacture of an exemplary
finned tube 100 using an exemplary tool arbor containing a plurality offinning disks 63, achannel marking disk 68, aflattening disk 67, and a notchingdisk 66 is shown inFIG. 1 . It should be appreciated that thefinning disks 63, thechannel marking disk 68, theflattening disk 67, and the notchingdisk 66 may be collectively referred to as thetool gang 62. As shown inFIG. 1 , thetube 100 may be viewed to include atube body 110 with anexterior surface 111 and aninterior surface 110. The finned tube 100 (e.g., as a results of the tool gang 62) includes a plurality of adjacenthelical fins 120 protruding (e.g., intermittently or continuously) circumferentially around theexterior surface 111 of thetube body 110. At least one channel 130 (shown inFIGs. 2-8 ) may be disposed between the plurality of adjacent helical fins 120 (e.g., to separate the different rows Rf (shown inFIGs. 7 and8 ) offins 120 from one another. It should be appreciated that eachchannel 130 may be viewed as a void between adjacenthelical fins 120. As shown inFIGs. 2-6 , each respectivehelical fin 120 may be viewed to include at least onesidewall 122 and afin top 121. Eachchannel 130 may include at least onechannel enhancement 131 impressed radially into and transversely through at intervals around the circumference of theexterior surface 111 of the tube body 110 (e.g., by the channel marking disk 68). This placement of thechannel enhancements 131 at intervals may enhance the heat transfer characteristics of thefinned tube 100. These intervals may be generated by spacing of the surface features 70 (shown inFIGs. 2-5 ) on thechannel marking disk 68. - It is envisioned that the
finned tube 100 described herein may be readily manufactured by a rolling process. This rolling process is illustrated inFIG. 1 . As shown, the finningmachine 60 may operate on a tube 10, made of a malleable metal such as copper or aluminum, to produce both interior ribs andexterior fins 120 on the tube 10. For example, thefinned tube 100 described herein may, in certain instances, be viewed to be manufactured in a rolling process where thefins 120 are created through extrusion of the metal (e.g., copper or aluminum), instead of using an applied process where the fins are applied by winding an independent metal around the tube. It should be appreciated that the finningmachine 60 may include one ormore tool arbors 61, each containing one ormore tool gangs 62. As shown inFIG. 1 , extending into thetube 100 is themandrel shaft 65 to which themandrel 64 is attached. During manufacture, thetube body 110 is pressed between themandrel 64 and thefinning disks 63 as thetube 100 rotates. Under pressure, the metal, of which thetube 100 is made of, flows into the grooves between the finningdisks 63, which forms the beginnings of the fins 120 (and thechannels 130 therebetween, as shown inFIG. 2 ) on theexterior surface 111 of thetube 100. As thetube 100 continues to rotate thetube 100 advances between themandrel 64 and the tool gang 62 (from left to right inFIG. 1 ) resulting in a number of rows Rf of helical fins being formed on thetube 100. For purposes of clarify,FIGs. 2-5 may be viewed as cross-sectional side views of rows Rf of helical fins (e.g., where eachfin 120 represents a different row Rf). It should be appreciated that the number of rows Rf generated may be a function of the number offinning disks 63 on thetool arbor 61 in use on the finningmachine 60. - As shown in
FIGs. 1 and2 , after thefinning disks 63 form the beginnings of the fins 120 (and thechannels 130 therebetween), achannel marking disk 68, which includes one or more surface features 70 (e.g., which may be configured as a star, rectangle, square, triangle, star, etc.), may be used to impress radially into and transversely through within thechannels 130 so as to form thechannel enhancements 131. It should be appreciated that the intervals at which thechannel enhancements 131 are spaced within thechannel 130 may be a function of the spacing of the surface features 70 on thechannel marking disk 68. It is envisioned that all embodiments, as described below, include at least onechannel enhancement 131 in each channel 130 (defined between adjacent helical fins 120). Thischannel enhancement 131, either alone or in combination with the designed density of the helical fins 120 (e.g., which may be viewed in terms of number offins 120 pertube 100 length), may contribute to the improved heat transfer characteristics of thefinned tube 100 described herein. - As shown in
FIGs. 1 and2 , in the same pass and after thefinning disks 63 andchannel marking disk 68 form thefins 120 and thechannel enhancements 131 on thetube 100, aflatting disk 67 may be used to flatten and spread the distal tips of the fins 120 (e.g., thereby closing the gaps 180 (shown inFIGs. 7 and8 ), at least partially, between adjacent rows Rf offins 120. Once thefins 120 are flattened, a notchingdisk 66 may be used to generate at least one top enhancement 124 (shown inFIGs. 2-5 ) on thefins 120. It should be appreciated that notchingdisk 66 may be omitted or removed from the finningmachine 60 when thefinned tube 100 does not includetop enhancements 124. In addition, although not shown, it should be appreciated that the notching disk may be combined with theflattening disk 67 in certain instances. As shown inFIG. 1 , themandrel 64 may be configured in such a way that it will impress some type of pattern into theinterior surface 112 of thetube body 110. A typical pattern is of one or more helical rib convolutions, which can improve the efficiency of the heat transfer between the fluid flowing through thetube 100 and thetube body 110. It should be appreciated that any pattern, or no pattern at all, may be impressed by themandrel 64 for thefinned tube 100 described herein. - As shown
FIGs. 2-6 , thefinned tube 100 described herein may be configured in various manners. For example, in certain embodiments, thefinned tube 100 may includetop enhancements 124, which may be absent in other embodiments. It should be appreciated that the various enhancements may be completed by modifying the finningmachine 60. However, it is envisioned that in all embodiments, thefinned tube 100 includes a plurality of adjacenthelical fins 120 protruding (e.g., either intermittently or continuously) circumferentially around theexterior surface 111 of thetube body 110, where each channel 130 (e.g., disposed between adjacent fins 120) includes at least onechannel enhancement 131 impressed radially into and transversely through at intervals (e.g., as compared to continuous, uninterrupted enhancements) around theexterior surface 111 of thetube body 110. -
FIG. 2 illustrates a magnified cross-sectional side view of a portion of a first embodiment of afinned tube 100. As shown, thefinned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by achannel 130 with at least onechannel enhancement 131 impressed radially into and transversely through at intervals around theexterior surface 111 of the tube body 110). It should be appreciated that although thechannel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized. In this embodiment, thefinned tube 100 may further include atop enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of theexterior surface 111 of thetube body 110. It is envisioned that eachrespective enhancement channel 130 or in the fin top 121), may have a certain depth De, which may be defined in terms of the fin height Hf. The depth De of theenhancement fin 120 may be designed to have a certain fin height Hf, which may be defined (e.g., as a ratio Hf/Do) in terms of the outer diameter Do of the tube body 110 (shown inFIG. 1 ). This ratio Hf/Do may be between 0.02 and 0.05 in certain instances. It should be appreciated that thefinned tube 100, as shown inFIG. 2 , may be designed with manufacturability in mind. For example, as shown, each respectivehelical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown inFIG. 6 ). -
FIG. 3 illustrates a magnified cross-sectional side view of a portion of a second embodiment of afinned tube 100. As shown, similar to the first embodiment (shown in -
FIG. 2 ), this embodiment of thefinned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by achannel 130 with at least onechannel enhancement 131 impressed radially into and transversely through at intervals around theexterior surface 111 of the tube body 110). It should be appreciated that although thechannel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized. In this embodiment, as with the first embodiment (shown inFIG. 2 ), thefinned tube 100 may further include atop enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of theexterior surface 111 of thetube body 110. In addition, this embodiment, unlike the first embodiment (shown inFIG. 2 ), thefinned tube 100 may further include at least onesidewall enhancement 123 impressed radially into and transversely through (e.g., with thesidewall marking disk 69, which may be included in the finning machine 60) at intervals around the circumference of theexterior surface 111 of thetube body 110. These intervals may be generated by spacing of the surface features 71 (shown inFIGs. 3-5 ) on thesidewall marking disk 69. As with thechannel enhancement 131, thesidewall enhancement 123 may be in any suitable configuration (e.g., rectangle, square, triangle, hatching, etc.). It is envisioned that eachrespective enhancement channel 130, in thefin top 121, or in the sidewall 122), may have a certain depth De, which may be defined in terms of the fin height Hf. The depth De of thechannel enhancement fin 120 may be designed to have a certain fin height Hf, which may be defined (e.g., as a ratio Hf/Do) in terms of the outer diameter Do of the tube body 110 (shown inFIG. 1 ). This ratio Hf/Do may be between 0.02 and 0.05 in certain instances. It should be appreciated that thefinned tube 100, as shown inFIG. 3 , may be designed with manufacturability in mind. For example, as shown, each respectivehelical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown inFIG. 6 ). -
FIG. 4 illustrates a magnified cross-sectional side view of a portion of a third embodiment of afinned tube 100. As shown, similar to the first embodiment (shown inFIG. 2 ) and the second embodiment (shown inFIG. 3 ), this embodiment of thefinned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by achannel 130 with at least onechannel enhancement 131 impressed radially into and transversely through at intervals around theexterior surface 111 of the tube body 110). It should be appreciated that although thechannel enhancement 131 is depicted as a cross, any suitable configuration (e.g., such as a rectangle, square, triangle, star, etc.) may be utilized. In this embodiment, as with the first embodiment (shown inFIG. 2 ) and the second embodiment (shown inFIG. 3 ), thefinned tube 100 may further include atop enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of theexterior surface 111 of thetube body 110. In addition, this embodiment, like the second embodiment (shown inFIG. 3 ), thefinned tube 100 may further include at least onesidewall enhancement 123 impressed radially into and transversely through (e.g., with the sidewall marking disk 69) at intervals around the circumference of theexterior surface 111 of thetube body 110. As shown in this embodiment, asingle sidewall 122 may includemultiple sidewall enhancements 123. As with thechannel enhancement 131, eachsidewall enhancement 123 may be in any suitable configuration (e.g., rectangle, square, triangle, hatching, etc.). It is envisioned that eachrespective enhancement channel 130, in thefin top 121, or in the sidewall 122), may have a certain depth De, which may be defined in terms of the fin height Hf. The depth De of thechannel enhancement fin 120 may be designed to have a certain fin height Hf, which may be defined (e.g., as a ratio Hf/Do) in terms of the outer diameter Do of the tube body 110 (shown inFIG. 1 ). This ratio Hf/Do may be between 0.02 and 0.05 in certain instances. It should be appreciated that thefinned tube 100, as shown inFIG. 4 , may be designed with manufacturability in mind. For example, as shown, each respectivehelical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown inFIG. 6 ). -
FIG. 5 illustrates a magnified cross-sectional side view of a portion of a fourth embodiment of afinned tube 100. As shown, similar to the first embodiment (shown inFIG. 2 ), the second embodiment (shown inFIG. 3 ), and the third embodiment (shown inFIG. 4 ), this embodiment of thefinned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by achannel 130 with at least onechannel enhancement 131 impressed radially into and transversely through at intervals around theexterior surface 111 of the tube body 110). Unlike the prior embodiments, in this embodiment, thechannel enhancement 131 is depicted as a triangle, which, as shown, may be formed alongside the sidewall enhancements 123 (which, as shown, may have the same triangular configuration) using a plurality of unitary enhancement disks 80 (which may be included in the finning machine 60). As shown, theunitary enhancement disks 80 may serve the combined functions of the finning disks 63 (by extruding the metal away from theexterior surface 111 of the tube body 110), the channel marking disk 68 (by impressing thechannel enhancements 131 in the channels 130), and the sidewall marking disk 69 (by impressing thesidewall enhancements 123 in the sidewalls 122). It should be appreciated that although thechannel enhancement 131 andsidewall enhancements 123 are depicted as a triangular, any suitable configuration (e.g., such as a rectangle, square, star, etc.) may be utilized. In this embodiment, as with previously described embodiments (shown inFIGs. 2-4 ), thefinned tube 100 may further include atop enhancement 124 impressed radially into and transversely through (e.g., with the notching disk 66) at intervals around the circumference of theexterior surface 111 of thetube body 110. It is envisioned that eachrespective enhancement channel 130, in thefin top 121, or in the sidewall 122) or how formed (e.g., whether through individual disks or aunitary enhancement disk 80, may have a certain depth De, which may be defined in terms of the fin height Hf. The depth De of thechannel enhancement fin 120 may be designed to have a certain fin height Hf, which may be defined (e.g., as a ratio Hf/Do) in terms of the outer diameter Do of the tube body 110 (shown inFIG. 1 ). This ratio Hf/Do may be between 0.02 and 0.05 in certain instances. It should be appreciated that thefinned tube 100, as shown inFIG. 5 , may be designed with manufacturability in mind. For example, as shown, each respectivehelical fin 120 may be approximately cross-sectionally symmetrical (e.g., along the vertical plane) and devoid of a protruding wing 141 (shown inFIG. 6 ). -
FIG. 6 illustrates a magnified cross-sectional side view of a portion of a fifth embodiment of afinned tube 100. As shown, similar to the previous embodiments (shown inFIGs. 2-4 ), this embodiment of thefinned tube 100 includes a plurality of adjacent helical fins 120 (e.g., separated by achannel 130 with at least onechannel enhancement 131 impressed radially into and transversely through at intervals around theexterior surface 111 of the tube body 110). Unlike the prior embodiments, in this embodiment, thehelical fins 120 are not symmetrical (e.g., along the vertical plane), thesidewalls 122 include protrudingwings 140, and the fin tops 121 do not include enhancements. In particular, the lack of symmetry may be created by the configuration of thesidewall enhancements 123 shown inFIG. 6 , which may be viewed as non-uniformly distributed in the cross-section of thefin 120. This non-uniform distribution of thesidewall enhancement 123 may be created during manufacture. For example, as thetube 100 is rotated and advanced, the notchingdisk 66 with oblique notches and theflattening disk 67 may cause the top of thefin 120 to twist slightly from the base (from the exterior surface 111) to its tip (toward the fin top 121) such that thesidewall enhancement 123 has a twisted, non-uniform asymmetrical configuration. In addition, while creating a notch, material will be pushed down in a perpendicular to thechannel length 130 forming thewings 140. - It is envisioned that each of the above-described embodiments (shown in
FIGs. 2-6 ) of thefinned tube 100 may have a certain designed density of the helical fins 120 (e.g., which, as mentioned above, may be viewed in terms of number offins 120 pertube 100 length). Regardless of the specific configuration of thefinned tube 100 thefinned tube 100 may have between thirteen (13) and twenty-eight (28)helical fins 120 per centimeter (between thirty-three (33) and seventy (70)helical fins 120 per inch) of tube length. It is envisioned that this density in combination with the specific enhancements may contribute to the improved heat transfer characteristics of thefinned tube 100 described herein. - In addition, it is envisioned that each of the above-described embodiments (shown in
FIGs. 2-6 ) of thefinned tube 100 may be configured with the plurality of adjacenthelical fins 120 being either intermittently (as shown inFIG. 7 ) or continuously (as shown inFIG. 8 ) protruding circumferentially around theexterior surface 111 of thetube body 110. When intermittently protruding, as shown inFIG. 7 , eachfin 120 within each respective row Rf may be separated by a void 170 (i.e., a space). This void 170 may be generated by the finningmachine 60 by intermittently pressing in between the fins 120 (e.g., after thefins 120 are extruded by the finning disk 63). When continuously protruding, as shown inFIG. 8 , eachfin 120 within each respective row Rf may not be separated (i.e., there is no void 170 generated by the finning machine 60). As shown inFIGs. 7 and8 , regardless of whether thefins 120 are intermittently or continuously protruding, thefinned tube 100 includes openings 180 (i.e., spaces) at the upper end of the fins 120 (e.g., between each respective helical fin 120) so as to allow refrigerant vapor to rise through thefin 120 and liquid refrigerant to go to the inner wall either in oneopening 180 or alternative openings. As shown, theseopenings 180 may be viewed to align with therespective fin 120 columns Cf, which are configured in a helical fashion. - The use of the terms "a" and "and" and "the" and similar referents, in the context of describing the invention, are to be construed to cover both the singular and the plural, unless otherwise indicated herein or cleared contradicted by context. The use of any and all example, or exemplary language (e.g., "such as", "e.g.", "for example", etc.) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed elements as essential to the practice of the invention.
- While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as set out in the appended claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.
- The following clauses set out aspects of the invention which may or may not be presently claimed but which may form basis for future amendments and/or a divisional application.
- 1. A finned tube comprising:
- a tube body comprising an interior surface and an exterior surface;
- a plurality of adjacent helical fins intermittently protruding circumferentially around the exterior surface of the tube body, at least one channel disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel comprising at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall comprising at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- 2. The finned tube of clause 1, wherein there are between thirteen (13) and twenty-eight (28) helical fins per centimeter (between thirty-three (33) and seventy (70) per inch) of tube length.
- 3. The finned tube of clause 1, wherein a ratio (Hf/Do) of a fin height (Hf) to an outer diameter (Do) of the tube body is between 0.02 and 0.05.
- 4. The finned tube of clause 1, wherein each respective channel enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 5. The finned tube of clause 1, wherein each respective sidewall enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 6. The finned tube of clause 1, wherein each fin top comprises at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- 7. The finned tube of clause 6, wherein each respective top enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 8. The finned tube of clause 1, wherein each respective sidewall is devoid of a protruding wing.
- 9. The finned tube of clause 1, wherein each respective helical fin is approximately cross-sectionally symmetrical.
- 10. A finned tube comprising:
- a tube body comprising an interior surface and an exterior surface;
- a plurality of adjacent helical fins continuously protruding circumferentially around the exterior surface of the tube body, at least one channel disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel comprising at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall comprising at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- 11. The finned tube of clause 10, wherein there are between thirteen (13) and twenty-eight (28) helical fins per centimeter (between thirty-three (33) and seventy (70) per inch) of tube length.
- 12. The finned tube of clause 10, wherein a ratio (Hf/Do) of a fin height (Hf) to an outer diameter (Do) of the tube body is between 0.02 and 0.05.
- 13. The finned tube of clause 10, wherein each respective channel enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 14. The finned tube of clause 10, wherein each respective sidewall enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 15. The finned tube of clause 10, wherein each fin top comprises at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- 16. The finned tube of clause 15, wherein each respective top enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- 17. The finned tube of clause 10, wherein each respective sidewall is devoid of a protruding wing.
- 18. The finned tube of clause 10, wherein each respective helical fin is approximately cross-sectionally symmetrical.
Claims (9)
- A finned tube comprising:a tube body comprising an interior surface and an exterior surface;a plurality of adjacent helical fins protruding circumferentially around the exterior surface of the tube body, at least one channel being disposed between the plurality of adjacent helical fins, each respective helical fin comprising at least one sidewall and a fin top, each channel comprising at least one channel enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, each sidewall comprising at least one sidewall enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body, wherein:the plurality of adjacent helical fins intermittently protrude circumferentially around the exterior surface of the tube body; orthe plurality of adjacent helical fins continuously protrude circumferentially around the exterior surface of the tube body.
- The finned tube of claim 1, wherein there are between thirteen (13) and twenty-eight (28) helical fins per centimeter (between thirty-three (33) and seventy (70) per inch) of tube length.
- The finned tube of claim 1 or 2, wherein a ratio (Hf/Do) of a fin height (Hf) to an outer diameter (Do) of the tube body is between 0.02 and 0.05.
- The finned tube of claim 1, 2 or 3, wherein each respective channel enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- The finned tube of any preceding claim, wherein each respective sidewall enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- The finned tube of any preceding claim, wherein each fin top comprises at least one top enhancement impressed radially into and transversely through at intervals around the circumference of the exterior surface of the tube body.
- The finned tube of claim 6, wherein each respective top enhancement comprises a depth (De) between 0.05 and 0.2 of a fin height (Hf).
- The finned tube of claim any preceding claim, wherein each respective sidewall is devoid of a protruding wing.
- The finned tube of any preceding claim, wherein each respective helical fin is approximately cross-sectionally symmetrical.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US202063198724P | 2020-11-09 | 2020-11-09 |
Publications (1)
Publication Number | Publication Date |
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EP3995773A1 true EP3995773A1 (en) | 2022-05-11 |
Family
ID=78592655
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP21207242.5A Pending EP3995773A1 (en) | 2020-11-09 | 2021-11-09 | Heat transfer tube |
Country Status (3)
Country | Link |
---|---|
US (1) | US20220146214A1 (en) |
EP (1) | EP3995773A1 (en) |
CN (1) | CN114459271A (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4796693A (en) * | 1985-10-31 | 1989-01-10 | Wieland-Werke Ag | Finned tube with indented groove base and method of forming same |
US5775411A (en) * | 1994-02-11 | 1998-07-07 | Wieland-Werke Ag | Heat-exchanger tube for condensing of vapor |
US20030024121A1 (en) * | 2001-01-16 | 2003-02-06 | Wieland-Werke Ag. | Method of fabricating a heat exchanger tube |
EP2917675B1 (en) * | 2012-11-12 | 2019-05-01 | Wieland-Werke AG | Evaporation heat transfer tube |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100547339C (en) * | 2008-03-12 | 2009-10-07 | 江苏萃隆精密铜管股份有限公司 | A kind of intensify heat transfer pipe and preparation method thereof |
CN102130622A (en) * | 2011-04-07 | 2011-07-20 | 上海威特力焊接设备制造股份有限公司 | High-efficiency photovoltaic inverter |
DE102011121733A1 (en) * | 2011-12-21 | 2013-06-27 | Wieland-Werke Ag | Evaporator tube with optimized external structure |
-
2021
- 2021-11-01 US US17/453,017 patent/US20220146214A1/en not_active Abandoned
- 2021-11-09 EP EP21207242.5A patent/EP3995773A1/en active Pending
- 2021-11-09 CN CN202111320307.6A patent/CN114459271A/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4796693A (en) * | 1985-10-31 | 1989-01-10 | Wieland-Werke Ag | Finned tube with indented groove base and method of forming same |
US5775411A (en) * | 1994-02-11 | 1998-07-07 | Wieland-Werke Ag | Heat-exchanger tube for condensing of vapor |
US20030024121A1 (en) * | 2001-01-16 | 2003-02-06 | Wieland-Werke Ag. | Method of fabricating a heat exchanger tube |
EP2917675B1 (en) * | 2012-11-12 | 2019-05-01 | Wieland-Werke AG | Evaporation heat transfer tube |
Also Published As
Publication number | Publication date |
---|---|
CN114459271A (en) | 2022-05-10 |
US20220146214A1 (en) | 2022-05-12 |
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