EP1271087A1 - Heizrohr mit gerillter innerer oberfläche - Google Patents
Heizrohr mit gerillter innerer oberfläche Download PDFInfo
- Publication number
- EP1271087A1 EP1271087A1 EP01917860A EP01917860A EP1271087A1 EP 1271087 A1 EP1271087 A1 EP 1271087A1 EP 01917860 A EP01917860 A EP 01917860A EP 01917860 A EP01917860 A EP 01917860A EP 1271087 A1 EP1271087 A1 EP 1271087A1
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- EP
- European Patent Office
- Prior art keywords
- groove
- lead angle
- heat transfer
- line
- transfer tube
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- 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.)
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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
- F28F1/40—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only inside the tubular element
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
- F28D2021/0068—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for refrigerant cycles
- F28D2021/007—Condensers
Definitions
- the present invention relates to inner grooved heat transfer tubes for use in heat exchangers. More specifically, the invention relates to specific structures of the internal groove.
- a conventional heat exchanger serving as an evaporator or as a condenser in a refrigerating apparatus such as an air conditioner.
- a heat exchanger employs for example an inner grooved heat transfer tube comprising an inner surface in which are formed a large number of helical line grooves.
- these helical line grooves By virtue of these helical line grooves, the area of heat transfer of the inner grooved heat transfer tube is increased and, besides, the performance of heat transfer is upgraded by causing refrigerant to flow in the tube while forming an even and thin film of liquid.
- each line groove comprises a main groove of a first lead angle and a deformed portion of a second lead angle different from the first lead angle which are successively formed, and refrigerant is made to flow along the main groove while forming a thin film of liquid.
- the liquid refrigerant comes into collision with a groove side surface of the deformed portion and is scattered toward the center of the heat transfer tube.
- an object of the invention is to make it possible to make the performance of heat exchange much steadier than conventional by specifying concrete configurations about the main groove and deformed portion of the line groove in the inner grooved heat transfer tube.
- the invention provides first to twelfth problem-solving means. More specifically, in an inner grooved heat transfer tube according to each problem-solving means, a plurality of line grooves (11) are formed in an inner peripheral surface of the heat transfer tube and the line groove (11) comprises main grooves (12) formed at a first lead angle ( ⁇ ) and deformed portions (13) formed at a second lead angle ( ⁇ ) differing from the first lead angle ( ⁇ ) which are successively formed, wherein the main groove (12) and the deformed portion (13) of the line groove (11) are set to predetermined relationships specified as follows.
- the first problem-solving means implemented by the invention is a means in which the percentage of the length of the deformed portion (13) to the length of a single round of the line groove (11) is so set as to fall in the range of 10 to 35% in the configuration as set forth above.
- the second problem-solving means is a means in which the length of the deformed portion (13) is so set as to fall in the range of five to fifteen times the pitch of the line groove (11) .
- the third problem-solving means is a means in which from five to fifteen deformed portions (13) are so arranged as to intersect an extension of a single main groove (12).
- the fourth problem-solving means is a means in which a joint portion (14) of an electric welded tube and the deformed portion (13) are arranged at respective locations substantially equally dividing the direction of the circumference of the electric welded tube.
- an electric welded tube is meant, in general, a tube formed by connecting a long strip-shaped material by electric resistance welding.
- the electric welded tube includes any type of tube connected along the longitudinal direction by any connecting technique.
- the fifth problem-solving means is a means according to any one of the first to fourth problem-solving means in which the deformed portion (13) is formed at a plurality of positions in a single round of the line groove (11) .
- the sixth problem-solving means is a means according to any one of the first to fourth problem-solving means in which one of the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) is so set as to fall in the range of 5 to 30 degrees in one torsional direction with respect to a tube axis directional line whereas the other of the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) is so set as to fall in the range of 5 to 30 degrees in the other torsional direction with respect to the tube axis directional line.
- the seventh problem-solving means is a means according to the sixth problem-solving means in which the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are set in such a way that the main groove (12) and the deformed portion (13) of the line groove (11) are symmetrically directed with respect to the tube axis directional line.
- the eighth problem-solving means is a means according to the seventh solving means in which the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are specified. More specifically, the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are each set at 18 degrees in opposite directions with respect to the tube axis directional line.
- the ninth problem-solving means is a means according to any one of the first to fourth problem-solving means in which a secondary groove (16) made up of a plurality of intermittent recessed portions is formed in a convexity (15) forming the main groove (12) .
- the tenth problem-solving means is a means according to the ninth problem-solving means in which the secondary groove (16) is centrally formed in the convexity (15) of the main groove (12) so that the secondary groove (16) is spaced a predetermined distance apart from the deformed portion (13) .
- the eleventh problem-solving means is a mans according to the ninth problem-solving means in which the secondary groove (16) is formed to a depth of 0.25 to 0.75 times the depth of the line groove (11).
- the twelfth problem-solving means is a means according to the ninth problem-solving means in which the secondary groove (16) is formed substantially along the tube axis directional line.
- Each problem-solving means is an inner grooved heat transfer tube in which, as in the previous problem-solving means, a plurality of line grooves (11) are formed in an inner peripheral surface of the heat transfer tube and the line groove (11) comprises main grooves (12) formed at a first lead angle ( ⁇ ) and deformed portions (13) formed at a second lead angle ( ⁇ ) differing from the first lead angle ( ⁇ ) which are successively formed.
- the thirteenth problem-solving means is a means in which a secondary groove (16) made up of a plurality of intermittent recessed portions is formed in a convexity (15) forming the main groove (12) and the secondary groove (16) is centrally formed in the convexity (15) of the main groove (12) so as to be separated a predetermined distance apart from the deformed portion (13) .
- the fourteenth problem-solving means is a means in which a secondary groove (16) made up of a plurality of intermittent recessed portions is formed in a convexity (15) forming the main groove (12) and the secondary groove (16) is formed to a depth which is from 0.25 to 0.75 times the depth of the line groove (11) .
- the fifteenth problem-solving means is a means in which a secondary groove (16) made up of a plurality of intermittent recessed portions is formed in a convexity (15) forming the main groove (12) and the secondary groove (16) is formed substantially along the tube axis directional line.
- the percentage of the length of the deformed portion (13) to the length of a single round of the line groove (11) is so set as to fall in the range of 10 to 35%. If the percentage is less than 10%, liquid refrigerant is not scattered readily even when the deformed portion (13) is provided. However, the aforesaid setting provides a sufficient scattering action. On the other hand, if the percentage is greater than 35%, this increases the loss of pressure when used particularly in an evaporator. However, the aforesaid range suppresses the loss of pressure.
- the length of each deformed portion (13) is so set as to fall in the range of five to fifteen times the pitch of the line groove (11).
- liquid refrigerant flowing in the main groove (12) of the line groove (11) moves forward while climbing over a plurality of deformed portions (13) , during which the liquid refrigerant is scattered sufficiently.
- the aforesaid value is less than five times the pitch of the line groove (11)
- the liquid refrigerant is not scattered readily even when the deformed portion (13) is provided.
- the aforesaid setting provides a sufficient scattering action.
- the value is greater than fifteen times the pitch of the line groove (11) , this increases the loss of pressure when used particularly in an evaporator.
- the aforesaid setting suppresses the loss of pressure.
- the liquid refrigerant flowing in the main groove (12) is sufficiently scattered when climbing over a plurality of deformed portions (13) (five to fifteen deformed portions (13) ) . Accordingly, it is possible to secure a refrigerant scattering action when used in a condenser and to suppress the loss of pressure when used in an evaporator.
- the joint portion (14) of the electric welded tube and the deformed portion (13) are arranged at respective locations substantially equally dividing the direction of the circumference of the electric welded tube.
- the liquid refrigerant flowing in the main groove (12) of the line groove (11) is evenly scattered at the joint portion (14) and the deformed portion (13) in the heat transfer tube (10) .
- the action of scattering liquid refrigerant is obtained throughout the entire inner surface of the heat transfer tube (10) and the arrangement that the deformed portion (13) and the joint portion (14) are disposed in a scattering manner suppresses the loss of pressure when used in an evaporator.
- the deformed portion (13) is formed at multiple positions in a single round of the line groove (11) , as set forth in the fifth problem-solving means, the action of scattering liquid refrigerant can be obtained at each deformed portion (13) . This further ensures that the liquid layer is prevented from growing thicker.
- the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are so set as to fall in the range of 5 to 30 degrees in opposite torsional directions respectively with respect to the tube axis directional line, as set forth in the sixth problem-solving means (particularly if these angles are set at 18 degrees as set forth in the eighth problem-solving means), the refrigerant flows in a helical direction by the main groove (12) and efficiently forms an even and thin layer of liquid and, at the same time, the action of scattering by the deformed portion (13) is obtained reliably.
- the secondary groove (16) is provided in the convexity (15) which forms the main groove (12) , as set forth in the ninth problem-solving means, this means that a plurality of intermittent recessed portions are defined in the convexity (15) .
- the area of heat transfer increases.
- the provision of the secondary groove (16) reduces the loss of pressure because while producing a helical flow by a main groove (12) a part of the refrigerant is caused to flow into the next main groove (12) by the secondary groove (16) .
- the secondary groove (16) is formed centrally in the convexity (15) of the main groove (12) so that the secondary groove (16) is spaced a predetermined distance apart from the deformed portion (13) , as set forth in the tenth problem-solving means, this ensures a helical flow action by the main groove (12) .
- the secondary groove (16) is formed in close proximity to the deformed portion (13) , this causes refrigerant to escape from the secondary groove, and helical flows are less likely to occur.
- the above-mentioned configuration is free from such a danger.
- the depth of the secondary groove (16) is less than 0.25 times the depth of the line groove (11) , the area of heat transfer will not increase as expected.
- the depth of the secondary groove (16) is more than 0.75 times the depth of the line groove (11) , this will cause the refrigerant to readily escape from the secondary groove (16) thereby preventing a helical flow from being produced.
- this makes it possible to produce a helical flow while increasing the area of heat transfer.
- the secondary groove (16) is formed substantially along the tube axis directional line, as set forth in the twelfth problem-solving means, this makes it possible to suppress the loss of pressure while increasing the area of heat transfer because the flow of refrigerant becomes relatively less disturbed in the main groove (12) .
- the secondary groove (16) is formed in the convexity (15) which forms the main groove (12) . Accordingly, like the ninth problem-solving means, it is possible to reduce the loss of pressure while increasing the area of heat transfer. More specifically, the thirteenth problem-solving means ensures that helical flows are produced without fail by the same action as the tenth problem-solving means. The fourteenth problem-solving means produces helical flows while securing a heat transfer area by the same action as the eleventh problem-solving means. The fifteenth problem-solving means suppresses the turbulence of the flow of refrigerant by the same action as the twelfth problem-solving means, thereby reducing the loss of pressure.
- the percentage of the length of the deformed portion (13) to the length of a single round of the line groove (11) is so set as to fall within the range between 10% and 35%. This provides a sufficient scattering action by the deformed portion (13) when used in a condenser and reduces the loss of pressure when used in an evaporator. In other words, if it is intended to obtain only a refrigerant scattering action in the condenser, it is sufficient for the inner surface of the heat transfer tube (10) to be formed into an irregular convex-concave shape. In such a case, however, the loss of pressure in the evaporator will increase. On the other hand, if the percentage is so set as to fall within the above-mentioned range, this makes it possible to maintain well-balanced relationships between the action of scattering refrigerant and the loss of pressure.
- the length of a single deformed portion (13) is so set as to fall within the range between five times and fifteen times the pitch of the line groove (11) , and liquid refrigerant flowing in a main groove of the line groove (11) moves forward while climbing over a plurality of deformed portions (13) , during which the liquid refrigerant is scattered sufficiently.
- the relationship between the length of the deformed portion (13) and the pitch of the line groove (11) is not set greater than necessary but within the above-described range, thereby making it possible to suppress the loss of pressure while achieving a sufficient liquid refrigerant scattering action.
- the third problem-solving means five to fifteen deformed portions (13) are so arranged as to intersect a main groove (12) .
- liquid refrigerant flowing in the main groove (12) is scattered sufficiently at the time of climbing over a plurality of deformed portions (13) and the loss of pressure is suppressed when used in an evaporator, as in the second problem-solving means.
- the fourth problem-solving means it is arranged in such a way that liquid refrigerant is scattered evenly at the joint portion (14) and the deformed portions (13) in the electric welded tube.
- liquid refrigerant and gas refrigerant are dispersed evenly, which has an effect, particularly on a drifted flow of refrigerant.
- first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are so set as fall in the range of 5 to 30 degrees in opposite torsional directions respectively with respect to the tube axis directional line, as set forth in the sixth problem-solving means (particularly if these angles are set at 18 degrees as set forth in the eighth problem-solving means), this makes it possible to maintain well-balanced relationships between the heat transfer efficiency and the loss of pressure while securing the effect of a helical flow.
- first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are set in order that the main groove (12) and the deformed portion (13) of the line groove (11) may be directed symmetrically with respect to the tube axis directional line, this makes the manufacture of the heat transfer tube (10) relatively easy.
- the heat transfer tube (10) is an electric welded tube, this enables a roll for marking the line grooves (11) in a material of which the heat transfer tube (10) is made to have symmetrical grooves and ridge angles. This facilitates the manufacture of the roll itself and torsion of the material at the time of marking is less likely to occur.
- the secondary groove (16) is formed in the convexity (15) which forms the main groove (12) , as set forth in the ninth problem-solving means, this makes it possible to improve heat transfer efficiency by expanding a heat transfer area. Besides, it is possible to reduce the loss of pressure. Particularly, if the position, the depth, and the angle of the secondary groove are set to the foregoing predetermined values, as set forth in the tenth to twelfth problem-solving means, this further ensures the aforesaid effects.
- the secondary groove (16) is formed in the convexity (15) of the main groove (12) , thereby making it possible to provide not only improvement in heat transfer efficiency by heat transfer area expansion but also reduction in pressure loss. More specifically, even when the percentage of the deformed portion (13) in the line groove (11) is made relatively large, it is possible to suppress the loss of pressure when used as an evaporator. Further, when used as a condenser, it is possible to obtain an effect of scattering liquid refrigerant without fail. Accordingly, like the first to fourth problem-solving means, it is possible to improve the performance of heat exchangers.
- FIG. 1 is a partially broken-out front view of an inner grooved heat transfer tube (10) of the present embodiment.
- the heat transfer tube (10) has a U-bent shape, in other words the heat transfer tube (10) is a so-called hairpin tube.
- Formed in the internal surface of the heat transfer tube (10) are a great number of line grooves (11) oblique to the tube axis directional line.
- a plurality of such heat transfer tubes (10) and a plate fin (not shown) are combined together, and opening ends of the heat transfer tubes (10) are connected appropriately to form a plate-fin coil type heat exchanger.
- FIG. 2 shows the inner grooved heat transfer tube (10) with a part thereof developed.
- each of the line grooves (11) formed in the internal surface of the heat transfer tube (10) comprises an alternative series of main grooves (12) formed at a first lead angle ( ⁇ ) and deformed portions (13) formed at a second lead angle ( ⁇ ) which is different from the first lead angle ( ⁇ ).
- the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are formed in opposite directions relative to a tube axis directional line. More specifically, the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are formed at 18 degrees with respect to the tube axis directional line in opposite directions. Because of such arrangement, the main groove (12) and the deformed portion (13) of the line grooves are symmetrically directed with respect to the tube axis directional line.
- the deformed portion (13) is formed at two positions in a single round of the line groove (11).
- two deformed portions (13) in a line groove (11) extending from one circumferential end to the other circumferential end. Further, it is set such that the percentage of the total length of the two deformed portions (13) to the length of a single round of the line groove (11) is 28%.
- each deformed portion (13) is about 8.5 times the pitch (P) of the line groove (11) . And, by virtue of these set values, about twelve deformed portions (13) are so arranged as to intersect an extension of a single main groove (12) of the line groove (11) .
- the heat transfer tube (10) is an electric welded tube, wherein a joint portion (14) and each deformed portion (13) of the heat transfer tube (10) are arranged at respective locations substantially equally dividing the direction of the circumference of the heat transfer tube (10) , in other words they are spaced about 120 degrees apart from each other, as shown in Figure 3 which is an enlarged cross-sectional schematic view taken along the lines III-III of Figure 1.
- Figure 4 is an enlarged view showing a cross section of the line groove (11) .
- the line groove (11) is defined between adjoining convexities (15) .
- the convexities (15) have the same cross-sectional shape for both the main groove (12) and the deformed portion (13) .
- FIG. 5 which is a partially enlarged view of Figure 2 and to Figure 6 which is a schematic perspective view of the convexity (15)
- a plurality of intermittent recessed portions are formed in the convexity (15) constituting the main groove (12).
- each recessed portion forms a secondary groove (16) .
- the secondary groove (16) is formed only at a substantially central portion of the convexity (15) of each main groove (12) and is spaced a predetermined distance apart from both ends of each deformed portion (13) .
- the secondary groove (16) is illustrated in Figure 2 in which only the region where it is formed is simplified.
- the secondary groove (16) is formed, having a depth of about 0. 5 times the groove depth of the line groove (11). Furthermore, the secondary groove (16) is formed substantially along the tube axis directional line.
- the refrigerant changes to liquid from a gas phase as it moves forward through the condenser and then flows along the main groove (12) of the line groove (11).
- the first lead angle ( ⁇ ) formed between the main groove (12) and the tube axis directional line is set at 18 degrees, this ensures that the refrigerant flows helically and forms a thin film of liquid. Furthermore, in such a setting of angle, the loss of pressure will not increase excessively by the angle of helix becoming too great.
- the refrigerant flows in the main groove (12) and reaches the deformed portion (13)
- the refrigerant comes into collision with a side wall of the convexity (15) of the deformed portion (13) and is scattered from the inner peripheral surface of the heat transfer tube (10) toward the center because the first lead angle ( ⁇ ) of the main groove (12) differs from the second lead angle ( ⁇ ) of the deformed portion (13).
- the deformed portion (13) is formed at a lead angle of 18 degrees in an opposite direction to the main groove (12).
- the percentage of the total length of the two deformed portions (13) to the length of a single round of the line groove (11) is 28%. Further, the length of each deformed portion (13) is so set as to be about 8.5 times the pitch of the line groove (11) .
- the refrigerant which flows along the main groove (12) and forms a thin film of liquid, is scattered definitely when climbing over the convexities (15) of the deformed portions (13) many times (twelve times in the present embodiment), so that formation of a thick layer of liquid is less likely to take place on the inner surface of the heat transfer tube (10) , thereby preventing the occurrence of an annular flow.
- the action of scattering refrigerant can be obtained sufficiently because the percentage of the total length of the deformed portions to the length of a single round of the line groove (11) is not set too small (28%), the ratio of the length of each deformed portion to the pitch of the line groove is not set too small (8.5 times), and the number of deformed portion ridges that the refrigerant climbs over is not set too small (12 ridges).
- the joint portion (14) and the plural deformed portions (13) of the heat transfer tube (10) are arranged at respective locations substantially equally dividing the direction of the circumference of the heat transfer tube (10).
- liquid refrigerant flowing in the main groove (12) of the line groove (11) is scattered evenly at the joint portion (14) and the deformed portions (13) in the heat transfer tube (10) . Accordingly, the action of equal scattering of liquid refrigerant can be obtained throughout the entire inner surface of the heat transfer tube (10) .
- the loss of pressure can be suppressed because the percentage of the total length of the deformed portions (13) to the length of a single round of the line groove (11) is not set too large (28%), the ratio of the length of each deformed portion (13) to the pitch of the line groove (11) is not set too large (8.5 times), and the number of the convexities of the deformed portions (13) that the refrigerant climbs over is not set too many (12 ridges) in the aforesaid configuration.
- the secondary groove (16) is formed in the convexity (15) which forms the main groove (12) , this provides an increased heat transfer area and reduces the loss of pressure by causing, while creating a helical flow by a main groove (12), a part of the refrigerant to flow to the next main groove (12) by the secondary groove (16). Further, the location, the depth, and the directionality of the secondary groove (16) are specified. This ensures that the loss of pressure is suppressed while at the same time definitely securing the action of a helical flow.
- the heat transfer tube (10) is used as a condenser.
- the efficiency of heat transfer can be improved.
- the increase in pressure loss can be suppressed.
- the heat transfer tube (10) it is sufficient for the heat transfer tube (10) to have, as its inner surface, an irregularly rugged surface, when it is intended just to improve the efficiency of heat transfer by upgrading the action of scattering refrigerant.
- the heat transfer tube (10) of the present embodiment it is possible to maintain well-balanced relationships between refrigerant scattering action and pressure loss by specifying the structure of the deformed portion (13) to the aforesaid structure. Accordingly, it becomes possible to upgrade the performance of heat exchangers.
- first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are each set at 18 degrees in opposite torsional directions relative to the tube axis directional line, which makes it possible to maintain highly well-balanced relationships between heat transfer efficiency and pressure loss by scattering refrigerant while securing a helical flow effect.
- the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are set in such a way that the main groove (12) and the deformed portion (13) of the line groove (11) are symmetrically directed with respect to the tube axis directional line, this makes the manufacture of the heat transfer tube (10) relatively easy.
- the heat transfer tube (10) is an electric welded tube, this enables a roll for marking the line grooves (11) in a material of which the heat transfer tube (10) is made to have symmetrical grooves and ridge angles. This facilitates the manufacture of the roll itself and torsion of the material at the time of marking is less likely to occur.
- the secondary grooves (16) are formed in the convexity (15) forming the main groove (12) , this makes it possible to provide improvements in heat transfer efficiency by heat transfer area expansion. Besides, it is possible to reduce the loss of pressure. Especially, setting the location, the depth, and the angle of the secondary groove to the foregoing predetermined values further ensures the effects.
- the provision of the secondary groove (16) is effective particularly for suppression of the loss of pressure, even when making the size of the deformed portion (13) relatively large.
- the following heat transfer tubes were prepared, namely a heat transfer tube (a comparative example) in which the line groove (11) comprises only a helical main groove (12) of 18 degrees; a heat transfer tube (the first embodiment) in which the line groove (11) comprises a main groove (12) and a deformed portion (13) ; and a heat transfer tube (the second embodiment) which further comprises a secondary groove (16) in the first embodiment.
- the heat transfer tube as a comparative example in which the line groove (11) comprising only a helical main groove (12) is formed is indicated by long dashed short dashed line
- the heat transfer tube of the first embodiment in which the line groove (11) comprises a main groove (12) and a deformed portion (13) is indicated by broken line
- the heat transfer tube of the second embodiment in which the line groove (11) is provided with a deformed portion (13) and a secondary groove (16) is indicated by solid line.
- both the heat transfer tube of the first embodiment and the heat transfer tube of the second embodiment are superior in condensation capability to the comparative example heat transfer tube. More specifically, when the front surface wind velocity of the heat exchanger is relatively slow, the heat transfer tube of the second embodiment is slightly superior in condensation capability to the heat transfer tube of the first embodiment. On the other hand, when the front surface wind velocity of the heat exchanger is relatively fast, the heat transfer tube of the first embodiment is slightly superior in condensation capability to the heat transfer tube of the second embodiment.
- these numeric values are in the range of error, and it is believed that the provision of the deformed portion (13) has a sufficient effect on the improvement in condensation capability, regardless of whether the secondary groove (16) is formed.
- the heat transfer tube of the first embodiment is superior in evaporation capability to the comparative example heat transfer tube in every wind velocity range used for measurement, and the heat transfer tube of the second embodiment provides further improved evaporation capabilities.
- the provision of the secondary groove (16) has a great effect on reducing the loss of pressure, thereby achieving improvement in evaporation capability.
- the percentage of the length of the deformed portion (13) of the line groove (11) to the length of a single round of the line groove (11) is 28%.
- Such setting provides a sufficient scattering action (if the percentage is less than 10%, liquid refrigerant is less likely to be scattered in the condenser even when the deformed portion (13) is provided), and suppresses the loss of pressure (if the percentage is more than 35%, this results in an increase in the loss of pressure when used in the evaporator).
- each deformed portion (13) is not limited to 8.5 times the pitch of the line groove (11).
- the length of each deformed portion (13) may be set so as to fall within the range between five times and fifteen times the pitch of the line groove (11). Such setting provides a sufficient scattering action (if the deformed portion length is less than five times the line groove pitch, liquid refrigerant is less likely to be scattered in the condenser even when the deformed portion (13) is provided), and suppresses the loss of pressure (if the deformed portion length is more than fifteen times the line groove pitch, this results in an increase in the loss of pressure when used in the evaporator).
- the number of the convexities (15) of the deformed portions (13) intersecting an extension of a single main groove (12) of the line groove (11) is not limited to twelve. If the number is set so as to fall in the range of from five to fifteen, this not only secures an effect of scattering refrigerant when used in a condenser but also effectively suppresses the loss of pressure when used in an evaporator.
- the invention is not necessarily required to meet all the above-mentioned conditions. For example, if at least one of the conditions, such as the percentage of the length of the deformed portion (13) to the length of a single round of the line groove (11) , is satisfied, this makes it possible to achieve better heat exchange performance than conventional heat transfer tubes.
- the provision of the secondary grooves (16) provides a higher effect of preventing the increase in pressure loss. Therefore, as long as the secondary grooves (16) are provided, the conditions, such as the percentage of the length of the deformed portion (13) to the length of a single round of the line groove (11), the relationship between the length of each deformed portion (13) and the pitch of the line groove (11), and the number of deformed portions (13) intersecting a single main groove (12), may fall outside the aforementioned ranges.
- the number of deformed portions (13) may be one or not less than 3. Even in such a case, it is preferable that the joint portion (14) and the deformed portion(s) (13) of the heat transfer tube (10) implemented by an electric welded tube are arranged at respective locations substantially equally dividing the direction of the circumference thereof. However, they are not necessarily arranged at equal intervals in cases including a case in which the number of deformed portions (13) is two, as in the previous embodiments.
- first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) are each set at 18 degrees in opposite torsional directions relative to the tube axis directional line.
- such a set angle may fall within the range between 5 degrees and 30 degrees.
- the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) may not be set in such a way that the main groove (12) and the deformed portion (13) are symmetrically directed with respect to the tube axis directional line.
- the first lead angle ( ⁇ ) and the second lead angle ( ⁇ ) may not be set in opposite directions, in other words they may be set in the same direction, having different values.
- the depth of the secondary groove (16) is not necessarily 0.5 times larger than the depth of the line groove (11) . As long as the secondary groove (16) is formed having a depth of 0.25 to 0.75 times the depth of the line groove (11) , it is possible to obtain a helical flow effect while increasing the area of heat transfer. Finally, the secondary groove (16) is not necessarily formed along the tube axis directional line. Even if the secondary groove (16) is formed in such a way that it is inclined about five degrees toward both sides with respect to the tube axis directional line, this still effectively reduces the loss of pressure.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Geometry (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000105836A JP2001289586A (ja) | 2000-04-07 | 2000-04-07 | 内面溝付伝熱管 |
JP2000105836 | 2000-04-07 | ||
PCT/JP2001/003019 WO2001077601A1 (fr) | 2000-04-07 | 2001-04-06 | Tube chauffant muni de rainures de la surface interieure |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1271087A1 true EP1271087A1 (de) | 2003-01-02 |
EP1271087A4 EP1271087A4 (de) | 2008-07-30 |
Family
ID=18619099
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01917860A Withdrawn EP1271087A4 (de) | 2000-04-07 | 2001-04-06 | Heizrohr mit gerillter innerer oberfläche |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1271087A4 (de) |
JP (1) | JP2001289586A (de) |
CN (1) | CN1253686C (de) |
AU (2) | AU4474001A (de) |
WO (1) | WO2001077601A1 (de) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02137609A (ja) * | 1988-11-15 | 1990-05-25 | Hitachi Cable Ltd | 管内凝縮用伝熱管およびその製造方法 |
JPH02137631A (ja) * | 1988-11-15 | 1990-05-25 | Hitachi Cable Ltd | 管内面溝付凝縮用伝熱管の拡管方法 |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57183487U (de) * | 1981-05-13 | 1982-11-20 | ||
JP2577502B2 (ja) * | 1990-10-16 | 1997-02-05 | 三菱伸銅株式会社 | 内面溝付き管の製造方法 |
JP2618084B2 (ja) * | 1990-10-17 | 1997-06-11 | 三菱伸銅株式会社 | 内面溝付き管の製造方法および製造装置 |
JPH04172187A (ja) * | 1990-11-02 | 1992-06-19 | Mitsubishi Shindoh Co Ltd | 内面溝付き管の製造方法 |
JP2930249B2 (ja) * | 1990-11-02 | 1999-08-03 | 三菱伸銅株式会社 | 内面溝付き管の製造方法 |
JP3199636B2 (ja) * | 1996-05-30 | 2001-08-20 | 住友軽金属工業株式会社 | 内面溝付伝熱管 |
JP3286171B2 (ja) * | 1996-08-06 | 2002-05-27 | 株式会社神戸製鋼所 | 内面溝付き伝熱管 |
JPH10153360A (ja) * | 1996-11-22 | 1998-06-09 | Daikin Ind Ltd | 内面溝付伝熱管 |
JP3331518B2 (ja) * | 1997-01-13 | 2002-10-07 | 株式会社日立製作所 | 内面フィン付き伝熱管及び熱交換器 |
JPH10300379A (ja) * | 1997-05-01 | 1998-11-13 | Sumitomo Light Metal Ind Ltd | 内面溝付伝熱管 |
JPH11108579A (ja) * | 1997-10-02 | 1999-04-23 | Kobe Steel Ltd | 内面溝付管 |
-
2000
- 2000-04-07 JP JP2000105836A patent/JP2001289586A/ja active Pending
-
2001
- 2001-04-06 AU AU4474001A patent/AU4474001A/xx active Pending
- 2001-04-06 AU AU2001244740A patent/AU2001244740B2/en not_active Ceased
- 2001-04-06 EP EP01917860A patent/EP1271087A4/de not_active Withdrawn
- 2001-04-06 CN CN 01810932 patent/CN1253686C/zh not_active Expired - Fee Related
- 2001-04-06 WO PCT/JP2001/003019 patent/WO2001077601A1/ja active IP Right Grant
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02137609A (ja) * | 1988-11-15 | 1990-05-25 | Hitachi Cable Ltd | 管内凝縮用伝熱管およびその製造方法 |
JPH02137631A (ja) * | 1988-11-15 | 1990-05-25 | Hitachi Cable Ltd | 管内面溝付凝縮用伝熱管の拡管方法 |
Non-Patent Citations (1)
Title |
---|
See also references of WO0177601A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU4474001A (en) | 2001-10-23 |
CN1436293A (zh) | 2003-08-13 |
JP2001289586A (ja) | 2001-10-19 |
EP1271087A4 (de) | 2008-07-30 |
AU2001244740B2 (en) | 2005-02-17 |
CN1253686C (zh) | 2006-04-26 |
WO2001077601A1 (fr) | 2001-10-18 |
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