JP2005061778A - Evaporator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporator capable of improving evaporation efficiency, and capable of remarkably reducing fluid resistance of a flowing refrigerant. <P>SOLUTION: This evaporator is arranged in a flowing part of a heat exchange medium, and partitions the flowing part into a plurality of medium passages, and is provided with an inner fin 5a for offsetting the partitioned respective medium passages at a prescribed interval in the direction orthogonal to the flowing direction of the heat exchange medium. The inner fin 5a has a plurality of louver parts R offset at a prescribed interval. An upstream side end part R1 in the flowing direction of the heat exchange medium of a wall surface for partitioning the flowing part of the respective louver parts R, is formed in the shape of inclining in a substantially V shape in the flowing direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an evaporator, and is suitable for application to an evaporator used in, for example, an air conditioner for automobiles.

  Conventionally, in a heat exchanger that is an evaporator of this type, the refrigerant that has flowed into a tube as a circulation part of a heat exchange medium (for example, a refrigerant) from a tank on the inlet side is overheated when passing through this circulation part. Evaporates. For this reason, as shown in FIG. 10, an inner fin 100 having a corrugated cross section in a direction orthogonal to the refrigerant flow direction is provided in the circulation portion, and the inner fin 100 allows the refrigerant passage 101 to pass through the tube. The heat transfer efficiency (that is, the evaporation efficiency of the refrigerant) is improved by partitioning into two and expanding the heat transfer area for the refrigerant.

Further, for example, in Patent Document 1, as the inner fin, as shown in FIG. 11, an offset fin 110 formed so that the coolant channel 111 is offset at a predetermined interval in a direction orthogonal to the coolant flow direction is used. Thus, a technique for further improving the heat transfer efficiency is disclosed.
JP-A-5-231792

  However, in the technique of Patent Document 1, when the refrigerant passing through the refrigerant flow path 111 is in a liquid state, the refrigerant is in the vicinity of the junction between the offset fin 110 and the tube 112 as shown in FIG. The liquid refrigerant in this portion tends to be thick, and the heat transfer efficiency (evaporation efficiency) to the refrigerant tends to be reduced. Conversely, in the wall surface portion defining the tube 112 of the offset fin 110, the liquid refrigerant Therefore, the heat transfer efficiency (evaporation efficiency) for the refrigerant tends to increase.

  For this reason, the evaporating efficiency with respect to a refrigerant | coolant differs in the junction part vicinity of the said offset fin 110 and the tube 112, and the wall surface part of the offset fin 110, and the performance of the heat exchanger might be reduced.

  Such a phenomenon becomes more prominent as the fin pitch of the inner fin (offset fin 110) becomes smaller, and the influence of the uneven distribution of the liquid refrigerant on the evaporation efficiency becomes larger.

  Further, since the upstream end portion of the offset fin 110 in the refrigerant flow direction in the wall surface of the offset fin 110 is formed in a straight line with respect to the refrigerant flow, the refrigerant flowing in the refrigerant flow path 111 is There was a tendency that the fluid flow resistance of the refrigerant increased because it collided almost vertically with the upstream end of 110.

  In addition, in this case, the refrigerant gathered in the vicinity of the junction between the offset fin 110 and the tube 112 reduces the passage cross-sectional area of the refrigerant in the refrigerant flow path 111, so that the flow resistance of the refrigerant is further increased. It was.

  Therefore, the present invention has been made in view of the above-described problems, and provides an evaporator that can improve the evaporation efficiency and can significantly reduce the flow resistance of the circulating heat exchange medium.

  In Claim 1, it arrange | positions in the distribution | circulation part of a heat exchange medium, and it divides | segments the said distribution | circulation part into several medium flow paths, and orthogonally crosses the divided each medium flow path with respect to the flow direction of a heat exchange medium. In an evaporator provided with inner fins that are offset at a predetermined interval in the direction in which the inner fin has a plurality of louver portions offset at a predetermined interval, the heat exchange medium on the wall surface that divides the flow portion of each louver portion The upstream end in the flow direction has a shape that is inclined so as to be recessed in a generally U shape toward the flow direction of the heat exchange medium.

  In claim 2, the heat exchange medium of claim 1 is made of a gas-liquid two-phase refrigerant.

  According to claim 1, the inner fin has a plurality of louver portions offset at a predetermined interval in a direction orthogonal to the flow direction of the heat exchange medium, and the flow direction of the heat exchange medium on the wall surface of each louver portion The upstream end of the heat exchange medium has a shape that is inclined so as to be recessed in a generally U shape toward the flow direction of the heat exchange medium. The heat exchange medium can be made to contact the respective louver parts substantially uniformly from the vicinity of the joints with the parts to the center of the wall surface of each louver part, thus improving the heat transfer efficiency, that is, the evaporation efficiency. In addition, it is possible to realize an evaporator that can significantly reduce the flow resistance of the heat exchange medium flowing through each louver part.

  According to claim 2, when the heat exchange medium of claim 1 is made of a gas-liquid two-phase refrigerant, the liquid phase part of the refrigerant is uniformly distributed in the medium flow path composed of the flow part and each louver part. The gas phase part of the refrigerant can be circulated in the medium flow path that can be contacted and in the medium flow path in which the liquid phase part of the refrigerant is uniformly contacted, that is, in the medium flow path surrounded by the liquid phase part of the refrigerant. It is possible to exchange heat from the medium flow path side (ie, the outside) with respect to the liquid phase portion of the refrigerant, and from the side (ie, the inside) where the refrigerant gas phase in the medium flow path circulates. Since the heat exchange can be promoted by the gas phase portion, the evaporation efficiency can be further improved.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
1 to 3 show a first embodiment of an evaporator according to the present invention, FIG. 1 is a perspective view showing a schematic configuration of a heat exchanger as an evaporator according to the present embodiment, and FIG. 2 is a heat exchange of FIG. FIG. 3 is an exploded perspective view showing a part of the heat exchanger of FIG. 1 in an enlarged manner.

  In FIG. 1, reference numeral 1 denotes a stacked heat exchanger according to the present embodiment, which is configured by attaching a pair of tanks 3 a and 3 b to both ends of the core 2 in the left-right direction (the direction of arrow a in the figure).

  As shown in FIGS. 2 and 3, the core 2 includes a plurality of (in this case, six) plates 41, 42, 43, 44, 45, and 46, and end portions (for example, plates) of these plates 41 to 46. 41 and 42 are provided at both ends of the core 2 in the front-rear direction (arrow b direction in the figure), and between the plates 42 and 43 are provided at both ends in the left-right direction of the core 2 (in this case, for each layer). Bars 6a, 6a and 6b, 6b as two spacers are alternately stacked, and each layer is configured to function as a tube which is a flow part through which the heat exchange medium flows.

  In addition, between the bars 6a, 6a and 6b, 6b between the plates 41 to 46, a louver portion R is formed in a rectangular shape to be described later, and divides the tube into a plurality of heat exchange medium flow paths. Inner fins 5a and outer fins 5b are provided as offset fins that are offset in a direction orthogonal to the flow direction of the heat exchange medium in the heat exchange medium flow path at predetermined intervals.

  At this time, as shown in FIG. 3, the layer between the plate 42 and the plate 43 at the next stage (that is, the third stage from the top) has both ends in the left-right direction (the direction of the arrow a) at the bar 6b, 6b, each corrugation of the outer fin 5b interposed between the bars 6b, 6b, that is, each louver portion R extends in the front-rear direction (arrow b direction). It communicates with the outside. The layers between the plates 44-45 are similarly constructed, and these layers are hereinafter referred to as even layers.

  On the other hand, the layer between the third-stage plate 43 and the fourth-stage plate 44 is closed at both ends in the front-rear direction (arrow b direction) by the bars 6a, 6a, and the bars 6a, 6a. Each louver portion R of the inner fin 5a interposed therebetween extends in the left-right direction (arrow a direction), and this layer communicates with the tanks 3a, 3b on the left and right sides, respectively. The layers between the plates 41-42 and the plates 45-46 are similarly configured, and these layers are hereinafter referred to as odd layers.

  Thus, in such a heat exchanger 1, the combination of the bar 6a and the inner fin 5a and the combination of the bar 6b and the outer fin 5b are alternately arranged, and each component constituting the core 2; That is, the plates 41 to 46, the inner fin 5a, the outer fin 5b, and the bars 6a and 6b are laminated to each other via the brazing material 8, and are brazed at the respective contact portions.

  Incidentally, reference numerals 7a and 7b in FIG. 1 and FIG. 2 are medium outlet and medium inflow pipes provided at the lower and upper parts of the tanks 3a and 3b, and the heat exchange flowing into the tank 3a from the medium inflow pipe 7a. A medium, for example, a refrigerant composed of two layers of gas and liquid, reaches the opposite tank 3b through the odd-numbered layer provided with the inner fin 5a, and flows out from the medium outlet pipe 7b.

  In addition, another heat exchange medium such as air flows through the even layer provided with the outer fin 5b, and the inner fin 5a, the outer fin 5b, and the plates 41 to 46 are interposed between the two heat exchange media flowing orthogonally. The heat exchange is performed sequentially through the.

  Here, as shown in FIGS. 1 and 3, the inner fin 5a and the outer fin 5b are formed by offsetting the louver portion R in a direction orthogonal to the flow direction of the heat exchange medium at predetermined intervals. In addition, the upstream end R1 of each louver portion R in the flow direction of the heat exchange medium is formed in a shape that is inclined so as to be recessed in a substantially U shape toward the flow direction of the heat exchange medium.

  In this way, by forming the upstream end R1 of the louver portion R in the inner fin 5a and the outer fin 5b so as to be inclined in a substantially square shape, the flow of the circulating heat exchange medium is bent, and FIG. As shown, the joints with the upper and lower plates 41-42, 42-43, 43-44, 44-45, and 45-46 in the inner fin 5a and the outer fin 5b (that is, each louver portion R) as the flow portion. The flow range of the heat exchange medium can be expanded from the vicinity toward the center of the wall surface of the inner fin 5a and the outer fin 5b (that is, each louver portion R).

In particular, in the inner fin 5a, since the flow range of the liquid phase portion in the refrigerant can be expanded, the upper and lower plates 41-42, 43-44, 45- 46 and the louver portion R can be contacted substantially uniformly in the refrigerant flow path to improve the evaporation efficiency (heat transfer efficiency), and the refrigerant flow in which the gas phase portion in the refrigerant is surrounded by the liquid phase By circulating through the passage, heat exchange can be efficiently promoted from the inside to the liquid phase portion in the refrigerant.

  In addition, at this time, since the upstream end R1 in each louver portion R is formed to be inclined in a substantially square shape toward the refrigerant flow direction, the flow resistance of the circulating refrigerant is greatly reduced. Can be made.

  Incidentally, each louver portion R of the inner fin 5a and the outer fin 5b is formed in a size appropriately set according to the size of the heat exchanger or the like, but the pitch P1 between a pair of adjacent upstream end portions R1 is 1.0. About 3.0 [mm], the height T1 in each layer (for example, between the plates 41-42) is about 1.0 to 2.0 [mm], and the length L1 between the upstream ends R1 in the refrigerant flow direction is 1.0 to 10.0 [ mm], and the inclination angle V1 of the upstream end R1 is preferably about 18 [°] to 80 [°].

  The inclination angle V1 of the louver portion R is set for the following reason. That is, the flow resistance changes according to the inclination angle V1 of the louver R, as can be seen from the graph in which the vertical axis shown in FIG. 5 indicates the flow resistivity and the horizontal axis indicates the inclination angle V1 of the louver R. The flow resistance tends to decrease as the inclination angle V1 decreases.

  For example, when the inclination angle V1 is around 80 [°], the inclination angle V1 is reduced to about 95 [%] of the flow resistance when the inclination angle V1 is 90 [°] (that is, when the louver portion R is not provided with the inclination angle V1), When the inclination angle V1 is around 60 [°], it decreases to about 65%. From this, the inclination angle V1 of the louver part R is preferably about 80 [°] or less, and more preferably about 75 [°] or less.

  On the other hand, when the inclination angle V1 of the louver part R is reduced, the length L2 from the root part where the inclination of the louver part R starts at the downstream end of the louver part R to the center part which is the apex of the inclination (hereinafter referred to as this). Is referred to as the protrusion amount L2), and when the protrusion amount L2 is increased in this manner, the temperature of the fins 5a and 5b decreases, and the heat transfer efficiency to the refrigerant may decrease. Therefore, it is desirable that the protrusion amount L2 is up to about 1.5 times the height T1 of each fin 5a, 5b (that is, the louver portion R) because it has an effective length.

  From this, according to the graph showing the ratio of the protrusion amount L2 to the height T1 of the louver portion R on the vertical axis and the inclination angle V1 of the louver portion R on the horizontal axis, the inclination angle V1 is about 18 [ Since the protrusion amount L2 is about 1.5 times or more the height of the louver portion R below the vicinity of [°], the inclination angle V1 of the louver portion R is preferably about 18 [°] or more.

  Thus, in this heat exchanger 1, the upstream end R1 of each louver portion R of the inner fin 5a and outer fin 5b interposed in the laminated core 2 is substantially directed toward the flow direction of the heat exchange medium. By inclining so as to be recessed in a U-shape, the flow range of the circulating heat exchange medium is set so that the upper and lower plates 41-42, 42-43, 43-44, 44-45, 45- in each louver portion R. 46 can be enlarged from the vicinity of the joint with 46 to the center of the wall surface of each louver R, and the heat exchange medium can be brought into substantially uniform contact with each louver R to improve the evaporation efficiency (heat transfer efficiency). The flow resistance of the heat exchange medium flowing through each louver part R can be significantly reduced.

  Further, in this heat exchanger 1, a gas-liquid two-phase refrigerant is used as a heat exchange medium flowing in the inner fin 5a, whereby the liquid phase portion of this refrigerant is divided into upper and lower plates 41-42 in each louver portion R. , 43-44, 45-46 and each louver portion R can be uniformly brought into contact with the refrigerant flow path, and the liquid phase portion of the refrigerant is in uniform contact with the refrigerant flow path. Can circulate the gas phase portion of the refrigerant in the refrigerant flow path surrounded by the liquid phase portion of the refrigerant, and exchange heat with respect to the liquid phase portion of the refrigerant from the refrigerant flow channel side (that is, outside) Since the heat exchange can be promoted by the gas phase portion of the refrigerant from the side (that is, the inside) where the gas phase portion of the refrigerant in the refrigerant channel flows, the evaporation efficiency can be further improved.

[Second Embodiment]
7 to 9 show a second embodiment of an evaporator according to the present invention, FIG. 7 is a perspective view showing a schematic configuration of a heat exchanger as an evaporator according to the present embodiment, and FIG. 8 is a heat exchange of FIG. Sectional drawing which shows the cross section of the principal part (core) in a container, FIG. 9 is AA sectional drawing in FIG.

  In FIG. 7, reference numeral 10 denotes the stacked heat exchanger according to the present embodiment, and includes a core 11 described later. As shown in FIG. 8 and FIG. 9, the core 11 includes a pair of refrigerant flow path forming recesses 41 that circulate a refrigerant that is a substantially U-shaped heat exchange medium, and a pair of upper ends of the refrigerant flow path forming recesses 41. The substantially rectangular plate 40 having the header forming recess 44 is sequentially stacked and joined in a state where the refrigerant flow path forming recess 41 and the header forming recess 44 face each other. Thus, a parallel flat tube portion 14 and a header portion 12 connected to the upper end of each flat tube portion 14 are formed, and the adjacent flat tube portions 14 and 14 are directed in the vertical direction of the drawing in FIG. Corrugated outer fins 5b are interposed.

  A partitioning convex portion 42 protrudes from the upper end of the refrigerant flow path forming concave portion 41 to a portion near the lower end at a substantially central portion of the refrigerant flow path forming concave portion 41 in each plate 14 in the vertical direction in FIG. It is extended. Due to this partitioning convex portion 42, each flat tube portion 14 has a substantially U portion formed by a vertical portion 43a formed on the left and right sides of the partitioning convex portion 42 and a horizontal communication portion 43b communicating the left and right vertical portions 43a. A letter-shaped refrigerant flow path 43 is formed. For example, circular convex portions 46 protrude from the horizontal communication portion 43b at a predetermined interval. Further, substantially circular coolant passage holes 45 are formed in the bottom walls of the pair of header forming recesses 44 except for the required portions.

  Side plates 13 are respectively disposed on both outer sides in the stacking direction of the core 11 in the heat exchanger 10, and outer fins 5 b are interposed between the side plates 13 and the flat tube portions 14.

  In the heat exchanger 10, the refrigerant introduced into the header portion 12 on the same side from the medium inflow pipe 7 a on the left side in FIG. 7 flows into the inside of the flat tube portion 14, but the plate at the required portion of the header portion 12. 40, the refrigerant passage hole 45 is not opened in the bottom wall of one of the header forming recesses 44, and the refrigerant flows through the refrigerant flow path 43 in each flat tube portion 14 in a U-shape. Further, at the same location, the refrigerant proceeds from the refrigerant passage hole 45 opened in the bottom wall of the other header forming recess 44 to the subsequent header portion 12 and flows in a meandering manner in the heat exchanger 10 as a whole, and the last header. The gas is discharged from the section 12 to the medium outlet pipe 7b.

  A pair of left and right inner fins 5 a is disposed in the refrigerant flow path 43 in each flat tube portion 14. Each inner fin 5a is formed by offsetting a louver portion R (see FIG. 3) in a direction orthogonal to the refrigerant flow direction at predetermined intervals, and upstream of the louver portion R in the refrigerant flow direction. The side end portion R1 is formed in an inclined shape so as to be recessed in a substantially U shape toward the refrigerant flow direction.

  At this time, each louver portion R of each inner fin 5a is formed in a size appropriately set according to the size of the heat exchanger, etc., and the details are set in substantially the same manner as in the first embodiment described above. Omitted.

  As described above, in the heat exchanger 10, the upstream end R1 of each louver portion R of the inner fin 5a interposed in the flat tube portion 14 of the laminated core 11 is substantially directed toward the refrigerant flow direction. By being formed so as to be recessed in the shape of a letter, the flow range of the circulating refrigerant is expanded from the vicinity of the junction between the adjacent plates 40, 40 in each louver portion R to the center of the wall surface in each louver portion R. In addition, it is possible to improve the evaporation efficiency (heat transfer efficiency) by bringing the refrigerant into contact with each louver part R substantially uniformly, and it is possible to significantly reduce the flow resistance of the refrigerant flowing through each louver part R.

  Further, in this heat exchanger 10, a gas-liquid two-phase refrigerant is used as a heat exchange medium that circulates in the inner fin 5 a, so that the liquid phase portion of this refrigerant is separated from the adjacent plates 40, 40 in each louver portion R. And each louver portion R can be uniformly contacted in the refrigerant flow path 43, and the liquid phase portion of the refrigerant is uniformly contacted, that is, the periphery is the liquid phase portion of the refrigerant. The refrigerant gas phase part can be circulated in the refrigerant channel 43 surrounded by the refrigerant channel 43, and heat is exchanged from the refrigerant channel 43 side (that is, the outside) to the liquid phase part of the refrigerant, Since the heat exchange can be promoted by the gas phase portion of the refrigerant from the side (that is, the inner side) through which the gas phase portion of the refrigerant flows in 43, the evaporation efficiency can be further improved.

  Although the heat exchanger 1 of the present invention has been described by taking the above-described first and second embodiments as examples, the present invention is not limited to this, and various embodiments can be made without departing from the gist of the present invention. Can be adopted.

  For example, in the first embodiment described above, the case where the outer fins 5b made of offset fins are provided between the plates 42-43, between the plates 44-45, that is, between the even-numbered bars 6b has been described. However, the present invention is not limited thereto, and the outer fins 5b may not be provided between the even-numbered bars 6b. In this case, the number of parts can be reduced, and the advantage that the cost in production can be reduced can be obtained. On the other hand, the outer fins 5b in the heat exchanger 10 of the second embodiment (that is, simply in a direction perpendicular to the flow direction of the heat exchange medium) between the even-numbered bars 6b of the heat exchanger 1 of the first embodiment described above. When the corrugated fins are provided, it is possible to increase the flow resistance of the heat exchange medium in the even-numbered layer and to improve the heat exchange efficiency in substantially the same manner as in the first embodiment described above.

It is a perspective view showing a schematic structure in a 1st embodiment of a heat exchanger concerning the present invention. It is sectional drawing which shows the longitudinal cross-section in the heat exchanger of FIG. It is a perspective view which decomposes | disassembles and shows the principal part in the heat exchanger of FIG. It is an expanded sectional view which shows the distribution | circulation state of the refrigerant | coolant in the heat exchanger of FIG. It is a curve graph which shows the relationship between the flow resistivity of the refrigerant | coolant concerning this invention, and the inclination-angle of a louver part. It is a curve graph which shows the relationship between the ratio of the protrusion amount with respect to the height of the louver part concerning this invention, and the inclination angle of a louver part. It is a perspective view which shows schematic structure in 2nd Embodiment of the heat exchanger concerning this invention. It is sectional drawing which shows the cross section of the principal part (core) in the heat exchanger of FIG. It is AA sectional drawing in FIG. It is a perspective view which shows the conventional inner fin. It is a perspective view which shows the conventional offset fin. It is an expanded sectional view which shows the distribution | circulation state of the refrigerant | coolant in the offset fin of FIG.

Explanation of symbols

1, 10 ... Heat exchanger (evaporator)
2, 11 ... Core 40, 41, 42, 43, 44, 45, 46 ... Plate 5a ... Inner fin 5b ... Outer fin R ... Louver part R1 ... Upstream end L2 ... Projection amount T1 ... Height V1 ... Inclination angle

Claims (2)

Arranged in the heat exchange medium flow section, the flow section is partitioned into a plurality of medium flow paths, and the partitioned medium flow paths are offset at predetermined intervals in a direction perpendicular to the flow direction of the heat exchange medium. In the evaporator (1, 10) provided with the inner fin (5a)
The inner fin (5a) has a plurality of louver portions (R) offset at the predetermined interval,
The upstream end (R1) in the flow direction of the heat exchange medium on the wall surface defining the flow part of each louver part (R),
An evaporator (1, 10) characterized by having a shape inclined so as to be recessed in a generally U shape toward the flow direction of the heat exchange medium. The evaporator (1, 10) according to claim 1, wherein the heat exchange medium is a gas-liquid two-phase refrigerant.

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