JP3805665B2 - Heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchanger, and more specifically, is suitable for use in a vehicle air conditioner evaporator or condenser, a heater core, a radiator, or the like, and is constituted only by a plate constituting an internal fluid passage through which an internal fluid flows. It relates to a heat exchanger.
[0002]
[Prior art]
In a conventional heat exchanger, for example, a vehicular air conditioning evaporator, in order to expand the heat transfer area on the air side between two tubes having a flat cross section formed by joining two plates in the middle. A corrugated fin with a louver was interposed.
[0003]
However, in this type of heat exchanger, the cost reduction and miniaturization of the heat exchanger have reached the limit due to the limit of the louver processing man-hours.
[0004]
Therefore, in JP-A-11-287580, JP-A-2000-205785, etc., a finless member that does not require corrugated fins and can ensure the necessary heat transfer performance only with the heat transfer plate constituting the refrigerant flow path. A type of cooling heat exchanger has been proposed.
[0005]
13, FIG. 2 to FIG. 4 and FIG. 14 show the configuration of a heat exchanger (evaporator for vehicle air conditioning) proposed in Japanese Patent Application Laid-Open No. 2000-205785. FIG. 13 is an exploded perspective view showing the configuration of the entire evaporator, and FIGS. 2, 3, and 4 are configurations of the heat transfer plate 12a, the heat transfer plate 12b, and the heat transfer plate 12c used in the evaporator, respectively. 14 (A) and 14 (B) are sectional views of the heat transfer plate 12a and the heat transfer plate 12b (12c) in FIG. It is sectional drawing in A and cut surface BB.
[0006]
As shown in FIG. 13, this evaporator is a cross-flow heat exchanger in which the air-conditioning air flow direction A and the refrigerant flow direction B (vertical direction shown in FIG. 13) in the heat transfer plate section are substantially orthogonal to each other. It is configured. In this evaporator, a core portion that performs heat exchange between air-conditioning air and a refrigerant is configured by simply laminating a large number of heat transfer plates 12a, 12b, and 12c.
[0007]
Although the detailed configuration of the heat transfer plates 12a to 12c will be described later, each of the heat transfer plates 12a to 12c is formed with a large number of protrusions for disturbing the flow of fluid on one side. The pitch P1 (see FIG. 14B) is the same for all the heat transfer plates. Then, the heat transfer plate 12a and the heat transfer plate 12b or the heat transfer plate 12c are arranged so that the positions of the protrusions are shifted, and a flat portion other than the protrusions (hereinafter referred to as “substrate portion”). The core part is comprised by mutually bonding, and also laminating | stacking several heat-transfer plate pairs obtained by this. Accordingly, a plurality of air-conditioning air flow paths indicated by arrows A in FIG. 14B are arranged in the vertical direction on the paper surface of FIG. 14B with the same shape.
[0008]
In this evaporator, as shown in FIG. 13, the refrigerant in the order of arrow o direction, arrow p direction, arrow q direction, arrow r direction, arrow s direction, arrow t direction, arrow u direction, arrow v direction, and arrow w direction. In addition, the air-conditioning air is caused to flow in the direction A, thereby performing heat exchange between the refrigerant and the air-conditioning air.
[0009]
According to this evaporator, by the action of a large number of protrusions provided on the heat transfer plates 12a to 12c, the air flow forms a flow that undulates the gaps between the heat transfer plates 12a to 12c. Therefore, the air flow becomes a turbulent state, and the heat transfer rate (heat transfer performance) on the air side can be dramatically improved.
[0010]
By the way, in order to reduce the size of such a finless type heat exchanger without deteriorating the heat transfer performance, first, it is necessary to improve the heat transfer performance with the same size.
[0011]
Therefore, in the finless type heat exchanger as shown in FIG. 13, in order to improve the heat transfer performance, the technique described in Japanese Patent Application Laid-Open No. 2001-41678 uses protrusions of each heat transfer plate. It is necessary to reduce the pitch P1 and increase the number of protrusions.
[0012]
[Problems to be solved by the invention]
However, when the number of protrusions is increased, there is a problem that the ventilation resistance generated by the flow of fluid through the heat exchanger increases. An increase in ventilation resistance is not preferable because it causes an increase in power for flowing a fluid.
[0013]
Moreover, in the technique described in the publication, as the pitch P1 is decreased, the bonding allowance (see FIG. 14B) of each heat transfer plate is narrowed, and the adhesiveness of each heat transfer plate is deteriorated. There was also. This is because the heat transfer plates, in which the protrusions for disturbing the flow of the fluid are formed at the same pitch, are arranged so that the positions of the protrusions are shifted, and the core part is bonded by bonding the substrate parts to each other. This occurs because of the configuration.
[0014]
The present invention has been made in order to solve the above-mentioned problems, and a heat exchanger that can be downsized without causing an increase in ventilation resistance and a deterioration in adhesiveness of a heat transfer plate constituting a flow path. The purpose is to provide.
[0015]
[Means for Solving the Problems]
  To achieve the above object, the heat exchanger according to claim 1, wherein the first fluid and the second fluid are caused to flow by crossing a first fluid having a low temperature and a second fluid having a temperature higher than the first fluid so as to cross each other. A heat exchanger for exchanging heat with a second fluid, wherein at least one flow path of the first fluid and the second fluidTwo types, a first flow path having a large number of protrusions for disturbing the flow and a second flow path having a protrusion having a smaller ventilation resistance than the protrusions of the first flow pathIt is formed by the combination of the flow path shapes. In the following, the case where the temperature of the first fluid is lower than the temperature of the second fluid and the present invention is applied to an air-conditioning evaporator will be described. However, the temperature of the first fluid is the temperature of the second fluid. It is also possible to apply the present invention to a radiator or an air conditioning condenser by increasing the temperature.
[0016]
  According to the heat exchanger according to claim 1, at least one flow path of the low temperature first fluid and the high temperature second fluid is higher than the first fluid.Two types, a first flow path having a large number of protrusions for disturbing the flow and a second flow path having a protrusion having a smaller ventilation resistance than the protrusions of the first flow pathIt is formed by the combination of the flow path shapes.
[0017]
In other words, as described above, a smaller ventilation resistance is advantageous in terms of power, but a reduction in ventilation resistance decreases heat transfer performance.Therefore, there is a trade-off between ventilation resistance and heat transfer performance. is there. Needless to say, the airflow resistances of different channel shapes are different from each other.
[0018]
  Utilizing these points, in the present invention, as in the conventional heat exchanger shown in FIG. 13, the flow path for flowing one fluid (air conditioning air in FIG. 13) is a lamination of only one kind of flow path shape. Rather than formed by2 typesThe flow resistance is increased by determining the shape of each flow path to the minimum resistance that can ensure the required heat transfer performance. It is possible to prevent. As a result, the heat transfer performance with the same size can be improved, and as a result, the heat exchanger can be downsized without causing an increase in ventilation resistance.
[0019]
  In the above-described conventional heat exchanger, it is possible to adjust the ventilation resistance by adjusting the flow channel shape.2 typesFor example, a certain channel shape is a shape with many protrusions to improve heat transfer performance, and the other channel shape is fine with less projections to reduce ventilation resistance. Adjustment is possible, and the superiority of adjustment is improved.
In the present invention, the first flow path is provided with a plurality of protrusions for disturbing the flow so that the heat transfer performance is high, and the second flow path is ventilated from the protrusions of the first flow path. By having protrusions with small resistance, the heat transfer performance is lower than that of the first flow path but the flow resistance is small, and a heat exchanger is obtained by combining the first flow path and the second flow path having different characteristics. As a result, the ventilation resistance of the heat exchanger as a whole can be minimized while ensuring the necessary heat transfer performance.
[0020]
  Thus, according to the heat exchanger according to claim 1, at least one flow path of the first fluid and the second fluid that performs heat exchange is provided.Two types, a first flow path having a large number of protrusions for disturbing the flow and a second flow path having a protrusion having a smaller ventilation resistance than the protrusions of the first flow pathTherefore, it is possible to reduce the size while ensuring the necessary heat transfer performance without causing an increase in ventilation resistance.
[0021]
  The heat exchanger according to claim 2 is the invention according to claim 1.The first channel and the second channelWhen the flow path of either the first fluid or the second fluid is formed by combining the flow path shapes of,otherThis is a shape that can form the flow path of the other fluid.
[0022]
  According to the heat exchanger according to claim 2, in the invention according to claim 1,The first channel and the second channelWhen the flow path of either the first fluid or the second fluid is formed by the combination of the flow path shapes of,otherIt is set as the shape which can form the flow path of the other fluid.
[0023]
Note that this means that when the flow path according to the present invention is configured by stacking a plurality of heat transfer plates as shown in FIG. 13, one of the first fluid and the second fluid is formed. When the heat transfer plates to be stacked are stacked, the shape of the heat transfer plate corresponds to a shape in which the flow path of the other fluid can be formed.
[0024]
  Thus, according to the heat exchanger of claim 2, the same effect as that of the invention of claim 1 can be obtained, and in the invention of claim 1The first channel and the second channelWhen the flow path of either the first fluid or the second fluid is formed by the combination of the flow path shapes of,otherTherefore, the member for forming the flow path of one fluid can be used as the member for forming the flow path of the other fluid. Cost reduction can be realized.
[0025]
  Furthermore, the heat exchanger according to claim 3 is the invention according to claim 1 or 2,The second flow path,The channel width is narrower than the first channelStuffIt is what.
[0026]
  According to the heat exchanger according to claim 3, in the invention according to claim 1 or claim 2.Second flow pathBut,SaidThe channel width is narrower than the first channelStuffIt is said.
[0028]
  IeIn the present invention, when it is assumed that the channel widths of the first channel and the second channel are equal, the heat transfer performance in the second channel is lower than that of the first channel. Therefore, in the present invention, in order to prevent a decrease in the heat transfer performance of the second flow path, the flow path width of the second flow path is narrower than that of the first flow path.
In the present invention, as in the invention described in claim 4, the projection having a small ventilation resistance may have a height lower than the projection for disturbing the flow.
Further, according to the present invention, as in the invention described in claim 5, the first flow path and the second flow path are formed in a state in which a gap is formed between the heat transfer plate having protrusions for disturbing the flow. The heat transfer plates that are adjacent to each other and that have protrusions having a small ventilation resistance may be stacked in a state where the heat transfer plates are adjacent to each other with a gap narrower than the gap.
Further, according to the present invention, as in the sixth aspect of the present invention, the flow path shapes of the first flow path and the second flow path can be ensured with the ventilation resistance as the whole heat exchanger and the heat transfer performance can be ensured. You may determine so that it may become the minimum resistance.
Further, in the present invention, as in the invention described in claim 7, the protrusions may be formed by stamping.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the case where the heat exchanger of the present invention is applied to a vehicle air-conditioning evaporator (hereinafter simply referred to as “evaporator”) will be described.
[0032]
[First Embodiment]
FIGS. 1-7 shows 1st Embodiment of this invention, FIG. 1 is a disassembled perspective view which shows the structure of the whole evaporator 10 which concerns on this embodiment, FIG.2, FIG.3, FIG.4. And FIG. 5 and FIG. 6 are front views showing the configuration of the heat transfer plate 12a, the heat transfer plate 12b, and the heat transfer plate 12c with projections for disturbing the flow, respectively. FIG. 7 is a front view showing the configuration of the heat transfer plate 22a and the heat transfer plate 22b that are used in No. 10 and that have no protrusions and have a substantially smooth surface. FIG. It is sectional drawing in cut surface CC (refer FIG.2 and FIG.5) of each heat-transfer plate 12a, 12b (12c), 22a, 22b in FIG.
[0033]
As shown in FIG. 1, the evaporator 10 is an orthogonal flow heat exchanger in which the flow direction A of air-conditioning air and the refrigerant flow direction B (vertical direction shown in FIG. 1) in the heat transfer plate section are substantially orthogonal. It is configured. The evaporator 10 is configured by simply stacking a large number of heat transfer plates 12a, 12b, 12c, 22a, and 22b as a core 11 that performs heat exchange between air-conditioning air and refrigerant.
[0034]
In the present embodiment, the first heat transfer plate 12a shown in FIG. 2, the second heat transfer plate 12b shown in FIG. 3, the fourth heat transfer plate 22a shown in FIG. 5, and the fifth heat transfer plate 22b shown in FIG. The core portion 11 is constituted by the combination region X and the combination region Y of the first heat transfer plate 12a, the third heat transfer plate 12c, the fourth heat transfer plate 22a, and the fifth heat transfer plate 22b shown in FIG. is doing.
[0035]
Each of the heat transfer plates 12a to 12c, 22a, and 22b is made of a double-sided clad material in which an A4000 series aluminum brazing material is clad on both sides of an A3000 series aluminum core material, and a plate thickness t = 0.1 to 0.4 mm. A thin plate of a certain degree is press-molded. The heat transfer plates 12a to 12c, 22a, and 22b have a substantially rectangular planar shape as shown in FIGS. 2 to 6, the outer dimensions are the same, and the length in the long side direction is, for example, 245 mm. The width in the short side direction is, for example, 45 mm.
[0036]
Although the launch shapes of the heat transfer plates 12a to 12c may be basically the same, the specific shapes are for reasons such as formation of a refrigerant passage, assembly of the evaporator, brazing, drainage of condensed water, and the like. Is different. 2 to 4, each heat transfer plate 12 a to 12 c is formed by projecting a protrusion (rib) 14 from the flat substrate portion 13 to the back side of the paper surface. The protrusion 14 has a low-pressure-side refrigerant after passing through a decompression means (an expansion valve or the like) of the refrigeration cycle by adhesion to the heat transfer plate 22a or 22b or adhesion to an end plate 21 or end plate 23 described later. The refrigerant passages 19 and 20 that flow are configured to continuously extend in parallel with the longitudinal direction of the heat transfer plate 12. Moreover, the cross-sectional shape of the protrusion part 14 is a substantially trapezoid as shown in FIG.
[0037]
As shown in FIGS. 2 to 4, the number of projecting portions 14 is six for the first heat transfer plate 12a and four for the second and third heat transfer plates 12b and 12c. Further, the second and third heat transfer plates 12b and 12c are formed with protrusions (ribs) 140 for detecting internal leakage at the center in the width direction. The protrusion 140 is also stamped and formed in the same form as the protrusion 14, but for the purpose of detecting internal leakage, in the second heat transfer plate 12 b, the protrusion 140 is formed at both ends 140 a and 140 b in the plate longitudinal direction. Is open to the outside of the heat exchanger. On the other hand, the protruding portion 140 of the third heat transfer plate 12c is opened to the outside of the heat exchanger only by the upper end (one end) portion 140a in the plate longitudinal direction, and the lower end (other end) portion 140b is in front of the tank portion described later. A closed end is formed at the position. The protrusions 14 and 140 have the same launch height h (FIG. 7), for example, about 1.5 mm.
[0038]
As described above, the first heat transfer plate 12a has six punches, and the second and third heat transfer plates 12b and 12c have five punches 14 and 140 in total. Since the number of launches is different between the plate 12a and the second and third heat transfer plates 12b and 12c, as shown in FIG. 7, the first heat transfer plate 12a and the second heat transfer plate 12b or the third heat transfer plate When the plate 12c and the plate 12c are stacked so that the protrusions face each other inward, the protrusions of the second heat transfer plate 12b or the third heat transfer plate 12c are intermediate between the protrusions 14 of the first heat transfer plate 12a. 14, the protrusion 140 is located.
[0039]
Moreover, the small protrusion 14a which protrudes in the heat-transfer plate width direction (air flow direction A) from the side part of each protrusion part 14 of the heat-transfer plates 12a-12c is formed. A large number of the small protrusions 14 a are provided at the same position in the longitudinal direction of each protrusion 14. In the present embodiment, a large number of small protrusions 14a of the protrusions 14 of the second and third heat transfer plates 12b and 12c are projected in the opposite direction one by one with respect to the heat transfer plate width direction. The large number of small protrusions 14a of each protrusion 14 of the first heat transfer plate 12a are in the same direction as the small protrusions 14a of the second and third heat transfer plates 12b and 12c with respect to the width direction of the heat transfer plate. So that it protrudes.
[0040]
On the other hand, in FIGS. 5 and 6, each heat transfer plate 22a, 22b is formed by punching a small protrusion 24a from the flat substrate portion 23 to the back side of the paper surface. The small protrusions 24a are for forming an air passage 30b (see also FIG. 7), which will be described later, by bonding the heat transfer plate 22a and the heat transfer plate 22b. In addition, the cross-sectional shape of the small protrusion 24a is a substantially trapezoid.
[0041]
The small protrusion 24a of the heat transfer plate 22a is formed at the same position as the small protrusion 14a of the heat transfer plate 12a in the plate longitudinal direction and the width direction when laminated with other heat transfer plates. The small protrusions 24a of 22b are formed at the same positions as the small protrusions 14a of the heat transfer plate 12b in the plate longitudinal direction and the width direction when stacked with other heat transfer plates.
[0042]
The core portion 11 of the evaporator 10 according to the present embodiment causes the small protrusions 24a of the heat transfer plate 22a and the heat transfer plate 22b to contact each other, and the heat transfer plate 12a and the heat transfer plate 12b, or the heat transfer plate. 12a and the heat transfer plate 12c are brought into contact with each other, the substrate portion 23 of the heat transfer plate 22a is brought into contact with the substrate portion 13 of the heat transfer plate 12b or 12c, and the heat transfer plate 22b The substrate portion 23 and the substrate portion 13 of the heat transfer plate 12a are brought into contact with each other and joined.
[0043]
Therefore, the heat transfer plates 12a to 12c, 22a, and 22b are joined to each other in a state where the pressing force in the heat transfer plate stacking direction is applied to the contact portion between the small protrusions 24a and the contact portion between the small protrusions 14a. Can do.
[0044]
Further, by this joining, a passage for allowing the coolant to flow is formed between the heat transfer plate 12a and the heat transfer plate 22b by the protrusion 14 of the heat transfer plate 12a, and the heat transfer plate 12b or 12c and the heat transfer plate 22a A passage for allowing the coolant to flow is formed by the protrusion 14 of the heat transfer plate 12b.
[0045]
That is, in the width direction of each of the heat transfer plates 12a to 12c, an upwind side refrigerant passage 20 is formed on the inner side of the protrusion 14 positioned on the windward side from the center (position of the protrusion 140), and each heat transfer is performed. In the width direction of the plates 12a to 12c, a refrigerant passage 19 on the leeward side is formed on the inner side of the protrusion 14 positioned on the leeward side from the center portion. Further, an internal leak detection passage 141 is formed inside the central protrusion 140.
[0046]
Here, the substrate portion 23 of the heat transfer plate 22a or 22b to be bonded to the substrate portion 13 of each of the heat transfer plates 12a to 12c is flat in most regions although there is a depression for forming a small protrusion 24a in part. Since it becomes the shape, the adhesion allowance between the heat-transfer plates 12a-12c and the heat-transfer plates 22a or 22b can be enlarged. Therefore, it is possible to satisfactorily braze the substrate portions of the heat transfer plates, and to prevent refrigerant leakage from the refrigerant passages 19 and 20 due to poor brazing.
[0047]
On the other hand, among the heat transfer plates 12a to 12c, 22a, and 22b, the heat transfer plates are divided into the heat transfer plate width direction (air flow direction A) at both ends of the direction B (heat transfer plate longitudinal direction) B orthogonal to the air flow direction A. Two tank portions 15 to 18 are formed. The tank portions 15 to 18 are ejected in the same direction as the projections 14 and 140 and the small projections 24a (the back side of the paper in FIGS. 2 to 6) in each of the heat transfer plates 12a to 12c, 22a and 22b. The height is the same as the protrusions 14 and 140 and the small protrusion 24a.
[0048]
In this way, the tank portions 15 to 18 are driven out in the same direction as the protruding portion 14, and the concave shape due to the driving is made continuous with the protruding concave shape of the tank portions 15 to 18 at both ends in the longitudinal direction of the protruding portion 14. Therefore, both end portions of the leeward refrigerant passage 20 communicate with the tank portions 17 and 18 on the leeward side, and both end portions of the leeward refrigerant passage 19 communicate with the tank portions 15 and 16 on the leeward side.
[0049]
Further, the tank portions 15 and 17 at the upper end of the heat transfer plate and the tank portions 16 and 18 at the lower end of the heat transfer plate are divided into two in the heat transfer plate width direction. 2 to 6, the shape is substantially D-shaped. However, as shown in the example of FIG. 1, the tank portions 15 to 18 may be formed in a substantially oval shape.
[0050]
Communication holes 15a to 18a are opened in the central portions of the tank portions 15 to 18, respectively. Through the communication holes 15a to 18a, the flow paths of the tank portions 15 to 18 communicate with each other between adjacent heat transfer plates in the left-right direction (heat transfer plate stacking direction) shown in FIG.
[0051]
In the heat transfer plate 12c shown in FIG. 4, the lower end (other end) portion 140b of the protrusion 140 is terminated at the position in front of the tank portions 16 and 18 as described above, and is closed here. Instead, a communication passage 120 for directly communicating the tank portion 16 and the tank portion 18 is formed. The communication path 120 can be formed by driving an intermediate portion between the tank portion 16 and the tank portion 18 in the same direction as the tank portions 16 and 18.
[0052]
Moreover, as shown in FIGS. 2-6, in any of the 1st-3rd heat-transfer plate 12a-12c and the 4th, 5th heat-transfer plate 22a, 22b, it compares with the tank parts 17 and 18 of an upwind side. Thus, the height of the tank portions 15 and 16 on the leeward side is reduced by a predetermined dimension L. This is for expanding the ventilation area in the leeward region in the core portion 11 as compared with the leeward region as will be described later.
[0053]
By the way, in the width direction (air flow direction A) of the heat transfer plates 12a to 12c, the plurality of protrusions 14 and the protrusions 140 for detecting internal leakage of the second and third heat transfer plates 12b and 12c are shown in FIG. As shown in FIG. 4, the formation positions of the projections 14 and 140 of the adjacent heat transfer plates 12a to 12c are shifted from each other, whereby the projections 14 and 140 are disposed on the substrates of the adjacent heat transfer plates 12a to 12c. It can be positioned on the concave surface formed by the portion 13.
[0054]
As a result, a gap is always formed between the tops of the projections 14 and 140 on the convex surface side and the concave surfaces of the substrate portions 13 of the other heat transfer plates 12a to 12c. This gap is a gap having a size obtained by subtracting the thickness of the plate from the launch height h of the protrusion 14, and this gap causes the entire length in the heat transfer plate width direction (air flow direction A) as indicated by an arrow A1. An air passage 30a meandering in a wave shape is formed.
[0055]
Therefore, the conditioned air blown in the direction of the arrow A may pass between the two heat transfer plates 12a and 12b or the heat transfer plates 12a and 12c while meandering in the air passage 30a as indicated by the arrow A1. it can.
[0056]
On the other hand, since the heat transfer plates 22a and 22b adjacent to each other are stacked such that the small protrusions 24a come into contact with each other, a gap is always formed between the heat transfer plates 22a and 22b. This gap is a gap having a size that is twice the value obtained by subtracting the plate thickness from the launch height of the small protrusion 24a. The gap extends across the entire length in the heat transfer plate width direction (air flow direction A). A linear air passage 30b is formed as in A2.
[0057]
Therefore, the conditioned air blown in the direction of arrow A can pass straight through the air passage 30b as shown by arrow A2.
[0058]
The air passage 30a corresponds to the first flow path of the present invention, and the air passage 30b corresponds to the second flow path of the present invention.
[0059]
Next, a part for entering and exiting the refrigerant with respect to the core part 11 will be described. As shown in FIG. 1, end plates 21 and 23 having the same size as the heat transfer plates 12a to 12c are disposed on both ends in the heat transfer plate stacking direction. The end plate 21 has a flat plate shape that contacts the substrate 13 of the heat transfer plate 12b and the concave surfaces of the tank portions 15 to 18 and is joined to the heat transfer plate 12b. The end plate 23 is the heat transfer plate 12a. The plate portion 13 and the tank portions 15 to 18 are in contact with the concave surfaces of the plate portion 13 and the tank portions 15 to 18 so as to be joined to the heat transfer plate 12a.
[0060]
The left end plate 21 in FIG. 1 has a refrigerant inlet hole 21a and a refrigerant outlet hole 21b in the vicinity of the lower end thereof, and the refrigerant inlet hole 21a is formed in the leeward tank section 16 at the lower end of the heat transfer plate 12b. The refrigerant outlet hole 21b communicates with the communication hole 16a, and the refrigerant outlet hole 21b communicates with the communication hole 18a of the windward side tank section 18 at the lower end of the heat transfer plate 12b. A refrigerant inlet pipe 24 and a refrigerant outlet pipe 25 are joined to the refrigerant inlet hole 21a and the refrigerant outlet hole 21b of the end plate 21, respectively.
[0061]
One end plate 21 has both sides of an A3000 series aluminum core clad on both sides of an A3000 series aluminum brazing material, similar to the heat transfer plates 12a to 12c, for joining to the refrigerant inlet and outlet pipes 24, 25. Made of clad material. The other end plate 23 is made of a single-side clad material in which an A4000 series aluminum brazing material is clad only on one side of the A3000 series aluminum core (the side to be joined to the heat transfer plate 12a). Further, the end plates 21 and 23 have a plate thickness t thicker than that of the heat transfer plate 12 (for example, plate thickness t = about 1.0 mm) to improve strength.
[0062]
A gas-liquid two-phase refrigerant decompressed by decompression means such as an expansion valve (not shown) flows into the refrigerant inlet pipe 24, and the refrigerant outlet pipe 25 is connected to a compressor suction side (not shown) and is evaporated by the evaporator 10. The refrigerant is led to the compressor suction side. In each of the heat transfer plates 12a to 12c, 22a, and 22b, the refrigerant channel 19 on the leeward side constitutes an inlet side refrigerant channel in the refrigerant channel of the entire evaporator because the refrigerant from the refrigerant inlet pipe 24 flows in. The refrigerant on the windward side 20 constitutes an outlet-side refrigerant passage because the refrigerant that has passed through the refrigerant passage 19 on the leeward side (inlet side) flows in and flows into the refrigerant outlet pipe 25.
[0063]
Next, the refrigerant path of the evaporator 10 as a whole will be described with reference to FIG. In the evaporator 10 according to the present embodiment, the refrigerant passage configuration is realized by the following means.
[0064]
First, in the left-right direction in FIG. 1 (heat transfer plate stacking direction), in the half region X on one end plate 21 side, a large number of four heat transfer plates 12a, 12b, 22a, 22b are stacked as one set, Further, in the half region Y on the other end plate 23 side, a large number of four heat transfer plates 12a, 12c, 22a, and 22b are stacked as one set, and the core portion 11 is bonded by joining the heat transfer plates. It is composed.
[0065]
Of the tank portions 15 to 18 located at both upper and lower ends of the evaporator 10, the leeward tank portions 15 and 16 constitute a refrigerant inlet side tank portion, and the leeward tank portions 17 and 18 are refrigerants. It constitutes the outlet side tank. The refrigerant inlet side tank portion 16 on the leeward side is separated from the left channel (region) in FIG. 1 by a partition portion 27 disposed at an intermediate position in the stacking direction of the heat transfer plate 12 (boundary portion between the region X and the region Y). X channel) and the right channel (region Y channel) in FIG.
[0066]
Similarly, the refrigerant outlet side tank portion 18 on the lower side of the windward side is also divided into the left side flow channel (region X side flow channel) in FIG. And a flow path on the region Y side). These partition parts 27 and 28 block | close the communication holes 15a and 18a part of the tank parts 15 and 18 only in the heat transfer plate located in an applicable part among the heat transfer plates 12a-12c, 22a, and 22b mentioned above. It can be configured by using a blind lid.
[0067]
According to the evaporator 10 according to the present embodiment, the low-pressure gas-liquid two-phase refrigerant decompressed by the expansion valve enters the inlet side tank unit 16 on the leeward side from the refrigerant inlet pipe 24 as indicated by an arrow a. Since the flow path of the inlet side tank section 16 is divided into the left and right areas X and Y by the partition section 27, the refrigerant enters only the flow path of the left area X of the inlet side tank section 16. The refrigerant is formed by the leeward protrusion 14 and the heat transfer plate 22b of the heat transfer plate 12a or the leeward protrusion 14 of the heat transfer plate 12b and the heat transfer plate 22a or end plate 21 in the left region X of FIG. The refrigerant passage 19 is lifted as indicated by an arrow b and enters the upper inlet side tank unit 15.
[0068]
Next, the refrigerant moves from the upper inlet side tank portion 15 to the right region Y of FIG. 1 as indicated by an arrow c, and the leeward projection 14 of the heat transfer plate 12a and the heat transfer plate 22b or the end plate 23, or The refrigerant passage 19 formed by the leeward projection 14 of the heat transfer plate 12c and the heat transfer plate 22a descends as indicated by an arrow d and enters the flow path in the right region Y of the lower inlet tank 16.
[0069]
Here, a communication passage 120 for directly communicating the tank portions 16 and 18 is provided at an intermediate position between the tank portion 16 and the tank portion 18 on the lower side of the third heat transfer plate 12c incorporated in the right region Y. Therefore, the refrigerant in the right region Y of the tank portion 16 then enters the windward outlet side tank portion 18 as shown by an arrow e through the communication path 120.
[0070]
Here, since the flow path of the outlet side tank section 18 is divided into the left and right areas X and Y by the partition section 28, the refrigerant enters only the flow path of the right area Y of the outlet side tank section 18.
[0071]
Next, in the right side region Y of the tank portion 18, the refrigerant is heated with the windward projection 14 and the heat transfer plate 22 b or the end plate 23 of the heat transfer plate 12 a or the windward projection 14 of the heat transfer plate 12 c. The refrigerant passage 20 formed by the plate 22a rises as indicated by an arrow f and enters the right region Y of the upper outlet side tank unit 17.
[0072]
From this right side area Y, the refrigerant moves from the upper outlet side tank part 17 to the left side area X in FIG. 1 as indicated by an arrow g, and thereafter, the windward side protrusion part 14 of the heat transfer plate 12a and the heat transfer plate 22b, or The refrigerant passage 20 formed by the windward projection 14 of the heat transfer plate 12b and the heat transfer plate 22a or the end plate 21 descends as indicated by an arrow h, and the flow path in the left region X of the lower outlet side tank 18 to go into. The refrigerant flows through the outlet side tank portion 18 to the left as indicated by an arrow i and flows out of the evaporator from the refrigerant outlet pipe 25.
[0073]
In the present embodiment, the refrigerant passage of the evaporator 10 is configured as described above, and the components shown in FIG. 1 are stacked in contact with each other, and the stacked state (assembled state) is appropriately set. The assembly is held in the brazing heating furnace and heated to the melting point of the brazing material, and the assembly is brazed integrally. Thereby, the assembly | attachment of the evaporator 10 can be completed.
[0074]
In this integrated brazing, the four adjacent heat transfer plates 12a, 12b, 22a, 22b or the heat transfer plates 12a, 12c, 22a are joined at the longitudinal joining surfaces of the heat transfer plates 12a-12c, 22a, 22b. 22b, the small protrusions 14a and the small protrusions 24a are brought into contact with each other, and the pressing force in the heat transfer plate stacking direction is applied to the contact portions between the small protrusions 14a and the small protrusions 24a by the jig. Thus, the heat transfer plates 12a to 12c, 22a and 22b can be joined to each other.
[0075]
As a result, in the heat transfer plate 12, the substrate portion 13 of the heat transfer plate 12 is also made to act on the intermediate portion (the formation portion of the refrigerant passages 19 and 20) excluding the tank portions 15 to 18 at both ends in the longitudinal direction by applying the pressing force. And the substrate portion 23 of the heat transfer plate 22 can be surely brought into full contact with each other, and the contact surfaces of the substrate portions can be brazed satisfactorily. Refrigerant leakage can be prevented.
[0076]
By the way, in order to find a product defect due to refrigerant leakage, the refrigerant leakage inspection of the evaporator 10 is performed. For example, the evaporator 10 after brazing is carried into a sealed chamber and the refrigerant inlet pipe 24 is used. And one of the refrigerant outlet pipes 25 is closed with an appropriate blind cover, and a leakage inspection fluid (for example, helium gas) is pressurized to a predetermined pressure from the other pipe and supplied to the refrigerant passage in the evaporator 10, whereby the evaporator 10. Check for fluid leaking outside (fluid leaking into the sealed chamber).
[0077]
Next, the operation of the evaporator 10 according to this embodiment will be described. The evaporator 10 is housed in an air conditioning unit case (not shown) with the vertical direction in FIG. 1 being up and down, and air is blown in the direction of arrow A by the action of an air conditioning blower (not shown).
[0078]
When the compressor of the refrigeration cycle is operated, the low-pressure gas-liquid two-phase refrigerant decompressed by an expansion valve (not shown) flows according to the above-described passage configuration indicated by arrows a to i in FIG.
[0079]
On the other hand, a heat transfer plate width direction (air flow direction A) is formed by a gap formed between the projections 14 and 140 projecting outwardly of the heat transfer plates 12a to 12c of the core portion 11 and the substrate portion 13. The air passage 30a meandering in the shape of a wave as indicated by the arrow A1 is formed over the entire length of the heat transfer plate in the width direction of the heat transfer plate by the small protrusions 24a protruding in a convex shape on the outer surface side of the adjacent heat transfer plates 22a, 22b. A linear air passage 30a is formed over the entire length as indicated by arrow A2.
[0080]
As a result, the conditioned air blown in the direction of arrow A is meandering in the air passage 30a in the shape of a wave as indicated by arrow A1, and is transferred between the two heat transfer plates 12a and 12b or between the heat transfer plate 12a and the heat transfer plate 12a. While passing through between the heat plates 12c, the air passage 30b can pass between the two heat transfer plates 22a and 22b in a straight line as indicated by an arrow A2.
[0081]
Since the refrigerant absorbs the latent heat of vaporization and evaporates from the air flow, the conditioned air is cooled and becomes cold air. At this time, the inlet-side refrigerant passage 19 is disposed on the leeward side and the outlet-side refrigerant passage 20 is disposed on the leeward side with respect to the flow direction A of the conditioned air, so that the refrigerant inlet / outlet with respect to the air flow is in a counterflow relationship. Become.
[0082]
Further, on the air side, the air flow direction A is a direction orthogonal to the longitudinal direction of the protrusions 14 and 140 of the heat transfer plates 12a to 12c (the refrigerant flow direction B in the refrigerant passages 19 and 20). Since the protrusions 14 and 140 form a convex surface (heat transfer surface) that protrudes perpendicular to the air flow, the air is prevented from going straight by the convex shape of the protrusions 14 and 140 extending orthogonally.
[0083]
For this reason, the air flow forms a meandering flow in the gap between the heat transfer plates 12a to 12c as shown by the arrow A1 in FIG. 7, and disturbs the flow. The heat transfer coefficient can be dramatically improved.
[0084]
Here, since the core part 11 is comprised only by heat-transfer plate 12a-12c, 22a, 22b, compared with the normal evaporator provided with the conventional fin member, the heat-transfer area on the air side is large. However, since the heat transfer coefficient on the air side is dramatically improved by setting the turbulent flow state, it is possible to compensate for the decrease in the air side heat transfer area by improving the air side heat transfer coefficient. Can be secured.
[0085]
Further, according to the present embodiment, the communication path 120 is formed at an intermediate position between the tank part 16 and the tank part 18 on the lower side of the third heat transfer plate 12c incorporated in the right region Y, and the communication path 120 Since the tank portions 16 and 18 are in direct communication with each other, it is not necessary to form a refrigerant passage in the end plate 23 portion, and a simple flat plate may be used as the end plate 23. Therefore, the heat transfer plate arrangement volume in the core part 11 can be expanded, and the heat transfer performance can be improved as the volume increases.
[0086]
Next, the drainage of the condensed water of the evaporator 10 according to the present embodiment will be described. The evaporator 10 is actually used by being arranged so that the longitudinal direction of the heat transfer plates 12a to 12c, 22a and 22b is the vertical direction as shown in FIG. Therefore, when the evaporator 10 is in use, a gap (see FIG. 7) extending in the longitudinal direction (vertical direction) can be continuously formed between the heat transfer plates. As a result, the condensed water generated on the surface of each heat transfer plate can be smoothly dropped downward along the gap extending in the vertical direction.
[0087]
Some of the condensed water tends to move to the leeward side due to the wind pressure of the blown air. However, according to the present embodiment, the tank portions 17 and 18 on the leeward side are used in any of the heat transfer plates 12a to 12c, 22a, and 22b. The height of the tank parts 15 and 16 on the leeward side is reduced by a predetermined dimension L as compared with FIG. Thereby, in the core part 11, the ventilation area in the leeward region can be enlarged compared to the leeward region, and the air flow velocity in the leeward region can be reduced.
[0088]
Therefore, even if a part of the condensed water moves to the leeward side, it is more effective that the condensed water scatters from the leeward side end portions of the heat transfer plates 12a to 12c, 22a, 22b to the downstream side due to the decrease in the air flow velocity. Can be suppressed.
[0089]
By the way, the height of the leeward tank portions 15 and 16 is reduced by a predetermined dimension L as compared with the leeward tank portions 17 and 18, and accordingly, compared with the upwind tank portions 17 and 18. As a result, the flow passage cross-sectional area of the leeward tank portions 15 and 16 is reduced, and there is a concern about an increase in pressure loss of the refrigerant flow passage, but the leeward tank portions 15 and 16 are in the refrigerant passage of the entire evaporator. Refrigerant inlet side, low dryness of refrigerant, specific volume of refrigerant (m^Three(Kg / kg) is small, the influence of an increase in pressure loss due to a decrease in the cross-sectional area of the flow path can be reduced. From this point of view, the refrigerant passage configuration of this embodiment is extremely advantageous.
[0090]
FIG. 8 shows a result example of the heat flow analysis performed using each of the conventional heat exchanger shown in FIG. 13 and the evaporator 10 according to the present embodiment. Here, the temperature of the air for air conditioning was 27 ° C., and the temperature of the refrigerant was 60 ° C. Further, the flow path interval H2 shown in FIG. 7 was set to 0.5 mm, the flow path interval H1 was set to 2.5 mm, and the pitch P1 was set to 6.8 mm.
[0091]
As shown in FIG. 8, compared with the conventional heat exchanger shown in FIG. 13, the evaporator 10 according to the present embodiment was found to have an approximately 10% improvement in heat transfer performance with the same ventilation resistance. This is because by setting the flow path interval H2 to 0.5 mm, which is smaller than the flow path interval H1, the temperature gradient of the plate wall surface important for heat exchange (the temperature difference between the air and the heat transfer plate is divided by the flow path interval). This is an effect obtained by increasing the heat transfer area as compared with the case where the heat exchanger is configured only by the first flow path having the protrusions.
[0092]
As described in detail above, in the evaporator 10 according to the present embodiment, there are a plurality of types of flow paths for flowing air-conditioning air for heat exchange (in this embodiment, two types of air passage 30a and air passage 30b). ), The evaporator 10 can be downsized while ensuring the necessary heat transfer performance without causing an increase in ventilation resistance.
[0093]
Further, in the evaporator 10 according to the present embodiment, the plurality of types of flow channel shapes are formed so that flow channels (in the present embodiment, the refrigerant passages 19 and 20) through which the refrigerant flows can be formed. The heat transfer plate for forming the flow path and the heat transfer plate for forming the flow path for flowing the refrigerant can be used together, and the evaporator 10 can be reduced in size and cost.
[0094]
Further, in the evaporator 10 according to the present embodiment, the plurality of types of flow channel shapes are formed with an air passage 30a having a large number of protrusions for disturbing the air flow, the flow passage width is narrower than the air passage 30a, and the above Since the air passage 30b does not have a projection and has two types of shapes, it is possible to prevent deterioration of the adhesiveness of the heat transfer plate due to the downsizing of the evaporator 10 when formed by bonding a plurality of heat transfer plates.
[0095]
[Second Embodiment]
In the second embodiment, a modified example of the air passage 30a and the air passage 30b (corresponding to the first flow path and the second flow path of the present invention) will be described.
[0096]
As shown in FIG. 9, in the second embodiment, each of the heat transfer plates 12a to 12c has a windward front end portion 34 and each of the heat transfer plates 22a and 22b has a windward front end portion 32. An inclined surface inclined toward the stacking direction of the heat plates is formed.
[0097]
As a result, in the heat exchanger according to the second embodiment, the forward stagnation area of the protrusion 14 can be reduced, and as a result, compared to a case where an inclined surface is not formed at the tip of each heat transfer plate. The heat transfer performance can be improved.
[0098]
In addition, since it is the same as that of the evaporator 10 which concerns on the said 1st Embodiment regarding parts other than an air path, description here is abbreviate | omitted.
[0099]
As described above in detail, the evaporator according to the second embodiment can achieve the same effects as those of the evaporator according to the first embodiment, and air can be introduced at the windward tip of the heat transfer plate. Since the inclined surface for reducing the stagnation area is provided, the heat transfer performance can be further improved as compared with the case where the inclined surface is not provided.
[0100]
[Third Embodiment]
In the third embodiment, another modification of the air passage 30a and the air passage 30b will be described.
[0101]
In order to reduce the size of the evaporator without deteriorating the heat transfer performance, the pitch P1 of each protrusion 14 of the heat transfer plates 12a to 12c is decreased to increase the number of protrusions, or the launch height L1 is increased. The ventilation resistance of the air passage 30a increases.
[0102]
Therefore, in the evaporator according to the third embodiment, in order to prevent an increase in ventilation resistance, the flow passage interval H2 of the air passage 30b is increased as shown in FIG. However, if the flow path interval H2 is simply increased, the flow rate of the air passage 30b is significantly increased and the heat transfer performance is degraded.
[0103]
Therefore, in the third embodiment, an L-shaped bent portion is formed at each tip portion of the heat transfer plates 22a and 22b so that the throttle 36 can be formed at the windward tip portion of the air passage 30b. . The throttle height L2 is determined according to the balance between the ventilation resistance and the heat transfer performance. As a result, the air flow distribution between the air passage 30a and the air passage 30b can be corrected.
[0104]
In addition, since it is the same as that of the evaporator 10 which concerns on the said 1st Embodiment regarding parts other than an air path, description here is abbreviate | omitted.
[0105]
As described above in detail, the evaporator according to the third embodiment can achieve the same effects as those of the evaporator according to the first embodiment, and the air at the windward front end of the air flow path 30b. Since the throttle 36 for adjusting the inflow amount of air is provided, the flow distribution of air-conditioning air between the air passage 30a and the air passage 30b can be corrected.
[0106]
[Fourth Embodiment]
Also in the fourth embodiment, another modification of the air passage 30a and the air passage 30b will be described.
[0107]
As shown in FIG. 11, in the fourth embodiment, a second small projection 24b having a launch height smaller than the small projection 24a for disturbing the air flow is punched and formed on the heat transfer plates 22a and 22b. ing.
[0108]
As shown in the figure, the position of the second small protrusion 24b in the plate width direction is the same position as the protrusion 14 of the heat transfer plate 12 to be bonded.
[0109]
As a result, the cross-sectional area of the refrigerant flow paths 19 and 20 is increased without deteriorating the adhesion between the heat transfer plate 12 and the heat transfer plate 22, the refrigerant ventilation resistance is reduced, and the second small protrusion 24 b. Due to the heat transfer enhancement effect by the heat transfer performance to the air for air conditioning can be improved.
[0110]
In addition, since it is the same as that of the evaporator 10 which concerns on the said 1st Embodiment regarding parts other than an air path, description here is abbreviate | omitted.
[0111]
As explained in detail above, in the evaporator according to the fourth embodiment, the same effect as the evaporator according to the first embodiment can be obtained, and the heat transfer plate 22a forming the air passage 30b, Since the second small protrusions 24b are provided on 22b, it is possible to reduce the ventilation resistance of the refrigerant and to improve the heat transfer performance of the air-conditioning air as compared with the case where the second small protrusions 24b are not provided.
[0112]
[Fifth Embodiment]
Also in the fifth embodiment, another modification of the air passage 30a and the air passage 30b will be described.
[0113]
As shown in FIG. 12, in the fifth embodiment, one or more holes 38 are provided in a portion where the heat transfer plate 22a and the heat transfer plate 12b or 12c are joined. As a result, air can be mixed between the air passage 30a and the air passage 30b. As a result, the heat transfer performance can be improved as compared with the case where the air passage 30a and the air passage 30b are not mixed.
[0114]
In addition, since it is the same as that of the evaporator 10 which concerns on the said 1st Embodiment regarding parts other than an air path, description here is abbreviate | omitted.
[0115]
As described above in detail, the evaporator according to the fifth embodiment can achieve the same effects as those of the evaporator according to the first embodiment, and can be provided between the air passage 30a and the air passage 30b. Since the holes for mixing air for air conditioning are provided, the heat transfer performance can be improved as compared with the case where the holes are not provided.
[0116]
In each of the embodiments described above, the case where the flow path is formed by combining a plurality of types of flow path shapes for only one fluid (air conditioning air) for heat exchange has been described, but the present invention is limited to this. For example, for both fluids (air conditioning air and refrigerant) for heat exchange, each flow path may be formed by a combination of a plurality of types of flow path shapes. In this case, an increase in ventilation resistance can be prevented for both fluids, and as a result, the heat transfer performance can be greatly improved. Furthermore, the present invention can be applied not only to air conditioning but also to a radiator.
[0117]
【The invention's effect】
  According to the heat exchanger according to the present invention, the flow path of at least one of the first fluid and the second fluid that performs heat exchange is provided.Two types, a first flow path having a large number of protrusions for disturbing the flow and a second flow path having a protrusion having a smaller ventilation resistance than the protrusions of the first flow pathTherefore, it is possible to reduce the size while ensuring the necessary heat transfer performance without causing an increase in ventilation resistance.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of an entire evaporator 10 according to an embodiment.
FIG. 2 is a front view showing a configuration of a heat transfer plate 12a used in the evaporator 10 according to the embodiment.
FIG. 3 is a front view showing a configuration of a heat transfer plate 12b used in the evaporator 10 according to the embodiment.
4 is a front view showing a configuration of a heat transfer plate 12c used in the evaporator 10 according to the embodiment. FIG.
FIG. 5 is a front view showing a configuration of a heat transfer plate 22a used in the evaporator 10 according to the embodiment.
FIG. 6 is a front view showing a configuration of a heat transfer plate 22b used in the evaporator 10 according to the embodiment.
7 is a cross-sectional view taken along a section C-C of each heat transfer plate in a state of being incorporated in the evaporator 10. FIG.
FIG. 8 is a graph for explaining the effect of the present invention, and is a graph showing an example of a result of heat flow analysis performed using each of the conventional heat exchanger and the evaporator 10 according to the first embodiment.
FIG. 9 is a cross-sectional view taken along a cut surface CC of each heat transfer plate in a state of being incorporated in the evaporator 10 according to the second embodiment.
FIG. 10 is a cross-sectional view taken along a cut surface CC of each heat transfer plate in a state of being incorporated in an evaporator 10 according to a third embodiment.
FIG. 11 is a cross-sectional view taken along a cut surface CC of each heat transfer plate in a state of being incorporated in the evaporator 10 according to the fourth embodiment.
FIG. 12 is a cross-sectional view taken along a section CC of each heat transfer plate in a state of being incorporated in an evaporator 10 according to a fifth embodiment.
FIG. 13 is an exploded perspective view showing a configuration example of the entire conventional evaporator.
14 is a cross-sectional view taken along section AA and section BB of the heat transfer plate 12a and the heat transfer plate 12b (12c) in a state of being incorporated in the evaporator shown in FIG.
[Explanation of symbols]
10 Vehicular air conditioning evaporator
11 Core part
12a-12c Heat transfer plate
13 Board part
14 Protrusion
14a small protrusion
15-18 tank
19, 20 Refrigerant passage
22a, 22b Heat transfer plate
23 Board part
24a small protrusion
30a Air passage (first passage)
30b Air passage (second passage)

Claims (7)

A heat exchanger for performing heat exchange between the first fluid and the second fluid by flowing a low temperature first fluid and a second fluid higher in temperature than the first fluid so as to cross each other;
At least one flow path of the first fluid and the second fluid has a first flow path having a large number of protrusions for disturbing the flow, and a second flow path having a protrusion having a smaller ventilation resistance than the protrusions of the first flow path. A heat exchanger formed by a combination of two types of flow channel shapes. When forming either of the flow path of the first fluid and the second fluid by a combination of the channel shape of the first flow path and the second flow path, shape the flow path of the other side of the fluid can be formed The heat exchanger according to claim 1. Wherein the second flow path, the heat exchanger according to claim 1 or claim 2 wherein the flow path width than the first flow path has a narrow casting. The projection having a small ventilation resistance is lower than the projection for disturbing the flow.
  The heat exchanger according to any one of claims 1 to 3. The first flow path and the second flow path are adjacent to each other in a state where a gap is formed in a heat transfer plate having a protrusion for disturbing the flow, and the heat transfer plate having a protrusion having a small ventilation resistance is Stacked in a state where a gap narrower than the gap is formed adjacent to each other
  The heat exchanger according to any one of claims 1 to 4. The flow channel shapes of the first flow channel and the second flow channel are determined so that the ventilation resistance of the entire heat exchanger is the minimum resistance that can ensure the necessary heat transfer performance.
  The heat exchanger according to any one of claims 1 to 5. The protrusion was formed by stamping
  The heat exchanger according to any one of claims 1 to 6.

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