Heat exchanger plate, heat exchanger plate stack, and microchannel heat exchanger

Abstract

To provide a plate for a heat exchanger, a plate laminate for the heat exchanger, and a microchannel heat exchanger realizing both of high strength and high overall heat transfer coefficient.SOLUTION: A plate for a first heat exchanger includes: an inlet header formed by a first opening; an outlet header formed by a second opening; a plurality of partition walls disposed between the inlet header and the outlet header to partition a flow channel of a fluid from the inlet header toward the outlet header into a plurality of parallel flow channels; and a connection portion for connecting the plurality of partition walls. One or more partition walls among the plurality of partition walls have notches on a position of the connection portion in a flowing direction of the fluid, and a pair of parallel flow channels at both sides of the partition wall having the notch communicate with each other through the notch.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to heat exchanger plates, heat exchanger plate stacks, and microchannel heat exchangers. [Background technology]

[0002] Known microchannel heat exchangers use thin plates of metals, such as stainless steel or copper, less than a few millimeters thick as heat exchanger plates. Fine channels are formed in these plates by etching, and these plates are then stacked to allow different fluids to flow alternately across a heat transfer wall, thereby exchanging heat. Microchannel heat exchangers can achieve a large heat transfer area in a small volume by stacking a large number of fine channels, each with a hydraulic diameter of less than a few millimeters, densely arranged in parallel. Because the fine channels are composed of multiple parallel channels connected to inlet and outlet headers, they are prone to drift. This is particularly true when the fluid is a liquid or gas-liquid two-phase flow, which involves boiling and evaporation. Patent Document 1, for example, reports that evaporation of the liquid phase of a first fluid flowing through a first channel generates bubbles, causing the first fluid to flow backward, resulting in drift of the first fluid in the first channel. To address this issue, the upstream section of the first channel is formed in a corrugated shape, while the downstream section is formed in a straight shape. This allows the air bubbles to flow more easily downstream, and prevents the first fluid from drifting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-020068 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the findings of the present inventors, when forming fine flow channels in heat exchanger plates using etching, there are two methods: etching from one side to form semicircular flow channels, or etching from both sides and connecting the etched surfaces to form flow channels with cross sections approaching square or rectangular. For a given flow channel hydraulic diameter, etching from both sides of the plate is preferable to achieve a compact heat exchanger with a larger heat transfer area per volume. Furthermore, square and rectangular flow channels have more corners than semicircular flow channels. Surface tension causes liquid films to collect at the corners, thinning the liquid film thickness in other areas, resulting in an enhanced evaporation heat transfer effect, resulting in a higher heat transfer coefficient. However, because this structure results in slit-shaped flow channels, it is difficult to maintain a constant spacing between the flow channel walls when the flow channel length is long. Furthermore, when the plates are stacked and assembled by diffusion bonding, the flow channel walls may deform, making it impossible to maintain the flow channel shape, resulting in poor bonding and flow drift. Furthermore, although the above-mentioned patent documents have a certain effect in suppressing uneven flow of the first fluid, there is room for further improvement.

[0005] An object of the present disclosure is to provide a heat exchanger plate, a heat exchanger plate stack, and a microchannel heat exchanger that achieve both compactness and a high heat transfer coefficient. [Means for solving the problem]

[0006] A heat exchanger plate according to at least one embodiment of the present disclosure comprises: an inlet header formed by the first opening; an outlet header formed by the second opening; a plurality of partition walls provided between the inlet header and the outlet header so as to divide a fluid flow path from the inlet header to the outlet header into a plurality of parallel flow paths; a connecting portion that connects the plurality of partition walls, one or more of the plurality of partition walls has a notch at a position of the connecting portion in the flow direction of the fluid, The pair of parallel flow paths on both sides of the partition wall having the notch communicate with each other via the notch.

[0007] A plate stack for a heat exchanger according to at least one embodiment of the present disclosure comprises: a plurality of first heat exchanger plates configured to allow a first fluid to flow from the inlet header to the outlet header; and a plurality of second heat exchanger plates configured to allow a second fluid to flow from the inlet header to the outlet header and arranged alternately with the plurality of first heat exchanger plates.

[0008] A microchannel heat exchanger according to at least one embodiment of the present disclosure includes the above-described heat exchanger plate stack. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a heat exchanger plate, a heat exchanger plate stack, and a microchannel heat exchanger that achieve both compactness and a high heat transfer coefficient. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual illustration of a microchannel heat exchanger according to one embodiment. [Figure 2] FIG. 2 is another conceptual illustration of a microchannel heat exchanger according to one embodiment. [Figure 3] 3 is a conceptual cross-sectional view of the plate stack taken along the line AA in FIG. 2. FIG. [Figure 4] FIG. 2 is a conceptual explanatory diagram of a first heat exchanger plate according to one embodiment. [Figure 5] FIG. 3 is a conceptual explanatory diagram of a second heat exchanger plate according to one embodiment. [Figure 6] FIG. 10 is a conceptual enlarged view of a partition wall and a notch according to one embodiment. [Figure 7]7 is a conceptual cross-sectional view of the partition wall and the notch as viewed in the direction of the arrow BB in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," or "have" one element are not exclusive expressions that exclude the presence of other elements. Note that the same components will be denoted by the same reference numerals and the description thereof will be omitted.

[0012] <1. Overview of Microchannel Heat Exchanger 1> 1 to 5, an overview of a microchannel heat exchanger 1 (hereinafter, sometimes simply referred to as "heat exchanger 1") according to an embodiment of the present disclosure will be illustrated. FIG. 1 is a conceptual explanatory diagram of the heat exchanger 1 according to an embodiment. FIG. 2 is another conceptual explanatory diagram of the heat exchanger 1 according to an embodiment. FIG. 3 is a conceptual cross-sectional view of a plate stack 30 as viewed in the direction of the arrow AA in FIG. 2. FIG. 4 is a conceptual explanatory diagram of a first heat exchanger plate 31 according to an embodiment. FIG. 5 is a conceptual explanatory diagram of a second heat exchanger plate 32 according to an embodiment.

[0013] As shown in FIG. 1 , a heat exchanger 1 according to an embodiment of the present disclosure is incorporated into a refrigeration cycle including a primary refrigerant circuit 11 through which a first fluid F1 circulates and a secondary refrigerant circuit 12 through which a second fluid F2 circulates. In this embodiment, the first fluid F1 flows into the heat exchanger 1 in a two-phase gas-liquid state, and the second fluid F2 flows into the heat exchanger 1 in a gas phase having a higher saturation temperature than the first fluid F1, and exchanges heat with the first fluid F1. The first fluid F1 is heated and evaporated by the heat exchange, exits the heat exchanger 1, and returns to a two-phase gas-liquid state while circulating through the primary refrigerant circuit 11 as a primary refrigerant. Although not shown in detail, the primary refrigerant circuit 11 in this example includes a compressor, a condenser, an expansion valve, and the like. The first fluid F1 in a two-phase gas-liquid state, expanded by the expansion valve, flows into the heat exchanger 1. Meanwhile, the second fluid F2 is cooled by heat exchange and flows out of the heat exchanger 1 in a relatively low-temperature liquid phase. The second fluid F2 cools other heat transfer media while circulating through the secondary refrigerant circuit 12 as a secondary refrigerant. The secondary refrigerant circuit 12 in this example includes a receiver, a pump, a cooler, and the like. The cooler may be configured to exchange heat between the second fluid F2 and a heat transfer media such as air circulating inside the freezer. The second fluid F2, evaporated through heat exchange in the cooler, returns to the heat exchanger 1 in a gaseous phase. As an example, the first fluid F1 is NH3 in a gaseous or liquid phase, and the second fluid F2 is CO2 in a gaseous or liquid phase. However, the first fluid F1 and the second fluid F2 may be refrigerants other than those mentioned above, and the second fluid F2 may be a liquid that does not undergo a phase change, such as brine.

[0014] A heat exchanger 1 according to an embodiment of the present disclosure includes a plate stack 30 including a plurality of stacked plates 35 and a pair of end plates 37, 38 that sandwich the plurality of plates 35. The plates included in the plate stack 30 are connected to each other by, for example, diffusion bonding.

[0015] 1 and 2, a first supply pipe 51 that supplies a first fluid F1 in a gas-liquid two-phase state that has passed through an expansion valve to the plate stack 30, and a first discharge pipe 59 that discharges the first fluid F1 are joined to the end plate 37. The first supply pipe 51 and the first discharge pipe 59 are respectively connected to a first communication port 41 and a second communication port 42 that are provided in each of the plurality of stacked plates 35.

[0016] Furthermore, the end plate 37 is provided with a second supply pipe 52 for supplying the second fluid F2 in a gas phase at a relatively high temperature supplied from the cooler to the plate stack 30, and a second discharge pipe 57 for discharging the second fluid F2 in a liquid phase at a relatively low temperature toward the receiver. The second supply pipe 52 and the second discharge pipe 57 are respectively connected to a third communication port 43 and a fourth communication port 44 provided in each of the plurality of stacked plates 35.

[0017] 2 and 3, the description of the configuration of the plurality of plates 35 of this embodiment continues. A plurality of parallel flow paths 318 through which the first fluid F1 supplied from the first communication port 41 flows, and a plurality of parallel flow paths 328 through which the second fluid F2 supplied from the third communication port 43 flows are formed inside the plurality of plates 35. The plurality of parallel flow paths 318 and the plurality of parallel flow paths 328 are separated from each other.

[0018] Specifically, the multiple plates 35 sandwiched between a pair of end plates 37, 38 include multiple first heat exchanger plates 31 and multiple second heat exchanger plates 32 alternately arranged along the stacking direction, and multiple partition plates 33. The first heat exchanger plates 31 and the second heat exchanger plates 32 are each sandwiched between a pair of partition plates 33 on both sides of the stacking direction. In other words, the multiple plates 35 are configured such that, from one side of the stacking direction, the first heat exchanger plates 31, the partition plates 33, the second heat exchanger plates 32, and the partition plates 33 are arranged in this order. Hereinafter, these three types of plates will be collectively referred to simply as "plates 35," and the thickness direction of the plates 35 will sometimes be referred to as the "plate thickness direction." The plate thickness direction coincides with the stacking direction of the plate stack 30.

[0019] As shown in FIG. 4 , the first heat exchanger plate 31 includes an inlet header 311 formed by first openings 111 including the first communication ports 41, an outlet header 312 formed by second openings 122 including the second communication ports 42, and a plurality of partition walls 315 provided between the inlet header 311 and the outlet header 312. The plurality of partition walls 315 are provided so as to divide the flow path of the first fluid F1 toward the inlet header 311 and the outlet header 312 into a plurality of parallel flow paths 318. In this example, each partition wall 315 extends linearly between the inlet header 311 and the outlet header 312. In the following description, the extension direction of the partition walls 315 will sometimes be referred to as the “flow direction of the first fluid F1,” and the direction in which the plurality of partition walls 315 are arranged will sometimes be referred to as the “width direction of the parallel flow paths 318.” As described above, in this embodiment, the first heat exchanger plate 31 is sandwiched between a pair of partition plates 33 (see FIG. 3). Therefore, the parallel flow paths 318 are defined by the plurality of partition walls 315 and the pair of partition plates 33. Furthermore, the inlet header 311 in this embodiment is configured so that the flow path width becomes narrower toward the downstream side, but the inlet header 311 in other embodiments may be configured so that the flow path width on the upstream side is the same as the flow path width on the downstream side.

[0020] As shown in FIG. 5 , the second heat exchanger plate 32 includes an inlet header 321 formed by the first openings 221 including the third communication port 43, an outlet header 322 formed by the second openings 222 including the fourth communication port 44, and a plurality of partition walls 325 provided between the inlet header 321 and the outlet header 322. The plurality of partition walls 325 are provided so as to divide the flow path of the second fluid F2 toward the inlet header 321 and the outlet header 322 into a plurality of parallel flow paths 328. In this example, each partition wall 325 extends linearly and bends between the inlet header 321 and the outlet header 322. In the following description, the extension direction of the partition wall 325 will sometimes be referred to as the “flow direction of the second fluid F2,” and the direction in which the plurality of partition walls 325 are arranged will sometimes be referred to as the “width direction of the parallel flow paths 328.” As described above, in this embodiment, the second heat exchanger plate 32 is sandwiched between a pair of partition plates 33 (see FIG. 3). Therefore, the parallel flow paths 328 are defined by the plurality of partition walls 315 and the pair of partition plates 33.

[0021] Heat exchange between the first fluid F1 and the second fluid F2 in the heat exchanger 1 having the structure described above with reference to FIGS. 1 to 5 is carried out as follows: The first fluid F1 flowing from the inlet header 311 into the multiple parallel flow paths 318 exchanges heat with the second fluid F2 flowing from the inlet header 321 into the multiple parallel flow paths 328 via the partition plate 33. The first fluid F1 that flows in in a gas-liquid two-phase state is heated as it moves downstream in the flow direction of the first fluid F1, and is discharged from the heat exchanger 1 in a vaporized state from the outlet header 312 via the first discharge pipe 59. On the other hand, the second fluid F2 that flows in in a relatively high-temperature gas phase is cooled and condensed as it moves downstream in the flow direction of the second fluid F2, and is discharged from the heat exchanger 1 in a relatively low-temperature liquid phase from the outlet header 322 via the second discharge pipe 57.

[0022] <2. Details of the Configuration of the First Heat Exchanger Plate 31> 4, 6, and 7, details of the first heat exchanger plate 31 according to one embodiment of the present disclosure are illustrated. Fig. 6 is a conceptual enlarged view of a partition wall 315 and a notch 314 according to one embodiment. Fig. 7 is a conceptual cross-sectional view of the partition wall 315 and the notch 314 as viewed in the direction of the arrow BB in Fig. 6.

[0023] <2-1. Structure of the connecting portion 317 and the notch 314> 6, the first heat exchanger plate 31 of this embodiment includes at least one connecting portion 317 that connects the plurality of partition walls 315. In this embodiment, all of the partition walls 315 are connected to any of the connecting portions 317, but two or more partition walls 315 without any connecting portion 317 may be provided.

[0024] In this embodiment, one or more of the multiple partition walls 315 have a notch 314 at the position of the connecting portion 317 in the flow direction of the first fluid F1. The notch 314 is aligned with the connecting portion 317 in the width direction of the parallel flow paths 318. In this example, the notch 314 is provided in each of all of the partition walls 315. Furthermore, in this embodiment, a pair of parallel flow paths 318 on either side of the partition wall 315 having the notch 314 communicate with each other via the notch 314. In other words, the notch 314 defines a communication path 316 that communicates with the pair of parallel flow paths 318.

[0025] Therefore, as illustrated in the enlarged view of FIG. 4 , the first fluid F1 can move between the multiple parallel flow paths 318 via the communication paths 316 defined by the notches 314. Mixing and branching of the first fluid F1 flowing through each of the multiple parallel flow paths 318 occurs, thereby equalizing the flow patterns of the first fluid F1 in the multiple parallel flow paths 318. This can prevent localized dryout, in which the liquid-phase first fluid F1 disappears, for example, downstream of the parallel flow paths 318. Therefore, the first heat exchanger plate 31 can achieve a high heat transfer coefficient. Furthermore, the provision of the connecting portions 317 can prevent deformation and misalignment of the partition walls 315 before and during assembly of the first heat exchanger plate 31. In particular, when diffusion bonding is performed on plates constituting the plate stack 30, such as the first heat exchanger plate 31, uniform heating is not possible immediately after heating begins, resulting in a temperature gradient in the plates. As a result, there is a risk that the partition wall 315 may be deformed due to the difference in expansion caused by the temperature gradient, but in this embodiment, the provision of the connecting portion 317 makes it possible to suppress such deformation.

[0026] A processing method for fabricating the connecting portions 317 according to an embodiment of the present disclosure is, for example, as follows (see FIGS. 6 and 7 ). First, a plate-shaped substrate for fabricating the first heat exchanger plate 31 is subjected to double-sided etching so as to form the parallel flow paths 318. Then, instead of double-sided etching, half-etching is performed only at the locations where the connecting portions 317 are to be installed, thereby forming the connecting portions 317. Therefore, the connecting portions 317 are connected only to one end 315A of each of the partition walls 315, which is located on one of both ends of each of the partition walls 315 in the plate thickness direction. Therefore, the connecting portions 317 can function as throttles that partially block the parallel flow paths 318. In the example of FIG. 7 , the portions of the partition walls 315 from approximately the center in the plate thickness direction to the one end 315A are connected to the connecting portions 317.

[0027] According to the inventors' speculation, the pressure of the first fluid F1 flowing through the parallel flow path 318 may fluctuate significantly. For example, pressure fluctuations due to boiling of the liquid phase first fluid F1 (bubbles are indicated by the symbol Bu in the enlarged view at the bottom of FIG. 4) or differences in the pressure difference due to differences in the dryness fraction of the first fluid F1 may occur. In this case, drift of the first fluid F1 is likely to occur. In this regard, according to the above configuration, the connecting portion 317 is connected to only one end 315A of each partition wall 315 in the plate thickness direction. Therefore, the connecting portion 317 also functions as a throttle that partially blocks the parallel flow paths 318. This causes an appropriate pressure loss in the connecting portion 317, making it possible to reduce the pressure difference between the multiple parallel flow paths 318 caused by the pressure fluctuations described above. Therefore, the first fluid F1 can easily flow through the communication passages 316 defined by the notches 314, thereby suppressing the weaving of the first fluid F1 in the multiple parallel flow passages 318. Therefore, the first heat exchanger plate 31 can achieve a high heat transfer coefficient.

[0028] While FIG. 4 illustrates the connecting portions 317 and the notches 314 aligned in a row, the present disclosure is not limited thereto. For example, the connecting portions 317 may be arranged in a row in a row at positions that avoid the notches 314. As one example, the connecting portions 317 may be arranged in a row so as to connect the upstream ends of the plurality of partition walls 315 (i.e., so as to face the inlet header 311). As another example, the connecting portions 317 may be arranged in a row so as to connect the downstream ends of the plurality of partition walls 315 (i.e., so as to face the outlet header 312). As yet another example, the connecting portions 317 may be arranged in a row between the notches 314A and 314D, between the notches 314D and 314C, or between the notches 314C and 314B shown in FIG. 4. The connecting portions 317 may be arranged at regular intervals from the inlet header 311 toward the outlet header 312. In this case, any of the connecting portions 317 arranged at regular intervals in the flow direction of the first fluid F1 is aligned in a left-right row with the notch 314. Note that the connecting portions 317 do not have to be arranged at regular intervals from the inlet header 311 toward the outlet header 312.

[0029] As shown in FIGS. 6 and 7 , the notch 314 in this embodiment is formed at the other end 315B of each of the partition walls 315, which is the other end in the plate thickness direction. The notch bottom 309 of the notch 314 and the other surface 317F of the connecting portion 317 are located at the same position in the plate thickness direction. That is, the surface 317F of the connecting portion 317 and the notch bottom 309 are directly connected. With this configuration, the first fluid F1 that passes through the communicating passage 316 defined by the notch 314 can flow into the parallel flow passage 318 along the other surface 317F of the connecting portion 317. The first fluid F1 passing through the connecting portion 317 mixes and branches as it flows from the communicating passage 316 to the parallel flow passage 318. This suppresses the turbulence of the first fluid F1 in the multiple parallel flow passages 318, and the first heat exchanger plate 31 can achieve a high overall heat transfer coefficient.

[0030] 6, an upstream end 399 of the connecting portion 317 in the flow direction of the first fluid F1 is recessed in an arc shape toward the downstream side. With the above configuration, it is possible to prevent excessive pressure loss that occurs when the first fluid F1 passes through the connecting portion 317 along the flow direction of the first fluid F1. This makes it possible to prevent separation of the flow of the first fluid F1 along the extension direction of the partition wall 315. Therefore, it is possible to prevent an increase in pressure loss.

[0031] In addition, in the flow direction of the first fluid F1, both ends of the connecting portion 317 are positioned outside of both ends of the notch 314. According to the above configuration, deformation of the partition wall 315 and the parallel flow path 328 due to the connecting portion 317 can be prevented.

[0032] <2-2. Example of arrangement of notch 314 (communicating passage 316)> 4, an example of the arrangement of the notch 314 will be described. Note that, in the following description, an embodiment will be illustrated in which the notch 314 and the connecting portion 317 are arranged at the same position relative to each other in the flow direction of the first fluid F1, but the positions of the notch 314 and the connecting portion 317 in the flow direction may be different.

[0033] In this embodiment, the multiple notches 314 arranged in the width direction of the parallel flow path 318 are arranged in four rows along the flow direction of the first fluid F1. Of the four rows of notches 314, the notch 314 in the row located most upstream is a first notch 314A, and the notch 314 in the row located most downstream is a second notch 314B. The notch 314 adjacent to the second notch 314B in the flow direction of the first fluid F1 is a third notch 314C, and the notches 314 adjacent to each of the first notch 314A and the third notch 314C are fourth notches 314D. That is, the plurality of notches 314 include, in order from the upstream side, a plurality of first notches 314A (first row), a plurality of fourth notches 314D (second row), a plurality of third notches 314C (third row), and a plurality of second notches 314B (fourth row). The communication passage 316 defined by the first notches 314A is the first communication passage 316A. Similarly, the communication passages 316 defined by the second notches 314B, the third notches 314C, and the fourth notches 314D are the second communication passage 316B, the third communication passage 316C, and the fourth communication passage 316D, respectively. Note that in the present embodiment, as an example, the respective numbers of the first notches 314A, the second notches 314B, the third notches 314C, and the fourth notches 314D are the same.

[0034] In this embodiment, a first distance between the inlet header 311 and the one or more notches 314 in the flow direction of the first fluid F1 is shorter than a second distance between the outlet header 312 and the one or more notches 314 in the flow direction of the first fluid F1. As a more specific example, the first distance is the shortest distance (dimension L1) from the inlet header 311 to the center of the first notch 314A, and the second distance is the shortest distance (dimension L2) from the outlet header 312 to the center of the second notch 314B. According to the above configuration, because the first distance is shorter than the second distance, the first communication passage 316A (communication passage 316) defined by the first notch 314A approaches the inlet header 311. As a result, even if bubbles are generated or grow due to boiling of the liquid phase of the first fluid F1 between the inlet header 311 and the first notch 314A, the bubbles can be guided to the first communication passage 316A formed by the first notch 314A. Therefore, uneven flow of the first fluid F1 in the multiple parallel flow passages 318 caused by bubbles flowing back into the inlet header 311 is suppressed, and a first heat exchanger plate 31 with a high overall heat transfer coefficient can be provided. In other embodiments, the notches 314 may not include at least one of the first notch 314A, the second notch 314B, the third notch 314C, and the fourth notch 314D. For example, in an embodiment in which the second notch 314B, the third notch 314C, and the fourth notch 314D are not provided, the second distance is the distance (dimension M) between the first notch 314A and the outlet header 312. Even in this case, the above-described advantages are obtained. Similarly, in an embodiment in which only the third notch 314C and the fourth notch 314D are provided among the second notch 314B, the third notch 314C, and the fourth notch 314D, the second distance is the distance between the third notch 314C and the outlet header 312.

[0035] Furthermore, in this embodiment, the one or more notches 314 are included in each of the plurality of partition walls 315, and the plurality of first notches 314A are arranged at the same positions as one another in the flow direction of the first fluid F1. Therefore, the first communication passages 316A, which are communication passages 316 defined by the first notches 314A, are aligned in the width direction of the parallel flow passages 318. With the above configuration, even if bubbles are generated in any of the plurality of parallel flow passages 318, they can flow into any of the first communication passages 316A, thereby suppressing drift of the first fluid F1 and preventing backflow of bubbles into the inlet header 311.

[0036] In this embodiment, the first distance (dimension L1 in the example of FIG. 4) is greater than 0% and less than 10% of the total length (dimension K) of the parallel flow path 318, and more preferably greater than 0% and 5% or less. The effects brought about by this configuration are as follows. According to the above configuration, the first distance is greater than 0% and less than 10% of the total length of the parallel flow paths 318, and therefore the first fluid F1 that has just flowed from the inlet header 311 into each of the multiple parallel flow paths 318 mixes through the first communication passage 316A formed by the first notch 314A. That is, the first communication passage 316A functions similarly to the inlet header 311, and the first fluid F1 that has flowed from the inlet header 311 into the parallel flow paths 318 passes through the throttles of each parallel flow path 318 and is supplied downstream. Furthermore, unlike the inlet header 311, the first communication passage 316A does not have a rightward (unidirectional) flow; instead, it allows flow in both directions. Therefore, even if there is an imbalance in the gas-liquid ratio (dryness fraction) among the multiple parallel flow paths 318, the first fluid F1 can be mixed and redistributed within the first communication passage 316A to eliminate this imbalance. Furthermore, even if bubbles are generated in the first fluid F1 in the parallel flow paths 318 and cause a backflow, the bubbles are mixed with the flow from the inlet header 311 in the first communication passage 316A, redistributed, and supplied to the parallel flow paths 318. Therefore, the dryness fraction of the first fluid F1 on the upstream side of the multiple parallel flow paths 318 can be equalized, and uneven flow of the first fluid F1 can be suppressed. Therefore, a first heat exchanger plate 31 that achieves a high coefficient of overall heat transfer can be provided.

[0037] The first heat exchanger plate 31 of this embodiment also includes one or more adjacent notches 313 located downstream of the first notch 314A and adjacent to the first notch 314A in the flow direction of the first fluid F1. In this example, the fourth notch 314D corresponds to the adjacent notch 313. An adjacent distance (dimension A), which is the shortest distance between the first notch 314A and the adjacent notch 313, is not less than 25% and less than 90% of the entire length of the parallel flow path 318. It is more preferable that this adjacent distance be not less than 25% and less than 35% of the entire length of the parallel flow path 318. If the first notch 314A and the adjacent notch 313 are too close to each other in the flow direction, the flow of the first fluid F1 in the communicating passage 316 (fourth communicating passage 316D in this example) formed by the adjacent notch 313 becomes excessively weak, making it difficult for the first fluid F1 to mix among the multiple parallel flow passages 318. In this regard, with the above configuration, the first notch 314A and the adjacent notch 313 are appropriately spaced apart, which optimizes the flow of the first fluid F1 in the communicating passage 316 and promotes mixing of the first fluid F1 in the multiple parallel flow passages 318. Therefore, a heat exchanger plate with a high heat transfer coefficient can be achieved.

[0038] Note that the present disclosure is not limited to an embodiment in which the fourth notch 314D corresponds to the adjacent notch 313. In an embodiment in which the fourth notch 314D is not provided among the second notch 314B, the third notch 314C, and the fourth notch 314D, the third notch 314C corresponds to the adjacent notch 313 adjacent to the first notch 314A in the flow direction of the first fluid F1. In this case, the adjacent distance is preferably 50% or more and less than 60% of the entire length of the parallel flow path 318.

[0039] In this embodiment, as described above, the one or more notches 314 include first notches 314A and second notches 314B. According to the above configuration, the first fluid F1 can flow between the plurality of parallel flow paths 318 via the second communication path 316B, which is the communication path 316 formed by the second notch 314B located downstream of the first notch 314A. Therefore, the first fluid F1 can be appropriately mixed between the plurality of parallel flow paths 318. Therefore, it is possible to suppress uneven flow of the first fluid F1 between the plurality of parallel flow paths 318, and the heat exchanger plate can achieve a high heat transfer coefficient.

[0040] The second distance (dimension L2 in the example of FIG. 4) in this embodiment is 10% or more and 35% or less of the total length of the parallel flow paths 318. According to the findings of the inventors, when the first heat exchanger plate 31 is used so that the first fluid F1 in a gas-liquid two-phase state is supplied to the inlet header 311, the dryness fraction tends to vary depending on the parallel flow paths 318 on the upstream side of the plurality of parallel flow paths 318. In particular, the dryness fraction of the first fluid F1 tends to be high in the parallel flow paths 318 connected to the upstream portion (the portion close to the first communication port 41) of the first openings 111 forming the inlet header 311, and dryout tends to occur more easily on the downstream side of the parallel flow paths 318 in the flow direction. On the other hand, a thinner liquid film of the liquid-phase first fluid F1 flowing through the parallel flow paths 318 exhibits a higher heat transfer coefficient. Therefore, it is preferable that the position where the first fluid F1 flows from another parallel flow path 318 into a parallel flow path 318 where dryout may occur be close to the position where dryout may occur. In this regard, according to the above configuration, the second communication passages 316B defined by the second notches 314B are appropriately spaced from the outlet header 312, which promotes mixed flow of the first fluid F1 slightly upstream of the region where dryout is expected to occur. Therefore, the first heat exchanger plate 31 can effectively suppress dryout of the first fluid F1 while suppressing a decrease in the overall heat transfer coefficient.

[0041] As described above, the notch 314 of this embodiment further includes one or more third notches 314C. The third notch 314C is located between the first notch 314A and the second notch 314B and adjacent to the second notch 314B in the flow direction of the first fluid F1. The distance (dimension B) between the inlet header 311 and the third notch 314C is 50% or more and less than 60% of the total length of the parallel flow passage 318. According to the above configuration, the first fluid F1 mixes among the multiple parallel flow passages 318 via the third communication passage 316C, which is the communication passage 316 formed by the third notch 314C. In addition to increasing the opportunity for the first fluid F1 to mix, the first notch 314A and the third notch 314C are appropriately spaced apart from each other, which ensures the flow of the first fluid F1 in the third communication passage 316C and further effectively promotes the mixing of the first fluid F1 between the multiple parallel flow paths 318.

[0042] As described above, the notches 314 of this embodiment include one or more fourth notches 314D. The fourth notches 314D are located between the first notches 314A and the second notches 314B and adjacent to the first notches 314A in the flow direction of the first fluid F1. The shortest distance (dimension A) between the inlet header 311 and the fourth notches 314D is 25% or more and less than 35% of the total length of the parallel flow paths 318. According to the above configuration, the first fluid F1 mixes among the multiple parallel flow paths 318 via the fourth communication paths 316D, which are communication paths 316 formed by the fourth notches 314D located between the first notches 314A and the second notches 314B. In addition to increasing the opportunity for the first fluid F1 to mix, the first notch 314A and the fourth notch 314D are appropriately spaced apart from each other, which ensures the flow of the first fluid F1 in the fourth communication passage 316D and further effectively promotes the mixing of the first fluid F1 between the multiple parallel flow paths 318.

[0043] 3. Details of the Configuration of the Second Heat Exchanger Plate 32 5, the detailed configuration of the second heat exchanger plate 32 is illustrated. The second heat exchanger plate 32 has a configuration similar to that of the first heat exchanger plate 31. Specifically, the second heat exchanger plate 32 includes an inlet header 321 formed in the first opening 221, an outlet header 322 formed by the second opening 222, and a plurality of partition walls 325 provided between the inlet header 321 and the outlet header 322. The plurality of partition walls 325 are provided to separate the flow path of the second fluid F2 from the inlet header 321 to the outlet header 322.

[0044] <5.Other> The present disclosure is not limited to the above-described embodiments. The parallel flow paths 318 may partially include flow paths formed in a zigzag pattern instead of extending linearly over the entire length of the parallel flow paths 318. The zigzag pattern is a concept that includes a pattern with curved corners and a pattern with straight bent corners.

[0045] <6. Summary> The present disclosure can be understood, for example, as follows.

[0046] 1) The heat exchanger plate (first heat exchanger plate 31) according to at least one embodiment of the present disclosure has an inlet header (311) formed by a first opening (111); an outlet header (312) formed by the second opening (122); a plurality of partition walls (315) provided between the inlet header and the outlet header so as to divide a flow path of a fluid (first fluid F1) flowing from the inlet header to the outlet header into a plurality of parallel flow paths (318); a connecting portion (317) that connects the plurality of partition walls; Equipped with At least one of the plurality of partition walls has a notch (314) at the position of the connecting portion in the flow direction of the fluid, The pair of parallel flow paths on both sides of the partition wall having the notch communicate with each other via the notch.

[0047] The above configuration 1) prevents deformation of the partition walls and parallel flow paths, which are issues when fabricating a compact heat exchanger with a high heat transfer coefficient using double-sided etching, and the resulting poor joining during assembly. Furthermore, fluids can move between multiple parallel flow paths through the communication paths defined by the notches. This allows fluids with different dryness levels to mix, thereby equalizing the flow patterns of the fluids in the multiple parallel flow paths. This prevents localized dryout in the parallel flow paths, in which liquid fluid disappears, and allows the heat exchanger plate to achieve a high heat transfer coefficient. As a result, a heat exchanger plate that achieves both compactness and a high heat transfer coefficient can be provided.

[0048] 2) In some embodiments, the heat exchanger plate according to 1) above, The connecting portion is connected to only one end (315A) of each of the partition walls on one side of both ends of each of the partition walls in the plate thickness direction.

[0049] According to the inventors' speculation, the pressure of the fluid flowing through the parallel flow paths can fluctuate significantly. For example, if bubbles are generated or grow in a particular parallel flow path due to the evaporation of the fluid, the fluid pressure in that parallel flow path fluctuates significantly. To give another example, if the dryness fraction of the fluid increases as the fluid flows through the parallel flow paths, the fluid pressure also fluctuates significantly. In this regard, according to the configuration 2) above, the connecting portion is connected to only one end of each partition wall in the plate thickness direction. Therefore, the connecting portion also functions as a throttle that partially blocks the parallel flow paths. This generates an appropriate pressure loss at the connecting portion, thereby minimizing the pressure difference between the multiple parallel flow paths due to the pressure fluctuations. Therefore, the fluid flows more easily through the connecting passages defined by the notches, thereby suppressing the weaving of the fluid in the multiple parallel flow paths. Therefore, the heat exchanger plate can achieve a high overall heat transfer coefficient.

[0050] 3) In some embodiments, the heat exchanger plate according to 1) or 2) above, The notch is formed at an end (315B) of the plurality of partition walls on the other side in the plate thickness direction, The notch bottom (309) of the notch and the surface (317F) on the other side of the connecting portion are at the same position in the plate thickness direction.

[0051] According to the configuration of 3) above, the fluid that passes through the communication passage defined by the notches can flow along the other surface of the connecting portion into the parallel passage. By passing the fluid through the connecting portion, excessive pressure loss of the fluid flowing from the communication passage to the parallel passage can be prevented, and fluid stagnation in the communication passage can be suppressed. This prevents the fluid from interweaving in the multiple parallel passages, and the heat exchanger plate can achieve a high overall heat transfer coefficient.

[0052] 4) In some embodiments, the heat exchanger plate according to 2) or 3) above, An upstream end (399) of the connecting portion in the flow direction of the fluid is recessed in an arc shape toward the downstream side.

[0053] The configuration of 4) above can prevent excessive pressure loss that occurs when the fluid passes through the connecting portion along the flow direction, and can prevent the flow of the fluid along the flow direction from the upstream side to the downstream side of the connecting portion from becoming excessively weak. In other words, it can prevent the flow of the fluid in the communicating passage defined by the notch from becoming excessively dominant, and can equalize the flow pattern of the fluid among the multiple parallel flow passages.

[0054] 5) In some embodiments, the heat exchanger plate according to any one of 1) to 4) above, In the direction of flow of the fluid, both ends of the connecting portion are positioned outward relative to both ends of the notch.

[0055] According to the above configuration 5), it is possible to prevent deformation of the partition wall and the parallel flow path shape due to the connecting portion.

[0056] 6) In some embodiments, the heat exchanger plate stack (30) described in any one of 1) to 5) above is The heat exchanger includes a plurality of first heat exchanger plates (first heat exchanger plates 31) according to any one of 1) to 5) above.

[0057] According to the configuration 6) above, for the same reason as in 1), it is possible to provide a plate stack for a heat exchanger that is both compact and has a high heat transfer coefficient.

[0058] 7) In some embodiments, the microchannel heat exchanger described in 6) above is The heat exchanger plate stack according to 6) above is provided.

[0059] According to the configuration of 7) above, for the same reason as 1), it is possible to provide a heat exchanger that is both compact and has a high heat transfer coefficient. [Explanation of symbols]

[0060] 1: Heat exchanger (microchannel heat exchanger) 30: Plate stack 31: First heat exchanger plate 32: Second heat exchanger plate 35: Plate 111, 122: First opening 122, 222: Second opening 309: Notched bottom 311, 321: Inlet header 312, 322: Exit header 314, 324: Notch 315, 325: Partition wall 315A: One end 317, 327: Connection part 317F:Face 318, 328: Parallel flow paths 325: Partition wall 327: Links 399: Upstream F1: First fluid F2: Second fluid

Claims

1. an inlet header defined by a first opening; an outlet header formed by the second opening; a plurality of partition walls provided between the inlet header and the outlet header so as to divide a fluid flow path from the inlet header to the outlet header into a plurality of parallel flow paths; a connecting portion that connects the plurality of partition walls in a partial region of an area in which the plurality of partition walls extend along the flow direction of the fluid; and Equipped with one or more of the partition walls has a notch at a position of the connecting portion in the flow direction of the fluid, The pair of parallel flow paths on both sides of the partition wall having the notch communicate with each other via the notch, Among the plurality of partition walls, a pair of partition walls adjacent to each other across one of the parallel flow paths in the width direction of the flow path are separated from each other in a region other than the partial region of the range. Heat exchanger plate.

2. The connecting portion is connected to only one end of each of the partition walls on one side of both ends of the partition walls in the plate thickness direction. The heat exchanger plate according to claim 1 .

3. the notch is formed at an end of one of the plurality of partition walls on the other side in the plate thickness direction, The notch bottom and the surface on the other side of the connecting portion are at the same position in the plate thickness direction. The heat exchanger plate according to claim 2.

4. an inlet header defined by a first opening; an outlet header formed by the second opening; a plurality of partition walls provided between the inlet header and the outlet header so as to divide a fluid flow path from the inlet header to the outlet header into a plurality of parallel flow paths; a connecting portion that connects the plurality of partition walls; Equipped with one or more of the partition walls has a notch at a position of the connecting portion in the flow direction of the fluid, a pair of the parallel flow paths on both sides of the partition wall having the notch communicate with each other via the notch; the connecting portion is connected to only one end of each of the partition walls on one side of both ends of the partition walls in the plate thickness direction, The upstream end of the connecting portion in the flow direction of the fluid is recessed in an arc shape toward the downstream side. Heat exchanger plate.

5. In the direction of flow of the fluid, both ends of the connecting portion are positioned outward relative to both ends of the notch. The heat exchanger plate according to any one of claims 1 to 4.

6. A heat exchanger plate stack comprising a plurality of first heat exchanger plates according to any one of claims 1 to 5.

7. A microchannel heat exchanger comprising the heat exchanger plate stack according to claim 6.

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