Micro-channel plate-fin heat exchanger

Abstract

The invention relates to the field of heat exchangers, and provides a micro-channel plate-fin heat exchanger which is mainly characterized in that a heat exchange core body is composed of a heat exchange single body and an independent partition plate or a flat plate fin, and the heat exchange single body is obtained by machining a single-face fin cooling fin which is integrally formed through secondary cutting and slotting; a cold fluid channel, a cold fluid channel side sealing strip, a base plate and fins of the cold fluid channel are arranged on an integrally-formed single-face fin cooling fin, and a heat exchange single body is formed through secondary machining of cutting and slotting on the base plate. Each heat exchange single body is a whole made of the same material and composed of a partition plate, a fin of a hot fluid channel, a fin of a cold fluid channel, the hot fluid channel, the cold fluid channel, a hot fluid channel side seal and a cold fluid channel side seal. Product manufacturing is simpler, the product size is more flexible, and the heat exchange efficiency is higher.

Description

Technical Field

[0001] This invention application relates to the field of heat exchangers, and more particularly to plate-fin heat exchangers and microchannel heat exchangers. Background Technology

[0002] Plate-fin heat exchangers and microchannel heat exchangers are widely used in industries such as petroleum, chemical, natural gas, pharmaceutical, air conditioning, and automobiles. They have advantages such as being compact, lightweight, and having high heat transfer efficiency.

[0003] The manufacturing process of plate-fin heat exchangers is complex. They are usually made of multiple materials such as baffles, fins, guide vanes, hot fluid channel side seals, and cold fluid channel side seals, which are then brazed to form the heat exchange core. During the brazing process, there are technical defects such as poor welding thermal resistance, missing welding thermal resistance, and the thermal resistance of the brazing filler metal itself at the connection between the baffles and fins. These defects seriously affect the heat exchange efficiency of plate-fin heat exchangers. High-standard, high-density fins are difficult to achieve due to limitations in equipment processing capabilities.

[0004] While the manufacturing process of microchannel heat exchangers is relatively simpler than that of plate-fin heat exchangers, they still suffer from the same technical defects: poor soldering thermal resistance at the connection between the flat tube and fins, incomplete soldering thermal resistance, and the thermal resistance of the brazing filler metal itself. Furthermore, the center dimension of the two channels within the flat tube is generally greater than 2mm. Even if it is reduced to less than 2mm, the cost is extremely high. Moreover, the width of the center dimension of the two fluid channels and the thickness of the fins are determined by a single mold for each flat tube product, resulting in poor product dimensional flexibility and difficulty in adapting to the demands of modern development. I believe that in today's booming online sales platforms, the future direction of enterprise development will primarily focus on end-users. While the demand from end-users is not very large, the variability in product dimensions is enormous. In this context, the cost of flat tube molds will drive product costs to an unacceptable level for customers, forcing them to choose other sizes. Summary of the Invention

[0005] The purpose of this invention application is to simplify the manufacturing of heat exchanger products, make product sizes more flexible and mobile, and improve product heat exchange efficiency, by providing a microchannel plate-fin heat exchanger to solve the existing technical defects of the aforementioned plate-fin and microchannel heat exchangers.

[0006] A microchannel plate-fin heat exchanger mainly consists of a heat exchange unit and independent baffles or flat plate fins forming the heat exchange core. The heat exchange unit is obtained by secondary cutting and grooving of a one-piece molded single-sided heat exchange fin or plate. The one-piece molded single-sided heat exchange fin has cold fluid channels, cold fluid channel side seals, a base plate, and cold fluid channel fins. The heat exchange unit is formed by secondary processing of the base plate through cutting and grooving. The heat exchange unit is composed of baffles, hot fluid channel fins, cold fluid channel fins, hot fluid channels, cold fluid channels, hot fluid channel side seals, and cold fluid channel side seals, all made of the same material. The main technical... The technical features are: the baffle, hot fluid channel fins, and cold fluid channel fins are made of the same material as a whole. The hot or cold fluid channel fins are parallel to each other and perpendicular to both sides of the baffle. The hot and cold fluid channel fins are intersected, with a minimum angle between 30° and 90°. To create a turbulence pattern in the hot and cold fluid channels, the secondary-processed hot and cold fluid channel fins can be bent so that the fin feet of the hot or cold fluid channel fins are parallel to each other, and the hot or cold fluid channel fins are inclined to both sides of the baffle. The series combination also forms a fluid guiding channel on the cold fluid side seal. For high-end, custom-sized products, the channels on both sides of the baffle can be directly cut and grooved from sheet metal, but this results in significant material waste and is only suitable for high-end, custom-sized products.

[0007] This invention discloses a microchannel plate-fin heat exchanger with the following positive technical effects: 1. Simplified product manufacturing. As can be seen from the invention, the heat exchange core of a microchannel plate-fin heat exchanger is composed of a heat exchange unit and independent baffles or flat fins. The heat exchange unit is a whole of the same material, which greatly reduces the product assembly steps and the manufacturing and processing costs of fins, hot and cold channels and side seals, as well as the cost of fin forming equipment. 2. More flexible and mobile product dimensions: The dimensions of the heat exchanger equipment's y-axis, x-axis, hot fluid channel, and fin thickness can be freely and flexibly adjusted according to customer needs. It is known that the length of the one-piece molded single-sided fin heat sink can fully meet the needs of various product dimensions along the y-axis. Since the width of the single-sided fin heat sink is limited by the one-piece molding equipment, when the dimension in the x-axis direction is larger than the limitation of the existing one-piece molding equipment, we can adopt a butt joint method in the x-axis direction. Since the cross-section of the hot fluid channel is usually relatively small, we can assume that the hot fluid is under static pressure and calculate the cross-sectional area pressure value of the hot fluid channel according to the cross-sectional area pressure formula, that is, calculate the axial tensile force in the direction of the hot fluid channel. Adding the contact area of ​​the hot fluid side seal and the fin height as the sealing surface, and with the support of independent baffles or flat fins, there is no need to worry about the axial pressure resistance in the direction of the hot fluid channel. As for the size of the hot fluid channel and the thickness of the fins, we can meet the size requirements of different products by changing the cutting and grooving tools. Through practical testing, I have found that the center size of the two hot fluid channels can easily reach 1m or even lower by using the cutting and grooving process. Moreover, the equipment cost and equipment operating cost of this solution are very low. In air conditioning applications, it can significantly reduce the amount of refrigerant used. Of course, in special fields, EDM or etching technology can be used to achieve a smaller channel cross-sectional area, but the manufacturing cost will increase significantly. 3. The heat exchange efficiency of the product is more efficient, mainly reflected in the fact that the fins of the baffle and the hot and cold channels are made of the same material as a whole, and the arrangement of the hot and cold channels and fins. As mentioned above, the fins of the baffle and the hot and cold fluid channels are made of the same material as a whole. This means that the problems of poor welding, missing welding, and the thermal resistance of the brazing filler metal itself at the connection between the baffle and the fins or the microchannel flat tube and the fins in the above-mentioned plate-fin heat exchanger will no longer exist. However, in implementing this invention, I found that, when comparing the various combinations of embodiments of this invention, under the condition that the cross-sectional area of ​​the hot and cold fluid channels, the surface area of ​​the fins, and the number of hot and cold channels are all the same, it is better to solve some of the poor welding, missing welding, and the thermal resistance of the brazing filler metal itself than to completely solve the aforementioned technical defects. The heat exchange performance will be better (which will be explained in detail in the accompanying drawings).Regarding the hot and cold channels and fin arrangement, I believe that the smaller the heat exchange efficiency of plate-fin heat exchangers and microchannel heat exchangers and the smaller the surface area difference of the fins on both sides of the baffle, the better the heat exchange effect. However, the processing size of the fins of plate-fin heat exchangers and the processing size of the flat tubes of microchannel heat exchangers are limited by the equipment, making it impossible to achieve standard microchannels and standard fin arrangements. Through practical implementation, this invention can easily achieve a center size of about 1mm for the two hot fluid channels. In addition, the fins of the hot and cold channels and the baffle are made of the same material, thereby greatly improving the heat exchange efficiency. Therefore, this application can better adapt to the heat exchange needs of special environments.

[0008] A microchannel plate-fin heat exchanger, through optimized product structure and processing technology, achieves simpler manufacturing, more flexible product size, and higher heat exchange efficiency. It demonstrates the outstanding substantive features and significant progress of a microchannel plate-fin heat exchanger, and the positive effects are obvious. Attached Figure Description

[0009] Figure 1 This is a single-channel combined series mode of a microchannel plate-fin heat exchanger and a partially unfolded schematic diagram.

[0010] Figure 2 This is a schematic diagram of a microchannel plate-fin heat exchanger with a dual-channel combined parallel mode and a partial unfolded diagram.

[0011] In the diagram: 1. Heat exchanger unit; 2. Baffle plate; 3. Fin; 4. Flat plate fin; 5. Hot fluid channel side seal; 6. Cold fluid channel side seal; 7. Fluid guide channel; 8. Cover plate; 9. Bottom plate; 10. Guide cover plate; 11. Manifold; 12. Diverter box; 13. Hot fluid inlet; 14. Hot fluid outlet; 15. Cold fluid inlet; 16. Cold fluid outlet; 17. Hot fluid channel; 18. Cold fluid channel; 19. Independent baffle plate; 20. Heat exchanger unit docking point. Detailed Implementation

[0012] Figure 1 This is a single-channel combined series configuration of a microchannel plate-fin heat exchanger, along with a partial unfolded diagram, as shown below. Figure 1As shown in the figure, the heat exchange unit 1 is a single-sided finned heat exchanger that has been integrally formed and then cut and slotted through secondary processing to form a baffle 2, fins 3, hot fluid channel 17, hot fluid channel side seal 5, and fluid guide channel 7. The baffle 2, the fins 3 of the hot and cold channels, the hot fluid channel side seal 5, and the cold fluid channel side seal 6 on the heat exchange unit 1 are all made of the same material. The fins 3 of the hot and cold channels are perpendicular to the baffle 2. Fluid guide channels 7 are provided on the side seal 6 of the cold fluid channel and on the independent baffle 19 on one side of the heat exchange unit 1. Several heat exchange units 1 and independent baffles 19 are stacked in sequence, and the openings of the hot and cold channels of the heat exchange unit 1 and the adjacent heat exchange unit 1 are oriented in the same direction until the design requirements are met. Finally, the cover plate 8, the bottom plate 9, and the guide cover plates 10 on both sides are added and brazed to form a complete microchannel plate-fin heat exchanger.

[0013] Figure 2 This is a schematic diagram of a microchannel plate-fin heat exchanger with a dual-channel parallel configuration and a partial unfolded diagram, as shown below. Figure 2 As shown in the figure, heat exchange unit 1 and Figure 1 Similar to heat exchanger unit 1, which will not be described again here, several heat exchanger units 1 and flat plate fins 4 are stacked sequentially, with the openings of the hot and cold channels of heat exchanger unit 1 and adjacent heat exchanger units 1 facing opposite directions, until the design requirements are met. Finally, a cover plate 8, a base plate 9, a manifold box 11, and a distribution box 12 are added, and then brazed to form a complete microchannel plate-fin heat exchanger. If the pressure, the height of the hot and cold channel fins 3, and other operating conditions permit, the flat plate fins 4 can be omitted. The contact points of the hot fluid channel side seals 5 and cold fluid channel side seals 6 of the upper and lower heat exchanger units 1 can be directly laser welded or argon arc welded, which can reduce the investment in brazing equipment and space, making it suitable for customers with smaller order volumes and greatly increasing the flexibility and mobility of product production. When the dimension in the x-axis direction exceeds the limitations of the one-piece molding equipment, the product dimension limit in the x-axis direction can be increased by butt welding of heat exchanger units 1, forming a heat exchanger unit butt joint point 20, which is also suitable for... Figure 1 Implementation plan.

[0014] The principle of heat exchange is as follows Figure 1As shown, the hot fluid enters the hot fluid channel 17 directly through the hot fluid inlet 13, flows through the hot fluid channel 17 of the first heat exchange unit 1, and enters the fluid guide channel 7 at the end of the heat exchange unit 1. The hot fluid then enters the second heat exchange unit 1, and so on, finally flowing out from the hot fluid outlet 14. The hot fluid is in close contact with the fins 3 of the hot fluid channel 17. The fins 3 transfer most of the heat to the baffle 2. Because the fins 3 and the baffle 2 are made of the same material, there is no thermal resistance from poor soldering, missing soldering, or the solder itself. Therefore, the fins 3 will transfer most of the heat to the baffle 2, and the baffle 2 will then transfer the heat to the fins of the cold fluid channel 18. 3. Finally, the fins 3 of the cold fluid channel 18 release heat to the cold fluid. Only a small portion of the heat is transferred to the independent partition 19 through the fins 3 of the hot fluid channel 17. This is because there are thermal resistances such as poor soldering, missing soldering, and the thermal resistance of the solder itself at the contact points between the independent partition 19 and the fins 3 on both sides. Finally, a small portion of the heat is transferred to the fins 3 of the cold fluid channel 18 by the independent partition 19. The fins 3 of the cold fluid channel 18 then release a small portion of the heat to the cold fluid. The cold fluid enters the cold fluid channel 18 through the cold fluid inlet 15, carrying away the heat released by the fins 3 of the cold fluid channel 18 and discharging it from the cold fluid outlet 15, thus realizing the heat exchange process.

[0015] The principle of heat exchange is as follows Figure 2 As shown, it is similar to Figure 1 There are differences; flow channel patterns can be divided into series and parallel patterns. Figure 2 The independent baffle 19 is replaced with a flat plate fin 4. The flat plate fin 4 has a three-stage heat transfer function and increases the overall strength of the heat exchanger. The hot fluid enters the distribution box 12 through the hot fluid inlet 13. After entering the distribution box 12, the hot fluid enters several hot fluid channels 17, which are in close contact with the fins 3 of the hot fluid channels 17. The hot fluid absorbs the heat of the hot fluid and transfers the heat to the baffle 2. The baffle 2 then transfers the heat to the fins 3 of the cold fluid channel 18. The fins 3 of the cold fluid channel 18 release heat to the cold fluid. After passing through several hot fluid channels 17, the hot fluid enters the collector box 11 and finally exits from the hot fluid outlet 14. The cold fluid enters the cold fluid channel 18 through the cold fluid inlet 15, carries away the heat released by the fins 3 of the cold fluid channel 18, and exits from the cold fluid outlet 16. This completes the heat exchange process. Of course, the flat plate fins 4 of the hot and cold fluid channels also absorb or release some heat. The heat exchange principle is obvious and does not need to be described in detail here.

[0016] Through the Figure 1 , Figure 2 The heat exchange performance of the combination is not difficult to see. Figure 1 Only some of the thermal resistance issues at the connection between partition 2 and fin 3, such as poor soldering thermal resistance, missing soldering thermal resistance, and the thermal resistance of the brazing itself, were resolved. Figure 2When the combination is used, the aforementioned technical defects will no longer exist. Logically, solving all of the aforementioned technical defects is better than solving only some. However, given the superior heat exchange performance of the combination mode in this application, the opposite is true. We can assume... Figure 1 , Figure 2 Given that the cross-sectional area of ​​the hot and cold channels, the thickness of the fins 3, the length, width, and height of the heat exchange unit 1, and the number of hot and cold channels are all the same, regardless of Figure 2 How small does the cross-sectional area of ​​the hot and cold channels become, according to Figure 1 The combination method will have an additional heat transfer path for the independent partition 19, so from the perspective of heat exchange performance, Figure 1 The combination mode is far superior to Figure 2 The combination of, and Figure 2 The combination mode has better maneuverability than Figure 1 .

[0017] Figure 1 , Figure 2 The middle fins can be further processed, such as openings or holes in the fins 3 of the hot and cold channels, or bending them with the fin peaks of the fins 3 of the hot and cold channels as the force points to create a certain turbulence function.

[0018] The combination of the figures described in this application does not represent the scope of protection of this application. Hot and cold channels, axial directions, and combination modes of the figures can be interchanged or combined.

Claims

1. A microchannel plate-fin heat exchanger comprising a heat exchange unit, characterized in that: The heat exchange unit is a single-sided finned heat sink or plate that has been cut and slotted twice. The heat exchange unit is a whole made of the same material, consisting of a baffle, hot fluid channel fins, and cold fluid channel fins. The fin feet of the hot fluid channel fins or the cold fluid channel fins are parallel to each other. The hot fluid channel fins or the cold fluid channel fins are perpendicular or inclined to both sides of the baffle. The fin feet of the hot fluid channel fins and the fin feet of the cold fluid channel fins are intersected, and the minimum angle formed by the intersection is between 30° and 90°.

2. A microchannel plate-fin heat exchanger according to claim 1, characterized in that: The openings of the hot and cold channels of the heat exchange unit and the adjacent heat exchange unit are oriented in the same direction, and an independent partition is provided between the two heat exchange units.

3. A microchannel plate-fin heat exchanger according to claim 1, characterized in that: The openings of the hot and cold channels of the heat exchange unit and the adjacent heat exchange unit face opposite directions, and flat plate fins are provided between the two heat exchange units.

4. A microchannel plate-fin heat exchanger according to claim 1, characterized in that: The openings of the hot and cold channels of the heat exchange unit and the adjacent heat exchange unit face opposite directions, and there are no flat plate fins between the two heat exchange units.

5. A microchannel plate-fin heat exchanger according to claim 1, characterized in that: The heat exchanger unit has a heat exchanger unit docking point in the X-axis direction.

6. A microchannel plate-fin heat exchanger according to claim 1, characterized in that: The partition, hot fluid channel fins, cold fluid channel fins, hot fluid channel side seal, and cold fluid channel side seal are all made of the same material.

7. A microchannel plate-fin heat exchanger according to claim 6, characterized in that: Fluid guiding channels are provided on the hot fluid channel side seal or cold fluid channel side seal and independent partition.

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