Micro-channel heat exchanger

Abstract

The invention discloses a micro-channel heat exchanger, and relates to the technical field of heat exchangers. The micro-channel heat exchanger comprises a first collecting pipe, a second collecting pipe and a plurality of connecting pipes. The multiple connecting pipes are arranged in parallel at intervals and connected between the first collecting pipe and the second collecting pipe, the first collecting pipe, the second collecting pipe and the multiple connecting pipes jointly form a heat exchange flow channel, the heat exchange flow channel is used for refrigerant circulation, a first partition plate is arranged in the first collecting pipe to divide the first collecting pipe into a first collecting section and a second collecting section, and a second partition plate is arranged in the second collecting pipe to divide the second collecting pipe into a second collecting section. Wherein the first flow collecting section is arranged below the second flow collecting section, an inlet communicated with the heat exchange runner is formed in the first flow collecting section, a drainage pipe is arranged at the bottom end of the second flow collecting section in an extending mode, and the drainage pipe is communicated with the inlet. According to the micro-channel heat exchanger, backflow of the retained liquid refrigerant can be achieved, the refrigerant inlet flow is increased, the flowing and distribution uniformity of the refrigerant is improved, the heat exchange efficiency is improved, and the heat exchange effect is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a microchannel heat exchanger. Background Art

[0002] In the refrigerant heat exchanger, since there are large differences in the density, viscosity and other physical properties of gaseous refrigerant and liquid refrigerant, and the density of liquid refrigerant is much greater than that of gaseous refrigerant, under the combined action of inertia and gravity, liquid refrigerant is easily deposited at the bottom of the flow channel and retained during the flow process, affecting the uniformity of refrigerant flow and distribution, thereby reducing the heat exchange efficiency, and directly causing this part of the liquid refrigerant to be unable to continue to participate in heat exchange, causing some flow paths to overheat severely due to insufficient liquid refrigerant, affecting the heat exchange effect.

[0003] In view of this, it is particularly important to design and manufacture a microchannel heat exchanger that can improve the flow and distribution uniformity of the refrigerant, especially in the production of heat exchangers. Summary of the invention

[0004] The object of the present invention is to provide a microchannel heat exchanger that can achieve the reflux of retained liquid refrigerant, increase the refrigerant inlet flow rate, improve the uniformity of refrigerant flow and distribution, improve heat exchange efficiency, and ensure heat exchange effect.

[0005] The present invention is achieved by adopting the following technical solutions.

[0006] A microchannel heat exchanger comprises a first header, a second header and a plurality of connecting tubes, wherein the plurality of connecting tubes are arranged in parallel and spaced apart and are all connected between the first header and the second header, the first header, the second header and the plurality of connecting tubes together form a heat exchange flow channel, the heat exchange flow channel is used for circulating a refrigerant, a first partition is arranged in the first header to separate the first header into a first header section and a second header section, wherein the first header section is arranged below the second header section, the first header section is provided with an inlet connected to the heat exchange flow channel, a drainage tube is extended from the bottom end of the second header section, the drainage tube is connected to the inlet, and the drainage tube is used to drain the liquid refrigerant deposited at the bottom of the second header section to the inlet.

[0007] Optionally, the inner diameter of the drainage tube and the diameter of the inlet satisfy the following relationship: d≤D / 5; wherein d is the inner diameter of the drainage tube, and D is the diameter of the inlet.

[0008] Optionally, the drainage tube is arranged on a side of the first collecting tube away from the second collecting tube, and the inlet end of the drainage tube is 0-3 mm higher than the first partition plate.

[0009] Optionally, a first joint is provided on an outer wall of the first manifold, and a first through hole communicating with the inlet is provided in the first joint;

[0010] The drainage tube and the first collecting tube are integrally formed, and the first joint is fixedly connected to both the drainage tube and the first collecting tube; or, the drainage tube and the first joint are integrally formed, and the first collecting tube is fixedly connected to both the drainage tube and the first joint; or, the first joint and the first collecting tube are integrally formed, and the drainage tube is fixedly connected to both the first joint and the first collecting tube; or, the drainage tube, the first collecting tube and the first joint are separately arranged and fixedly connected to each other; or, the drainage tube, the first collecting tube and the first joint are integrally formed.

[0011] Optionally, the microchannel heat exchanger also includes a first liquid pump and a first liquid extraction pipe. The first collecting section is also provided with a first liquid discharge port, which is arranged at the bottom end of the first collecting section and is located below the inlet. One end of the first liquid pump is connected to the first liquid discharge port, and the other end is connected to the inlet through the first liquid extraction pipe.

[0012] Optionally, a second partition is arranged in the second collecting tube to separate the second collecting tube into a third collecting section and a fourth collecting section, and the first partition and the second partition are staggered in the height direction of the microchannel heat exchanger, wherein the third collecting section is arranged below the fourth collecting section, and the fourth collecting section is provided with an outlet connected to the heat exchange channel.

[0013] Optionally, the microchannel heat exchanger further includes a second liquid pump and a second liquid extraction pipe, a second liquid discharge port is provided at the bottom end of the third collecting section, one end of the second liquid pump is connected to the second liquid discharge port, and the other end is connected to the inlet through the second liquid extraction pipe.

[0014] Optionally, the microchannel heat exchanger also includes a third liquid pump and a third liquid extraction pipe, and the fourth collecting section is also provided with a third liquid discharge port, the third liquid discharge port is arranged at the bottom end of the fourth collecting section and is located below the outlet, one end of the third liquid pump is connected to the third liquid discharge port, and the other end is connected to the inlet through the third liquid extraction pipe.

[0015] Optionally, there are multiple first partitions and multiple second partitions, and the multiple first partitions divide the first collecting pipe into a first collecting section and multiple second collecting sections, and the multiple second partitions divide the second collecting pipe into a fourth collecting section and multiple third collecting sections.

[0016] Optionally, the microchannel heat exchanger further includes a plurality of fins, the fins are wavy, and each fin is disposed between two adjacent connecting tubes.

[0017] The microchannel heat exchanger provided by the present invention has the following beneficial effects:

[0018] The microchannel heat exchanger provided by the present invention has a plurality of connecting tubes arranged in parallel and spaced apart, and all connected between a first header and a second header, the first header, the second header and the plurality of connecting tubes together form a heat exchange channel, the heat exchange channel is used for circulating refrigerant, a first partition is provided in the first header to separate the first header into a first header section and a second header section, wherein the first header section is provided below the second header section, the first header section is provided with an inlet connected to the heat exchange channel, a drainage tube is extended from the bottom end of the second header section, the drainage tube is connected to the inlet, and the drainage tube is used to drain the liquid refrigerant deposited at the bottom of the second header section to the inlet. Compared with the prior art, the microchannel heat exchanger provided by the present invention can realize the reflux of the retained liquid refrigerant, increase the refrigerant inflow flow, improve the uniformity of the refrigerant flow and distribution, improve the heat exchange efficiency, and ensure the heat exchange effect because it adopts a drainage tube connected between the bottom end of the second header section and the inlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic structural diagram of a microchannel heat exchanger provided in the first embodiment of the present invention;

[0021] Figure 2 A cross-sectional view of a microchannel heat exchanger provided in a first embodiment of the present invention;

[0022] Figure 3 A partial cross-sectional view of a microchannel heat exchanger provided in a first embodiment of the present invention;

[0023] Figure 4 A flow velocity model diagram of the refrigerant flowing in the inlet of the microchannel heat exchanger provided in the first embodiment of the present invention;

[0024] Figure 5 A mathematical model diagram of the drainage pipe and the inlet connection in the microchannel heat exchanger provided in the first embodiment of the present invention;

[0025] Figure 6 A schematic structural diagram of a microchannel heat exchanger provided in the second embodiment of the present invention.

[0026] Icons: 100-microchannel heat exchanger; 110-first collecting pipe; 111-first partition; 112-first collecting section; 113-second collecting section; 114-first joint; 115-inlet; 116-first drain port; 117-drainage pipe; 118-first through hole; 120-second collecting pipe; 121-second partition; 122-third collecting section; 123-fourth collecting section; 124-second joint; 125-outlet; 126-second through hole; 130-connecting pipe; 140-end cover; 150-heat exchange channel; 160-ventilation cavity; 170-fin; 180-first liquid pump; 190-first liquid extraction pipe. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0030] In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "horizontal", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connect", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0033] First embodiment

[0034] Please refer to Figures 1 to 3 ( Figure 2 The hollow arrow in the figure indicates the flow direction of the refrigerant. The embodiment of the present invention provides a microchannel heat exchanger 100 for heat exchange. It can realize the reflux of the retained liquid refrigerant, increase the refrigerant inlet flow, improve the uniformity of the refrigerant flow and distribution, improve the heat exchange efficiency, and ensure the heat exchange effect.

[0035] The microchannel heat exchanger 100 includes a first header 110, a second header 120 and a plurality of connecting pipes 130. The first header 110 and the second header 120 are arranged in parallel and spaced apart, and both ends of the first header 110 and the second header 120 are provided with end caps 140 for blocking to prevent refrigerant from overflowing. The plurality of connecting pipes 130 are arranged in parallel and spaced apart, and are all connected between the first header 110 and the second header 120, and the connecting pipe 130 is arranged perpendicular to the first header 110. The first header 110, the second header 120 and the plurality of connecting pipes 130 together form a heat exchange channel 150, and the heat exchange channel 150 is used for the circulation of refrigerant, that is, the refrigerant in the first header 110 can flow to the second header 120 through the connecting pipe 130, and the refrigerant in the second header 120 can flow to the first header 110 through the connecting pipe 130. Specifically, there is a ventilation cavity 160 between two adjacent connecting tubes 130, and a plurality of connecting tubes 130 together form a plurality of ventilation cavities 160, and the ventilation cavity 160 is used for air to pass through. In this way, in the process of air blowing through the microchannel heat exchanger 100, the refrigerant in the heat exchange channel 150 can exchange heat with the air to heat up or cool the air, thereby realizing the heat exchange function of the microchannel heat exchanger 100.

[0036] Furthermore, the microchannel heat exchanger 100 is placed vertically, that is, the first header 110 and the second header 120 are extended in the vertical direction, and the connecting pipe 130 is extended in the horizontal direction. A first partition 111 is arranged in the first header 110 to separate the first header 110 into a first header section 112 and a second header section 113, wherein the first header section 112 is arranged below the second header section 113, and the first header section 112 is provided with an inlet 115 connected to the heat exchange flow channel 150. The refrigerant entering the first header section 112 from the inlet 115 first flows to the second header 120 through a part of the connecting pipe 130, and then flows to the second header section 113 through another part of the connecting pipe 130. In this process, since the first header 110 is extended in the vertical direction, part of the liquid refrigerant will be deposited on the bottom of the second header section 113 (that is, on the first partition 111) and retained, affecting the heat exchange effect. Specifically, a drainage pipe 117 is extended from the bottom end of the second collecting section 113, and the drainage pipe 117 is connected to the inlet 115. The drainage pipe 117 is used to drain the liquid refrigerant deposited at the bottom of the second collecting section 113 to the inlet 115, so as to realize the reflux of the retained liquid refrigerant, increase the refrigerant inlet flow rate, improve the uniformity of the refrigerant flow and distribution, improve the heat exchange efficiency, and ensure the heat exchange effect.

[0037] Preferably, the outer wall of the first manifold 110 is provided with a first joint 114, and a first through hole 118 communicating with the inlet 115 is provided in the first joint 114, the inlet 115 is directly connected with the first through hole 118, and the drainage pipe 117 is provided through the first joint 114 and communicates with the first through hole 118, thereby communicating with the inlet 115. Specifically, the first joint 114 is used to connect with an external pipeline to facilitate the introduction of external gas-liquid two-phase refrigerant.

[0038] In an optional embodiment, the drainage pipe 117 and the first collecting pipe 110 are integrally formed, and the first joint 114 is provided separately. In this case, the first joint 114 is fixedly connected to both the drainage pipe 117 and the first collecting pipe 110 .

[0039] In an optional embodiment, the drainage tube 117 is integrally formed with the first joint 114, and the first header 110 is separately provided. In this case, the first header 110 is fixedly connected to the drainage tube 117 and the first joint 114. In this case, the drainage tube 117 can be a flow channel in the first joint 114, or can be extended outside the first joint 114.

[0040] In an optional embodiment, the first joint 114 and the first collecting pipe 110 are integrally formed, and the drainage pipe 117 is provided separately. In this case, the drainage pipe 117 is fixedly connected to both the first joint 114 and the first collecting pipe 110 .

[0041] In an optional embodiment, the drainage pipe 117, the first collecting pipe 110 and the first joint 114 are all arranged separately and fixedly connected to each other.

[0042] In an optional embodiment, the drainage pipe 117, the first collecting pipe 110 and the first joint 114 are integrally formed.

[0043] It should be noted that one end of the drainage pipe 117 is connected to the bottom end of the second collecting section 113, and the other end is connected to the inlet 115. Since the height of the bottom end of the second collecting section 113 is higher than the height of the inlet 115, and the refrigerant flow at the inlet 115 is relatively large, under the combined effect of gravity and the pressure difference at both ends of the drainage pipe 117, the liquid refrigerant deposited at the bottom of the second collecting section 113 will flow into the inlet 115 along the drainage pipe 117, and then mix with the gas-liquid two-phase refrigerant introduced at the inlet 115 and then enter the first collecting section 112, so as to realize the reflux function of the retained liquid refrigerant and improve the heat exchange efficiency.

[0044] Furthermore, the inner diameter of the drainage tube 117 and the diameter of the inlet 115 satisfy the following relationship: d≤D / 5; wherein d is the inner diameter of the drainage tube 117, and D is the diameter of the inlet 115. According to the Bernoulli principle, reducing the diameter of the inlet 115 can make the gas-liquid two-phase refrigerant entering the inlet 115 have a larger flow velocity and dynamic pressure, thereby reducing the static pressure near the connection between the drainage tube 117 and the inlet 115, ensuring that the liquid refrigerant deposited at the bottom of the second manifold section 113 can flow into the inlet 115 along the drainage tube 117, and avoiding the gas-liquid two-phase refrigerant introduced at the inlet 115 directly flowing back from the drainage tube 117 to the second manifold section 113.

[0045] Please refer to Figure 4 and Figure 5 It is worth noting that the drainage tube 117 is a circular tube, and the inlet 115 is circular. In the steady fully developed laminar flow in the circular tube, the cross-sectional velocity distribution of the refrigerant is parabolic, which satisfies the following relationship:

[0046]

[0047] Where, R is the radius of the inlet 115, R = D / 2; v max v is the refrigerant flow rate at the center of inlet 115; r is the refrigerant flow rate at a point with a radius of r and a center of the inlet 115 .

[0048] In order to prevent the gas-liquid two-phase refrigerant at the inlet 115 from flowing back into the drainage pipe 117, when the drainage pipe 117 does not penetrate into the inlet 115, it is required that the end of the drainage pipe 117 extending into the inlet 115 is located in the low refrigerant flow rate area in the inlet 115. According to the physical properties of the refrigerant such as density and viscosity, it is required here That is to say, (h is the maximum depth where the drainage tube 117 and the inlet 115 intersect each other), taking the square root of the left and right terms of the inequality, we get According to the Pythagorean theorem, we get (D / 2)2 =(D / 2-h) 2 +(d / 2) 2 , and thus it is calculated that d≤D / 5.

[0049] Preferably, the drainage tube 117 is arranged on the side of the first collecting tube 110 away from the second collecting tube 120, the inlet end of the drainage tube 117 is higher than the first partition 111, and the height difference is 0-3mm, that is, the bottom of the inlet end of the drainage tube 117 can be flush with the upper surface of the first partition 111, or can be higher than the upper surface of the first partition 111 by less than 3mm to ensure the drainage effect.

[0050] Preferably, the inner diameter of the drainage tube 117 is 3 mm to 8 mm. A reasonable inner diameter of the drainage tube 117 can prevent the gas-liquid two-phase refrigerant at the inlet 115 from backflowing while ensuring drainage efficiency, and is convenient for production and processing. In this embodiment, the inner diameter of the drainage tube 117 is 5 mm, but it is not limited to this. In other embodiments, the inner diameter of the drainage tube 117 can be 3 mm or 5 mm, and the inner diameter of the drainage tube 117 is not specifically limited.

[0051] Preferably, the inner diameters of the first header 110 and the second header 120 are the same, and the inner diameters of the first header 110 and the second header 120 are both 12 mm to 25 mm. Reasonable inner diameters of the first header 110 and the second header 120 can increase the flow rate of the refrigerant in the heat exchange flow channel 150, thereby improving the heat exchange efficiency and enhancing the heat exchange effect. In this embodiment, the inner diameters of the first header 110 and the second header 120 are both 20 mm, but are not limited thereto. In other embodiments, the inner diameters of the first header 110 and the second header 120 can be both 12 mm or both 25 mm, and the inner diameters of the first header 110 and the second header 120 are not specifically limited.

[0052] Please continue to refer to Figures 1 to 3Optionally, a second partition 121 is provided in the second header 120 to divide the second header 120 into a third header section 122 and a fourth header section 123. The first partition 111 and the second partition 121 are staggered in the height direction of the microchannel heat exchanger 100, wherein the third header section 122 is provided below the fourth header section 123, and the fourth header section 123 is provided with an outlet 125 connected to the heat exchange channel 150. The refrigerant entering the first header section 112 from the inlet 115 first flows to the third header section 122 through a part of the connecting pipe 130, then flows to the second header section 113 through another part of the connecting pipe 130, and then flows to the fourth header section 123 through another part of the connecting pipe 130, and finally flows out from the outlet 125.

[0053] Preferably, the outer wall of the second manifold 120 is provided with a second joint 124, and a second through hole 126 communicating with the outlet 125 is provided in the second joint 124, and the outlet 125 is directly connected to the second through hole 126. Specifically, the second joint 124 is used to connect with an external pipeline to facilitate the outflow of the refrigerant.

[0054] In this embodiment, the number of the first partition 111 and the number of the second partition 121 are both one, the first partition 111 divides the first header 110 into a first header section 112 and a second header section 113, and the second partition 121 divides the second header 120 into a fourth header section 123 and a third header section 122. Accordingly, the number of the drainage pipe 117 is one, and the drainage pipe 117 is connected between the bottom end of the second header section 113 and the inlet 115.

[0055] However, it is not limited to this. In other embodiments, the number of the first partition 111 and the second partition 121 can also be multiple. The multiple first partitions 111 divide the first collecting pipe 110 into a first collecting section 112 and multiple second collecting sections 113, and the multiple second partitions 121 divide the second collecting pipe 120 into a fourth collecting section 123 and multiple third collecting sections 122. At this time, the number of drainage pipes 117 is multiple, and each drainage pipe 117 is connected between the inlet 115 and the bottom end of a second collecting section 113. Specifically, if the number of the first partitions 111 and the second partitions 121 are both two, the two first partitions 111 separate the first collecting pipe 110 into a first collecting section 112 and two second collecting sections 113, and the two second partitions 121 separate the second collecting pipe 120 into a fourth collecting section 123 and two third collecting sections 122. At this time, the number of the drainage pipes 117 is two, and each drainage pipe 117 is connected between the inlet 115 and the bottom end of a second collecting section 113.

[0056] Preferably, the microchannel heat exchanger 100 further includes a plurality of fins 170. The fins 170 are wavy in shape, and each fin 170 is disposed between two adjacent connecting tubes 130, that is, the fins 170 are disposed in the ventilation cavity 160, and the air will simultaneously pass through the fins 170 during the process of passing through the ventilation cavity 160, and the fins 170 are used to increase the heat exchange area of ​​the air, thereby improving the heat exchange efficiency of the air and enhancing the heat exchange effect.

[0057] In this embodiment, the connecting tube 130 is a flat tube to increase the cross-sectional area of ​​the ventilation cavity 160, thereby increasing the ventilation volume and improving the heat exchange efficiency. Specifically, the fin 170 is welded and fixed between two adjacent connecting tubes 130 to ensure the structural strength of the microchannel heat exchanger 100 and prevent the fin 170 from accidentally falling off.

[0058] The microchannel heat exchanger 100 provided in the embodiment of the present invention has a plurality of connecting tubes 130 arranged in parallel and spaced apart, and all connected between the first collecting tube 110 and the second collecting tube 120. The first collecting tube 110, the second collecting tube 120 and the plurality of connecting tubes 130 together form a heat exchange channel 150. The heat exchange channel 150 is used for circulating refrigerant. A first partition 111 is arranged in the first collecting tube 110 to separate the first collecting tube 110 into a first collecting section 112 and a second collecting section 113, wherein the first collecting section 112 is arranged below the second collecting section 113, and the first collecting section 112 is provided with an inlet 115 connected to the heat exchange channel 150. A drainage pipe 117 is extended from the bottom end of the second collecting section 113, and the drainage pipe 117 is connected to the inlet 115. The drainage pipe 117 is used to drain the liquid refrigerant deposited at the bottom of the second collecting section 113 to the inlet 115. Compared with the prior art, the microchannel heat exchanger 100 provided by the present invention adopts a drainage pipe 117 connected between the bottom end of the second collecting section 113 and the inlet 115, so it can realize the reflux of retained liquid refrigerant, increase the refrigerant inlet flow rate, improve the uniformity of refrigerant flow and distribution, improve heat exchange efficiency, and ensure heat exchange effect.

[0059] Second embodiment

[0060] Please refer to Figure 6 The embodiment of the present invention provides a microchannel heat exchanger 100. Compared with the first embodiment, the difference of this embodiment is that the microchannel heat exchanger 100 further includes a liquid pump and a liquid extraction pipe.

[0061] In this embodiment, the microchannel heat exchanger 100 further includes a first liquid pump 180 and a first liquid extraction pipe 190. The first manifold section 112 is further provided with a first liquid discharge port 116, which is disposed at the bottom end of the first manifold section 112 and is located below the inlet 115. One end of the first liquid pump 180 is connected to the first liquid discharge port 116, and the other end is connected to the inlet 115 through the first liquid extraction pipe 190. Since the first collecting pipe 110 is extended in the vertical direction, part of the liquid refrigerant will be deposited at the bottom of the first collecting section 112 and retained. Since the first drain port 116 is arranged below the inlet 115, the liquid refrigerant deposited at the bottom of the first collecting section 112 cannot be drained back to the inlet 115 by the drainage pipe 117. Therefore, in this embodiment, the liquid refrigerant deposited at the bottom of the first collecting section 112 is extracted and sent to the inlet 115 by suction by the first liquid pump 180, which can also realize the reflux function of the retained liquid refrigerant, further increase the refrigerant inlet flow rate, improve the uniformity of refrigerant flow and distribution, improve the heat exchange efficiency, and ensure the heat exchange effect.

[0062] Preferably, the microchannel heat exchanger 100 further includes a second liquid pump and a second liquid extraction pipe. A second liquid discharge port is provided at the bottom of the third manifold section 122, one end of the second liquid pump is connected to the second liquid discharge port, and the other end is connected to the inlet 115 through the second liquid extraction pipe. Since the second manifold 120 is extended in the vertical direction, part of the liquid refrigerant will be deposited at the bottom of the third manifold section 122 and retained. Since the first manifold 110 and the second manifold 120 are far apart, the liquid refrigerant deposited at the bottom of the third manifold section 122 cannot be drained back to the inlet 115 by the drainage pipe 117. Therefore, the liquid refrigerant deposited at the bottom of the third manifold section 122 is extracted and sent to the inlet 115 by the suction of the second liquid pump, which can also realize the reflux function of the retained liquid refrigerant, further improve the heat exchange efficiency, and ensure the heat exchange effect.

[0063] Preferably, the microchannel heat exchanger 100 further includes a third liquid pump and a third liquid extraction pipe, and the fourth manifold section 123 further includes a third liquid discharge port, which is arranged at the bottom of the fourth manifold section 123 and below the outlet 125. One end of the third liquid pump is connected to the third liquid discharge port, and the other end is connected to the inlet 115 through the third liquid extraction pipe. Since the second manifold 120 is extended in the vertical direction, part of the liquid refrigerant will be deposited at the bottom of the fourth manifold section 123 and retained. Since the first manifold 110 and the second manifold 120 are far apart, the liquid refrigerant deposited at the bottom of the fourth manifold section 123 cannot be drained back to the inlet 115 by the drainage pipe 117. Therefore, the liquid refrigerant deposited at the bottom of the fourth manifold section 123 is extracted and sent to the inlet 115 by the suction of the third liquid pump, which can also realize the reflux function of the retained liquid refrigerant, further improve the heat exchange efficiency, and ensure the heat exchange effect.

[0064] The beneficial effects of the microchannel heat exchanger 100 provided in the embodiment of the present invention are the same as those of the first embodiment, and will not be described in detail herein.

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A microchannel heat exchanger, characterized in that: It includes a first collecting pipe, a second collecting pipe and a plurality of connecting pipes, the plurality of connecting pipes are arranged in parallel and spaced apart, and are all connected between the first collecting pipe and the second collecting pipe, the first collecting pipe, the second collecting pipe and the plurality of connecting pipes together form a heat exchange channel, the heat exchange channel is used for circulating refrigerant, a first partition is arranged in the first collecting pipe to separate the first collecting pipe into a first collecting section and a second collecting section, wherein the first collecting section is arranged below the second collecting section, the first collecting section is provided with an inlet connected to the heat exchange channel, the bottom end of the second collecting section is extended with a drainage pipe, the drainage pipe is connected to the inlet, and the drainage pipe can drain the liquid refrigerant deposited at the bottom of the second collecting section to the inlet.

2. The microchannel heat exchanger according to claim 1, characterized in that: The inner diameter of the drainage tube and the diameter of the inlet satisfy the following relationship: d≤D / 5; Wherein, d is the inner diameter of the drainage tube, and D is the diameter of the inlet.

3. The microchannel heat exchanger according to claim 1 or 2, characterized in that: The drainage pipe is arranged on a side of the first collecting pipe away from the second collecting pipe, and an inlet end of the drainage pipe is 0-3 mm higher than the first partition plate.

4. The microchannel heat exchanger according to claim 1 or 2, characterized in that: The outer wall of the first manifold is provided with a first joint, and the first joint is provided with a first through hole communicating with the inlet; The drainage tube is integrally formed with the first collecting tube, and the first joint is fixedly connected to both the drainage tube and the first collecting tube; or, the drainage tube is integrally formed with the first joint, and the first collecting tube is fixedly connected to both the drainage tube and the first joint; or, the first joint is integrally formed with the first collecting tube, and the drainage tube is fixedly connected to both the first joint and the first collecting tube; or, the drainage tube, the first collecting tube and the first joint are separately arranged and fixedly connected to each other; or, the drainage tube, the first collecting tube and the first joint are integrally formed.

5. The microchannel heat exchanger according to claim 1, characterized in that: The microchannel heat exchanger also includes a first liquid pump and a first liquid extraction pipe. The first collecting section is also provided with a first liquid discharge port, which is arranged at the bottom end of the first collecting section and is located below the inlet. One end of the first liquid pump is connected to the first liquid discharge port, and the other end is connected to the inlet through the first liquid extraction pipe.

6. The microchannel heat exchanger according to claim 1, characterized in that: A second partition is arranged in the second collecting pipe to separate the second collecting pipe into a third collecting section and a fourth collecting section, and the first partition and the second partition are staggered in the height direction of the microchannel heat exchanger, wherein the third collecting section is arranged below the fourth collecting section, and the fourth collecting section is provided with an outlet connected to the heat exchange channel.

7. The microchannel heat exchanger according to claim 6, characterized in that: The microchannel heat exchanger also includes a second liquid pump and a second liquid extraction pipe. A second liquid discharge port is provided at the bottom end of the third collecting section. One end of the second liquid pump is connected to the second liquid discharge port, and the other end is connected to the inlet through the second liquid extraction pipe.

8. The microchannel heat exchanger according to claim 6, characterized in that: The microchannel heat exchanger also includes a third liquid pump and a third liquid extraction pipe. The fourth collecting section is also provided with a third liquid discharge port. The third liquid discharge port is arranged at the bottom end of the fourth collecting section and is located below the outlet. One end of the third liquid pump is connected to the third liquid discharge port, and the other end is connected to the inlet through the third liquid extraction pipe.

9. The microchannel heat exchanger according to claim 6, characterized in that: There are multiple first partitions and multiple second partitions. The multiple first partitions divide the first collecting pipe into one first collecting section and multiple second collecting sections. The multiple second partitions divide the second collecting pipe into one fourth collecting section and multiple third collecting sections.

10. The microchannel heat exchanger according to claim 1, characterized in that: The microchannel heat exchanger further includes a plurality of fins, each of which is wavy in shape, and each of the fins is disposed between two adjacent connecting pipes.

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