Distribution device for heat exchanger, heat exchanger assembly and air conditioner

Abstract

The utility model provides a distribution device for a heat exchanger, a heat exchanger assembly and an air conditioner. The distribution device for the heat exchanger comprises a distribution body, a partition plate and a plurality of branch pipes. The partition plate is arranged in the distribution cavity of the distribution body, a mixing cavity is formed in the area, opposite to the liquid inlet, of the partition plate, and a plurality of partition plate holes annularly distributed around the center line of the distribution body are formed in the partition plate plane on the periphery of the mixing cavity. Each branch pipe comprises a first branch pipe section and a connecting section which is positioned at the downstream of the first branch pipe section, and the inner diameter of the connecting section is reduced relative to the inner diameter of the downstream end of the first branch pipe section; the difference d between the inner diameter d1 at the downstream end of the first branch pipe section and the inner diameter d2 at the downstream end of the connecting section is more than or equal to 0.1 mm and less than or equal to 3.5 mm; a reflection absorption section which bends and extends towards one side relative to the center line of the branch pipe hole is formed on the first branch pipe section, the axis of the upstream end of the reflection absorption section and the axis of the downstream end of the reflection absorption section intersect to form an included angle alpha which is larger than or equal to 90 degrees and smaller than or equal to 175 degrees, and the axis of the connecting section intersects with the center line of the branch pipe hole.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigerant distribution, and particularly relates to a distribution device for a heat exchanger, a heat exchanger assembly and an air conditioner. Background Art

[0002] In a compression refrigeration system, a two-phase refrigerant flows through an expansion valve and then into a distribution device and is distributed to each branch of an evaporator. Ideally, the distribution device can provide an equal amount of uniform refrigerant to each branch. However, in actual operation, due to the limitation of the installation working conditions, the existing distributors generally have problems of poor flow distribution uniformity and large influence of the installation angle on the uniformity. In a traditional reflective distributor, the two-phase refrigerant is reflected by a spherical crown-shaped or V-shaped reflective surface, which enhances the disorder degree of the gas-liquid two-phase, so that this type of distributor is less affected by gravity, and thus can have a relatively good flow distribution performance even when not vertically installed. However, in this type of distributor, since the reflective surface is very close to each branch pipe, although the reflection and commutation of the reflective surface enhance the disorder degree of the refrigerant, the two-phase flow is quickly distributed to each branch pipe under the pressure in the distributor body before it has time to be fully mixed, so it is difficult to effectively improve the mixing uniformity of the two-phase flow.

[0003] At present, the optimization of the reflective flow divider mainly focuses on the adjustment of the reflection angle of the V-shaped reflective surface. However, this optimization has a limited improvement on the flow distribution uniformity, and these optimizations are all aimed at the research before refrigerant distribution, while few people study after the refrigerant is distributed to each branch pipe. Although the improvement of the liquid outlet side structure is mentioned in other types of distributors, this improvement mainly solves the problems of branch pipe welding assembly, such as the assembly interference of multiple branch pipes and the welding quality problem of branch pipes. Someone once proposed to set the branch pipe as a bent pipe to avoid the space interference during the assembly of multiple branch pipes, and at the same time, a sleeve is arranged at the end of the branch pipe to be compatible with heat exchanger capillaries of different specifications. Although this scheme solves the problem of branch pipe assembly, it completely ignores the problem of the deterioration of the refrigerant distribution performance caused by the bending of the branch pipe and the capillary assembly step on the sleeve. Specifically, to solve the problem of space interference, it is necessary to control the bending angle of the branch pipe (the included angle between the central axis of the pipe section before bending and the central axis of the pipe section after bending) so that the pipe section after bending is farther away from other branch pipes; and the bending of the pipeline will inevitably cause refrigerant pressure loss, and the smaller the bending angle, the greater the pressure loss. At the same time, when the refrigerant flows, it will also impact the capillary assembly step on the sleeve, generating vortices at the step, forming a high-pressure area at the vortices and squeezing the flow channel cross-sectional area at that place, which will cause the refrigerant to be difficult to enter the capillary through the step, not only seriously affecting the refrigerant flow rate in the heat exchanger capillary, but also causing a sharp increase in the refrigerant pressure loss. And excessive pressure loss will lead to a low average evaporation temperature of the evaporator and reduce the operating efficiency of the system.

[0004] In addition, some people have proposed to solve the problems of blockage, deformation or leakage in the welding of the branch pipes by adjusting the diameter of the branch pipes at the distribution ports. At the same time, it is also hoped that the distribution ports with larger diameters can reduce the uneven distribution of the refrigerant near the branch pipe holes. However, due to the requirements of the heat exchanger for the refrigerant flow rate, it is necessary to connect capillary tubes with smaller diameters or add atomizing nozzles 400 (such as Figure 1 ) behind the branch pipes with larger diameters to narrow the refrigerant flow channel to increase the refrigerant flow rate. However, the narrowing of the flow channel will inevitably cause throttling of the refrigerant at this place. Throttling will not only bring pressure loss, but also the cavitation phenomenon caused by the change of the refrigerant pressure after throttling will cause pressure waves to appear at the throttling place. This pressure wave will propagate upstream along the branch pipe to the main body distribution port, hindering the inflow of the refrigerant at the distribution port and also affecting the atomization state of the refrigerant in the distribution main body, thereby seriously affecting the liquid separation performance.

[0005] The purpose of setting the distribution device is to improve the performance of the heat exchanger based on its flow splitting performance. The flow splitting performance of the distribution device is affected not only by the mixing degree of the two-phase flow in the distribution main body, but also by factors such as the pressure drop loss of the refrigerant during the distribution process, the flow rate of the refrigerant after distribution, and the downstream pressure wave disturbance. The influence of any one factor may offset the improvement brought by other factors, thereby leading to the deterioration of the heat exchanger performance. Therefore, it is urgent to improve the structure of the liquid outlet side of the liquid distributor to solve the influence of factors such as the refrigerant pressure loss, flow rate and pressure wave disturbance on the heat exchanger performance at the liquid outlet side. Utility Model Content

[0006] The utility model aims to overcome the deficiencies of the prior art and provides a distribution device for a heat exchanger, a heat exchanger assembly and an air conditioner.

[0007] To achieve the above object, the utility model provides a distribution device for a heat exchanger, which includes a distribution main body, a partition plate and a plurality of branch pipes. The distribution main body includes a liquid inlet end, a liquid outlet end and a distribution cavity surrounded by the liquid inlet end and the liquid outlet end. An inlet port is formed on the liquid inlet end of the distribution main body, and a plurality of branch pipe holes communicating with the distribution cavity are formed on the liquid outlet end thereof. The partition plate is arranged in the distribution cavity. A mixing cavity surrounded by an annular peripheral wall and a reflecting bottom wall and opening towards the inlet port is formed on the partition plate. The longitudinal section contour line of the annular peripheral wall is square or trapezoidal, and the reflecting bottom wall is flat or partially spherical; a plurality of partition holes are formed on the partition plate plane outside the mixing cavity, which are annularly distributed around the center line of the distribution main body and correspond to the plurality of branch pipe holes one by one. The refrigerant mixed in the mixing cavity is distributed to the liquid outlet end of the distribution main body through the plurality of partition holes;

[0008] Wherein, each branch pipe includes a first branch pipe section connected to the branch pipe hole and at least one connecting section located downstream of the first branch pipe section and having an inner diameter reduced relative to the inner diameter of the downstream end of the first branch pipe section. The difference △d between the inner diameter d1 at the downstream end of the first branch pipe section and the inner diameter d2 at the downstream end of the connecting section is: 0.1 mm ≤ △d ≤ 3.5 mm; a reflection absorption section is formed on the first branch pipe section and bends and extends toward one side of the center line of the branch pipe hole. An included angle α is formed between the axis at the upstream end of the reflection absorption section and the axis at the downstream end thereof, and 90° ≤ α ≤ 175°. Based on the reflection absorption section, the axis of the connecting section intersects the center line of the branch pipe hole.

[0009] According to an embodiment of the present invention, a flow guiding hole section with a gradually decreasing inner diameter along the direction of fluid entering the branch pipe hole is further formed at one end of each branch pipe hole close to the distribution cavity.

[0010] According to an embodiment of the present invention, the shape enclosed by the annular peripheral wall contour line is any one of a cylinder, a truncated cone, a prism or a frustum of a prism.

[0011] According to an embodiment of the present invention, the number of partition holes is the same as the number of branch pipe holes. Each partition hole is substantially coaxial with the corresponding branch pipe hole, and the ratio of the downstream end aperture D1 of the partition hole to the outer diameter D2 of the branch pipe inserted into the branch pipe hole is 0.8 - 1.2.

[0012] According to an embodiment of the present invention, the depth H1 of the mixing cavity satisfies: 0.2D0 ≤ H1 ≤ 1.4D0 mm. The depth H1 of the mixing cavity refers to the vertical distance from the center of the reflection bottom wall to the end face of the opening of the mixing cavity, and D_{0} is the inner diameter of the opening of the mixing cavity.

[0013] According to an embodiment of the present invention, the first branch pipe section further includes an extension section connected between the reflection absorption section and the connecting section, and the extension section extends along the axis direction of the downstream end of the reflection absorption section.

[0014] According to an embodiment of the present invention, along the flow direction of the fluid in the branch pipe, the straight section length L from the starting bending point of the reflection absorption section relative to the center line of the branch pipe hole to the end face of the connection end of the first branch pipe section and the branch pipe hole is: 3 mm ≤ L ≤ 150 mm.

[0015] According to an embodiment of the present invention, the connecting section is a tapered structure integrally formed with the first branch pipe section and having a gradually decreasing inner diameter. Each branch pipe further includes a second branch pipe section, and the second branch pipe section is welded to the connecting section; or the first branch pipe section, the connecting section and the second branch pipe section are integrally formed.

[0016] According to an embodiment of the present invention, each branch pipe further includes a second branch pipe section welded to the downstream of the first branch pipe section, and a connecting section is formed at the socket area between the second branch pipe section and the first branch pipe section; or the connecting section is integrally formed on the second branch pipe section.

[0017] According to an embodiment of the present utility model, the inner diameter of the second branch pipe section located downstream of the connection section is substantially close to the inner diameter at the downstream end of the connection section;

[0018] Alternatively, the inner diameter of the second branch pipe section located downstream of the connection section is greater than the inner diameter at the downstream end of the connection section, and a maintaining straight section with a substantially constant inner diameter is provided on the connection section.

[0019] According to an embodiment of the present utility model, a guiding section with an inner diameter gradually decreasing in the refrigerant inflow direction is formed at one end of the first branch pipe section connected inside the branch pipe hole, and the inner wall generatrix of the guiding section is an inclined straight line or an arc curve; the axis of each branch pipe hole is substantially parallel to the axis of the distribution main body.

[0020] On the other hand, the present utility model also provides a heat exchanger assembly, which includes the above-mentioned distribution device for heat exchanger.

[0021] On the other hand, the present utility model also provides an air conditioner including the above-mentioned heat exchanger assembly.

[0022] In summary, in the distribution device for heat exchanger provided by the present utility model, by providing a mixing cavity opposite to the liquid inlet on the partition plate, the reflective bottom wall reflects the high-speed refrigerant input from the liquid inlet to promote the collision of gas-liquid two phases and enhance the disorder degree of the refrigerant. The setting of the annular peripheral wall provides a space for the full mixing of the two-phase flow after collision in the axial and radial directions of the distribution main body, so that the reflected refrigerant can be fully mixed into a uniformly dispersed flow and then redistributed to each partition hole. On the liquid outlet side, by providing that each branch pipe includes a first branch pipe section and a connection section located downstream of the first branch pipe section, the first branch pipe section with a larger inner diameter increases the refrigerant flow rate distributed into each branch pipe and reduces the distribution resistance of the refrigerant; while the connection section improves the refrigerant flow rate by reducing the flow channel cross-section. On this basis, by setting the inner diameter difference △d, the pressure reduction and speed increase degree of the connection section on the refrigerant are precisely controlled, avoiding excessive throttling resulting in too large fluid pressure loss, and thus realizing the balanced control of the flow rate, flow velocity and pressure during refrigerant distribution. Further, by providing a reflection absorption section on the first branch pipe section that bends and extends to one side relative to the center line of the branch pipe hole, the connection section is no longer coaxial with the center line of the branch pipe hole. When the pressure wave generated by the change of flow velocity and pressure at the connection section propagates upstream, a part of the pressure wave is reflected and absorbed by the outer wall of the reflection absorption section, and the other part turns at the reflection absorption section and rapidly decays after the propagation mode conversion, which well solves the problem of the reduction of the refrigerant flow rate and flow velocity at the branch pipe hole caused by the downstream pressure wave oscillation, and effectively improves the flow splitting performance of the distribution device for heat exchanger. In addition, in order to take into account the refrigerant pressure loss caused by the bending of the reflection absorption section and the impact resistance of the outer wall of the reflection absorption section, an included angle α is formed between the axis at the upstream end of the reflection absorption section and the axis at the downstream end of the reflection absorption section, and 90° ≤ α ≤ 175°.

[0023] To make the above and other objects, features, and advantages of the present utility model more obvious and understandable, the following provides preferred embodiments in conjunction with the accompanying drawings and makes a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure shows a schematic structural diagram of a distribution device for an existing heat exchanger.

[0025] Figure 2 The figure shows a schematic structural diagram of a distribution device for a heat exchanger provided in the first embodiment of the present utility model.

[0026] Figure 3A and Figure 3B The figure shows a schematic structural diagram of a partition in another embodiment of the present utility model.

[0027] Figure 4 The figure shows Figure 2 A schematic structural diagram after removing the liquid inlet pipe and multiple branch pipes.

[0028] Figure 5 The figure shows Figure 4 An enlarged schematic diagram of part A in [[ ]].

[0029] Figure 6 The figure shows Figure 2 A schematic structural diagram of a branch pipe in [[ ]].

[0030] Figure 7 The figure shows Figure 6 An enlarged schematic diagram of part B in [[ ]].

[0031] Figure 8 , Figure 9 , Figure 10 and Figure 11 The figure shows a schematic structural diagram of a branch pipe in a distribution device for a heat exchanger provided in another embodiment of the present utility model.

[0032] Figure 12 The figure shows a schematic structural diagram of a distribution device for a heat exchanger provided in another embodiment of the present utility model.

[0033] Figure 13 The figure shows a schematic structural diagram of a distribution device for a heat exchanger provided in the second embodiment of the present utility model.

[0034] Figure 14 , Figure 15 and Figure 16 The figure shows a schematic structural diagram of a branch pipe in a distribution device for a heat exchanger provided in another embodiment of the present utility model.

[0035] Figure 17 The figure shows a schematic structural diagram of a new refrigerant distributor provided in the third embodiment of the present utility model.

[0036] Figure 18 The following is a schematic structural diagram of the novel refrigerant distributor provided in the fourth embodiment of the present utility model. Specific implementation manner

[0037] Embodiment 1

[0038] Compared with single-phase flow, the action mechanism of gas-liquid two-phase refrigerant during transmission and distribution in the distribution device is more complex. The performance of the distribution device is closely related to factors such as the refrigerant flow pattern in the inlet pipe, the atomization degree of the refrigerant in the distribution main body, and the flow performance of the refrigerant on the liquid outlet side. At present, the research on the performance of the distribution device mainly focuses on the distribution main body and the inlet pipe, and the improvement of the structure on the liquid outlet side of the distribution device mainly solves the assembly and welding problems of multiple branch pipes. In fact, factors such as the pressure drop loss of the refrigerant on the liquid outlet side, the flow rate of the refrigerant after distribution, and the downstream pressure wave disturbance will all have a great impact on the distribution performance of the distribution device.

[0039] In view of this, this embodiment provides a distribution device for a heat exchanger that improves the performance of the distribution device based on the improvement of the structure on the liquid outlet side. As Figures 2 to 7 shown, this embodiment provides a refrigerant distribution device including a distribution main body 1, a plurality of branch pipes 2, and a partition plate 3. The distribution main body 1 includes an inlet end 101, an outlet end 102, and a distribution cavity 103 surrounded by the inlet end 101 and the outlet end 102. An inlet port 105 is formed on the inlet end 101 of the distribution main body, and a plurality of branch pipe holes 104 communicating with the distribution cavity 103 are formed on its outlet end 102. The partition plate 3 is arranged in the distribution cavity 301, and a mixing cavity 301 surrounded by an annular peripheral wall 302 and a reflecting bottom wall 303 and opening towards the inlet port is formed on the partition plate 3. The longitudinal section contour line of the annular peripheral wall 302 is square or trapezoidal, and the reflecting bottom wall 303 is flat or partially spherical; a plurality of partition plate holes 31 that are annularly distributed around the center line of the distribution main body 1 and correspond to the plurality of branch pipe holes 104 one by one are formed on the partition plate plane outside the mixing cavity 301 (that is, when projected along the axial direction of the distribution main body 1, the plurality of partition plate holes 31 are located outside the mixing cavity 301), and the refrigerant mixed in the mixing cavity 301 is evenly distributed to the outlet end 104 of the distribution main body through the plurality of partition plate holes 31.

[0040] The plurality of branch pipes 2 are respectively welded to the plurality of branch pipe holes 104 on the outlet end 102 of the distribution main body.

[0041] Wherein, each branch pipe 2 includes a first branch pipe section 21 connected to the branch pipe hole 104 and at least one connection section 22 located downstream of the first branch pipe section 21 and having an inner diameter reduced relative to the inner diameter of the downstream end of the first branch pipe section 21. The difference △d between the inner diameter d1 at the downstream end of the first branch pipe section 21 and the inner diameter d2 at the downstream end of the connection section 22 is: 0.1 mm ≤ △d ≤ 3.5 mm; a reflection absorption section 211 is formed on the first branch pipe section 21 and extends bent towards one side relative to the center line of the branch pipe hole 104. An included angle α is formed between the axis at the upstream end of the reflection absorption section 211 and the axis at the downstream end thereof, and 90° ≤ α ≤ 175°. Based on the reflection absorption section 211, the axis of the connection section 22 intersects the center line of the branch pipe hole 104.

[0042] In this application, downstream or upstream is divided based on the flow direction of the refrigerant. Generally, the refrigerant flows from upstream to downstream, and the area located downstream receives the refrigerant from upstream. In a refrigeration device, the distribution device is generally installed vertically or obliquely, and the liquid inlet end of the distribution device is located below the liquid outlet end along the direction of gravity. The inertial force of the refrigerant in the distribution device overcomes gravity and flows in the direction opposite to gravity; at this time, the upstream and downstream are still divided according to the flow direction of the refrigerant.

[0043] The distribution device for a heat exchanger provided in this embodiment integrates reflection and mixing. The high-speed two-phase flow refrigerant is input into the mixing chamber 301 through the liquid inlet 105 on the liquid inlet end 102, and after being reflected by the reflection bottom wall 303 to enhance the degree of disorder, it is fully mixed in the mixing chamber 301 surrounded by the annular peripheral wall 302 and the reflection bottom 303 to form a dispersed flow pattern. The setting of the annular peripheral wall 302 enables the mixing chamber to provide a suitable mixing space for the reflected refrigerant both axially and radially of the distribution main body 1, promoting the full mixing of the two-phase refrigerant and ensuring that the mixed refrigerant always maintains a dispersed flow pattern during the process of being distributed to the plurality of partition holes 31.

[0044] In this embodiment, the longitudinal section contour line of the annular peripheral wall 301 is square and the reflection bottom wall 302 is a plane, so the mixing chamber 301 surrounded by the two is cylindrical. However, the present utility model does not make any limitation thereto. In other embodiments, the mixing chamber surrounded by the annular peripheral wall with a square longitudinal section contour line and the plane-shaped reflection bottom wall can also be a prismatic shape, such as a quadrangular prism shape. Or, in other embodiments, a cylinder or prism with a square longitudinal section contour line of the annular peripheral wall 302 can also be provided, while the reflection bottom wall 303 is in a partial spherical shape, such as Figure 3A shown. Or, the annular peripheral wall is a frustum of a cone or a frustum of a pyramid with a trapezoidal longitudinal section contour line, and the reflection bottom wall is either a plane or a partial spherical shape; specifically, when the reflection bottom wall 303 is a plane, the shape of the mixing chamber 301 is a frustum of a cone (such as Figure 3B shown) or a frustum of a pyramid.

[0045] In this embodiment, the depth H1 of the mixing chamber satisfies: 0.2D0 ≤ H1 ≤ 1.4D0. The depth H1 of the mixing chamber refers to the vertical distance from the center of the reflective bottom wall to the end face of the opening of the mixing chamber, and D0 is the inner diameter of the opening of the mixing chamber. The setting of the depth H1 of the mixing chamber based on the inner diameter D0 of the opening of the injection-type mixing chamber realizes the accurate setting of the aspect ratio of the mixing chamber, providing conditions for the sufficient mixing of the two-phase refrigerant and maintaining a dispersed flow pattern to further improve the flow distribution uniformity. Preferably, when D0 is relatively large, 0.25D0 ≤ H1 ≤ 0.8D0 can also be set; such as 0.3, 0.4.

[0046] In this embodiment, the number of the partition holes 31 is the same as the number of the branch pipe holes 104. Each partition hole 31 is substantially coaxial with a corresponding branch pipe hole 104, and the ratio of the downstream end aperture D11 of the partition hole to the outer diameter D12 of the branch pipe inserted into the branch pipe hole is 0.8 - 1.2 (such as proportional values of 0.9, 0.95, 1.0, 1.05, 1.1 or 1.15, etc.). The corresponding and substantially coaxial partition holes 31 and branch pipe holes 104 form the shortest axial transmission path therebetween, and the uniform refrigerant output from the partition holes 31 can quickly enter the corresponding branch pipe holes 104, maintaining the flow pattern after the refrigerant mixing as much as possible and further improving the flow distribution uniformity of the refrigerant. However, the present utility model does not make any limitation thereto. In other embodiments, considering the partition area, the number of the partition holes can also be set to be twice the number of the branch pipe holes, and each branch pipe hole can also correspond to two partition holes, but the ratio of the downstream end aperture D11 of the partition hole to the outer diameter D12 of the branch pipe inserted into the branch pipe hole still needs to satisfy 0.8 - 1.2. Further, in this example, the axis of each branch pipe hole 104 is also substantially parallel to the axis of the distribution body 1. However, the present utility model does not make any limitation thereto.

[0047] After the two-phase refrigerant is sufficiently mixed in the mixing chamber 103, it will enter the second cavity 1032 through the multiple partition holes 31 on the partition 3, and after being mixed again in the second cavity 1032, it will be evenly distributed to the first branch pipe sections 21 of each branch pipe 2 through the branch pipe holes 104. Then, the refrigerant reaches the connection section 22 after passing through the reflection absorption section 211, and after being depressurized and accelerated in the connection section 22, it is transported to the evaporator. In each branch pipe 2, by setting the inner diameter difference △d related to the connection section 22 and the reflection absorption section 211, problems such as excessive pressure loss caused by excessive throttling in the connection section 22 and the transmission of pressure waves caused by throttling to the upstream are well solved while being depressurized and accelerated, so that the flow rate, flow velocity, and pressure of the refrigerant in each branch pipe 2 can all meet the working conditions requirements of the heat exchanger, ensuring that the heat exchanger has excellent and stable heat exchange performance. To better illustrate the influence of the structure of the branch pipe 2 on the liquid separation performance, the following will be combined with Figures 2 to 7 A detailed description will be made on the liquid outlet side structure of the distribution device for the heat exchanger provided in this embodiment.

[0048] In a refrigeration system, the distribution device for the heat exchanger provided in this embodiment is connected between a throttle valve and an evaporator. The gas-liquid two-phase refrigerant after pressure reduction and evaporation by the throttle valve enters the distribution main body 1 for full mixing, and then is distributed to each branch of the evaporator through a plurality of branch pipes 2. Limited by the evaporation temperature and heat transfer coefficient, the pressure loss and flow velocity in each branch pipe of the distribution device need to meet certain requirements. Specifically, excessive pressure loss on the liquid outlet side of the distribution device will cause the liquid refrigerant to evaporate prematurely, thereby affecting the refrigerant flow rate entering the evaporator and resulting in too low an average evaporation temperature of the evaporator; when the condensation temperature remains unchanged, the decrease in the evaporation temperature will increase the compression ratio of the compressor and cause an increase in the compressor power. While too low a refrigerant flow velocity will result in too small a heat transfer coefficient of the evaporator, increasing the heat transfer temperature difference and irreversible loss and affecting the energy efficiency of the refrigeration system.

[0049] Therefore, in order to balance the pressure loss and flow velocity of the refrigerant distributed into each branch pipe 2, the distribution device for the heat exchanger provided in this embodiment is provided such that each branch pipe 2 includes a first branch pipe section 21 connected to the branch pipe hole 104 and a connection section 22 located downstream of the first branch pipe section 21 and having a reduced inner diameter relative to the first branch pipe section 21. The first branch pipe section 21 with a larger inner diameter increases the refrigerant distribution flow path between the distribution cavity 103 in the distribution main body 1 and the branch pipe 2, reducing the pressure loss of the refrigerant distribution while increasing the refrigerant flow rate. To compensate for the problem of the decrease in the refrigerant flow velocity caused by the increase in the inner diameter of the first branch pipe section 21, the connection section 22 reduces the pressure of the refrigerant and increases its velocity by reducing the inner diameter. On this basis, the difference △d between the inner diameter d2 of the downstream end of the connection section 22 and the inner diameter d1 of the downstream end of the first branch pipe section 21 (for the convenience of description, hereinafter simply referred to as the inner diameter difference △d) is controlled to precisely control the throttling degree of the refrigerant by the connection section 22 and avoid a sharp increase in the refrigerant pressure loss due to excessive throttling. This setting realizes the comprehensive control of the refrigerant flow velocity and the refrigerant pressure loss, ensuring that the heat transfer coefficient of the evaporator and its average evaporation temperature can be uniformly within the design range of the evaporator, and comprehensively improving the heat transfer performance of the evaporator.

[0050] Further, according to Bernoulli's equation, when the refrigerant flows through the connection section 22, its gas pressure value will drop to a very low level. When the refrigerant pressure value at the connection section 22 is lower than the saturated vapor pressure of the refrigerant, the gas nuclei in the refrigerant will grow into cavitation bubbles. Subsequently, the cavitation bubbles collapse to generate cavitation, and the intense cavitation will trigger a large-amplitude pipeline vibration accompanied by noise, that is, a pressure wave is formed. The pressure wave propagates upstream and downstream along the branch pipe 2. When the pressure wave propagates upstream into the distribution main body 1, it not only directly affects the refrigerant distribution flow rate and velocity at the branch pipe hole 104, but even affects the mixing and atomization degree of the refrigerant in the distribution cavity 103, thus seriously affecting the two-phase flow distribution process and deteriorating the phase separation phenomenon. To reduce the influence of the pressure wave on the upstream refrigerant distribution, on the one hand, the distribution device for the heat exchanger provided in this embodiment controls the throttling degree of the connection section 22 through the inner diameter difference △d to achieve the limitation of the lowest pressure value at this place of the refrigerant, and tries to weaken the pressure wave energy brought by the cavitation phenomenon. On the other hand, a reflection and absorption section 211 is formed on the first branch pipe section 21 and extends bent to one side with respect to the center line of the branch pipe hole 104. The setting of the reflection and absorption section 211 makes the connection section 22 no longer coaxial with the branch pipe hole 104. When the pressure wave generated at the connection section 22 propagates upstream to the reflection and absorption section 211, a part of it is reflected back to the downstream by the outer inner wall of the reflection and absorption section 211 (referring to the inner wall of the reflection and absorption section that is farthest from the bending center in the radial direction) and is absorbed while being reflected; while the other part turns at the reflection and absorption section 211 and changes the propagation form of the pressure wave to make it easier to be absorbed by the first branch pipe section 21, accelerating the attenuation speed of the pressure wave when it propagates upstream. This setting effectively reduces the influence of the pressure wave on the refrigerant performance at the branch pipe hole 104, and thus greatly improves the flow splitting performance of the distribution device.

[0051] Based on the influence of the throttling intensity on the average evaporation temperature and pressure wave of the evaporator, in this embodiment, the inner diameter difference △d is set to satisfy: 0.1 mm ≤ △d ≤ 3.5 mm. Specifically, the inner diameter d1 at the downstream end of the first branch pipe section 21 is set to 5.5 mm, the inner diameter d2 at the downstream end of the connection section 22 is set to 5 mm, and the inner diameter difference △d is 0.5 mm. However, the present utility model does not make any limitation thereto. In other examples, the inner diameter difference △d can also be set to other values within 0.1 mm ≤ △d ≤ 3.5 mm, such as 0.2 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm. Although this embodiment is described by taking the inner diameter d1 at the downstream end of the first branch pipe section 2 as 5.5 mm as an example. However, the present utility model does not make any limitation thereto. In other embodiments, d1 can also be other pipe diameter specifications, such as other pipe diameter specifications within 3 mm to 10 mm.

[0052] For the reflection and absorption section 211, the curved structure enables it to reflect and absorb pressure waves and change the propagation mode of pressure waves, causing the pressure waves to rapidly decay after passing through the reflection and absorption section 211. However, the curved structure will inevitably bring about local resistance losses. To reduce the local resistance losses at the reflection and absorption section 211, the bending angle of the reflection and absorption section 211 is controlled. Specifically, an included angle α is formed between the axis at the upstream end of the reflection and absorption section 211 and the axis at the downstream end of the reflection and absorption section 211, and 90° ≤ α ≤ 175°. Further, since the reflection and absorption of pressure waves mainly act on the outer inner wall of the reflection and absorption section 211, the setting of the included angle α also needs to take into account the thickness of the outer pipe wall of the reflection and absorption section 211 to ensure that while meeting the requirements of the system's pressure resistance strength and service life, it can also well meet the reflection impact of pressure waves. The thickness of the outer pipe wall of the reflection and absorption section 211 also refers to the thickness of the pipe wall at the farthest point from the center of curvature in the radial direction.

[0053] To study the influence of the bending angle of the reflection and absorption section 211 on the attenuation of pressure waves and local resistance losses, based on CFD (Computational Fluid Dynamics) simulation, Figure 2 the flow distribution uniformity and pressure loss of the distribution device for heat exchangers shown in the figure are analyzed. In this embodiment, the number of branch pipes 2 is four, and a reflection and absorption section 211 and a connection section 22 are formed on each branch pipe 2. However, the present utility model does not make any limitation in this regard. In other embodiments, the number of branch pipes can be two, three, or more than five.

[0054] Under the condition that other structural parameters remain the same, based on the included angle α, several schemes of 180°, 175°, 172°, 170°, 168°, 165°, 162°, 160°, 155°, 150°, 140°, 135°, 130°, 120°, 110°, 100°, 90°, and 85° are selected. After simulation, Table 1 is formed. Among them, ΔP is the pressure difference between the refrigerant pressure at the liquid inlet 105 and the total outlet pressure in the distribution device for heat exchangers; STD is the evaluation index of flow distribution uniformity, which is the mean square deviation of the refrigerant mass flow rates at the outlets of each branch pipe, and its expression is as follows:

[0055]

[0056] Among them, is the average value of the refrigerant mass flow rates at the outlets of all branch pipes, x j is the refrigerant mass flow rate at the outlet of the jth branch pipe, and n is the number of branch pipes.

[0057] The software used for CFD simulation analysis is ANSYS software, and its conditions are set as follows:

[0058] Turbulence model: Realizable k-ε model;

[0059] Network parameters: Tetrahedral unstructured grids are adopted;

[0060] Operating conditions: The working medium is R410A refrigerant, the wall boundary is an adiabatic boundary, the inlet dryness is 0.2, and the installation condition is vertical installation;

[0061] Inlet boundary conditions: Inlet total mass flow rate: 120 Kg / h; Inlet gas phase velocity: 3.92 m / s; Inlet liquid phase velocity: 0.46 m / s; Liquid phase volume fraction: 0.1032; Turbulence intensity: 5%; Hydraulic diameter value: 8.12 mm.

[0062] Table 1

[0063]

[0064]

[0065] Based on the data in Table 1, it can be obtained that after adjusting the included angle α from 180° to 175°, the flow splitting uniformity STD has increased by 39.6%, and the flow splitting uniformity has been greatly improved; when the included angle α is adjusted to 165°, the flow splitting uniformity STD has even increased by 68.3%; the data in Table 1 shows that setting the reflection absorption section 211 can greatly improve the performance of the distribution device. Then, observing the pressure difference △P in Table 1, it can be obtained that the setting of the reflection absorption section 211 has little overall impact on the pressure difference △P, and the partial pressure difference △P within the range of 162° to 175° of the included angle α is even slightly lower than the pressure difference △P when α is 180°, which is very likely the beneficial effect brought by effectively reducing the influence of the downstream pressure wave on the upstream refrigerant transmission after setting the reflection absorption section 211. However, as the included angle α decreases, the pressure difference △P shows an upward trend, and the closer the included angle α is to 9o°, the faster the pressure difference △P increases. Further, when the included angle α is less than 90°, the flow splitting uniformity STD deteriorates sharply.

[0066] Combining the liquid separation performance in Table 1 and taking into account the influence of the included angle α on the outer wall thickness of the reflection absorption section 211, preferably, set the included angle α to an angle value within 170° to 140°, such as 165°, 162°, 140°, etc. However, the present utility model does not make any limitation in this regard. In other embodiments, when the overall pressure loss of the distribution device and the wall thickness of the outer wall of the reflection absorption section permit, the included angle α can also be set to other values within 90° ≤ α ≤ 175°.

[0067] To further reduce the influence of the downstream pressure wave on the refrigerant flow pattern and flow state in the branch pipe hole 104 and the distribution chamber 103, in this embodiment, along the refrigerant flow direction in the branch pipe 2, the straight section length L from the bending start point K of the reflection and absorption section 211 relative to the center line of the branch pipe hole to the end face of the connection end of the first branch pipe section 21 and the branch pipe hole 104 is: 3 mm ≤ L ≤ 150 mm. Although the downstream pressure wave is rapidly attenuated after being reflected and absorbed by the reflection and absorption section 211 and the transformation of the propagation form, when the pressure wave energy is large or the included angle α is large, the remaining pressure wave after attenuation inevitably continues to propagate upstream. Therefore, in this embodiment, by setting the straight section length L, an attenuation distance is provided for the pressure wave to ensure that the pressure wave is completely attenuated before reaching the branch pipe hole 104, thereby well solving the influence of the downstream pressure wave on the refrigerant in the distribution main body 1.

[0068] Furthermore, the setting of the straight section length L also provides a wider design space for the included angle α. Specifically, when the included angle α is limited by factors such as local resistance loss or the wall thickness at the reflection and absorption section 211 and is at a large angle, the reflection and absorption effect of the outer inner wall of the reflection and absorption section 211 on the pressure wave is weakened. At this time, the straight section length L can be increased to make up for it to ensure that the pressure wave is completely attenuated before reaching the branch pipe hole 104; when the included angle α is relatively small, the straight section length L can be shortened to control the axial length of the distribution device for the heat exchanger. The cooperation between the included angle α and the straight section length L makes the distribution device for the heat exchanger provided in this embodiment not only have excellent performance but also can be well installed in a narrow or short-axial-length installation space, greatly improving the compatibility of the distribution device with the installation space. Preferably, the straight section length L can be set to 30 mm or 50 mm. However, the present utility model does not make any limitation in this regard. In other embodiments, the straight section length L can also be any length value within 3 mm ≤ L ≤ 150 mm.

[0069] In this embodiment, the first branch pipe section 21 further includes an extension section 212 connected between the reflection and absorption section 211 and the connection section 22. The extension section 212 extends along the axis direction at the downstream end of the reflection and absorption section 211, and the inner diameter d1 at the downstream end of the first branch pipe section 21 is the inner diameter at the downstream end of the extension section 212. Similarly, the absorption of the pressure wave by the extension section 212 can also weaken the energy of the pressure wave propagating upstream and weaken the impact of the pressure wave on the outer inner wall of the reflection and absorption section 211 to improve the pressure resistance strength and service life at the reflection and absorption section 211. In addition, in other embodiments, the extension section 212 also provides an assembly position for the welding connection of the second branch pipe section at the rear end. However, the present utility model does not make any limitation in this regard. In other embodiments, the extension section is not required to be provided on the first branch pipe section, as Figure 8 shown.

[0070] In this embodiment, the connecting section 22 is a tapered structure integrally formed with the first branch pipe section 21 and having a gradually decreasing inner diameter. The tapered connecting section 22 allows the refrigerant to smoothly enter the connecting section 22 from the first branch pipe section 21. This setting not only reduces the flow resistance of the refrigerant but also effectively weakens the high-pressure vortices generated by the sudden change in the cross-sectional area of the flow channel, preventing the flow channel at the connecting section 22 from being occupied by the high-pressure vortices and ensuring that the actual effective cross-sectional area of the flow channel at the connecting section 22 is basically close to the designed value to promote the smooth flow of the refrigerant. However, the present utility model makes no limitation thereto.

[0071] In this embodiment, each branch pipe 2 further includes a second branch pipe section 23, and the inner diameter of the second branch pipe section 23 is basically close to the inner diameter d2 at the downstream end of the connecting section 22. Specifically, in this embodiment, the first branch pipe section 21, the connecting section 22, and the second branch pipe section 23 are integrally formed, and the second branch pipe section 23 is a straight pipe extending gradually along the axis direction at the downstream end of the connecting section 22. However, the present utility model makes no limitation thereto. In other embodiments, the second branch pipe section 23 can also be welded to the assembly section 221 downstream of the connecting section 22, as Figure 9 shown. Or, the second branch pipe section may not be provided on the distribution device for the heat exchanger, and the system pipeline of the refrigeration equipment can be directly connected to the assembly section 221 downstream of the connecting section 22, as Figure 10 shown. In addition, the second branch pipe section 23 can also be a bent pipe extending and bending to one side relative to the axis at the downstream end of the connecting section 22, as Figure 11 shown.

[0072] Specifically, during the process that the high-speed refrigerant entering from the liquid inlet end 101 is fully mixed and distributed to multiple branch pipes 2 in the distribution cavity 103, some of the refrigerant will inevitably impact on the end wall of the second cavity 1032 near the liquid outlet end and flow back along the peripheral wall of the second cavity 1032. The backflow of the refrigerant will generate an eddy current area near the branch pipe hole 104. The existence of the eddy current area will squeeze the refrigerant flow channel at the entrance of the branch pipe hole 104 and reduce the refrigerant flow rate entering the branch pipe 2, thereby affecting the flow splitting performance of the distribution device. To weaken the adverse effect of the eddy current area near the branch pipe hole 104 on the flow splitting performance, as Figure 4 and Figure 5As shown in the figure, at one end of each branch pipe hole 104 close to the distribution cavity 103, a flow guiding hole section 1041 is formed, and the inner diameter of the flow guiding hole section 1041 gradually decreases along the direction of the fluid entering the branch pipe hole 104. Specifically, each branch pipe hole 104 includes a branch pipe hole section 1042 welded to the corresponding first branch pipe section 21 and a flow guiding hole section 1041 communicating the branch pipe hole section 1042 and the distribution cavity 103. The inner diameter of the flow guiding hole section 1041 gradually decreases along the refrigerant flow direction. On the premise that the inner diameter of the branch pipe hole section 1042 remains unchanged, the gradual decrease of the aperture of the flow guiding hole section 1041 will inevitably increase the aperture at the entrance of the flow guiding hole section 1041 (that is, increase the refrigerant flow channel at the entrance of the branch pipe hole 104), so that the refrigerant can better enter the flow guiding hole section 1041. In addition, the increase of the aperture at the entrance of the flow guiding hole section 1041 also reduces the reflection area of the refrigerant by the end wall of the distribution cavity 103 close to the liquid outlet end, thereby reducing the action range of the eddy current area and weakening its extrusion of the refrigerant distribution flow channel, so as to further improve the flow distribution uniformity and reduce the flow distribution resistance.

[0073] Furthermore, in this embodiment, it is also set that the aperture of the downstream end of the flow guiding hole section 1041 is smaller than the aperture of the branch pipe hole section 1042. A limiting part 1043 protruding towards the center of the branch pipe hole 104 is formed at the connection between the flow guiding hole section 1041 and the branch pipe hole section 1042, and the inner diameter d3 at the limiting part 1043 is basically close to the inner diameter d4 of the branch pipe 2 connected to the branch pipe hole section 1042. The limiting part 1043 is configured to abut against the insertion end face of the branch pipe 2 to realize the insertion and assembly limit of the branch pipe 2. The inner diameter d3 of the limiting part 1043 being basically close to the inner diameter d4 of the branch pipe makes there no longer a step at the insertion front end face of the branch pipe 2, and the refrigerant flowing into the flow guiding hole section 1041 can smoothly enter the branch pipe 2 to further reduce the flow resistance of the refrigerant.

[0074] In this embodiment, the first branch pipe section 21 is a circular pipe fitting with a basically consistent inner diameter. However, the present utility model does not make any limitation thereto. In other embodiments, it is also possible to set that a guiding section 213 with an inner diameter gradually decreasing along the refrigerant inflow direction is formed at one end of the first branch pipe section 21 connected to the branch pipe hole 104, and the inner wall generatrix of the guiding section 213 is an inclined straight line (as Figure 12 shown), an arc curve or a combination of both. Similar to the flow guiding hole section 1041, the guiding section 213 can also guide the refrigerant to better enter the branch pipe 2 to reduce the distribution resistance of the refrigerant.

[0075] Correspondingly, this embodiment also provides a heat exchanger assembly including the above-mentioned distribution device for heat exchangers, and this heat exchanger assembly is an evaporator or a condenser.

[0076] On the other hand, this embodiment also provides an air conditioner including the above-mentioned heat exchanger assembly.

[0077] Embodiment 2

[0078] This embodiment is basically the same as Embodiment 1 and its variations, except that: the formation method of the connecting section 22 is different. In this embodiment, as Figure 13 shown, each branch pipe 2 further includes a second branch pipe section 23 welded downstream of the first branch pipe section 21, and the connecting section 22 is integrally formed on the second branch pipe section 23.

[0079] Specifically, the second branch pipe section 23 has a connecting portion 231 sleeved on the extension section 212 and having a flared structure, and a connecting section 22 with a gradually decreasing inner diameter is formed downstream of the connecting portion 231. However, the present utility model does not make any limitation on the assembly method of the second branch pipe section and the first branch pipe section. In other embodiments, the extension section 212 may also be set to have a flared structure (or a flared section is formed after the extension section) to sleeve and weld the connecting portion 231 on the second branch pipe section, and the connecting section 22 is still a structure with a gradually decreasing inner diameter located downstream of the connecting portion 231, as Figure 14 shown.

[0080] [[ID=z10]]Although both this embodiment and Embodiment 1 are described by taking the connecting section 22 as a gradually decreasing structure as an example. However, the present utility model does not make any limitation on this. Based on the control of the inner diameter difference △d, the connecting section 22 may also be formed at the socket area between the second branch pipe section 23 and the first branch pipe section 21, that is, the connecting section is directly formed based on the inner diameter difference between the end of the first branch pipe section 21 and the connecting portion 213 of the branch pipe section, as Figure 15 shown. In this structure, no flaring or necking processing is required on both the first branch pipe section and the connecting portion of the second branch pipe section.

[0081] Although both this embodiment and Embodiment 1 are described by taking only one connecting section 22 on the branch pipe 2 as an example. However, the present utility model does not make any limitation on this. In other embodiments, as Figure 16 shown, multiple connecting sections 22' may also be provided after the reflection absorption section 211, and the refrigerant is subjected to multi-stage pressure reduction and speed increase based on the multiple connecting sections 22', and at the same time, the inner diameter difference △d' between adjacent connecting sections is controlled to control the throttling degree of each connecting section, and the pressure loss and downstream pressure wave oscillation caused by throttling pressure reduction are weakened as much as possible. Specifically, the inner diameter difference △d' between adjacent connecting sections refers to the difference between the inner diameter at the downstream end of each connecting section and the inner diameter at the downstream end of the adjacent connecting section.

[0082] Embodiment 3

[0083] This embodiment is basically the same as Embodiment 2 and its variations, except that: the structure of the second branch pipe section 23 is different, as Figure 17 shown.

[0084] In order to better accommodate the pipeline system of the refrigeration equipment during assembly, in this embodiment, the inner diameter of the second branch pipe section 23 downstream of the connection section 22 is larger than the inner diameter d2 at the downstream end of the connection section 22. At this time, there is a straight section 222 with a substantially constant inner diameter on the connection section 22, and the end of the straight section 222 is the downstream end of the connection section 22. The straight section 222 provides a stable interval for the refrigerant after acceleration, avoiding the influence of the second branch pipe section 23, which is downstream of the connection section 22 and has a relatively large inner diameter, on the flow rate of the refrigerant, and ensuring a stable increase in the flow rate of the refrigerant.

[0085] The present utility model does not impose any limitation on the length L1 of the straight section.

[0086] Embodiment Four

[0087] This embodiment is basically the same as Embodiment One and its variations, except that: the specific structure of the distribution body 1 and the bending direction of the reflection absorption section 211 are different.

[0088] In Embodiment One, the reflection absorption section 211 extends by bending away from the center line of the distribution body 1; while in this embodiment, as Figure 18 shown, the reflection absorption section 211 extends towards the center line of the distribution body 1. Similarly, in this embodiment, the included angle α formed by the intersection of the axis at the upstream end of the reflection absorption section 211 and the axis at the downstream end of the reflection absorption section 211 still satisfies: 90° ≤ α ≤ 175°. However, the present utility model does not impose any limitation on the bending direction of the reflection absorption section. In the present utility model, the reflection absorption section can extend in any direction (i.e., 360-degree bending) relative to the center line of the branch pipe hole where it is located.

[0089] In addition, in this embodiment, the center lines of the branch pipe holes 104 intersect at the center line of the distribution body 1, that is, relative to the center line of the distribution body 1, the branch pipe holes 104 are inclined holes. Similarly, in this embodiment, along the refrigerant flow direction in the branch pipe 2, the straight section length L from the starting point of the bending of the reflection absorption section 211 relative to the center line of the branch pipe hole to the end face of the connection end of the first branch pipe section 21 and the branch pipe hole 104 still satisfies: 3 mm ≤ L ≤ 150 mm.

[0090] In summary, in the distribution device for a heat exchanger provided by the present utility model, a mixing chamber opposite to the liquid inlet is arranged on the partition plate, and the reflective bottom wall reflects the high-speed refrigerant input from the liquid inlet to promote the collision of the gas-liquid two-phase and enhance the disorder degree of the refrigerant. The arrangement of the annular peripheral wall provides a space for the full mixing of the two-phase flow after collision in the axial and radial directions of the distribution main body, so that the reflected refrigerant can be fully mixed into a uniformly dispersed flow and then redistributed to each partition hole. On the liquid outlet side, by setting that each branch pipe includes a first branch pipe section and a connection section located downstream of the first branch pipe section, the first branch pipe section with a larger inner diameter increases the refrigerant flow rate distributed into each branch pipe and reduces the distribution resistance of the refrigerant; while the connection section increases the refrigerant flow velocity by reducing the flow channel cross-section. On this basis, by setting the inner diameter difference △d, the pressure reduction and speed increase degree of the connection section on the refrigerant are precisely controlled, avoiding excessive throttling resulting in too large fluid pressure loss, and thus realizing the balanced control of the flow rate, flow velocity and pressure during refrigerant distribution. Further, by arranging a reflection absorption section on the first branch pipe section that bends and extends to one side relative to the center line of the branch pipe hole, the connection section is no longer coaxial with the center line of the branch pipe hole. When the pressure wave generated by the change of the flow velocity and pressure at the connection section of the refrigerant propagates upstream, part of the pressure wave is reflected and absorbed by the outer inner wall of the reflection absorption section, and the other part turns at the reflection absorption section and rapidly decays after the propagation mode conversion, which well solves the problem of the reduction of the refrigerant flow rate and flow velocity at the branch pipe hole caused by the oscillation of the downstream pressure wave, and effectively improves the flow splitting performance of the distribution device for the heat exchanger. In addition, in order to take into account the refrigerant pressure loss caused by the bending of the reflection absorption section and the impact resistance of the outer inner wall of the reflection absorption section, an included angle α is formed between the axis at the upstream end of the reflection absorption section and the axis at the downstream end of the reflection absorption section, and 90° ≤ α ≤ 175°.

[0091] Although the present utility model has been disclosed above with the preferred embodiments, it is not intended to limit the present utility model. Any person skilled in this art can make some modifications and refinements without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the scope claimed in the claims.

Claims

1. A distribution device for a heat exchanger, characterized in that, Comprising: A distribution body, including a liquid inlet end, a liquid outlet end, and a distribution cavity surrounded by the liquid inlet end and the liquid outlet end. An inlet port is formed on the liquid inlet end of the distribution body, and a plurality of branch pipe holes communicating with the distribution cavity are formed on the liquid outlet end thereof; A partition plate is disposed in the distribution cavity. A mixing cavity surrounded by an annular peripheral wall and a reflecting bottom wall and opening towards the inlet port is formed on the partition plate. The longitudinal sectional contour line of the annular peripheral wall is square or trapezoidal, and the reflecting bottom wall is flat or partially spherical; a plurality of partition plate holes are formed on the partition plate plane outside the mixing cavity, which are annularly distributed around the center line of the distribution body and correspond to the plurality of branch pipe holes one by one. The refrigerant mixed in the mixing cavity is distributed to the liquid outlet end of the distribution body through the plurality of partition plate holes; A plurality of branch pipes are respectively welded to the plurality of branch pipe holes on the liquid outlet end of the distribution body; Wherein, each branch pipe includes a first branch pipe section connected to the branch pipe hole and at least one connecting section located downstream of the first branch pipe section and having an inner diameter reduced relative to the inner diameter of the downstream end of the first branch pipe section. The difference △d between the inner diameter d1 at the downstream end of the first branch pipe section and the inner diameter d2 at the downstream end of the connecting section is: 0.1mm ≤ △d ≤ 3.5mm; a reflection absorption section is formed on the first branch pipe section and bends and extends towards one side relative to the center line of the branch pipe hole. An included angle α is formed between the axis at the upstream end and the axis at the downstream end of the reflection absorption section, and 90° ≤ α ≤ 175°. Based on the reflection absorption section, the axis of the connecting section intersects the center line of the branch pipe hole.

2. The distribution device for a heat exchanger according to claim 1, characterized in that, A flow guiding hole section with a gradually decreasing inner diameter along the direction of fluid entering the branch pipe hole is further formed at one end of each branch pipe hole close to the distribution cavity.

3. The distribution device for a heat exchanger according to claim 1, characterized in that, The shape surrounded by the contour line of the annular peripheral wall is any one of a cylinder, a frustum of a cone, a prism, or a frustum of a pyramid.

4. The distribution device for a heat exchanger according to claim 1, characterized in that, The number of the partition plate holes is the same as the number of the branch pipe holes. Each partition plate hole is substantially coaxial with the corresponding branch pipe hole, and the ratio of the downstream end aperture D1 of the partition plate hole to the outer diameter D2 of the branch pipe inserted into the branch pipe hole is 0.8 - 1.

2.

5. The distribution device for a heat exchanger according to claim 1, characterized in that The depth H1 of the mixing cavity satisfies: 0.2D0 ≤ H1 ≤ 1.4D0mm. The depth H1 of the mixing cavity refers to the vertical distance from the center of the reflecting bottom wall to the end face of the opening of the mixing cavity, and D0 is the inner diameter of the opening of the mixing cavity.

6. The distribution device for a heat exchanger according to claim 1, characterized in that, The first branch pipe section further includes an extension section connected between the reflection absorption section and the connecting section, and the extension section extends along the axis direction of the downstream end of the reflection absorption section.

7. The distribution device for a heat exchanger according to claim 1, characterized in that, Along the flow direction of the fluid in the branch pipe, the straight section length L from the starting bending of the reflection absorption section relative to the center line of the branch pipe hole to the end face of the connection end of the first branch pipe section and the branch pipe hole is: 3mm ≤ L ≤ 150mm.

8. The distribution device for a heat exchanger according to claim 1, characterized in that The connecting section is a tapered structure integrally formed with the first branch pipe section and having a gradually decreasing inner diameter. Each branch pipe further includes a second branch pipe section, and the second branch pipe section is welded to the connecting section; or the first branch pipe section, the connecting section, and the second branch pipe section are integrally formed.

9. The distribution device for a heat exchanger according to claim 1, characterized in that, Each branch pipe further includes a second branch pipe section welded to the downstream of the first branch pipe section, and a connecting section is formed at the socket area between the second branch pipe section and the first branch pipe section; or, the connecting section is integrally formed on the second branch pipe section.

10. The distribution device for a heat exchanger according to claim 8 or 9, characterized in that, The inner diameter of the second branch pipe section located downstream of the connection section is substantially close to the inner diameter at the downstream end of the connection section; Alternatively, the inner diameter of the second branch pipe section located downstream of the connection section is greater than the inner diameter at the downstream end of the connection section, and a maintaining straight section with a substantially constant inner diameter is provided on the connection section.

11. The distribution device for a heat exchanger according to claim 1, characterized in that, A guiding section with an inner diameter gradually decreasing in the refrigerant inflow direction is formed at one end of the first branch pipe section connected within the branch pipe hole, and the inner wall generatrix of the guiding section is an inclined straight line or an arc curve; the axis of each branch pipe hole is substantially parallel to the axis of the distribution main body.

12. A heat exchanger assembly, characterized in that, Comprising the distribution device for a heat exchanger according to any one of claims 1 to 11.

13. An air conditioner, characterized in that, Comprising the heat exchanger assembly according to claim 12.

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