Liquid equalization flow divider and use thereof

Abstract

This application belongs to the field of refrigeration equipment technology, and specifically relates to a liquid equalization and flow splitting baffle and its application. Existing microchannel heat exchangers have low heat exchange efficiency when used as evaporators. When used as condensers, they reduce the latent heat utilization efficiency of the refrigerant and decrease the heat dissipation of the heat exchanger. This application provides a liquid equalization and flow splitting baffle, including a baffle plate with several flow direction changing components. When the gas-liquid two-phase refrigerant flows forward through the flow direction changing components, its flow direction changes. Simultaneously, the refrigerant, after its direction change, collides with adjacent flow direction changing components, changing its velocity direction to form a swirling flow and dispersing bubbles. When the gas-liquid two-phase refrigerant flows backward through the flow direction changing components, it can separate the gas and liquid phases of the refrigerant. This is a baffle plate that can simultaneously achieve liquid equalization and flow splitting, with one component performing two functions; it also has high heat exchange efficiency.

Description

Technical Field

[0001] This application belongs to the field of refrigeration equipment technology, and in particular relates to a liquid equalization and distribution baffle and its application. Background Technology

[0002] The heat exchanger is an important component of a heat pump system. During year-round operation, the heat pump system can be divided into cooling and heating modes. Cooling mode includes rated cooling, intermediate cooling, and minimum cooling; heating mode includes rated heating, intermediate heating, and minimum heating.

[0003] When operating in summer cooling mode, the indoor heat exchanger functions as an evaporator; when operating in winter heating mode, the outdoor heat exchanger functions as an evaporator. When the heat exchanger is used as an evaporator, its inlet contains a two-phase refrigerant (gas and liquid). During the distribution of the two-phase refrigerant to each branch or channel, there is a serious problem of uneven distribution. Some channels contain less liquid refrigerant, resulting in "dry evaporation"; while others are rich in liquid refrigerant, resulting in "liquid carryover at the outlet." "Dry evaporation" prevents the full utilization of the heat exchange area, while "liquid carryover at the outlet" causes system fluctuations, which severely degrades system performance.

[0004] Microchannel heat exchangers are widely used in heat pump systems due to their excellent heat transfer performance, small charge requirements, and low cost. A microchannel heat exchanger mainly consists of a manifold and microchannel flat tubes, with the manifold distributing the two-phase refrigerant into the microchannel flat tubes. To address drainage and frosting issues, heat exchangers are typically placed vertically. However, the two-phase refrigerant within the vertical manifold is more prone to severe uneven distribution due to the combined effects of gravity and phase separation, leading to significant deterioration of system performance.

[0005] Furthermore, the different mass flow rates of the two-phase refrigerant at the evaporator inlet under rated, intermediate, and minimum operating conditions result in varying distribution characteristics. For instance, under rated conditions, due to the larger inlet mass flow rate of the two-phase refrigerant, the liquid refrigerant is more likely to reach the top of the microchannel heat exchanger, resulting in more liquid refrigerant in the upper channel and more gaseous refrigerant in the lower channel. However, under minimum operating conditions, the smaller inlet mass flow rate allows the liquid refrigerant to easily enter the lower channel under the influence of gravity, while the upper channel contains more gaseous refrigerant.

[0006] Existing microchannel heat exchangers in dual-mode (cooling / heating) air conditioners function as both evaporators and condensers in different modes. When used as an evaporator, uneven liquid-gas refrigerant distribution occurs within the manifold due to gravity, affecting heat exchange efficiency and potentially causing failure. Conversely, when used as a condenser, the increased liquid refrigerant volume reduces the contact area between the gaseous refrigerant and the flat tubes, lowering the latent heat utilization efficiency and reducing heat dissipation. Summary of the Invention

[0007] 1. Technical problems to be solved

[0008] Based on existing microchannel heat exchangers used in dual-mode (cooling / heating) air conditioners, which function as evaporators and condensers in different modes, uneven distribution of the gas-liquid two-phase refrigerant occurs within the manifold due to gravity when used as an evaporator. This affects the heat exchanger's efficiency and, in severe cases, can lead to its failure. When used as a condenser, the increased liquid refrigerant volume reduces the contact area between the gaseous refrigerant and the flat tube 8, lowering the latent heat utilization efficiency and reducing heat dissipation. This application provides a liquid equalization and distribution baffle and its application.

[0009] 2. Technical Solution

[0010] To achieve the above objectives, this application provides a liquid equalization and flow distribution baffle, including a baffle plate on which a plurality of flow direction changing components are disposed. When the gas-liquid two-phase refrigerant passes through the flow direction changing components in the forward direction, the flow direction changes. At the same time, the gas-liquid two-phase refrigerant with the changed direction collides with the adjacent flow direction changing components, and the velocity direction changes to form a swirling flow and disperse the bubbles. When the gas-liquid two-phase refrigerant passes through the flow direction changing components in the reverse direction, the gas phase and liquid phase refrigerant can be separated.

[0011] Another embodiment provided in this application is as follows: the flow direction changing component includes a curved surface, the curved surface is disposed on the partition plate, a through hole is disposed in the curved surface, the through hole is disposed on the partition plate, one end of the curved surface is connected to the partition plate, the other end of the curved surface is free, and a fluid outlet is formed between the other end of the curved surface and the partition plate.

[0012] Another embodiment provided in this application is: an inclined baffle is provided in the curved surface, the inclined baffle is disposed on the partition, the inclined baffle is disposed between the through hole and the fluid outlet, and the inclined baffle is inclined from the through hole to the fluid outlet.

[0013] Another embodiment provided in this application is as follows: the height H of the curved surface is 0.5 to 1.5 mm, the length L of the curved surface is 1.5 to 2*H; the length d of the inclined baffle is 0.3 to 0.5*L, and the height h of the inclined baffle is 0.2 to 0.5*H.

[0014] Another embodiment provided in this application is that the through hole is fan-shaped.

[0015] Another embodiment provided by this application is: several curved surfaces have different heights, several curved surfaces have different lengths, several inclined baffles have different lengths, and several inclined baffles have different heights.

[0016] Another embodiment provided in this application is as follows: the flow direction changing component is arranged in N rows, where N is a positive integer >1, and the flow direction changing components in each row are arranged in a ring with a spacing of 10 to 20°, and the spacing between each row is 0.5 to 2 mm.

[0017] Another embodiment provided in this application is that several of the flow direction changing components are fish-scale shaped when viewed from above.

[0018] This application also provides an application of the aforementioned liquid equalization and diversion baffle, which is applied to a microchannel heat exchanger. When the microchannel heat exchanger is used as an evaporator, the liquid equalization and diversion baffle is used to equalize the refrigerant; when it is used as a condenser, the liquid equalization and diversion baffle is used to divert the refrigerant.

[0019] Another embodiment provided by this application includes a first manifold, a microchannel flat tube assembly, and a second manifold connected in sequence. The first manifold is provided with the liquid equalization and diversion baffle and the second solid baffle, which divide the first manifold into a first compartment, a second compartment, and a third compartment. The second manifold is provided with a first solid baffle, which divides the second manifold into a fourth compartment and a fifth compartment.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the beneficial effects of the liquid equalization and diversion baffle and its application provided in this application are as follows:

[0022] The liquid equalization and diversion baffle provided in this application is a baffle that can simultaneously perform liquid equalization and diversion functions, with one component realizing two functions.

[0023] The liquid-distribution baffle provided in this application disperses and mixes the gas-liquid two-phase refrigerant, while forming a swirling flow. This further mixes the gas-liquid two-phase refrigerant and also suppresses the bubble coalescence phenomenon that may occur in subsequent flow.

[0024] The application of the liquid distribution baffle provided in this application ensures the uniformity of liquid distribution when the microchannel heat exchanger is used as an evaporator. At the same time, when the microchannel heat exchanger is used as a condenser and the refrigerant flows in reverse, the viscosity and density difference between the gas and liquid phases is used to separate the gas and liquid phases, reducing the contact area between the liquid refrigerant and the flat tube and increasing the contact area between the gas refrigerant and the flat tube, making full use of the latent heat of the refrigerant and enhancing the heat exchange performance of the heat exchanger. Attached Figure Description

[0025] Figure 1 This is a top view of the liquid equalization and distribution baffle of this application;

[0026] Figure 2 This is a schematic diagram of the liquid equalization and diversion baffle structure of this application;

[0027] Figure 3 This is a side view of the liquid equalization and diversion baffle of this application;

[0028] Figure 4 This is a second side view schematic diagram of the liquid equalization and diversion baffle of this application;

[0029] Figure 5 This is a schematic diagram of the fluid flow in the equalization and diversion baffle of this application;

[0030] Figure 6 This is a second schematic diagram of fluid flow in the equalization and diversion baffle of this application;

[0031] Figure 7 This is a schematic diagram of the microchannel heat exchanger structure of this application;

[0032] Figure 8 This is a schematic diagram of the second structure of the microchannel heat exchanger in this application;

[0033] Figure 9 This is a schematic diagram illustrating an example of the liquid equalization and diversion baffle structure of this application. Detailed Implementation

[0034] In the following, specific embodiments of this application will be described in detail with reference to the accompanying drawings. Based on these detailed descriptions, those skilled in the art will be able to clearly understand and implement this application. Without departing from the principles of this application, features from various embodiments can be combined to obtain new implementations, or certain features from some embodiments can be substituted to obtain other preferred implementations.

[0035] See Figures 1-9 This application provides a liquid equalization and flow distribution baffle, including a baffle 1. The baffle 1 is provided with a plurality of flow direction changing components 2. When the gas-liquid two-phase refrigerant passes through the flow direction changing components 2, the flow direction changes. At the same time, the gas-liquid two-phase refrigerant with the changed direction collides with the adjacent flow direction changing components 2, and the velocity direction changes to form a swirling flow and disperse the bubbles. When the gas-liquid two-phase refrigerant passes through the flow direction changing components 2 in the opposite direction, the gas phase and liquid phase refrigerant can be separated.

[0036] Furthermore, the flow direction changing component 2 includes a curved surface 3, which is disposed on the partition 1. A through hole 4 is provided within the curved surface 3, and the through hole 4 is disposed on the partition 1. One end of the curved surface 3 is connected to the partition 1, and the other end of the curved surface 3 is free, forming a fluid outlet between the other end of the curved surface 3 and the partition 1. Here, the curved surface 3 can be a quarter-ellipsoid.

[0037] Furthermore, an inclined baffle 5 is provided within the curved surface 3. The inclined baffle 5 is disposed on the partition 1 and is located between the through hole 4 and the fluid outlet. The inclined baffle 5 is inclined from the through hole 4 towards the fluid outlet. The inclined baffle 5 reduces the outlet area and increases the refrigerant flow rate at the outlet. On the other hand, the interlayer between the inclined surface and the partition 1 can further prevent liquid refrigerant from flowing into the channel.

[0038] Furthermore, the height H of the curved surface 3 is 0.5 to 1.5 mm, and the length L of the curved surface 3 is 1.5 to 2 * H; the length d of the inclined baffle 5 is 0.3 to 0.5 * L, and the height h of the inclined baffle 5 is 0.2 to 0.5 * H.

[0039] Furthermore, the through-hole 4 is fan-shaped. On the one hand, this reduces the orifice diameter, disperses air bubbles, and increases the flow rate; on the other hand, it increases the tortuosity of the flow channel during liquid separation, reducing the amount of liquid flowing through the opening.

[0040] Furthermore, the heights and lengths of the curved surfaces 3 are different, as are the lengths and heights of the inclined baffles 5. The parameters of the curved surfaces 3 and inclined baffles 5 can be different between rows and within rows, and the size of each curved surface 3 and inclined baffle 5 can be designed according to the actual flow pattern.

[0041] Furthermore, the flow direction changing component 2 is arranged in N rows, where N is a positive integer >1. Each row of the flow direction changing component 2 is arranged in a ring with a spacing of 10 to 20°, and the spacing between each row is 0.5 to 2 mm; the components are arranged in a ring with the center of the partition 1 as the center.

[0042] Furthermore, several of the flow direction changing components 2 have a fish-scale-like shape when viewed from above.

[0043] This application also provides an application of the liquid equalization and flow distribution baffle, which is applied to a microchannel heat exchanger. When the microchannel heat exchanger acts as an evaporator, the refrigerant flows from bottom to top through the liquid equalization and flow distribution baffle, at which time the baffle plays a role in equalizing the liquid. The gas-liquid two-phase refrigerant is affected by the shape and angle of the curved surface 3 and the inclined baffle 5, and the flow direction changes from vertical to horizontal. Upon impacting the front curved surface 3, the velocity direction changes to oblique upward and forms a swirling flow along the manifold, breaking up the bubbles. This not only mixes the gas-liquid two-phase refrigerant but also suppresses the phenomenon of bubble re-merging that may occur in subsequent flow, ensuring the uniformity of liquid distribution when the microchannel heat exchanger acts as an evaporator.

[0044] When the microchannel heat exchanger is used as a condenser, the refrigerant flows from top to bottom through the liquid distribution baffle, which then functions as a flow divider. When the gas-liquid two-phase refrigerant flows through curved surface 3, the gaseous refrigerant, with its lower viscosity and density, more easily passes through the complex flow channels, exiting from the fluid outlet through curved surface 3 and then through through-hole 4, flowing out from baffle 1. The liquid refrigerant, with its higher viscosity and density, does not easily pass through the complex flow channels and is thus partially carried away by the gaseous refrigerant, flowing away from the top (side). At this point, the liquid distribution baffle acts as a gas-liquid separation component, separating the gas and liquid phases. Most of the gas flows away from the bottom, while most of the liquid flows away from the top (side). Separating the gas and liquid phases of the two-phase refrigerant increases the heat transfer area of ​​the gaseous refrigerant in the flat tube and enhances the heat transfer coefficient of the gaseous phase in the flat tube 8, fully utilizing the latent heat of phase change of the refrigerant, increasing the heat exchanger's heat transfer capacity, and reducing pressure drop. For a detailed description of the flow process, please refer to the microchannel heat exchanger introduction.

[0045] Further, the system includes a first manifold, a microchannel flat tube assembly 8, and a second manifold connected in sequence. The first manifold contains the liquid equalization and distribution baffle and a second solid baffle 6, which divide the first manifold into a first compartment 601, a second compartment 602, and a third compartment 603. The second manifold contains a first solid baffle 7, which divides the second manifold into a fourth compartment 604 and a fifth compartment 605. The microchannel flat tube assembly 8 includes several flat tubes 8, and the compartments are connected by the flat tubes 8.

[0046] When the refrigerant is used as an evaporator, it flows into the heat exchanger from the third chamber 603, then through the flat tube 8 into the fifth chamber 605. At this point, the refrigerant splits into two parts: one part flows through the flat tube 8 into the second chamber 602, then through the liquid equalization and distribution baffle into the first chamber 601; the other part flows directly into the first chamber 601 through the flat tube 8 and mixes with the other refrigerant. The remaining refrigerant flows through the flat tube 8 into the right-hand first chamber 601 and then out of the heat exchanger. The liquid equalization and distribution baffle acts as a liquid equalizer, thoroughly dispersing the gas-liquid two-phase refrigerant flowing from the second chamber 602 into the first chamber 601 and creating a swirling flow (the purpose of the swirling flow is to further disperse the bubbles and prevent them from re-merging during the subsequent long-distance flow), and carrying the refrigerant flowing from the fifth chamber 605 upwards. This fully dispersed gas-liquid two-phase refrigerant can be more evenly distributed by the flat tube 8 in a mist-like flow state, enhancing the heat exchanger's efficiency and performance. When the refrigerant is used as a condenser, it flows into the heat exchanger from the fourth chamber 604, passes through the flat tubes 8, and then flows into the first chamber 601. At this point, under the action of the liquid-equalizing flow divider, most of the gaseous refrigerant flows from the bottom into the second chamber 602 and then through more flat tubes 8 into the fifth chamber 605; while most of the liquid refrigerant is entrained by a small portion of the gaseous refrigerant and flows directly through fewer flat tubes 8 into the fifth chamber 605. After mixing here, it flows through the cooling section into the third chamber 603 and then out of the heat exchanger. Here, the liquid-equalizing flow divider acts as a flow divider, separating the gaseous and liquid refrigerant phases. Most of the gaseous phase and a small portion of the liquid phase pass through the divider into the second chamber 602, and after being cooled and condensed by more flat tubes 8, flow into the fifth chamber 605; while most of the liquid phase and a small portion of the gaseous phase flow directly into the fifth chamber 605 after being cooled by fewer flat tubes 8. By using the flow distribution baffle, the gaseous refrigerant that needs further cooling and condensation is divided into the flow path of more flat tubes 8, while the already condensed liquid is divided into the flow path of fewer flat tubes 8. This increases the contact area between the gaseous refrigerant and the flat tubes 8, fully utilizes the latent heat of the refrigerant, increases the heat exchange capacity of the heat exchanger, fully utilizes the heat exchanger area, and improves the efficiency of the heat exchanger.

[0047] This application incorporates a liquid equalization and flow distribution baffle in a microchannel heat exchanger, which solves the aforementioned problems encountered when using microchannel heat exchangers as both evaporators and condensers using only a single low-cost device.

[0048] Example

[0049] See Figure 7The specific implementation methods of the liquid equalization and diversion baffle and the microchannel heat exchanger are illustrated with examples. The nine microchannel flat tubes 8 connecting the third chamber 603 and the fifth chamber 605 constitute the first flow; the ten flat tubes 8 connecting the fifth chamber 605 and the second chamber 602 constitute the second flow; the four flat tubes 8 connecting the fifth chamber 605 and the first chamber 601 constitute the third flow; and the twenty-one flat tubes 8 connecting the first chamber 601 and the fourth chamber 604 constitute the fourth flow.

[0050] When the microchannel heat exchanger is used as an evaporator, the refrigerant flows into the heat exchanger from the third chamber 603, passes through the nine flat tubes 8 in the first flow, and then flows into the fifth chamber 605. At this point, the refrigerant is divided into two parts: one part flows into the second chamber 602 through the ten flat tubes 8 in the second flow, then passes through the liquid equalization and flow divider and flows into the first chamber 601; the other part flows directly into the first chamber 601 through the four flat tubes 8 in the third flow and mixes with the other refrigerant. The remaining refrigerant flows into the first chamber 604 on the right side through the twenty-one flat tubes 8 in the fourth flow and then exits the heat exchanger. At this point, the liquid equalization and flow divider acts as a liquid equalization plate, which fully disperses the gas-liquid two-phase refrigerant flowing from the second chamber 602 into the first chamber 601 and forms a swirling flow (the purpose of the swirling flow is to further disperse the bubbles and prevent them from re-merging during the subsequent long-distance flow), and carries the refrigerant flowing in from the fifth chamber 605 upwards together. The fully dispersed gas-liquid two-phase refrigerant can be more evenly distributed by the flat tube 8 in a mist-like flow state, enhancing the heat exchange efficiency and performance of the heat exchanger.

[0051] When the microchannel heat exchanger is used as a condenser, the refrigerant flows into the heat exchanger from the fourth chamber 604, passes through the 21 flat tubes 8 of the fourth flow path, and then flows into the first chamber 601. At this time, under the action of the liquid distribution baffle, most of the gaseous refrigerant flows into the second chamber 602 from the bottom and then into the fifth chamber 605 through the 10 flat tubes 8 of the second flow path; while most of the liquid refrigerant is entrained by a small portion of the gaseous refrigerant and flows directly into the fifth chamber 605 through the 4 flat tubes 8 of the third flow path. After mixing here, it flows into the third chamber 603 through the 9 flat tubes 8 of the first flow path (which is the subcooling section) and then out of the heat exchanger. At this point, the liquid equalization and diversion baffle acts as a diversion plate, separating the gaseous and liquid refrigerant phases. Most of the gaseous phase and a small portion of the liquid phase pass through the baffle and flow into the second chamber 602. After being cooled and condensed by a plurality of flat tubes 8 (10 tubes), they flow into the fifth chamber 605. Conversely, most of the liquid phase and a small portion of the gaseous phase flow directly into the fifth chamber 605 after being cooled by a smaller number of flat tubes 8 (4 tubes). Through the diversion effect of the liquid equalization and diversion baffle, the gaseous refrigerant requiring further cooling and condensation is diverted to the flow path of the larger number of flat tubes 8, while the already condensed liquid is diverted to the flow path of the smaller number of flat tubes 8. This increases the contact area between the gaseous refrigerant and the flat tubes 8, fully utilizing the latent heat of the refrigerant, increasing the heat exchanger's heat transfer capacity, maximizing the heat exchanger area, and improving the heat exchanger's efficiency.

[0052] See Figure 9 A specific embodiment of the liquid equalization and flow distribution baffle suitable for the above-mentioned microchannel heat exchanger layout is illustrated below. This liquid equalization and flow distribution baffle is designed with three layers of annular flow direction changing components 2, namely the first layer, the second layer, and the third layer from the outside in, with 18, 18, and 9 flow direction changing components 2 in each layer, respectively. The spacing between each flow direction changing component 2 in the first and second layers is 20°, and the spacing between each flow direction changing component in the third layer is 40°, with a spacing of 1.5 mm between each layer. To accommodate the flow characteristics of the heat exchange described above, the size of the flow direction changing components 2 (including the curved surface 3, the through hole 4, and the inclined baffle 5) increases sequentially from right to left.

[0053] Although this application has been described above with reference to specific embodiments, those skilled in the art will understand that many modifications can be made to the configurations and details disclosed in this application within the principles and scope of the disclosure. The scope of protection of this application is determined by the appended claims, and the claims are intended to cover all modifications included in the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A liquid equalization flow dividing baffle characterized by: The device includes a baffle plate with several flow direction changing components. When the gas-liquid two-phase refrigerant passes through the flow direction changing components in the forward direction, its flow direction changes. At the same time, the gas-liquid two-phase refrigerant with the changed direction collides with the adjacent flow direction changing components, changing its velocity direction to form a swirling flow and breaking up the bubbles. When the gas-liquid two-phase refrigerant passes through the flow direction changing components in the reverse direction, it can separate the gas phase and liquid phase refrigerant.

2. The liquid equalization and diversion baffle as described in claim 1, characterized in that: The flow direction changing component includes a curved surface disposed on the partition plate. A through hole is provided in the curved surface and disposed on the partition plate. One end of the curved surface is connected to the partition plate, and the other end of the curved surface is free. A fluid outlet is formed between the other end of the curved surface and the partition plate.

3. The liquid equalization and diversion baffle as described in claim 2, characterized in that: An inclined baffle is provided within the curved surface. The inclined baffle is disposed on the partition plate and is located between the through hole and the fluid outlet. The inclined baffle is inclined from the through hole toward the fluid outlet.

4. The liquid equalization and diversion baffle as described in claim 3, characterized in that: The height H of the curved surface is 0.5 to 1.5 mm, and the length L of the curved surface is 1.5 H to 2H; the length d of the inclined baffle is 0.3 L to 0.5 L, and the height h of the inclined baffle is 0.2 H to 0.5 H.

5. The liquid equalization and diversion baffle as described in claim 2, characterized in that: The through hole is fan-shaped.

6. The liquid equalization and diversion baffle as described in claim 4, characterized in that: The curved surfaces have different heights, the curved surfaces have different lengths, the inclined baffles have different lengths, and the inclined baffles have different heights.

7. The liquid equalization and diversion baffle as described in any one of claims 1 to 6, characterized in that: The flow direction changing components are arranged in N rows, where N is a positive integer greater than 1. The flow direction changing components in each row are arranged in a ring with a spacing of 10 to 20°, and the spacing between each row is 0.5 to 2 mm.

8. The liquid equalization and diversion baffle as described in claim 7, characterized in that: Several of the flow direction changing components appear fish-scale-like when viewed from above.

9. An application of the liquid equalization and diversion baffle according to any one of claims 1 to 8, characterized in that: The liquid equalization and diversion baffle is applied to a microchannel heat exchanger.

10. A microchannel heat exchanger, comprising the liquid equalization and flow distribution baffle according to any one of claims 1 to 8, characterized in that: The device includes a first manifold, a microchannel flat tube assembly, and a second manifold connected in sequence. The first manifold is provided with a liquid equalization and diversion baffle and a second solid baffle, which divide the first manifold into a first compartment, a second compartment, and a third compartment. The second manifold is provided with a first solid baffle, which divides the second manifold into a fourth compartment and a fifth compartment.

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