Novel fin structure of heat exchanger for rail transit

Abstract

The utility model discloses a novel fin structure of heat exchanger for rail transit, including a plurality of fin units set on microchannel heat exchanger, the fin unit is by a plurality of fin components and the connecting component of connecting each group fin component constitutes, the fin component is the corrugated structure, including upper bellows and the lower bellows of integrative connection with upper bellows, one end of fin unit is provided with the flow collection mechanism, the flow collection mechanism includes the support baffle between the flat pipe of microchannel heat exchanger and is fixed to a plurality of groups flow collection cylinder on this support baffle, the utility model belongs to heat exchanger technical field, and specifically refers to a novel fin structure of heat exchanger for rail transit.

Description

Technical Field

[0001] This utility model belongs to the field of heat exchanger technology, specifically referring to a novel fin structure for a heat exchanger used in rail transit. Background Technology

[0002] Heat exchangers in rail transit vehicle air conditioning systems have long faced challenges such as harsh operating environments, strict space constraints, and extremely high reliability requirements. Their performance and reliability directly affect the comfort of the passengers and the system's operation and maintenance costs.

[0003] Currently, most common microchannel heat exchangers adopt straight or conventional corrugated fin structures, which have the following significant drawbacks in application: First, in terms of heat exchange efficiency, traditional fin structures have limited ability to disrupt the airflow boundary layer and are prone to forming "heat exchange dead zones" at the fin roots. At the same time, conventional flow distribution structures are difficult to achieve absolutely uniform distribution of airflow among the various channels, resulting in the failure to maximize the overall heat exchange efficiency.

[0004] Secondly, in terms of structural reliability, the continuous high-frequency vibration and impact during rail transit operation can easily cause fatigue damage, loosening of components, and even abnormal noise at the brazing points between the fins and flat tubes. This is one of the main reasons for the early failure of the heat exchanger. Utility Model Content

[0005] To address the aforementioned problems of insufficient heat exchange efficiency and susceptibility to failure under long-term vibration, this invention provides a novel finned structure for a heat exchanger used in rail transit.

[0006] To achieve the above functions, the technical solution adopted by this utility model is as follows: a novel fin structure for a heat exchanger for rail transit, comprising multiple fin units disposed on a microchannel heat exchanger, wherein the fin unit is composed of multiple sets of fin assemblies and connecting assemblies connecting each set of fin assemblies. A current collection mechanism is provided at one end of the fin unit.

[0007] Furthermore, the fin assembly has a corrugated structure, including an upper corrugated tube and a lower corrugated tube integrally connected to the upper corrugated tube, wherein the ratio H / P of the wave height H to the wave pitch P of the corrugated structure is 0.1 to 0.5.

[0008] Furthermore, both the upper and lower corrugated pipes are provided with a hydrophobic surface treatment layer, the thickness of which is 5-20 μm; The hydrophobic surface treatment layer is made of polytetrafluoroethylene coating or fluorocarbon resin coating.

[0009] Furthermore, the flow collection mechanism includes a support baffle installed between the flat tubes of the microchannel heat exchanger, and a plurality of flow collection cylinders fixed to the support baffle.

[0010] Furthermore, the air inlets of the collector tube correspond one-to-one with and are fixedly connected to the upper and lower corrugated pipes; The collector tube consists of a circular tube located outside the support baffle and a conical tube extending into the inside of the bellows.

[0011] Furthermore, the diameter of the conical cylinder near the inside of the bellows is smaller than the diameter at its connection with the circular cylinder.

[0012] Furthermore, the support baffle is fixedly connected to the flat tube of the microchannel heat exchanger by welding or brazing; The upper corrugated tube is connected to the flat tube located above the fin assembly; The lower corrugated pipe is connected to the flat pipe located below the fin assembly, and together with the support baffle, they form a support frame for the flat pipe.

[0013] Furthermore, the connection between the circular cylinder and the conical cylinder is fixedly connected to the supporting baffle by welding or brazing.

[0014] Furthermore, the connecting assembly includes a mounting groove disposed on the outer edge of the upper corrugated pipe and a T-shaped mounting block disposed on the outer edge of the lower corrugated pipe; The T-shaped mounting block is movably inserted into the mounting slot.

[0015] Furthermore, the innermost end of the mounting groove is a sealed structure; The support baffle abuts against the outer end face of the T-shaped mounting block.

[0016] Compared with the prior art, the present invention achieves the following beneficial effects by adopting the above structure: 1. Significantly improved heat exchange efficiency: By adopting a corrugated fin structure with a specific wave height-to-wave pitch ratio (H / P=0.1-0.5) and combining it with a tapered conical collector, the airflow boundary layer is disrupted, the flow field disturbance is enhanced, and the high-speed airflow is effectively introduced into the fin root, eliminating the heat exchange dead zone. This achieves the optimal balance between heat exchange intensity and flow resistance in a compact space, resulting in a significant improvement in overall heat exchange efficiency.

[0017] 2. Excellent vibration resistance and reliability: Through the three-dimensional support frame composed of support baffles and upper and lower corrugated pipes, and the closed double limiting structure of the connecting components, the core components are rigidly connected into a high-rigidity whole, which fundamentally solves the problems of fin loosening, brazing point fatigue cracking and structural noise that are prone to occur in traditional heat exchangers under the high-frequency vibration environment of rail transit, and greatly enhances the service life and operational stability of the equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the microchannel heat exchanger proposed in this utility model; Figure 2 This is a schematic diagram of the overall structure of the microchannel heat exchanger and air supply assembly proposed in this utility model. Figure 3 This is a schematic diagram of the air supply of the microchannel heat exchanger and air supply assembly proposed in this utility model. Figure 4 This is a schematic diagram of the overall structure of a novel finned structure and flat tube for a heat exchanger used in rail transit, as proposed in this utility model. Figure 5 This utility model presents a schematic diagram of the overall structure of a novel finned structure for a heat exchanger used in rail transit. Figure 1 ; Figure 6 This utility model presents a schematic diagram of the overall structure of a novel finned structure for a heat exchanger used in rail transit. Figure 2 ; Figure 7 This is a schematic diagram illustrating the definition of the wave height H and wave distance P parameters proposed in this utility model; Figure 8 This is a schematic diagram of the fin assembly and connecting assembly proposed in this utility model; Figure 9 This is a partial structural diagram of the support baffle and the flow collector proposed in this utility model.

[0019] Among them, 1. Microchannel heat exchanger, 11. Flat tube, 2. Air supply assembly, 3. Finned unit, 31. Finned assembly, 311. Upper corrugated tube, 312. Lower corrugated tube, 32. Connecting assembly, 321. Mounting groove, 322. T-shaped mounting block, 33. Collection mechanism, 331. Support baffle, 332. Collection cylinder, 3321. Circular cylinder, 3322. Conical cylinder. Detailed Implementation

[0020] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. The present invention will be further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1-9 As shown, this utility model provides a novel finned structure for a heat exchanger used in rail transit, including multiple finned units 3 disposed on a microchannel heat exchanger 1. Each finned unit 3 consists of multiple sets of finned assemblies 31 and connecting assemblies 32 connecting each set of finned assemblies 31. One end of each finned unit 3 is provided with a flow-collecting mechanism 33 for guiding and distributing airflow. Through the modular design of the finned units 3, flexible combination and efficient assembly of the structure are achieved. The flow-collecting mechanism 33 optimizes the airflow distribution from the source, laying the foundation for subsequent heat exchange enhancement.

[0024] like Figure 2 , 4 As shown in Figure 8, the fin assembly 31 has a corrugated structure, including an upper corrugated pipe 311 and a lower corrugated pipe 312 integrally connected to the upper corrugated pipe 311. The ratio H / P of the wave height H to the wave pitch P of the corrugated structure is 0.1 to 0.5. When the airflow passes through the corrugated structure, the corrugated channel will periodically change the airflow direction, forcing the laminar boundary layer to break and regenerate continuously, which significantly improves the convective heat transfer coefficient. At the same time, the ratio of 0.1-0.5 ensures that while increasing the heat transfer area (increasing the wave height), the surge in wind resistance caused by the excessively small wave pitch is avoided, achieving a balance between high heat transfer intensity and low flow resistance in a limited space. Both the upper corrugated tube 311 and the lower corrugated tube 312 are provided with a hydrophobic surface treatment layer with a thickness of 5-20 μm. The material of the hydrophobic surface treatment layer is a polytetrafluoroethylene coating or a fluorocarbon resin coating. The hydrophobic coating reduces the surface energy of the fins, causing condensate to form spherical droplets on the surface and roll off under gravity, avoiding the formation of a continuous water film covering the heat exchange surface (a water film increases thermal resistance). The 5-20 μm thickness design ensures the durability of the hydrophobic effect while avoiding an excessively thick coating that hinders heat conduction. At the same time, the chemical inertness of the fluorine-based material can prevent fin corrosion in humid environments, ensuring long-term performance from both the perspectives of maintaining heat exchange efficiency and extending lifespan.

[0025] like Figure 1 , 4 As shown in Figures 6 and 9, the flow collection mechanism 33 includes a support baffle 331 installed between the flat tubes 11 of the microchannel heat exchanger 1, and several sets of flow collection cylinders 332 fixed on the support baffle 331. The support baffle 331, through rigid connection with the flat tubes 11, integrates the dispersed flat tubes 11 and the fin assembly 31 into a rigid whole. Its moment of inertia is much greater than that of a single flat tube 11, which can effectively absorb the vibration and impact energy during rail transit operation, enhance the rigidity and pressure-bearing capacity of the entire heat exchanger core, and cope with the vibration and impact during rail transit operation. The flow collection cylinders 332 are connected to the upper corrugated pipe 311 and the lower corrugated pipe 312. The air inlets of section 2 are connected one-to-one and fixedly. The collector tube 332 is composed of a circular tube 3321 located outside the support baffle 331 and a conical tube 3322 extending into the inside of the corrugated tube. The one-to-one connection ensures that the airflow can enter each independent corrugated tube channel evenly, avoiding uneven heat exchange caused by excessive or insufficient local flow. The combination structure of circular tube 3321 and conical tube 3322 is adopted. Circular tube 3321 is easy to connect with the external air duct, while conical tube 3322 is responsible for smoothly guiding and transitioning the airflow into the channel composed of upper corrugated tube 311, lower corrugated tube 312 and flat tube 11. The diameter of the conical cylinder 3322 near the inner side of the corrugated tube is smaller than the diameter at its connection with the circular cylinder 3321, forming a flow channel with a gradually narrowing cross-section along the airflow direction. This narrowing structure utilizes the Venturi effect to gradually accelerate the airflow as it flows through the conical cylinder 3322. When the airflow enters the conical cylinder 3322 from the circular cylinder 3321, the flow velocity increases along the path as the flow cross-section continuously narrows, reaching its maximum value at the outlet of the conical cylinder 3322 (i.e., the inlet of the corrugated tube). The high-speed airflow can enhance the impact on the surface of the corrugated fins, destroying the laminar boundary layer (the boundary layer is the main thermal resistance of air-side heat transfer) originally attached to the fin surface, thus significantly improving the convective heat transfer coefficient. On the other hand, the accelerated airflow has stronger penetration ability and can be directly "sprayed" into the "dead zone" at the root of the fins formed by the attenuation of flow velocity in the traditional structure, filling the airflow velocity gap in this area, allowing the entire heat transfer surface of the fins from the root to the top to fully contact the high-speed airflow, avoiding local heat accumulation.

[0026] like Figure 1 , 2 As shown in Figures 4-6 and 9, the support baffle 331 is fixedly connected to the flat tube 11 of the microchannel heat exchanger 1 by welding or brazing; the upper corrugated tube 311 is connected to the flat tube 11 located above the fin assembly 31; the lower corrugated tube 312 is connected to the flat tube 11 located below the fin assembly 31, together with the support baffle 331, forming a support frame for the flat tube 11. The support baffle 331, as the main transverse load-bearing component, forms a rigid connection with the flat tube 11 by welding or brazing, providing core structural strength; at the same time, the upper and lower corrugated tubes 312 not only undertake the heat exchange function, but also serve as longitudinal structural components connected to the upper and lower flat tubes 11 respectively; these three components together integrate the flat tube 11, fins, and baffle into a high-rigidity whole, greatly enhancing the heat exchanger core's ability to resist multidimensional vibrations and impacts generated during rail transit operation; The connection between the circular cylinder 3321 and the conical cylinder 3322 is fixedly connected to the support baffle 331 by welding or brazing. This connection method can completely eliminate assembly gaps, fundamentally avoid loosening of connections, gas leakage and structural noise caused by long-term vibration, and ensure the sealing reliability and structural integrity of the flow collection mechanism 33 during long-term operation.

[0027] like Figure 4-8As shown, the connecting assembly 32 includes a mounting groove 321 located on the outer edge of the upper corrugated pipe 311 and a T-shaped mounting block 322 located on the outer edge of the lower corrugated pipe 312. The T-shaped mounting block 322 is movably inserted into the mounting groove 321, enabling rapid alignment and assembly of the lower corrugated pipe 312 with the upper corrugated pipe 311 in the adjacent fin assembly 31, greatly improving installation efficiency. The innermost end of the mounting groove 321 is a sealed structure used to limit the insertion of the T-shaped mounting block 322. The support baffle 331 abuts against the outer end face of the T-shaped mounting block 322, used to limit its reverse movement. Together, they form a closed double-limiting structure, effectively constraining the displacement of the fin assembly 31 in the airflow direction and vibration impact direction, significantly improving the connection reliability and structural stability under high-frequency vibration conditions in rail transit.

[0028] In practical use 1. First, modular assembly is performed. Multiple finned units 3 are quickly plugged in and assembled using connecting components 32: the T-shaped mounting blocks 322 on the outer edge of the lower corrugated tube 312 are aligned and inserted into the mounting grooves 321 of the upper corrugated tube 311 of the adjacent finned assembly 31, completing the lateral stacking and positioning of the finned assemblies 31. Subsequently, the assembled finned units 3 are placed between the upper flat tube 11 and the lower flat tube 11 of the microchannel heat exchanger 1, so that the upper corrugated tube 311 and the lower corrugated tube 312 are respectively connected to the corresponding flat tube 11.

[0029] 2. Next, install the collection and support system. Place the support baffle 331 between the upper flat tube 11 and the lower flat tube 11, and rigidly connect it with the flat tube 11 and the fin unit 3 through welding or brazing to form a stable three-dimensional support frame. Subsequently, connect the circular cylinder 3321 section of each collection cylinder 332 to the external air supply assembly 2, and extend its conical cylinder 3322 section into the inlet end of the corresponding upper corrugated pipe 311 and lower corrugated pipe 312, and fix it to the support baffle 331 by welding to form a leak-free sealed connection.

[0030] 3. Finally, during operation, the external airflow enters the collector cylinder 332 under the action of the air supply component 2. After being accelerated through the gradually narrowing flow channel from the circular cylinder 3321 to the conical cylinder 3322, the airflow is evenly distributed to each corrugated pipe channel. When flowing through the corrugated surface with a specific H / P ratio, the airflow boundary layer is continuously disrupted, achieving efficient heat exchange. At the same time, the hydrophobic surface treatment layer promotes the rapid rolling off of condensate, preventing scaling and corrosion. Throughout the entire operation, the support frame and the double-limiting structure jointly ensure the long-term reliability and sealing integrity of the system under vibration environment.

[0031] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A novel finned structure for a heat exchanger used in rail transit, comprising multiple finned units (3) disposed on a microchannel heat exchanger (1), characterized in that: The fin unit (3) is composed of multiple fin assemblies (31) and connecting assemblies (32) that connect each fin assembly (31); The fin assembly (31) has a corrugated structure, including an upper corrugated tube (311) and a lower corrugated tube (312) integrally connected to the upper corrugated tube (311). One end of the fin unit (3) is provided with a current collection mechanism (33); The flow collection mechanism (33) includes a support baffle (331) installed between the flat tubes (11) of the microchannel heat exchanger (1), and a number of flow collection cylinders (332) fixed on the support baffle (331).

2. The novel finned structure of a heat exchanger for rail transit according to claim 1, characterized in that: The ratio of wave height H to wave distance P of the corrugated structure, H / P, is 0.1 to 0.

5.

3. A novel finned structure for a heat exchanger used in rail transit according to claim 2, characterized in that: The surfaces of the upper corrugated pipe (311) and the lower corrugated pipe (312) are both provided with a hydrophobic surface treatment layer, the thickness of which is 5-20 μm; The hydrophobic surface treatment layer is made of polytetrafluoroethylene coating or fluorocarbon resin coating.

4. A novel finned structure for a heat exchanger used in rail transit according to claim 1, characterized in that: The upper corrugated tube (311) is connected to the flat tube (11) located above the fin assembly (31); The lower corrugated tube (312) is connected to the flat tube (11) located below the fin assembly (31), and together with the support baffle (331), they form a support frame for the flat tube (11).

5. A novel finned structure for a heat exchanger used in rail transit according to claim 4, characterized in that: The air inlet of the collector tube (332) corresponds to and is fixedly connected to the air inlet of the upper corrugated pipe (311) and the lower corrugated pipe (312); The collector tube (332) consists of a circular tube (3321) located outside the support baffle (331) and a conical tube (3322) extending into the inside of the bellows.

6. A novel finned structure for a heat exchanger used in rail transit according to claim 5, characterized in that: The diameter of the conical tube (3322) near the inside of the bellows is smaller than the diameter at its connection with the cylindrical tube (3321).

7. A novel finned structure for a heat exchanger used in rail transit according to claim 5, characterized in that: The support baffle (331) is fixedly connected to the flat tube (11) of the microchannel heat exchanger (1) by welding or brazing.

8. A novel finned structure for a heat exchanger used in rail transit according to claim 5, characterized in that: The connection between the circular cylinder (3321) and the conical cylinder (3322) is fixedly connected to the support baffle (331) by welding or brazing.

9. A novel finned structure for a heat exchanger used in rail transit according to claim 2, characterized in that: The connecting assembly (32) includes a mounting groove (321) disposed on the outer edge of the upper corrugated pipe (311) and a T-shaped mounting block (322) disposed on the outer edge of the lower corrugated pipe (312). The T-shaped mounting block (322) is movably inserted into the mounting slot (321).

10. A novel finned structure for a heat exchanger for rail transit according to claim 9, characterized in that: The innermost end of the mounting groove (321) is a sealed structure; The support baffle (331) abuts against the outer end face of the T-shaped mounting block (322).

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