High-efficiency shell-and-tube heat exchanger and refrigerant distribution structure thereof
By introducing a combination structure of primary and secondary distribution plates into the shell-and-tube heat exchanger, the problem of uneven refrigerant distribution is solved, and uniform distribution of refrigerant in the heat exchange tube bundle is achieved, which improves heat exchange efficiency and compressor oil return performance, and enhances system energy efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- EXTEK ENERGY EQUIP ZHEJIANG
- Filing Date
- 2025-06-23
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional shell-and-tube heat exchangers suffer from uneven refrigerant distribution in refrigeration systems, leading to phase separation, overcooling or overheating of some heat exchange tubes, and difficulty in oil return from the compressor, thus affecting heat exchange efficiency and system energy efficiency.
The system employs a combination of primary and secondary distribution plates. The primary distribution plate performs initial diffusion, while the secondary distribution plate provides precise guidance, resulting in progressive flow regulation that ensures the refrigerant is evenly distributed to each heat exchange tube in both gas and liquid phases.
This achieves uniform distribution of refrigerant in the heat exchange tube bundle, improves heat exchange efficiency, avoids phase separation, improves compressor oil return performance, and enhances the overall energy efficiency of the heat exchanger.
Smart Images
Figure CN224415428U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of refrigeration equipment technology, and in particular to a high-efficiency shell and tube heat exchanger and its refrigerant distribution structure. Background Technology
[0002] As a core component of refrigeration systems, the performance of shell-and-tube heat exchangers directly impacts the overall system's energy efficiency. In evaporator applications, the uniformity of refrigerant distribution is particularly critical. Traditional distribution structures typically employ a single-stage baffle design, a simple structure that struggles to effectively handle the complex flow characteristics of two-phase fluids. When the gas-liquid mixture enters the tube box, the lack of a scientific flow separation mechanism easily leads to phase separation: the liquid refrigerant gathers downwards due to gravity, while the gaseous refrigerant rises, resulting in significant differences in refrigerant composition across different heat exchange tubes. This uneven distribution causes multiple problems: some heat exchange tubes become overcooled due to excessive refrigerant flow, while others become overheated due to insufficient flow, wasting heat exchange area and causing difficulties in compressor oil return. Furthermore, the insufficient precision in the fit between the baffles and tube openings in traditional distribution structures allows for refrigerant misalignment, further exacerbating the uneven distribution. These problems severely restrict the performance improvement of shell-and-tube heat exchangers, especially in large-capacity refrigeration systems.
[0003] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention
[0004] To address the aforementioned problems, the present invention aims to provide a high-efficiency shell-and-tube heat exchanger and its refrigerant distribution structure, which has the advantages of improving refrigerant distribution uniformity, avoiding phase separation, increasing heat exchange efficiency, and solving the compressor oil return problem.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This application provides a refrigerant distribution structure for a high-efficiency shell-and-tube heat exchanger, the technical solution of which is as follows:
[0007] include:
[0008] ●Heat exchange tube bundle inside the shell;
[0009] ● Tube sheet at the end of the closed shell;
[0010] ● A tube box connected to the tube sheet, the tube box being equipped with a refrigerant liquid interface;
[0011] Its features are:
[0012] The pipe box is equipped with a primary distribution plate and a secondary distribution plate;
[0013] • The primary distribution plate is fixed to the inner end of the refrigerant liquid interface;
[0014] ● The secondary distribution plate covers the inlets of the heat exchange tube bundle.
[0015] Furthermore, this application also proposes that the primary distribution plate has a hemispherical or cylindrical structure with distribution holes evenly distributed on its surface.
[0016] Furthermore, this application also proposes that the distribution channel of the secondary distribution plate has a flanged protrusion structure, with the protrusion direction facing the tube opening of the heat exchange tube bundle;
[0017] The number of distribution channels corresponds one-to-one with the number of heat exchange tubes in the heat exchange tube bundle.
[0018] Furthermore, this application also proposes that the distribution channel of the secondary distribution plate is formed by stamping, and the root of the channel is a tapered shape.
[0019] Furthermore, this application also proposes a high-efficiency shell-and-tube heat exchanger, comprising:
[0020] ●The shell has an inlet, an outlet and multiple sets of baffles on its side wall;
[0021] ●The above refrigerant distribution structure.
[0022] As can be seen from the above, the high-efficiency shell and tube heat exchanger and its refrigerant distribution structure provided in this application achieves the stepwise uniform distribution of refrigerant in the gas-liquid two-phase state through the synergistic effect of the primary distribution plate and the secondary distribution plate, effectively suppressing the phase separation phenomenon, ensuring the balanced flow of each heat exchange tube, and has the advantages of improving heat exchange efficiency, avoiding local overcooling or overheating, and improving the oil return performance of the compressor. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the refrigerant distribution structure of a high-efficiency shell-and-tube heat exchanger provided in Example 1.
[0024] Figure 2 This is a schematic diagram of a high-efficiency shell-and-tube heat exchanger provided in Example 2. Detailed Implementation
[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0026] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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.
[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.
[0028] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" 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 two...
[0029] The internal connections of each component. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0031] In existing technologies, when shell-and-tube heat exchangers are used as evaporators, the uniform distribution of refrigerant in the tubes is a key factor affecting heat exchange efficiency. Traditional distribution structures typically use a single baffle or a simple distributor, which is insufficient to effectively address the uneven flow rate of the two-phase refrigerant as it enters multiple heat exchange tubes. Abrupt velocity changes at the inlet can easily lead to gas-liquid separation, resulting in excessive flow in some heat exchange tubes and insufficient flow in others, reducing the utilization rate of the heat exchange area and limiting overall efficiency.
[0032] To address these issues, the inventors discovered that traditional structures cannot effectively guide refrigerant flow, especially in two-phase states where the gas-liquid mixture easily forms turbulence at the inlet. Through analysis of fluid dynamics characteristics, they recognized the need for a staged, step-by-step refrigerant distribution. First, an initial diffusion structure is installed at the inlet to mitigate pressure surges. Then, a precise guiding device is established at the heat exchanger tube inlet, forming a dual distribution mechanism. This step-by-step process both disperses concentrated flow and avoids phase separation, ultimately achieving uniform distribution.
[0033] Example 1:
[0034] like Figure 1 As shown, this embodiment provides a refrigerant distribution structure for a high-efficiency shell-and-tube heat exchanger, including a heat exchange tube bundle 5 inside a shell 1, a tube sheet 2 sealing the end of the shell 1, and a tube box 4 connected to the tube sheet 2. The tube box 4 is provided with a refrigerant liquid inlet 10. A primary distribution plate 13 and a secondary distribution plate 14 are provided inside the tube box 4. The primary distribution plate 13 is fixed to the inner end of the refrigerant liquid inlet 10, and the secondary distribution plate 14 covers the inlets of the heat exchange tube bundle 5. The primary distribution plate 13 is a diffuser located at the end of the refrigerant inlet channel, which performs initial diversion of the high-speed inflowing refrigerant to reduce fluid kinetic energy. The secondary distribution plate 14 is a flow guide structure covering the inlet end of the heat exchange tube bundle 5, used to accurately guide the refrigerant into the corresponding inlet. The tube box 4 is a sealed cavity connected to the outside of the tube sheet 2, specifically a welded or flanged steel container, used to house the distribution structure and form a refrigerant flow channel.
[0035] During operation, after the refrigerant enters the tube box 4 through the liquid interface 10, it first impacts the primary distribution plate 13. The through holes on the plate disperse the concentrated flow of refrigerant into multiple fine streams, reducing the kinetic energy difference between the gas and liquid phases. The refrigerant, after primary distribution, continues to flow to the secondary distribution plate 14. The raised structure on the plate forms independent guide channels, each corresponding to a heat exchange tube inlet, avoiding flow interference between adjacent tubes. The two distribution processes respectively solve the problems of uneven inlet flow velocity and insufficient tube guidance, ensuring that each heat exchange tube receives an equal amount of refrigerant.
[0036] This scheme employs a two-stage distribution structure to achieve progressive flow regulation. The primary distribution plate 13 weakens the inlet impact effect, while the secondary distribution plate 14 establishes a directional flow path. This dual action effectively suppresses gas-liquid phase separation, ensuring uniform refrigerant coverage across all heat exchange tubes. Through this technical solution, this application achieves uniform refrigerant distribution within the heat exchange tube bundle 5, improving heat exchange area utilization and avoiding a decrease in heat exchange efficiency due to uneven local flow. The two-phase refrigerant maintains a stable flow state during the two distribution processes, reducing heat exchange fluctuations caused by gas-liquid separation and ensuring consistent operating conditions for each heat exchange tube under evaporation conditions.
[0037] In a further embodiment, the primary distribution plate 13 has a hemispherical or cylindrical structure with distribution holes evenly distributed on its surface.
[0038] The hemispherical structure refers to a shell shape with spherical curvature, which can be manufactured using a stamping process. The curved surface forms a three-dimensional guiding surface to disperse the refrigerant flow direction. The cylindrical structure refers to a cylindrical shape with axial symmetry, which can be achieved through plate rolling and welding, utilizing circumferential symmetry to achieve uniform circumferential distribution. Uniform distribution of distribution holes means that the hole spacing remains equidistant at different positions on the curved surface. This can be achieved using CNC drilling equipment to ensure consistent flow cross-sectional area for each hole. During operation, after the refrigerant enters the casing 4, it first contacts the curved surface structure of the primary distribution plate 13. The curved guiding surface causes the fluid to diffuse tangentially, forming a circulation. The distribution holes are evenly spaced along the curved surface, ensuring the refrigerant receives the same flow resistance at different positions on the spherical or cylindrical surface. The spherical curvature of the hemispherical structure promotes uniform fluid dispersion in all directions, while the axial symmetry of the cylindrical structure ensures uniform fluid distribution along the circumference. By guiding the refrigerant through the three-dimensional curved surface to generate multi-directional flow, the fluid avoids concentrated impact on specific areas, resulting in a uniform flow field of the pre-distributed refrigerant across the casing 4 cross-section.
[0039] In a further embodiment, the distribution channels of the secondary distribution plate 14 are flanged protrusions, with the protrusions facing the inlets of the heat exchange tube bundle 5. The number of distribution channels corresponds one-to-one with the number of heat exchange tubes in the heat exchange tube bundle 5. The flanged protrusion structure refers to the protruding channels formed on the surface of the secondary distribution plate 14 through a stamping process, with the protrusion ends extending to the vicinity of the heat exchange tube inlets. This structure forms a directional flow path through physical deformation, ensuring that the refrigerant flow direction remains parallel to the axis of the heat exchange tubes.
[0040] The one-to-one correspondence of the distribution channels means that the outlet end of each flanged protrusion structure is fluidly connected to only a single heat exchange tube opening, eliminating the possibility of multiple tubes sharing a distribution channel through structural constraints. When the refrigerant passes through the secondary distribution plate 14, the throttling effect at the constriction root of the flanged protrusion structure balances the pressure differences between the channels. The protrusion extension guides the fluid to flow along the axis of the heat exchange tube, avoiding kinetic energy loss caused by sudden changes in fluid direction. Each flanged protrusion structure corresponds to a single heat exchange tube opening, ensuring that there is no path intersection or flow competition during the refrigerant flow process, and guaranteeing that each heat exchange tube receives an equal amount of refrigerant. This solution, through the combination of flanged protrusion structures and quantity matching, optimizes the fluid movement trajectory and achieves forced flow equalization through physical isolation. Through the above technical solution, this application solves the problem of unreasonable refrigerant distribution channel structure between the secondary distribution plate 14 and the heat exchange tube bundle 5, enabling the refrigerant to directly enter the corresponding heat exchange tube along a preset path, eliminating flow competition caused by multiple tubes sharing a channel, reducing energy loss caused by sudden changes in flow direction, and ensuring that each heat exchange tube receives a uniform refrigerant flow.
[0041] In a specific implementation, the distribution channel of the secondary distribution plate 14 is formed by stamping, and the root of the channel is a tapered shape.
[0042] Stamping, in particular, refers to a processing method that uses a die to apply pressure to a metal sheet, causing it to plastically deform. This process can precisely...
[0043] Control the geometry and positional distribution of the channels to ensure that each distribution channel is axially aligned with the heat exchanger inlet. The tapered shape refers to the tapered transition structure formed at the root region of the channel, which tapers towards the central axis. This can be achieved by adjusting the cavity contour of the stamping die. This structure increases the connection area between the channel root and the main body of the sheet metal, improving resistance to deformation.
[0044] Example 2:
[0045] like Figure 2 As shown, this embodiment proposes a high-efficiency shell-and-tube heat exchanger, including a shell 1, with an inlet 8, an outlet 9, and multiple sets of baffles 6 on its side wall; and adopts the refrigerant distribution structure described in Embodiment 1 above. The refrigerant distribution structure includes a heat exchange tube bundle 5 inside the shell 1, a tube sheet 2 that closes the end of the shell 1, and a tube box 4 connected to the tube sheet 2. The tube box 4 is provided with a refrigerant liquid interface 10. A primary distribution plate 13 and a secondary distribution plate 14 are provided inside the tube box 4. The primary distribution plate 13 is fixed to the inner end of the refrigerant liquid interface 10, and the secondary distribution plate 14 covers the opening of the heat exchange tube bundle 5.
[0046] The shell 1 is a sealed container that houses the heat exchange tube bundle 5 and the shell-side fluid. It can be formed by welding or casting carbon steel or stainless steel. The inlet 8 and outlet 9 on its sidewall are used for shell-side fluid circulation. The shell 1 isolates the shell side from the tube side. The baffle 6 is a plate-shaped structure installed inside the shell 1 to change the flow path of the shell-side fluid. It can be an arc-shaped or disc-shaped structure, and multiple sets of baffle channels are formed by spaced arrangement, forcing the shell-side fluid to laterally scour the heat exchange tube bundle 5 to enhance turbulent heat transfer. The refrigerant distribution structure is a combination of a tube box 4, a primary distribution plate 13, and a secondary distribution plate 14. The tube box 4 is sealed to the shell 1 through a tube sheet 2. The refrigerant liquid interface 10 is used to introduce two-phase refrigerant. Uniform refrigerant distribution is achieved through the initial diffusion of the primary distribution plate 13 and the tube-by-tube distribution of the secondary distribution plate 14. The primary distribution plate 13 refers to a porous structure located at the inner end of the refrigerant liquid interface 10. Specifically, it can be a hemispherical or cylindrical plate with uniformly distributed through holes on its surface, used to initially disperse the concentrated refrigerant into the internal space of the tube box 4. The secondary distribution plate 14 refers to a distribution device covering the openings of the heat exchange tube bundle 5. Its distribution channels are formed by stamping to create a flanged protrusion structure, with the protrusion direction aligned with the openings of the heat exchange tube bundle 5. Each channel corresponds to one heat exchange tube, used to accurately guide the refrigerant into each heat exchange tube.
[0047] After the refrigerant enters the tube box 4 through the refrigerant liquid interface 10, it first impacts the primary distribution plate 13, achieving initial diffusion through the evenly distributed holes on its surface, thus forming a uniform flow distribution of the refrigerant within the tube box 4. Subsequently, the refrigerant flows through the flanged protruding channels of the secondary distribution plate 14, with each channel corresponding to the inlet of a heat exchange tube. The constricted shape at the root of the channel constrains the fluid flow direction, ensuring that each heat exchange tube receives an equal amount of refrigerant. On the shell side, the cooling medium introduced through the inlet 8 forms multiple zigzag flows under the guidance of the baffle plate 6, laterally scouring the outer wall of the heat exchange tube bundle 5 and enhancing the heat exchange between the shell and tube sides. The synergistic effect of the primary distribution plate 13 and the secondary distribution plate 14 solves the problem of uneven distribution of the two-phase refrigerant in traditional evaporators, and the cooperation between the baffle plate 6 and the distribution structure further improves the overall heat exchange efficiency. Through the above technical solution, this application effectively solves the problem of reduced heat exchange efficiency caused by uneven refrigerant distribution under evaporation conditions. The two-stage distribution structure ensures uniform flow in each heat exchange tube, avoiding local overheating or undercooling. At the same time, the coordinated design of the baffle plate 6 and the distribution structure improves the heat exchange efficiency between the shell side and the tube side, and reduces the waste of heat exchange area.
[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.
Claims
1. A refrigerant distribution structure for a high-efficiency shell-and-tube heat exchanger, comprising: - Heat exchange tube bundle (5) inside the shell (1); - Tube sheet (2) at the end of the closed shell; - A tube box (4) connected to the tube sheet (2), the tube box (4) being provided with a refrigerant liquid interface (10); Its features are: - The pipe box (4) is provided with a primary distribution plate (13) and a secondary distribution plate (14); - The primary distribution plate (13) is fixed to the inner end of the refrigerant liquid interface (10); - The secondary distribution plate (14) covers the opening of the heat exchange tube bundle (5).
2. The refrigerant distribution structure according to claim 1, characterized in that: - The primary distribution plate (13) is a hemispherical or cylindrical structure with distribution holes evenly distributed on its surface.
3. The refrigerant distribution structure according to claim 1, characterized in that: - The distribution channel of the secondary distribution plate (14) is a flanged protrusion structure, with the protrusion direction facing the opening of the heat exchange tube bundle (5); - The number of distribution channels corresponds one-to-one with the number of heat exchange tubes in the heat exchange tube bundle (5).
4. The refrigerant distribution structure according to claim 3, characterized in that: - The distribution channel of the secondary distribution plate (14) is formed by stamping, and the root of the channel is a tapered shape.
5. A high efficiency shell and tube heat exchanger characterized by, include: - The shell (1) has an inlet (8), an outlet (9) and multiple sets of baffles (6) on its side wall; - The refrigerant distribution structure as described in any one of claims 1-4.