Corrugated heat exchange tube based on combination of multiple enhanced heat exchange structures and heat exchanger

Abstract

The invention relates to the technical field of heat exchange process equipment, in particular to a corrugated heat exchange tube based on combination of multiple enhanced heat exchange structures and a heat exchanger. The corrugated heat exchange pipe comprises spiral corrugated pipe sections and corrugated pipe sections which are alternately arranged in the axial direction of the pipe. Spiral protrusions are arranged on the outer circumferential wall of a pipe body of the spiral corrugated pipe section, corrugated protrusions are arranged on the outer circumferential wall of a pipe body of the corrugated pipe section, the screw pitch of the spiral protrusions is gradually decreased in the direction from a fluid inlet to a fluid outlet of the corrugated heat exchange pipe, and the slope of the corrugated protrusions is gradually increased. The spiral corrugated protrusions and the node protrusions are combined, gradient matching of the gradually-shrunk pitch and the slope gradient of the nodes is optimized, the fluid flow state is accurately regulated and controlled, vortex generation is reduced, the heat exchange efficiency is improved, the flow resistance is reduced, and meanwhile the resonance phenomenon is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange process equipment, and particularly to a corrugated heat exchange tube and a heat exchanger based on a combination of multiple enhanced heat transfer structures. Background Art

[0002] As a key device for efficient energy utilization in industrial production, the corrugated tube heat exchanger is widely used in the fields of efficient energy utilization and heat exchange, such as fuel cell thermal management, engine fuel heating, high-temperature steam or flue gas cooling in thermal power plants, heat exchange between high-temperature gases and cooling medium heat transfer oil in chemical plants, etc. The performance of the heat exchange tube, which is the core component, directly affects the heat exchange efficiency and operation stability of the heat exchanger. As a common type of heat exchange tube, the corrugated heat exchange tube enhances the turbulent effect of the fluid through the corrugated structure of the tube wall, thereby improving the heat exchange efficiency. However, there are still some problems to be improved in the actual application of existing corrugated heat exchange tubes.

[0003] Existing corrugated heat exchange tubes usually consist of periodic corrugated protrusions with constant corrugation pitch and height. When the fluid flows inside the tube, small vortices are generated within the arc of the corrugated tube section, and the eddies formed by these vortices will weaken the effect of enhanced heat transfer and increase the flow resistance. In addition, due to the constant corrugation size, the vibration frequency of the fluid flowing through the heat exchanger is fixed, which easily causes resonance phenomena and affects the stability and durability of the heat exchanger.

[0004] It can be seen that the technical problems existing in the existing corrugated heat exchange tubes include:

[0005] ① Small vortices are generated within the arc of the corrugated tube section, and the eddies formed by these vortices will weaken the effect of enhanced heat transfer and increase the flow resistance. ② The corrugated heat exchange tube with constant size will cause the vibration frequency of the fluid flowing through the heat exchanger to be fixed, thereby causing resonance phenomena and affecting the stability and durability of the equipment. ③ There is a lack of fine control of the fluid flow path in the prior art, resulting in difficulty in further improving the heat exchange efficiency and flow stability. Therefore, how to effectively reduce the generation of eddies in the corrugated tube section, reduce the flow resistance, and improve the heat exchange efficiency has become a key technical challenge in the field of corrugated tube heat exchangers. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the embodiments of the present invention is to provide a corrugated heat exchange tube based on a combination of multiple enhanced heat transfer structures. By combining the spiral corrugated protrusions with the corrugated protrusion structure, optimizing the matching of the gradually decreasing pitch and the slope gradient of the corrugations, precisely controlling the fluid flow state, reducing the generation of eddies, improving the heat exchange efficiency, reducing the flow resistance, and avoiding the generation of resonance phenomena at the same time.

[0007] To achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

[0008] A corrugated heat exchange tube based on the combination of multiple enhanced heat transfer structures, comprising: a spiral corrugated tube section and a corrugated tube section arranged alternately along the axial direction of the tube; a spiral protrusion is provided on the outer peripheral wall of the spiral corrugated tube section, and a corrugated protrusion is provided on the outer peripheral wall of the corrugated tube section. Along the direction from the fluid inlet to the fluid outlet of the corrugated heat exchange tube, the pitch of the spiral protrusion gradually decreases, and the slope of the corrugated protrusion gradually increases.

[0009] Optionally, the spiral shape of each spiral corrugated tube section follows the following mathematical equation:

[0010] x = c i t;

[0011]

[0012] wherein, x, y, and z respectively represent the coordinates on the x-axis, y-axis, and z-axis, i is the i-th spiral corrugated tube section starting from the heat exchange tube inlet, and c i is the coefficient corresponding to the control pitch of the i-th spiral corrugated tube section, D0 is the base tube diameter, and t and k0 are constants.

[0013] Optionally, the pitch attenuation function of the spiral shape of the spiral corrugated tube section is: a new curve constructed based on the Lindner growth curve and the Gompertz growth curve.

[0014] Optionally, the pitch of the spiral shape of the spiral corrugated tube section conforms to the following equation:

[0015] P = k0c i ;

[0016]

[0017] wherein, P is the pitch, i is the i-th spiral corrugated tube section starting from the heat exchange tube inlet, i = 1, 2, 3,..., i max , i max is the ordinal number corresponding to the last spiral corrugated tube section, and c max and c min are respectively the maximum value and the minimum value set by the coefficient c, and b, a1, a2, λ1, and λ2 are constants.

[0018] Optionally, the spiral protrusion of each spiral corrugated tube section in the corrugated heat exchange tube satisfies the equation:

[0019]

[0020] wherein, H1 is the height of the spiral corrugated protrusion, and k1 is a constant.

[0021] Optionally, the corrugation shape of each corrugated tube section in the corrugated heat exchange tube is composed of two curves. Taking the highest point of the corrugation bulge as the demarcation line, the g(x) curve is adopted on the side biased towards the fluid inlet, and the q(x) curve is adopted on the side biased towards the fluid outlet:

[0022]

[0023] wherein, H2 is the corrugation bulge height, and k2 and k3 are coefficients.

[0024] Optionally, the relationship between k2 and k3 conforms to the following formula:

[0025]

[0026] wherein, L2 is the length of each corrugated tube section.

[0027] Optionally, the mutual relationship between the spiral bulge shape of the spiral corrugated tube section and the corrugation bulge shape of the corrugated tube section is as follows:

[0028]

[0029] From this relational expression, the values of coefficients k2 and k0 can be obtained, thereby determining the corrugation bulge shape of each corrugated tube section.

[0030] Optionally, the values of the coefficients are:

[0031] The magnitude of k0 is 0.2, the magnitude of k1 is 1, t ∈ [0, 14], c max and c min are 10 and 3.5 respectively, b = 5.3, a1 = 0.3, a2 = 0.2, λ1 = 0.1, λ2 = 0.8.

[0032] An embodiment of the present invention also provides a heat exchanger, including a shell, a tube sheet, a tube box, and a corrugated heat exchange tube based on a combination of multiple enhanced heat exchange structures as described above. The shell is used to accommodate the tube box, the corrugated heat exchange tube is fixed in the tube box through the tube sheet, and the fluid conducts heat exchange through the corrugated heat exchange tube in the tube box;

[0033] The heat exchanger is used for fuel cell thermal management, heating of engine fuel, cooling of high-temperature steam or flue gas in a thermal power plant, and heat exchange between high-temperature gas in a chemical plant and cooling medium heat transfer oil.

[0034] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0035] The corrugated heat exchange tube alternately arranges spiral corrugated pipe sections and corrugated pipe sections along the axial direction of the tube. The outer peripheral wall of the spiral corrugated pipe section has spiral protrusions, while the outer peripheral wall of the corrugated pipe section has corrugated protrusions. The spiral pipe section guides the liquid flow, thereby reducing the generation of eddy currents within the arc of the corrugated pipe section. Therefore, not only the heat exchange efficiency is improved, but also the flow resistance is reduced. On the other hand, combined with the gradient matching of the gradually decreasing pitch and the corrugation slope, the flow pattern of the fluid is optimized, that is, from the fluid inlet to the fluid outlet direction, the pitch of the spiral pipe section gradually becomes smaller, and at the same time, the slope of the corrugated pipe section gradually becomes larger, thereby changing the vibration frequency, so that the frequencies of the corrugated pipes in the fluid flow direction are all different, avoiding the resonance phenomenon caused by the fixed size in the conventional corrugated pipes, enhancing the stability and durability of the equipment, and avoiding potential failures caused by resonance during long-term use. Generally speaking, the invention not only improves the heat exchange efficiency and flow stability of the heat exchanger, but also improves the reliability and durability of the equipment, and has important industrial application value.

[0036] Advantages of additional aspects of the present invention will be given in the following description, some of which will become obvious from the following description, or will be learned through the practice of the present invention. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In addition, the distances or sizes between components are exaggerated for showing the positions of the components, and the schematic diagrams are only for illustrative use.

[0038] Figure 1 It is the corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures of this embodiment.

[0039] Figure 2 It is the detail drawing of a certain part of the heat exchange tube in the corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures of this embodiment.

[0040] Figure 3 It is the spiral shape followed by a certain spiral corrugated pipe section in the heat exchange tube.

[0041] In the figure, 1 is the main body of the heat exchange tube, 2 is the omitted part in the middle of the heat exchange tube, 3 is the protrusion of the spiral corrugation, 4 is the left side of the nodular protrusion, 5 is the right side of the nodular protrusion, 6 is the shape of the corrugation rotation in the spiral corrugated pipe section, and 7 and 8 are certain parts of the heat exchange tube. AB is the spiral corrugated pipe section, CD is the nodular pipe section, L1 is the length of the spiral corrugated pipe section, L2 is the nodular pipe section, L is the wave pitch, σ is the wall thickness of the pipe, D0 is the base pipe diameter, D2 is the wave crest diameter of the nodular pipe section, H1 is the height of the spiral corrugation protrusion, H2 is the height of the nodular protrusion, and M is the outer elongation. Detailed implementation mode

[0042] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] Example 1

[0044] In order to improve the heat exchange efficiency of the nodular heat exchange tube and reduce the flow resistance caused by eddy currents, this embodiment proposes a nodular heat exchange tube based on a combination of multiple enhanced heat exchange structures, as Figure 1 、 Figure 2 shown in the figure. In the figure, 1 is the main body of the heat exchange tube, 2 is the omitted part in the middle of the heat exchange tube, 3 is the protrusion of the spiral corrugation, 4 is the left side of the nodular protrusion, 5 is the right side of the nodular protrusion, 6 is the shape of the corrugation rotation in the spiral corrugated pipe section, and 7 and 8 are certain parts of the heat exchange tube. AB is the spiral corrugated pipe section, and CD is the nodular pipe section.

[0045] The nodular heat exchange tube includes: a spiral corrugated pipe section and a nodular pipe section arranged alternately along the axial direction of the pipe; the outer peripheral wall of the spiral corrugated pipe section has spiral protrusions, and the outer peripheral wall of the nodular pipe section has nodular protrusions. Along the direction from the fluid inlet to the fluid outlet of the nodular heat exchange tube, the pitch of the spiral protrusions gradually becomes smaller, and the slope of the nodular protrusions gradually becomes larger.

[0046] By studying the mutual relationship between the spiral corrugation shape of the AB section and the nodular protrusion shape of the CD section, and combining the gradient matching of the tapered pitch and the nodular slope, that is, the pitch gradually decreases and the slope gradually becomes steeper from the inlet to the outlet, the fluid flows through the spiral corrugated pipe section (i.e., the AB section) and the nodular pipe section (i.e., the CD section) in turn and alternates between the two, realizing precise control of the liquid flow direction, effectively suppressing the eddy currents generated in the nodular pipe section, and reducing the flow resistance while improving the heat transfer efficiency.

[0047] The spiral shape of each spiral corrugated pipe section refers to Figure 3 , and follows the following mathematical equation:

[0048] x = c i t;

[0049]

[0050] Wherein, x, y, and z respectively represent the coordinates on the x-axis, y-axis, and z-axis, with the unit of mm. i is the i-th helical corrugated pipe section starting from the inlet of the heat exchange pipe, and c i is the coefficient corresponding to the control pitch of the i-th helical corrugated pipe section, which can control the pitch of the helical corrugation. D0 is the diameter of the base pipe, and t and k0 are constants. This precise mathematical description enables the helical corrugated pipe section to better adapt to the flow characteristics of the fluid, thereby enhancing the heat exchange efficiency.

[0051] The pitch decay function is a new curve constructed based on the Lindner growth curve (describing rapid decay in the initial stage) and the Gompertz growth curve (describing gentle decay in the later stage), forming a combined decay model.

[0052] The pitch of the helical shape of the helical corrugated pipe section conforms to the following equation:

[0053] P = k0c i ;

[0054]

[0055] Wherein, P is the pitch, i is the i-th helical corrugated pipe section starting from the inlet of the heat exchange pipe, i = 1, 2, 3,..., i max , i max is the ordinal number corresponding to the last helical corrugated pipe section, and c max and c min are respectively the maximum and minimum values set by the coefficient c, and b, a1, a2, λ1, and λ2 are constants.

[0056] The pitch of the helical corrugated pipe section is further precisely controlled by a specific equation. The parameters in the equation include the pitch, the serial number of the helical corrugated pipe section, and coefficients such as the maximum and minimum values. These parameters work together to enable the helical corrugated pipe section to provide different pitches at different positions. This precise pitch control method can effectively reduce the generation of eddy currents within the arc of the corrugated pipe section, not only improving the heat exchange efficiency but also reducing the flow resistance.

[0057] The helical protrusions of each helical corrugated pipe section in the corrugated heat exchange pipe satisfy the equation:

[0058]

[0059] Wherein, H1 is the height of the helical corrugation protrusion, and k1 is a constant.

[0060] The corrugated shape of each corrugated tube section in the corrugated heat exchange tube is composed of two curves. The highest point of the corrugated node is used as the dividing line. The g(x) curve is used on the side closer to the fluid inlet (i.e., the left side in the figure), and the q(x) curve is used on the side closer to the fluid outlet (i.e., the right side in the figure):

[0061]

[0062] Among them, H2 is the height of the node protrusion, k2 and k3 are coefficients.

[0063] The corrugated tube section's node shape is a combination of two curves, with the highest point of the node protrusion serving as the dividing line: the g(x) curve is used toward the fluid inlet, and the q(x) curve is used toward the fluid outlet. The wavelength of the g(x) curve is linked to the pitch coefficient of the helical segment, ensuring a precise match between the node and the helical structure. This design reduces eddy currents and lowers flow resistance. Furthermore, the node protrusion exhibits a gradual change in the direction of fluid flow, thereby suppressing resonance with other components.

[0064] The relationship between k2 and k3 conforms to the following formula:

[0065]

[0066] Wherein, L2 is the length of each corrugated tube section.

[0067] The relationship between the spiral convex shape of the spiral corrugated pipe section and the corrugated node convex shape of the corrugated pipe section is as follows:

[0068]

[0069] The values of coefficients k2 and k0 can be obtained from this relationship, thereby determining the shape of the corrugated node protrusion of each corrugated tube section.

[0070] There is a specific relationship between the spiral convex shape of the spiral corrugated pipe section and the corrugated node convex shape of the corrugated pipe section. By optimizing the synergistic effect of the spiral corrugation and the corrugated node convexity, the generation of eddy currents is reduced and the flow resistance is lowered.

[0071] The values of the above coefficients can be:

[0072] k0 is 0.2, k1 is 1, t∈[0,14], c max and c min They are 10 and 3.5 respectively, b=5.3, a1=0.3, a2=0.2, λ1=0.1, λ2=0.8.

[0073] The exact values of these parameters are determined through a large number of experiments and numerical simulations, which can ensure that the shape design of the spiral corrugated pipe section and the corrugated pipe section achieves the best heat exchange effect. In this way, the shapes of the spiral corrugations and the corrugation protrusions can precisely match the flow characteristics of the fluid, thereby significantly improving the heat exchange efficiency and reducing the flow resistance.

[0074] As Figure 1 、 Figure 2 shown, for each section of the corrugated heat exchange pipe, the length L1 of the spiral corrugated pipe section is 30 to 40 mm, the length L2 of the corrugated pipe section is 5 to 10 mm, the wave pitch is L = L1 + L2, the pipe length S is 1 to 1.5 m, the extension length M is 35 to 50 mm, the base pipe diameter D0 is 10 to 20 mm, the height H1 of the spiral corrugation protrusion is 2 to 2.5 mm, the height H2 of the corrugation protrusion is 3 to 4 mm, the wave peak diameter of the corrugated pipe section is D2 = D0 + 2H2, and the pipe wall thickness σ is 2.5 to 4 mm.

[0075] Preferably, for each section of the corrugated heat exchange pipe, the length L1 of the spiral corrugated pipe section (AB section) is 35 mm, the length L2 of the corrugated pipe section (CD section) is 5 mm, the pipe length S is 1010 mm, the extension length M is 50 mm, the base pipe diameter D0 is 10 mm, the height H1 of the spiral corrugation protrusion is 2 mm, the height H2 of the corrugation protrusion is 3 mm, the wave peak diameter (wave depth) of the corrugated pipe section is D2 = D0 + 2H2, and the pipe wall thickness σ is 2.5 mm.

[0076] In summary, the present invention can effectively control the eddy current generated when the fluid enters the corrugated pipe section, thereby reducing the flow resistance, decreasing the non-uniformity of heat transfer and the generation of resonance phenomenon, and thus ensuring the enhancement of the heat exchange effect.

[0077] Embodiment 2

[0078] This embodiment provides a heat exchanger, including a shell, a tube sheet, a tube box, and a corrugated heat exchange pipe based on a combination of various enhanced heat exchange structures as described in Embodiment 1. The shell is used to accommodate the tube box, the corrugated heat exchange pipe is fixed in the tube box through the tube sheet, and the fluid exchanges heat through the corrugated heat exchange pipe in the tube box; the heat exchanger is used for fuel cell thermal management, heating of engine fuel, cooling of high-temperature steam or flue gas in a thermal power plant, and heat exchange between high-temperature gas and cooling medium heat transfer oil in a chemical plant.

[0079] By adopting the optimized corrugated heat exchange pipe, the heat exchanger can provide efficient heat exchange performance in different application scenarios, while reducing energy loss and improving the operation efficiency and reliability of the equipment.

[0080] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A corrugated heat exchange tube based on the combination of multiple enhanced heat transfer structures, characterized in that, include: Spiral bellows sections and corrugated tube sections are alternately arranged along the axial direction of the tube; The spiral corrugated tube section has a spiral protrusion on the outer peripheral wall of the tube body, and the corrugated tube section has a corrugated node protrusion on the outer peripheral wall of the tube body. Along the direction from the fluid inlet to the fluid outlet of the corrugated heat exchange tube, the pitch of the spiral protrusion gradually decreases and the slope of the corrugated node protrusion gradually increases.

2. The corrugated heat exchange tube based on the combination of multiple enhanced heat transfer structures according to claim 1, wherein The spiral shape of each of the spiral bellows segments follows the following mathematical equation: x = c i t; Wherein, x, y, and z respectively represent the coordinates on the x-axis, y-axis, and z-axis, i is the i-th helical corrugated pipe section starting from the inlet of the heat exchange pipe, and c i is the coefficient corresponding to the control pitch of the i-th helical corrugated pipe section, D0 is the diameter of the base pipe, and t and k0 are constants.

3. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures as claimed in claim 2, wherein, The pitch attenuation function of the spiral shape of the spiral bellows segment is a new curve constructed based on the Lindenau growth curve and the Gompertz growth curve.

4. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures according to claim 3, characterized in that, The pitch of the helical shape of the spiral bellows section complies with the following equation: P = k0c i ; Wherein, P is the pitch, i is the i-th helical corrugated pipe section starting from the inlet of the heat exchange pipe, i = 1, 2, 3,..., i max , i max is the ordinal number corresponding to the last helical corrugated pipe section, c max and c min are respectively the maximum value and the minimum value set by the coefficient c, and b, a1, a2, λ1, λ2 are constants.

5. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures according to claim 4, characterized in that The spiral bulge of each spiral corrugated tube section in the corrugated heat exchange tube satisfies the equation: Among them, H1 is the height of the spiral corrugation protrusion, and k1 is a constant.

6. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures as claimed in claim 4, wherein The corrugated shape of each corrugated tube section in the corrugated heat exchange tube is composed of two curves. The highest point of the corrugated node is used as the dividing line. The g(x) curve is used on the side toward the fluid inlet, and the q(x) curve is used on the side toward the fluid outlet: Among them, H2 is the height of the node protrusion, k2 and k3 are coefficients.

7. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures according to claim 6, characterized in that The relationship between k2 and k3 conforms to the following formula: Wherein, L2 is the length of each corrugated tube section.

8. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures as claimed in claim 7, characterized in that, The relationship between the spiral convex shape of the spiral corrugated pipe section and the corrugated node convex shape of the corrugated pipe section is as follows: The values of coefficients k2 and k0 can be obtained from this relationship, thereby determining the shape of the corrugated node protrusion of each corrugated tube section.

9. The corrugated heat exchange tube based on the combination of multiple enhanced heat exchange structures according to claim 8, wherein The coefficient values are: The size of k0 is 0.2, the size of k1 is 1, t ∈ [0, 14], c max and c min are 10 and 3.5 respectively, b = 5.3, a1 = 0.3, a2 = 0.2, λ1 = 0.1, λ2 = 0.

8.

10. A heat exchanger, characterized in that, The invention comprises a shell, a tube sheet, a tube box, and a corrugated heat exchange tube based on a combination of multiple enhanced heat exchange structures according to any one of claims 1 to 9, wherein the shell is used to accommodate the tube box, the corrugated heat exchange tube is fixed in the tube box through the tube sheet, and the fluid is heat exchanged through the corrugated heat exchange tube in the tube box; The heat exchanger is used for thermal management of fuel cells, heating of engine oil, cooling of high-temperature steam or flue gas in thermal power plants, and heat exchange between high-temperature gas and cooling medium thermal oil in chemical plants.

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