Multi-layer coiled heat exchange structure and method based on spiral elliptical tubes

Abstract

The invention provides a multi-layer coiled heat exchange structure and method based on a spiral oval pipe, the multi-layer coiled heat exchange structure is a multi-layer coiled pipe type countercurrent heat exchange structure prepared on the basis of the spiral oval pipe, the multi-layer coiled pipe type countercurrent heat exchange structure comprises a multi-head parallel spiral oval coil pipe, a cold fluid channel is formed in the spiral oval pipe, and a cold fluid channel is formed in the cold fluid channel; cold fluid flows in from an inlet in the upper portion of the spiral oval coil pipe and flows out from an outlet in the lower portion of the spiral oval coil pipe, a hot fluid channel is arranged outside the spiral oval coil pipe, hot fluid flows in from the lower portion and flows out from the upper portion, and the cold fluid and the hot fluid conduct cross countercurrent flow heat exchange. Wherein the spiral oval pipe is formed by rotating a heat exchange pipeline with an oval section according to a certain angle, the weak link of the welding position of a traditional heat exchanger is eliminated, operability is high, the spiral oval pipe is suitable for the heat exchange process within various temperature ranges, and the equipment production process is simplified while efficient low-resistance enhanced heat exchange is achieved.

Description

Technical Field

[0001] This invention relates to the field of energy-saving heat exchange technology, and in particular to a multi-layer coiled heat exchange structure and method based on a spiral elliptical tube. Background Technology

[0002] Heat exchangers are essential equipment in the industrial sector, widely used in production processes such as raw material preheating and waste heat recovery. my country's metallurgical, building materials, chemical, and power industries are pillar industries of modern society, but they are also high-energy-consuming and high-emission sectors. Taking process industries such as metallurgy, building materials, and chemicals as examples, their annual energy consumption accounts for more than 40% of the country's total energy consumption, and their energy efficiency is low. More than half of the input energy is emitted as high-temperature waste gas, waste residue, and waste liquid, resulting in significant energy waste and loss.

[0003] Traditional industrial heat exchange / waste heat recovery equipment includes plate heat exchangers and tubular heat exchangers. Plate heat exchangers have a large specific surface area and a high heat transfer coefficient, but because the heat exchange plates are sealed with rubber strips, they are only suitable for heat exchange conditions of medium and low temperature media (generally not exceeding 200℃). Tubular heat exchangers integrate the heat exchange tube bundle into the heat exchange equipment through cover plate welding, and can adapt to high temperature heat exchange conditions (generally up to 800℃). However, conventional tubular heat exchangers use circular heat exchange tubes, which have a small specific surface area; and because they use straight tube heat exchange, a stable boundary layer is easily formed inside the tube, resulting in a low heat transfer coefficient. Currently, efforts are being made to increase the heat transfer surface area of ​​tubular heat exchangers by adding inserts or expanding the surface area, but this leads to problems such as increased resistance. On the other hand, optimizing the tube shape and heat exchanger structure can enhance fluid turbulence and improve the heat transfer coefficient by disrupting the flow boundary layer. However, spiral tube heat exchangers, typically made from circular heat exchange tubes, can only enhance heat transfer on the outer diameter side; heat transfer on the inner diameter side is difficult to enhance or may even be weakened, making it difficult to meet the requirements of high-efficiency heat exchange / deep waste heat recovery in industry. To reduce energy consumption in industrial production and improve energy utilization, there is an urgent need to develop a high-efficiency, low-resistance heat exchange method and equipment structure suitable for a wide range of temperature conditions.

[0004] Therefore, it is necessary to study a multi-layer coiled heat exchange structure and method based on a spiral elliptical tube to address the shortcomings of existing technologies and solve or mitigate one or more of the aforementioned problems. Summary of the Invention

[0005] In view of this, the present invention provides a multi-layer coiled heat exchange structure and method based on a spiral elliptical tube, which solves the problems of low heat transfer coefficient caused by the formation of a stable boundary layer in traditional straight tube heat exchange, and the fact that ordinary circular coil heat exchange can only enhance heat transfer on the outer diameter side. Furthermore, the heat exchange fluid enters the heat exchanger tangentially with low resistance, eliminating the need for an additional cover plate, eliminating the weak link at the weld of traditional heat exchangers, making it highly operable and applicable to heat exchange processes in various temperature ranges. It simplifies the equipment production process while enhancing heat exchange with high efficiency and low resistance.

[0006] On one hand, the present invention provides a multi-layer coiled heat exchange structure based on a spiral elliptical tube. The multi-layer coiled heat exchange structure based on the spiral elliptical tube is a multi-layer coiled tube counter-current heat exchange structure prepared on the basis of the spiral elliptical tube. The multi-layer coiled tube counter-current heat exchange structure includes multiple spiral elliptical tubes connected in parallel. The inside of the spiral elliptical tube is a cold fluid channel, inflowing from the upper inlet of the spiral elliptical tube and outflowing from the lower outlet of the spiral elliptical tube. The outside of the spiral elliptical tube is a hot fluid channel, inflowing from the lower part and outflowing from the upper part. The cold fluid and hot fluid cross-flow counter-current heat exchange. The spiral elliptical tube is formed by rotating a heat exchange pipe with an elliptical cross section at a certain angle.

[0007] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the multi-layer coiled tube counter-current heat exchange structure adjusts the pitch B between the multi-layer coils according to the type of heat exchange fluid and the heat load, thereby adjusting the number n of the multi-head parallel spiral elliptical tubes; the pitch B is equal to the number of spiral elliptical tubes n multiplied by the long side diameter b of the elliptical tube; the multi-head parallel spiral elliptical coils are arranged sequentially from top to bottom, and each cold fluid is configured with a corresponding inlet and outlet; the cold fluid enters the spiral elliptical tube from the corresponding inlet and flows out from the corresponding outlet, and the hot fluid enters the spiral elliptical tubes from the bottom and flows out from the top, wherein B, b, and n are all greater than 0 and n is an integer.

[0008] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the major axis of the cross-section of the spiral elliptical tube is a, the minor axis is b, and a is greater than b, and the horizontal distance d between two adjacent elliptical cross-sections with equal rotation angles is equal to the minor axis b; the elliptical cross-section is rotated and twisted along the center of the cross-section to form the spiral elliptical tube; the spiral elliptical tube is wound in a clockwise or counterclockwise direction to form a spiral coil; the multi-head parallel spiral coils constitute the multi-layer coiled tube counter-current heat exchange structure.

[0009] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the multi-head parallel spiral elliptical coil, if it is a single-head coil, is prepared by spiraling a single spiral elliptical tube, with the cold fluid configured with one inlet and one outlet.

[0010] In addition to the aspects and any possible implementations described above, a further implementation is provided in which, if the multi-head parallel spiral elliptical coil is a multi-head coil, it is prepared by n spiral elliptical tubes connected in parallel, with n inlets and n outlets for the cold fluid; the pitch B is increased accordingly, and the heat exchange tubes are arranged sequentially from top to bottom; the hot fluid flows into the space between the spiral elliptical tubes from the bottom and flows out from the top of the coil, realizing the cross-counterflow heat exchange.

[0011] In addition to the aspects and any possible implementations described above, a further implementation is provided in which cold fluid flows from the upper inlet of the coil into the spiral elliptical tube in the cold fluid channel; during the flow of the cold fluid along the spiral elliptical tube, the cross-section of the flow channel locally contracts; the cold fluid flows out from the lower outlet of the coil; and the hot fluid in the hot fluid channel flows from the lower part into the spiral elliptical tube and flows out from the upper part.

[0012] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the horizontal distance between adjacent elliptical cross sections with equal rotation angles during the rotation and twisting process of the spiral elliptical tube is the minor axis b; after the spiral elliptical tube is made into a spiral coil, the pitch of adjacent coils is the pitch B; and the multi-head parallel configuration of the coils is adapted to the type of heat exchange fluid and heat load.

[0013] In addition to the aspects described above and any possible implementation, a further implementation is provided in which a cold fluid flows inside the spiral elliptical tube and a hot fluid flows outside the spiral elliptical tube; the upper inlet of the cold fluid is opposite to the upper outlet of the hot fluid, and the lower outlet of the cold fluid is opposite to the lower inlet of the hot fluid; a multi-layer coil enables the cross-flow of the cold fluid and the hot fluid; after the pitch B is adjusted, the configuration of each inlet and outlet completes the multi-head parallel connection.

[0014] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the spiral elliptical coils are arranged in multiple layers to form cold fluid channels and hot fluid channels; the cold fluid and hot fluid enter the multi-layer coiled tube counter-current heat exchange structure tangentially; cross-countercurrent heat exchange occurs simultaneously inside and outside the spiral elliptical tubes; the number of parallel multi-head coils n is determined according to the pitch B.

[0015] In addition to the aspects described above and any possible implementation, a multi-layer coiled heat exchange method based on a spiral elliptical tube is further provided. The multi-layer coiled heat exchange method based on a spiral elliptical tube is implemented through the aforementioned multi-layer coiled heat exchange structure based on a spiral elliptical tube. The multi-layer coiled heat exchange method based on a spiral elliptical tube achieves cross-counterflow heat exchange between cold fluid and hot fluid through the special cross-sectional design and multi-layer coiled arrangement of the spiral elliptical tube. The spiral elliptical tube is a heat exchange pipe with an elliptical cross-section. By rotating and twisting along the central axis to form a spiral structure, the cold fluid flows inside the spiral elliptical tube, and the hot fluid flows outside the tube. The two form a counter-flow heat exchange mode to maximize the temperature difference driving the heat exchange process.

[0016] Compared with the prior art, the present invention can achieve the following technical effects: This invention features an ingenious method and structure that eliminates the need for an additional cover plate, simplifying equipment manufacturing and overcoming the obstacles to heat transfer caused by traditional connection methods. On one hand, it solves the problems of low heat transfer coefficients caused by the formation of a stable boundary layer in traditional straight-tube heat exchangers, and the fact that ordinary circular coil heat exchangers only enhance heat transfer on the outer diameter side. On the other hand, it eliminates the weak points in heat transfer caused by welding in traditional tubular heat exchangers. Furthermore, the heat transfer fluid enters the heat exchanger tangentially, resulting in low resistance. The device has a flexible structure, high operability, and is suitable for heat transfer processes within various temperature ranges. Moreover, by combining a spiral elliptical tube with a helical coil structure, it enhances heat transfer while avoiding increased resistance, achieving highly efficient and low-resistance enhanced heat transfer.

[0017] Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a spiral elliptical tube structure provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of a multi-layered coiled enhanced heat transfer structure based on a spiral elliptical tube, provided by an embodiment of the present invention.

[0020] Among them: (a) is a single-head coil structure of a spiral elliptical tube; (b) is a multi-head coil structure of a spiral elliptical tube (n=3). Detailed Implementation

[0021] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0024] The technical solution of the present invention will be described in detail below with reference to specific embodiments, so as to make the purpose, technical solution and advantages of the present invention clearer. The present invention provides a multi-layer coiled heat exchange structure based on a spiral elliptical tube, which aims to achieve a highly efficient counter-current heat exchange effect through a unique tube design and multi-layer coiled arrangement, and is suitable for various heat load scenarios. The following will gradually elaborate on the overall structural design, specific preparation steps, tube characteristics and heat exchange process.

[0025] First, this invention proposes a multi-layered coiled heat exchange structure based on a spiral elliptical tube. Its core lies in achieving counter-current heat exchange between cold and hot fluids through the special cross-sectional design and multi-layered coiling arrangement of the spiral elliptical tube. The spiral elliptical tube is a heat exchange pipe with an elliptical cross-section, which forms a spiral structure by rotating and twisting along its central axis. This design enhances the fluid turbulence effect, thereby improving heat exchange efficiency. In the overall structure, the cold fluid flows inside the spiral elliptical tube, while the hot fluid flows outside, forming a counter-current heat exchange mode to maximize the temperature difference driving the heat exchange process. The fabrication and operation process of this structure will be described in detail below.

[0026] Step S1 involves fabricating a multi-layered coiled tube counter-current heat exchange structure based on a spiral elliptical tube. This structure comprises multiple parallel spiral elliptical tubes. The interior of the spiral elliptical tube serves as a cold fluid channel, with the cold fluid flowing in from the upper inlet and out from the lower outlet. The exterior of the spiral elliptical tube serves as a hot fluid channel, with the hot fluid flowing in from the bottom and out from the top. Specifically, the fabrication of the spiral elliptical tube first requires selecting a suitable elliptical cross-section pipe material, such as stainless steel or copper alloy, to ensure heat exchange performance and corrosion resistance. Subsequently, the elliptical cross-section pipe is rotated and twisted at a certain angle to form a spiral elliptical tube structure. Multiple spiral elliptical tubes are then coiled in a spiral manner to form a multi-layered structure. The multi-layered coiling design significantly increases the heat exchange area, while the counter-current configuration of the cold and hot fluids fully utilizes the temperature difference, improving heat exchange efficiency.

[0027] In one embodiment, the coiling process of the spiral elliptical tubes can be adjusted according to the actual application scenario. For example, in an industrial boiler heat exchange system, the number of coil layers can be set to 3 to 5 layers, with each layer containing 2 to 4 parallel spiral elliptical tubes. The cold fluid inlet is located at the top of the uppermost coil, and a flow divider evenly distributes the cold fluid to each spiral elliptical tube, flowing through a spiral path and exiting from the bottom outlet of the lowermost coil. The hot fluid enters from the bottom through the outer shell, flows upward along the gaps between the coils, and finally exits from the top. This design ensures that the cold and hot fluids maintain counter-current flow throughout the heat exchange process, forming an efficient heat transfer path.

[0028] Furthermore, the unique cross-sectional design of the spiral elliptical tube is a major innovation of this invention. Compared to traditional circular cross-section pipes, the elliptical cross-section, after rotation and twisting, significantly enhances the secondary flow effect of the fluid, meaning that additional eddies and disturbances are generated when the fluid flows inside the tube. This disturbance effectively disrupts the fluid boundary layer, reduces thermal resistance, and thus improves heat transfer efficiency. When fabricating the multi-layer coiled structure, it is necessary to ensure that the rotation angle and coiling radius of each spiral elliptical tube are consistent to avoid uneven fluid distribution leading to a decrease in heat transfer efficiency. For example, in a chemical heat exchanger, the rotation angle of the spiral elliptical tube can be set to 90 degrees per meter of pipe, and the coiling radius can be controlled at around 0.5 meters to adapt to space constraints while ensuring the stability of fluid flow.

[0029] Step S2 involves cross-current counter-current heat exchange between the cold and hot fluids in the spiral elliptical multilayer coil. The spiral elliptical coil is formed by rotating heat exchange pipes with an elliptical cross-section at a certain angle. Specifically, cross-current counter-current heat exchange means that the cold and hot fluids form intersecting flow paths in space while maintaining opposite flow directions. The cold fluid enters the spiral elliptical coil from the top and flows downwards along a spiral path, while the hot fluid enters from the bottom and flows upwards along the coil gaps. The two fluids form multiple cross-contacts during the heat exchange process. This design not only fully utilizes the temperature difference but also enhances fluid mixing through the special shape of the spiral elliptical coil, further improving heat exchange efficiency.

[0030] In one possible implementation, achieving cross-current counter-current heat exchange requires optimizing the arrangement of the spiral elliptical tubes. For example, in a condenser device, each layer of the multi-layer coil can be arranged with a specific pitch, determined by the type and flow rate of the heat exchange fluid. When the cold fluid flows inside the tubes, the changing cross-section of the spiral elliptical tubes generates periodic flow channel contraction and expansion effects, which promote turbulence and enhance heat transfer. When the hot fluid flows outside the tubes, it is similarly affected by the coil arrangement, forming a complex flow path, thus achieving efficient heat exchange with the cold fluid. Such a design can significantly improve heat exchange performance within a limited space, making it particularly suitable for space-constrained industrial scenarios.

[0031] It should be noted that the rotation angle and cross-sectional parameters of the elliptical tube have a significant impact on heat transfer efficiency. During the fabrication process, the ratio of the major and minor axes of the elliptical cross-section, as well as the rotation angle, can be adjusted according to heat transfer requirements. For example, in high-temperature and high-pressure heat transfer environments, an elliptical cross-section with a larger ratio of major to minor axes can be selected to enhance fluid turbulence, while setting the rotation angle to 120 degrees per meter of pipe further increases turbulence intensity. In low-temperature and low-pressure environments, the ratio of major to minor axes can be appropriately reduced, and the rotation angle can be set to 60 degrees per meter of pipe to reduce fluid resistance and energy consumption. This flexible design approach can adapt to different operating conditions, ensuring the versatility and high efficiency of the heat transfer structure.

[0032] Furthermore, the design of cross-counterflow heat exchange also requires consideration of the fluid inlet and outlet configuration. In a multi-layer coil structure, the inlet and outlet of the cold fluid need to be positioned opposite to the inlet and outlet of the hot fluid to ensure the effectiveness of counter-current heat exchange. For example, in a heat recovery system, the cold fluid inlet is located on the left side of the top of the coil, and the outlet is located on the right side of the bottom, while the hot fluid inlet is located on the left side of the bottom, and the outlet is located on the right side of the top. This diagonal configuration allows the cold and hot fluids to form a continuous counter-current flow throughout the heat exchange path, maximizing the temperature difference-driven heat exchange efficiency while avoiding fluid short-circuiting.

[0033] Step S21: Adjust the pitch between the multi-layer coils according to the type of heat exchange fluid and heat load, thereby adjusting the number of multi-head parallel spiral elliptical tubes. Pitch refers to the vertical distance between two adjacent coil layers, and its size directly affects the heat exchange area and fluid flow resistance. In practical applications, pitch adjustment needs to comprehensively consider the physical properties of the heat exchange fluid, such as density, viscosity, and specific heat capacity, as well as the system's heat load requirements. For example, for high-viscosity fluids, the pitch can be appropriately increased to reduce flow resistance; while for low-viscosity fluids, the pitch can be decreased to increase the heat exchange area and the number of coils.

[0034] In one embodiment, the screw pitch adjustment can be customized according to specific industrial scenarios. For example, in a petrochemical heat exchanger where the heat exchange fluid is high-viscosity crude oil with a high heat load, the screw pitch can be set to 0.3 meters and the number of parallel spiral elliptical tubes to 6 to ensure sufficient heat exchange area while avoiding excessive fluid flow resistance. In a food processing equipment where the heat exchange fluid is a low-temperature aqueous solution with a lower heat load, the screw pitch can be set to 0.15 meters and the number of parallel spiral elliptical tubes to 3 to reduce equipment size and manufacturing costs. In this way, the adjustment of the screw pitch and the number of coils can flexibly adapt to the needs of different application scenarios.

[0035] Step S22: The pitch is equal to the number of spiral elliptical tubes multiplied by the long side diameter of the elliptical tube. Specifically, the pitch needs to be determined by considering the number of parallel spiral elliptical tubes and the long side dimension of the elliptical cross-section to ensure the uniformity of the coil arrangement and the stability of the heat exchange effect. For example, if there are 4 parallel spiral elliptical tubes and the long side diameter of the elliptical tube is 0.05 meters, then the pitch should be set to 0.2 meters. This design ensures sufficient clearance between adjacent coils, facilitating the flow of hot fluid outside the tubes, while avoiding a decrease in heat exchange efficiency caused by overly dense coils.

[0036] In one possible implementation, the pitch calculation can also consider the balance between equipment space constraints and heat exchange performance. For example, in a compact heat exchanger where the equipment height is limited and cannot accommodate an excessively large pitch, a smaller long-side diameter of the elliptical tube, such as 0.03 meters, can be selected, and the number of parallel spiral elliptical tubes can be set to 5, thereby controlling the pitch within 0.15 meters to meet the equipment size requirements. In contrast, in industrial heat exchange systems with ample space, a larger long-side diameter of the elliptical tube, such as 0.08 meters, can be selected, and the number of parallel spiral elliptical tubes can be set to 6, with a pitch of 0.48 meters, to increase the heat exchange area and improve heat exchange efficiency.

[0037] Step S23: The multi-head parallel spiral elliptical coils are arranged sequentially from top to bottom, with each cold fluid configured with a corresponding inlet and outlet. Specifically, the arrangement of the multi-layer coils needs to ensure that each spiral elliptical tube can independently complete the heat exchange process of the cold fluid; therefore, each tube must be configured with an independent inlet and outlet. The inlet is located at the upper part of the coil, and the outlet is located at the lower part of the coil, to ensure that the cold fluid flows from top to bottom, forming a counter-current heat exchange mode with the hot fluid. The top-down arrangement also utilizes gravity to assist the flow of the cold fluid within the tubes, reducing pumping energy consumption.

[0038] In one embodiment, the arrangement of the multi-head parallel spiral elliptical coils can be optimized according to the flow rate requirements of the heat exchange fluid. For example, in a large heat exchanger, there are a total of 8 parallel spiral elliptical coils, arranged in 4 layers, with 2 coils in each layer. The inlet of each coil is connected to the main inlet pipe through a flow divider to ensure that the cold fluid is evenly distributed to each coil; the outlet is connected to the main outlet pipe through a flow combiner to facilitate the centralized discharge of the cold fluid. This arrangement can effectively avoid the problem of uneven fluid distribution, and at the same time, the multi-layer design increases the heat exchange area and improves the overall heat exchange performance.

[0039] In step S24, the cold fluid enters the spiral elliptical tube through the corresponding inlet and flows out through the corresponding outlet, while the hot fluid enters the spiral elliptical tube from the bottom and flows out from the top. Specifically, after entering the spiral elliptical tube through the inlet, the cold fluid flows downward along a spiral path, exchanging heat with the hot fluid outside the tube, and finally flows out from the bottom outlet. The hot fluid enters from the bottom through the outer shell, flows upward along the gap between the coils, forming a counter-current heat exchange with the cold fluid inside the tube, and finally flows out from the top. This fluid path design ensures that the cold and hot fluids maintain a counter-current flow state throughout the heat exchange process, making full use of the temperature difference to drive the heat exchange process.

[0040] In one possible implementation, the configuration of the fluid inlet and outlet can be adjusted according to the equipment's operating conditions. For example, in a high-temperature heat exchange system, the cold fluid is cooling water, and the hot fluid is high-temperature steam. To prevent steam condensation and accumulation at the bottom of the equipment, an additional drainage device can be installed at the hot fluid outlet to ensure timely drainage of condensate. Simultaneously, a flow regulating valve can be installed at the cold fluid inlet to dynamically adjust the cooling water flow rate according to changes in heat load, ensuring the stability of the heat exchange effect. This design can effectively cope with heat exchange requirements under complex operating conditions, ensuring long-term stable operation of the equipment.

[0041] Step S31: The major and minor axes of the elliptical tube cross-section satisfy the condition that the major axis is greater than the minor axis, and the horizontal distance between two adjacent elliptical cross-sections with equal rotation angles is equal to the minor axis. Specifically, the cross-sectional design of the elliptical tube is one of its core features, and the ratio of the major and minor axes of the elliptical cross-section directly affects the fluid flow characteristics and heat transfer performance. A design where the major axis is greater than the minor axis can create periodic flow channel changes after rotation and twisting, promoting fluid turbulence. The horizontal distance between two adjacent elliptical cross-sections with equal rotation angles is equal to the minor axis, ensuring the uniformity of rotation and twisting and avoiding uneven fluid distribution caused by excessively narrow or wide local flow channels.

[0042] In one embodiment, the parameters of the elliptical tube cross-section can be optimized according to heat exchange requirements. For example, in an industrial condenser, the major axis of the elliptical cross-section is set to 0.06 meters, and the minor axis is set to 0.03 meters, with a ratio of 2:1, to enhance the secondary flow effect of the fluid within the tube. The horizontal distance between two adjacent elliptical cross-sections with equal rotation angles is 0.03 meters, consistent with the minor axis, ensuring uniformity of rotational torsion. This design can reduce fluid flow resistance and energy consumption while ensuring heat exchange efficiency. In another cryogenic heat exchange device, the major axis can be set to 0.05 meters, and the minor axis to 0.02 meters, with a ratio adjusted to 2.5:1, to accommodate lower heat load requirements while maintaining the rationality of the flow channel design.

[0043] Furthermore, the selection of elliptical cross-section parameters also needs to consider the processing difficulty and cost of the material. For example, when using stainless steel to prepare a spiral elliptical tube, the ratio of the major axis to the minor axis should not be too large to avoid material deformation or stress concentration during processing. The ratio is usually controlled between 1.5:1 and 3:1, while ensuring that the horizontal distance between adjacent cross-sections is consistent with the minor axis to guarantee the stability of rotational torsion. This design approach achieves a balance between performance and cost and is suitable for large-scale industrial production.

[0044] Step S32: The elliptical cross-section is rotated and twisted along its center to form a spiral elliptical tube. Specifically, the spiral elliptical tube is fabricated by rotating and twisting the elliptical cross-section pipe along its central axis at a certain angle, creating a spiral structure. This rotational twisting generates additional eddies and disturbances when the fluid flows inside the tube, disrupting the fluid boundary layer, reducing thermal resistance, and thus significantly improving heat transfer efficiency. The angle of rotation and twisting can be adjusted according to heat transfer requirements and fluid characteristics to achieve optimal heat transfer performance.

[0045] In one possible implementation, the rotational torsion angle can be customized according to the application scenario. For example, in a high-temperature heat exchanger, the rotation angle is set to 180 degrees per meter of pipe to enhance fluid turbulence, which is particularly suitable for heat exchange processes involving high-viscosity fluids. In a low-temperature heat exchanger, the rotation angle can be set to 90 degrees per meter of pipe to reduce fluid resistance and accommodate the flow requirements of low-viscosity fluids. The rotational torsion process is typically completed using specialized equipment, such as a pipe rotational molding machine, to ensure that the rotation angle of each pipe section is consistent, avoiding local deformation or uneven flow channels.

[0046] It should be noted that the design of the rotating and tortuous tube also needs to consider the fluid flow stability and heat transfer uniformity. For example, in a certain chemical heat exchange system, the rotation and tortuosity angle of the elliptical tube is set to 120 degrees per meter of pipe, and a guiding device is installed inside the pipe to ensure that the fluid is evenly distributed in the rotating channel, avoiding local overheating or undercooling. This design can effectively improve the overall performance of the heat exchange structure and extend the service life of the equipment.

[0047] Step S33: The elliptical tube is wound clockwise or counterclockwise to form a spiral coil. Specifically, after the elliptical tube is rotated and twisted, it needs to be further coiled into a spiral structure to form a multi-layered coil. The coiling direction can be clockwise or counterclockwise, depending on the spatial layout of the equipment and the configuration of the fluid inlet and outlet. The spiral coil design can significantly increase the heat exchange area, and the multi-layer arrangement achieves a compact structure, making it particularly suitable for space-constrained industrial scenarios.

[0048] In one embodiment, the winding direction of the spiral coil can be selected according to the equipment installation environment. For example, in a vertically installed heat exchanger, the spiral elliptical tube is wound clockwise with a winding radius of 0.4 meters and 5 layers to accommodate equipment height limitations. The cold fluid flows clockwise downwards from the top, forming a counter-current heat exchange with the hot fluid. In another horizontally installed heat exchanger, the spiral elliptical tube is wound counter-clockwise with a winding radius of 0.6 meters and 3 layers to accommodate equipment width limitations. This flexible winding method can adapt to different installation environments, ensuring the applicability of the heat exchange structure.

[0049] Furthermore, the winding process of the spiral coil also needs to consider the spacing and uniformity of the coils. For example, in a large heat exchange system, the spiral elliptical tubes are wound into a 5-layer spiral structure, with a vertical spacing of 0.2 meters between each layer, and the winding direction is clockwise to ensure that short-circuiting does not occur when the hot fluid flows between the tubes. During the winding process, special clamps can be used to fix the position of the coils to prevent deformation or misalignment, thereby ensuring the stability of the heat exchange effect.

[0050] Step S41: If it is a single-head coil, it is prepared by spiraling an elliptical tube, with one inlet and one outlet for the cold fluid. Specifically, the single-head coil design is suitable for scenarios with low heat exchange loads or limited equipment space. In this case, only one elliptical tube is used, prepared into a multi-layer structure by spiral winding. The cold fluid enters through a single inlet located at the top of the coil, flows downward along the spiral path, and finally flows out from a single outlet located at the bottom of the coil. This design simplifies the fluid distribution system, reduces manufacturing and installation costs, while still achieving a certain improvement in heat exchange efficiency through the special cross-section of the elliptical tube.

[0051] In one embodiment, a single-head coil can be applied to small heat exchange equipment. For example, in a household water heater system, the single-head coil consists of a single spiral elliptical tube wound into three layers, with a winding radius of 0.3 meters and an interlayer pitch of 0.15 meters. The cold fluid, tap water, enters from the inlet at the top of the coil, flows through a spiral path, and exits from the outlet at the bottom. The hot fluid, high-temperature flue gas, enters from the bottom of the equipment, flows upward along the gaps between the coils, and finally exits from the top. This design enables effective heat transfer within a limited space, meeting the household hot water needs while reducing equipment size and material usage.

[0052] Step S42: If it is a multi-head coil, it is prepared by multiple spiral elliptical tubes connected in parallel, with multiple inlets and outlets for the cold fluid. Specifically, the multi-head coil design is suitable for scenarios with high heat exchange loads or requiring a larger heat exchange area. In this case, multiple spiral elliptical tubes are arranged in parallel, each tube being spirally wound into a multi-layer structure. The cold fluid enters each spiral elliptical tube through multiple inlets, flows downward along the spiral path, and finally flows out from multiple outlets. This design can significantly increase the heat exchange area and improve heat exchange efficiency, while reducing the fluid resistance of a single tube through parallel connection.

[0053] In one possible implementation, the number of parallel tubes in a multi-head coil can be adjusted according to actual needs. For example, in an industrial condenser, a multi-head coil is constructed using six spiral elliptical tubes connected in parallel, wound into a four-layer structure with a pitch of 0.2 meters for each layer. The cold fluid is cooling water, which is evenly distributed to each tube through six inlets located at the top of the coil, flows through a spiral path, and exits from six outlets at the bottom. The hot fluid is high-temperature steam, which enters from the bottom of the equipment, flows upward along the gaps between the coils, and finally exits from the top. This multi-head parallel design can effectively cope with high heat load requirements and ensure the stability of the heat exchange process.

[0054] Furthermore, the inlet and outlet configuration of multi-head coils requires the use of diversion and manifold devices to achieve uniform fluid distribution and centralized discharge. For example, in a chemical heat exchange system, eight spiral elliptical tubes are connected in parallel to form a multi-head coil, coiled into a five-layer structure. A diversion device is installed at the cold fluid inlet to evenly distribute the total flow rate to the eight inlets, ensuring consistent fluid flow in each tube; a manifold device is installed at the outlet to centrally discharge the cold fluid flowing from each tube. This design avoids the problem of localized heat exchange efficiency reduction caused by uneven fluid distribution, while also facilitating equipment installation and maintenance.

[0055] Step S43: Increase the screw pitch accordingly and arrange the heat exchange tubes sequentially from top to bottom. Specifically, the increase in screw pitch is closely related to the number of multi-head parallel spiral elliptical tubes. The screw pitch directly affects the interlayer gap of the coils and the flow resistance of the hot fluid outside the tubes. In multi-head coil design, the screw pitch is usually determined based on the number of parallel tubes and the size of the elliptical tubes to ensure that when the heat exchange tubes are arranged sequentially from top to bottom, the heat exchange area is guaranteed while avoiding obstruction of hot fluid flow caused by excessively dense tube spacing.

[0056] In one embodiment, the pitch can be optimized based on the equipment's operating conditions. For example, in a large heat exchanger, ten spiral elliptical tubes are connected in parallel to form a multi-head coil. The long side of the elliptical tube is 0.06 meters, and the pitch is set to 0.6 meters. The coils are arranged in five layers from top to bottom. This pitch design ensures smooth flow of the heat transfer fluid between the tubes while increasing the heat exchange area and improving overall heat exchange performance. In another compact heat exchanger, four spiral elliptical tubes are connected in parallel. The long side of the elliptical tube is 0.04 meters, and the pitch is set to 0.16 meters. The coils are arranged in three layers to accommodate space constraints.

[0057] In step S44, the hot fluid flows into the space between the spiral elliptical tubes from the bottom and out from the top of the coils, achieving cross-current counter-current heat exchange. Specifically, the hot fluid enters through the inlet at the bottom of the equipment, flows upward along the gaps between the multiple layers of coils, forming a counter-current flow path with the cold fluid inside the tubes, and finally flows out from the outlet at the top of the coils. This counter-current heat exchange mode can fully utilize the temperature difference between the cold and hot fluids to drive heat transfer, and further enhances the heat exchange effect through the multi-layer arrangement of the spiral elliptical tubes and the cross-current flow path.

[0058] In one possible implementation, the flow path of the hot fluid can be optimized based on the equipment structure. For example, in a heat exchange system of an industrial boiler, the hot fluid is high-temperature flue gas, which enters from the bottom of the equipment through a specially designed flow guide device to ensure that the flue gas is evenly distributed in the gaps between each layer of coils, flows upward along a spiral path, and finally exits from the top outlet. The cold fluid is cooling water, which flows from top to bottom in the spiral elliptical tube, forming a cross-current counter-current heat exchange with the flue gas. This design can effectively recover waste heat from the flue gas and improve energy utilization efficiency.

[0059] In step S51, the cold fluid flows into the spiral elliptical tube from the upper inlet of the coil. Specifically, the design of the cold fluid channel is an important component of the multi-layer coiled heat exchange structure. The cold fluid enters the spiral elliptical tube through an inlet located at the upper part of the coil, typically positioned at the top layer of the coil to allow gravity to assist the fluid's downward flow. A flow regulating device can be installed at the inlet to dynamically adjust the cold fluid flow rate according to heat exchange requirements, ensuring the stability of the heat exchange process.

[0060] In one embodiment, the design of the cold fluid inlet can be adjusted according to the application scenario. For example, in a chemical condenser, the cold fluid is cooling water, which enters through multiple inlets at the top of the coil. Each spiral elliptical tube inlet is equipped with a flow regulating valve to adjust the cooling water flow in real time according to changes in heat load, thereby avoiding overcooling or overheating. The inlet pipes are made of corrosion-resistant materials to ensure long-term operational reliability. This design can flexibly meet the heat exchange requirements under different operating conditions.

[0061] In step S52, as the cold fluid flows along the spiral elliptical tube, the cross-section of the flow channel locally contracts. Specifically, after the elliptical cross-section of the spiral elliptical tube is rotated and twisted, it forms a periodic flow channel change, that is, the flow channel contracts locally at some locations and expands locally at other locations. This cross-section contraction effect can significantly enhance the turbulence of the fluid, disrupt the fluid boundary layer, reduce thermal resistance, and thus improve the heat transfer efficiency between the cold fluid inside the tube and the hot fluid outside the tube.

[0062] In one possible implementation, the utilization of the cross-sectional contraction effect can be optimized based on fluid characteristics. For example, in a high-temperature heat exchanger, the cold fluid is a high-viscosity liquid. The cross-section of the spiral elliptical tube is designed with a major-to-minor axis ratio of 2.5:1, and the rotation angle is 120 degrees per meter of pipe to enhance the cross-sectional contraction effect, promote fluid turbulence, and improve heat exchange efficiency. In another low-temperature heat exchanger, the cold fluid is a low-viscosity liquid, and the cross-section is designed with a major-to-minor axis ratio of 1.8:1, and the rotation angle is 90 degrees per meter of pipe to balance heat exchange efficiency and fluid resistance. This flexible design approach can adapt to different fluid characteristics and heat exchange requirements.

[0063] Furthermore, the realization of the cross-sectional contraction effect also requires consideration of the machining precision of the spiral elliptical tube. For example, during the fabrication of the spiral elliptical tube, precision equipment is needed to control the rotation angle and torsion uniformity of the cross-section, avoiding uneven fluid distribution caused by excessively large or small local cross-sectional changes. In a certain industrial heat exchange system, the cross-sectional contraction position of the spiral elliptical tube was optimized through computer simulation to ensure that the flow channel change cycle matches the fluid velocity, thereby achieving uniform heat transfer throughout the entire heat exchange path.

[0064] In step S53, the cold fluid flows out from the lower outlet of the coil. Specifically, after completing the heat exchange process inside the spiral elliptical tube, the cold fluid flows out through the outlet located at the bottom of the coil. The outlet is usually located at the bottom of the coil so that the cold fluid can flow out naturally under gravity, reducing pumping energy consumption. A manifold can be installed at the outlet to collect and discharge the fluid from each outlet of the multi-head coil for subsequent processing or recycling.

[0065] In one embodiment, the design of the cold fluid outlet can be adjusted according to the equipment layout. For example, in a heat recovery device, the cold fluid is cooling water, which flows out through multiple outlets at the bottom of the coil. Each outlet is connected to a main outlet via a manifold to ensure centralized fluid discharge. The outlet pipe is designed to slope downwards to avoid blockage caused by fluid accumulation inside the pipe. This design improves the smoothness of fluid discharge and ensures the long-term stable operation of the heat exchange system.

[0066] In step S54, the hot fluid flows from the bottom into the spiral elliptical tube and out from the top in the hot fluid channel. Specifically, the hot fluid channel is located outside the spiral elliptical tube and is typically formed by the equipment housing and the coil gaps. The hot fluid enters through the inlet at the bottom of the equipment, flows upward along the coil gaps, forms a counter-current heat exchange with the cold fluid inside the tube, and finally flows out from the outlet at the top of the equipment. This design can fully utilize the temperature difference to drive heat transfer, while increasing the heat exchange area through the multi-layer coil structure.

[0067] In one possible implementation, the design of the hot fluid channel can be optimized based on the characteristics of the hot fluid. For example, in an industrial boiler system where the hot fluid is high-temperature flue gas, a baffle plate is installed at the bottom inlet of the equipment to ensure that the flue gas is evenly distributed into the gaps between each layer of coils, avoiding localized overheating. An exhaust device is installed at the upper outlet to promptly remove condensate or impurities from the flue gas, ensuring unobstructed flow. This design can effectively improve the heat exchange efficiency of the hot fluid channel and extend the service life of the equipment.

[0068] Step S61: The elliptical cross-section has a major axis and a minor axis. Specifically, the cross-sectional design of the spiral elliptical tube is one of its core features. The ratio of the major axis to the minor axis of the elliptical cross-section directly affects the fluid flow characteristics and heat transfer performance. A design where the major axis is larger than the minor axis can create periodic flow channel changes after rotation and twisting, promoting fluid turbulence and enhancing the heat transfer effect. The specific dimensions of the major and minor axes can be adjusted according to heat transfer requirements and equipment space to achieve optimal performance.

[0069] In one embodiment, the parameters of the elliptical cross-section can be customized according to the application scenario. For example, in a high-temperature heat exchanger, the major axis of the elliptical cross-section is set to 0.07 meters, and the minor axis is set to 0.03 meters, with a ratio of 2.3 to 1, to enhance the turbulence of the fluid within the pipe and improve heat exchange efficiency. In another low-temperature heat exchanger, the major axis is set to 0.05 meters, and the minor axis is set to 0.025 meters, with a ratio of 2:1, to balance heat exchange performance and fluid resistance. This flexible parameter design can adapt to different operating conditions.

[0070] In step S62, during the rotational twisting process, the horizontal distance between adjacent elliptical cross-sections with equal rotation angles is the minor axis. Specifically, the rotational twisting process of the elliptical tube needs to ensure that the horizontal distance between adjacent cross-sections is consistent with the minor axis dimension to guarantee the uniformity of the flow channel change. This design can avoid the problem of uneven fluid distribution caused by excessively narrow or wide local flow channels, ensuring the stability of fluid flow within the tube.

[0071] In one possible implementation, the uniformity of the rotational twist can be controlled through processing equipment. For example, in the fabrication of an industrial heat exchanger tube, the minor axis of the elliptical cross-section is 0.03 meters, the horizontal distance between adjacent cross-sections is also controlled at 0.03 meters, and the rotation angle is 120 degrees per meter of pipe. Precision machining equipment ensures that the rotation angle and horizontal distance of each cross-section are consistent, avoiding localized deformation of the flow channel. This design improves the heat transfer uniformity of the elliptical tube and ensures overall performance.

[0072] Step S63: After the elliptical tube is formed into a spiral coil, the pitch between adjacent coils is the specified pitch. Specifically, after the elliptical tube is rotated and twisted, it needs to be further coiled into a spiral coil structure, and the vertical distance between adjacent coils is the pitch. The pitch directly affects the heat exchange area and the flow resistance of the hot fluid outside the tube. It needs to be rationally designed according to the number of parallel tubes and the equipment space to ensure a balance between heat exchange effect and fluid flow.

[0073] In one embodiment, the pitch design can be optimized based on the equipment's operating conditions. For example, in a large heat exchanger, the spiral elliptical tubes are wound into a six-layer helical structure with a pitch of 0.3 meters to ensure smooth flow of the hot fluid between the tubes while increasing the heat exchange area. In another compact heat exchanger, the pitch is set to 0.15 meters, and the coils are arranged in four layers to accommodate equipment height limitations. This flexible pitch design can meet the needs of different application scenarios.

[0074] Step S64: The multi-head parallel configuration adapts to the type of heat exchange fluid and the heat load. Specifically, the design of the multi-head parallel spiral elliptical tube needs to be adjusted according to the physical properties of the heat exchange fluid and the system's heat load requirements. Different types of fluids have significant differences in density, viscosity, and specific heat capacity, and the heat load will also affect the required heat exchange area. Therefore, the number of parallel tubes and the number of coil layers need to be comprehensively considered to achieve the best heat exchange effect.

[0075] In one possible implementation, a multi-head parallel configuration can be customized according to specific operating conditions. For example, in a petrochemical heat exchanger where the heat exchange fluid is high-viscosity crude oil with a high heat load, eight spiral elliptical tubes are connected in parallel, coiled into a five-layer structure with a pitch of 0.4 meters to ensure sufficient heat exchange area while reducing fluid resistance. In a food processing equipment where the heat exchange fluid is a low-temperature aqueous solution with a lower heat load, three spiral elliptical tubes are connected in parallel, coiled into a three-layer structure with a pitch of 0.15 meters to reduce equipment volume. This design approach can flexibly adapt to different fluid types and heat load requirements.

[0076] In step S71, the cold fluid flows inside the spiral elliptical tube, while the hot fluid flows outside. Specifically, cross-current counter-current heat exchange is one of the key features of this invention. The cold and hot fluids flow inside and outside the spiral elliptical tube, respectively, forming counter-current flow paths. The cold fluid flows from top to bottom inside the tube, while the hot fluid flows from bottom to top outside, exchanging heat through the tube wall. This design fully utilizes the temperature difference to drive the heat exchange process, improving heat exchange efficiency.

[0077] In one embodiment, the fluid flow path design can be optimized based on the equipment structure. For example, in an industrial condenser, the cold fluid is cooling water, flowing from top to bottom inside a spiral elliptical tube, while the hot fluid is high-temperature steam, flowing from bottom to top outside the tube. The cross-section of the spiral elliptical tube is designed with a major axis to minor axis ratio of 2:1, and a rotation angle of 120 degrees per meter of pipe to enhance fluid turbulence and improve heat exchange efficiency. This design can effectively cope with high heat load demands and ensure the stability of the heat exchange process.

[0078] In step S72, the upper inlet of the cold fluid is opposite to the upper outlet of the hot fluid, and the lower outlet of the cold fluid is opposite to the lower inlet of the hot fluid. Specifically, the relative configuration of the fluid inlets and outlets is key to achieving counter-current heat exchange. The cold fluid inlet is located at the upper part of the coil, opposite to the hot fluid outlet; the cold fluid outlet is located at the lower part of the coil, opposite to the hot fluid inlet. This diagonal configuration ensures that the cold and hot fluids form a continuous counter-current flow throughout the heat exchange path, maximizing the heat exchange efficiency driven by the temperature difference.

[0079] In one possible implementation, the configuration of the inlet and outlet can be adjusted according to the equipment layout. For example, in a heat recovery system, the cold fluid inlet is located on the left side of the top of the coil, and the hot fluid outlet is located on the right side of the top; the cold fluid outlet is located on the right side of the bottom, and the hot fluid inlet is located on the left side of the bottom. This diagonal configuration avoids fluid short-circuiting, ensuring that the cold and hot fluids always flow in opposite directions during heat exchange, thus improving heat transfer efficiency.

[0080] Step S73: The multi-layer coil enables cross-flow of cold and hot fluids. Specifically, the multi-layer coil design allows the cold and hot fluids to form cross-flow paths in space. The cold fluid flows downward along a spiral path inside the elliptical tube, while the hot fluid flows upward along the gaps between the coils outside the tube, resulting in multiple cross-contacts during heat exchange. This cross-flow enhances fluid mixing and further improves heat exchange efficiency.

[0081] In one embodiment, the cross-flow design can be optimized based on the number of coil layers. For example, in a large heat exchanger, spiral elliptical tubes are wound into a 6-layer structure, with each layer containing 4 parallel tubes and a pitch of 0.3 meters. The cold fluid flows from top to bottom inside the tubes, while the hot fluid flows from bottom to top outside the tubes, creating cross-contact at each coil layer, increasing heat exchange opportunities. This design can significantly improve heat exchange performance within a limited space and is particularly suitable for high heat load scenarios.

[0082] Step S74: After adjusting the screw pitch, the inlet and outlet configurations are completed, resulting in multiple parallel connections. Specifically, the screw pitch adjustment directly affects the coil arrangement and fluid channel design. After determining the screw pitch, the corresponding inlets and outlets need to be configured according to the number of parallel tubes. Each inlet and outlet must correspond one-to-one with a spiral elliptical tube to ensure that the cold fluid is evenly distributed into each tube and the hot fluid is evenly distributed into the coil gaps, thereby achieving a highly efficient heat exchange process.

[0083] In one possible implementation, the configuration of the inlet and outlet can be adjusted according to the screw pitch. For example, in an industrial heat exchange system, the pitch is adjusted to 0.25 meters, using five parallel spiral elliptical tubes coiled into a four-layer structure. Cold fluid enters through the five inlets at the top and exits through the five outlets at the bottom. A flow divider is installed at the inlet, and a flow combiner is installed at the outlet to ensure uniform fluid distribution. Hot fluid enters through the bottom inlet and exits through the top outlet. A flow guide is installed at the inlet to ensure uniform hot fluid distribution. This design improves the uniformity of fluid distribution and ensures effective heat exchange.

[0084] Step S81: The multi-layered arrangement of the spiral elliptical coils forms cold fluid channels and hot fluid channels. Specifically, the multi-layered coiled heat exchange structure forms independent cold fluid channels and hot fluid channels through the multi-layered arrangement of the spiral elliptical coils. The cold fluid channels are located inside the spiral elliptical coils, and the hot fluid channels are located outside the coils; heat exchange occurs between the two through the coil walls. The multi-layered arrangement design significantly increases the heat exchange area and improves heat exchange efficiency.

[0085] In one embodiment, the multi-layer arrangement can be optimized based on available space. For example, in a vertically installed heat exchanger, elliptical coils are arranged in a 5-layer structure with a pitch of 0.2 meters between layers, and each layer contains 3 parallel tubes. Cold fluid flows downwards through a spiral path within the tubes, while hot fluid flows upwards through the gaps between the tubes. This design enables efficient heat exchange within a limited height and adapts to space constraints.

[0086] Step S82: The cold and hot fluids enter the heat exchange structure tangentially. Specifically, the inlet design for the cold and hot fluids can adopt a tangential entry method, that is, the fluids enter the heat exchange structure at a certain angle to enhance the initial turbulence effect of the fluids and improve the heat exchange efficiency. Tangential entry allows the fluids to form a rotating flow when entering the channel, further disrupting the boundary layer and reducing thermal resistance.

[0087] In one possible implementation, the tangential inlet design can be adjusted according to fluid characteristics. For example, in a high-temperature heat exchanger, the cold fluid inlet is designed with a tangential inlet, with the inlet pipe at a 45-degree angle to the top of the coil. This ensures that the cold fluid forms a rotating flow when entering the elliptical tube, enhancing the turbulence effect. The hot fluid inlet is also designed with a tangential inlet, at a 30-degree angle to the bottom of the equipment, ensuring that the hot fluid forms a uniform distribution when entering the coil gap. This design can improve the turbulence of the initial fluid flow and enhance heat transfer performance.

[0088] Step S83: Cross-countercurrent heat exchange occurs simultaneously inside and outside the spiral elliptical tube. Specifically, cross-countercurrent heat exchange is one of the core features of this invention. The cold fluid flows from top to bottom inside the spiral elliptical tube, while the hot fluid flows from bottom to top outside the tube, and the two exchange heat simultaneously on both sides of the tube wall. Through the special cross-section of the spiral elliptical tube and the multi-layer coil design, the fluid forms multiple cross-contacts during the heat exchange process, enhancing the heat transfer effect.

[0089] In one embodiment, the design of cross-counterflow heat exchange can be optimized according to the heat load. For example, in an industrial condenser, spiral elliptical tubes are wound into a 5-layer structure with a pitch of 0.25 meters. The cold fluid is cooling water, which flows from top to bottom inside the tubes, while the hot fluid is high-temperature steam, which flows from bottom to top outside the tubes. The two fluids form cross-flow paths at each layer of the coil. This design can fully utilize the temperature difference to drive heat transfer, while increasing the heat exchange area through the multi-layer structure, thereby improving the overall heat exchange efficiency.

[0090] Step S84: The number of parallel multi-head tubes is determined based on the screw pitch. Specifically, the number of parallel multi-head spiral elliptical tubes is closely related to the screw pitch, which directly affects the interlayer gap and heat exchange area of ​​the coils. After determining the screw pitch, an appropriate number of parallel tubes needs to be selected based on the equipment space and heat load requirements to ensure a balance between heat exchange effect and fluid flow.

[0091] In one possible implementation, the number of parallel tubes can be adjusted according to specific operating conditions. For example, in a large heat exchanger, the pitch is set to 0.3 meters, using six spiral elliptical tubes connected in parallel and coiled into a five-layer structure to ensure sufficient heat exchange area. In another compact heat exchanger, the pitch is set to 0.15 meters, using three spiral elliptical tubes connected in parallel and coiled into a three-layer structure to adapt to space constraints. This design approach can flexibly address different pitches and heat load requirements, ensuring the applicability of the heat exchange structure.

[0092] Example 1: This invention provides a multi-layer coiled enhanced heat transfer method based on a spiral elliptical tube and a high-efficiency, low-resistance heat exchanger structure. The multi-layer coiled tube counter-current heat exchange structure is prepared based on a single spiral elliptical tube. This structure includes multiple parallel spiral elliptical coils. The inside of the spiral elliptical tube is a cold fluid channel, where the cold fluid flows in from the upper inlet and out from the lower outlet. The outside of the spiral elliptical tube is a hot fluid channel, where the hot fluid flows in from the lower part and out from the upper part. The cold and hot fluids in the spiral elliptical multi-layer coils exchange heat in a cross-current counter-current manner. The pitch B between the multi-layer coils can be adjusted according to the type of heat exchange fluid and the heat load, thereby adjusting the number n of the multi-head parallel spiral elliptical tubes to meet different heat exchange requirements. The spiral elliptical tube is formed by rotating a heat exchange pipe with an elliptical cross-section at a certain angle: on the one hand, the cross-section of the spiral elliptical tube gradually contracts locally, and the streamline direction and temperature gradient direction are almost parallel, which can achieve enhanced heat transfer; on the other hand, the spiral elliptical tubes are all ellipses with equal area, so the overall flow velocity inside the tube remains constant, and there is no increase in local resistance, thus achieving low-resistance, high-efficiency heat transfer. The relationship between the major axis *a* and minor axis of the elliptical tube cross-section is *a* = (1.5~2)b; the horizontal distance *d* between two adjacent elliptical cross-sections with equal rotation angles in the twisted elliptical tube is *d* = *b*. The pitch *B* is equal to the number of twisted elliptical tubes *n* multiplied by the diameter *b* of the elliptical tube (long side). The structure of this twisted elliptical tube is as follows: Figure 1 As shown, it is formed by rotating and twisting a straight pipe with an elliptical cross-section around the center of its cross-section. The major axis of the elliptical cross-section is a, the minor axis is b, and the horizontal distance d=b between two adjacent elliptical cross-sections with equal rotation angles. Then, the elliptical tube is wound clockwise or counterclockwise to form a spiral coil, with a pitch B between adjacent coils. If the cold fluid is a gas or the heat load is large, this structure can adjust the pitch B between the multiple coils according to the type of heat exchange fluid and the heat load, thereby adjusting the number n of multi-head parallel elliptical tubes, such as... Figure 2 As shown, this is to meet different heat exchange requirements. Among them, Figure 2 (a) is a single-head coil heat exchange structure made of a spiral elliptical tube, with only one inlet and one outlet for the cold fluid. Figure 2(b) is a spiral elliptical tube multi-head coil heat exchange structure. Here, we take 3 tubes connected in parallel as an example for illustration. The cold fluid has 3 inlets and 3 outlets respectively. If there are n tubes connected in parallel, the pitch B is increased accordingly, and the heat exchange tubes are arranged from top to bottom. The cold fluid is configured with n inlets and n outlets respectively.

[0093] The specific working process of this method and structure is as follows: Cold fluid flows into the spiral elliptical tube from the upper inlet of the coil and flows out from the lower outlet of the coil, while hot fluid flows into the spiral elliptical tube from the lower part and flows out from the upper part of the coil. The cold and hot fluids in the spiral elliptical multilayer coil exchange heat in a cross-current countercurrent manner.

[0094] Inside the spiral elliptical tube, on a microscopic level, the flow channel gradually contracts in cross-section, and the streamline direction is almost parallel to the temperature gradient direction, which can enhance heat transfer. On a macroscopic level, the heat exchange tube cross-section is an ellipse with equal area, and the overall flow velocity inside the tube remains constant, with no increase in local resistance, thus achieving low-resistance and high-efficiency heat transfer.

[0095] The foregoing has provided a detailed description of a multi-layer coiled heat exchange structure and method based on a spiral elliptical tube, as provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0096] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0097] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0098] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0099] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A multi-layer coiled heat exchange structure based on a spiral elliptical tube, characterized in that, The multi-layer coiled heat exchange structure based on a spiral elliptical tube is prepared by using a spiral elliptical tube as the basis to create a multi-layer coiled tube counter-current heat exchange structure. The multi-layer coiled tube counter-current heat exchange structure includes multiple spiral elliptical tubes connected in parallel. The inside of the spiral elliptical tube is a cold fluid channel, inflowing from the upper inlet and outflowing from the lower outlet of the spiral elliptical tube. The outside of the spiral elliptical tube is a hot fluid channel, inflowing from the lower part and outflowing from the upper part. The cold fluid and hot fluid exchange heat in a cross-current counter-current manner. The spiral elliptical tube is formed by rotating a heat exchange pipe with an elliptical cross section at a certain angle.

2. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 1, characterized in that, The multi-layer coiled tube counter-current heat exchange structure adjusts the pitch B between the multi-layer coils according to the type of heat exchange fluid and heat load, thereby adjusting the number n of the multi-head parallel spiral elliptical tubes; the pitch B is equal to the number of spiral elliptical tubes n multiplied by the long side diameter b of the elliptical tube; the multi-head parallel spiral elliptical coils are arranged sequentially from top to bottom, with each cold fluid configured with a corresponding inlet and outlet; the cold fluid enters the spiral elliptical tube from the corresponding inlet and flows out from the corresponding outlet, while the hot fluid enters the space between the spiral elliptical tubes from the bottom and flows out from the top, wherein B, b, and n are all greater than 0 and n is an integer.

3. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 1, characterized in that, The major axis of the elliptical tube is a, and the minor axis is b, and a is greater than b. The horizontal distance d between two adjacent elliptical sections with equal rotation angles is equal to the minor axis b. The elliptical section is rotated and twisted along the center of the section to form the elliptical tube. The elliptical tube is wound in a clockwise or counterclockwise direction to form a spiral coil. The multi-head parallel spiral coils constitute the multi-layer coiled tube counter-current heat exchange structure.

4. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 2, characterized in that, If the multi-head parallel spiral elliptical coil is a single-head coil, it is prepared by spiraling a single spiral elliptical tube, with one inlet and one outlet for the cold fluid.

5. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 2, characterized in that, If the multi-head parallel spiral elliptical coil is a multi-head coil, it is prepared by n spiral elliptical tubes connected in parallel, with n inlets and n outlets for the cold fluid; the pitch B is increased accordingly, and the heat exchange tubes are arranged sequentially from top to bottom; the hot fluid flows into the spiral elliptical tubes from the bottom and flows out from the top of the coil, realizing the cross-counterflow heat exchange.

6. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 1, characterized in that, In the cold fluid channel, cold fluid flows into the spiral elliptical tube from the upper inlet of the coil; as the cold fluid flows along the spiral elliptical tube, the cross-section of the flow channel contracts locally; the cold fluid flows out from the lower outlet of the coil; in the hot fluid channel, hot fluid flows into the spiral elliptical tube from the lower part and flows out from the upper part.

7. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 3, characterized in that, During the rotation and twisting process of the spiral elliptical tube, the horizontal distance between adjacent elliptical cross sections with equal rotation angles is the minor axis b; after the spiral elliptical tube is made into a spiral coil, the pitch of adjacent coils is the pitch B; the multi-head parallel configuration of the coils is adapted to the type of heat exchange fluid and heat load.

8. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 5, characterized in that, Cold fluid flows inside the spiral elliptical tube, and hot fluid flows outside the spiral elliptical tube; the upper inlet of the cold fluid is opposite to the upper outlet of the hot fluid, and the lower outlet of the cold fluid is opposite to the lower inlet of the hot fluid; the multi-layer coil enables the cross-flow of the cold fluid and the hot fluid; After adjusting pitch B, the various inlet and outlet configurations are completed with multiple heads connected in parallel.

9. The multi-layer coiled heat exchange structure based on a spiral elliptical tube according to claim 1, characterized in that, The spiral elliptical coils are arranged in multiple layers to form cold fluid channels and hot fluid channels; the cold fluid and hot fluid enter the multi-layer coiled tube counter-current heat exchange structure tangentially; cross counter-current heat exchange occurs simultaneously inside and outside the spiral elliptical tubes; the number of parallel multi-head coils n is determined according to the pitch B.

10. A multi-layer coiled heat transfer method based on a spiral elliptical tube, characterized in that, The multi-layer coiled heat exchange method based on a spiral elliptical tube is implemented by the multi-layer coiled heat exchange structure based on a spiral elliptical tube as described in any one of claims 1-9. The multi-layer coiled heat exchange method based on a spiral elliptical tube achieves cross-current countercurrent heat exchange between cold fluid and hot fluid through the special cross-section design and multi-layer coiled arrangement of the spiral elliptical tube. The spiral elliptical tube is a heat exchange pipe with an elliptical cross-section. It forms a spiral structure by rotating and twisting along the central axis. The cold fluid flows inside the spiral elliptical tube, and the hot fluid flows outside the tube. The two form a countercurrent heat exchange mode to maximize the temperature difference to drive the heat exchange process.

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