A coaxial conjugate anisotropic enhanced heat transfer tubular element and heat exchange device

Abstract

This invention provides a coaxial, conjugate, anisotropic enhanced heat exchange tubular element and heat exchange device, comprising an integrally formed base tube, outer fins, and inner fins. The surface of the inner fins is provided with a corrugated undulating structure. The base tube, outer fins, and inner fins are made of the same material, and there is no contact thermal resistance between the base tube and the inner and outer fins. The inner fins consist of multiple sets of longitudinal fins parallel to the axis of the base tube, symmetrically divided into two groups about the center plane of the base tube. The hollow area at the center of the base tube forms a flue gas corridor. The outer fins are helical fins. A corrugated plate or turbulence plate is provided axially inside the base tube as an enhanced heat exchange structure. The fin ratio of the outer fins is greater than 10, and the fin ratio of the inner fins is greater than 3. There is no contact thermal resistance between the inner and outer fins and the base tube, and an enhanced heat exchange unit is provided inside the tube. The heat exchange area of ​​the same length is more than three times that of a bare tube, the average surface heat transfer coefficient is more than twice that of a bare tube, and the overall heat transfer capacity is more than six times that of a bare tube, making the heat exchange device structure more compact and significantly reducing raw material consumption and carbon emissions.

Description

Technical Field

[0001] This invention belongs to the field of gas-enhanced heat transfer technology, specifically relating to a coaxial conjugate anisotropic enhanced heat transfer tubular element and heat exchange device. Background Technology

[0002] Under the dual carbon goals of achieving carbon peaking by 2030 and carbon neutrality by 2060, the benefits of energy conservation and emission reduction can no longer be measured solely by economic efficiency; their greater significance lies in reducing carbon emissions. Gas-to-gas heat exchange is widely used in various industrial processes. For example, the flue gas from fossil fuel furnaces contains a large amount of waste heat, requiring gas-to-gas heat exchangers to heat the air and recover this waste heat. In coal chemical and petrochemical industries, processes often rely on heating / cooling one gas with another to control the gases within the reaction temperature range, necessitating gas-to-gas heat exchangers. In food processing, agriculture, animal husbandry, and building heating systems, where fresh air needs to be heated, exhaust gas is often used to heat low-temperature fresh air, also requiring gas-to-gas heat exchangers. Installing air preheaters in these industrial processes can recover some of the waste energy from the flue gas, reducing energy consumption and thus lowering carbon emissions. The main obstacles restricting the widespread use of waste heat recovery devices include the large size of traditional bare tube gas-to-gas heat exchangers, the susceptibility to clogging and leakage in compact plate gas-to-gas heat exchangers, and the high initial investment in heat exchanger equipment. Therefore, the market needs a gas-to-gas heat exchanger with strong anti-clogging ability, compact size, and strong heat exchange capacity to achieve the environmental protection goals of energy saving and low carbon emissions.

[0003] Tianjin Chenchuang Environmental Engineering Technology Co., Ltd. has applied for a finned air preheater with a turbulence generator-cast iron tube combination (CN201520572963.9). This preheater consists of a turbulence generator and a cast iron tube heat exchange element. The turbulence generator is used in the high-temperature tube section, and the cast iron tube heat exchange element is used in the low-temperature tube section. The outer fins of the cast iron tube are discontinuous annular or needle-shaped, while the inner fins are longitudinal plate fins. The casting process results in a large fin spacing and weak expansion capability. Furthermore, cast iron has a low thermal conductivity, resulting in low fin efficiency and poor resistance to condensate corrosion, limiting its application conditions. Harbin Coupled Power Engineering Technology Center Co., Ltd. has applied for a finned heat exchanger with an internal spiral turbulence generator (CN206378035U). This finned heat exchanger inserts a spiral turbulence generator inside a spiral finned tube, simultaneously enhancing heat exchange inside and outside the tube. However, there is no expanded heating surface inside the tube, limiting the enhancement capability. The contact area between the turbulence generator and the tube wall is small, resulting in high contact thermal resistance, and the spiral turbulence generator also exhibits significant flow resistance. To achieve efficient enhancement of gas-to-gas heat exchange, it is necessary to simultaneously enhance the heat transfer coefficient and heat transfer area on both the inside and outside of the tube. Furthermore, the extended heating surface needs to have good contact with the base tube. Ideally, the extended heating surface should be a part that extends from the base tube material to completely eliminate contact thermal resistance. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a coaxial conjugate anisotropic reinforced heat exchange tube. Spiral fins are rolled onto the outer surface of a hot-extruded aluminum profile using a hobbing cutter, forming coaxial anisotropic fins with internal axially reinforced fins and external circumferentially reinforced fins. The inner and outer fins are directly connected to the base tube, eliminating contact thermal resistance. This structure of paired inner and outer fins is termed coaxial conjugate anisotropic reinforcement. Compared to traditional bare tubes, this reinforced heat exchange tube has a heat exchange area more than three times that of a bare tube of the same length, an average surface heat transfer coefficient more than twice that of a bare tube, and a combined heat transfer capacity of more than six times that of a bare tube.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a coaxial conjugate anisotropic enhanced heat transfer tubular element, comprising an integrally formed base tube, outer fins, and inner fins. The surface of the inner fins is provided with a wavy undulating structure. The base tube, outer fins, and inner fins are made of the same material, and there is no contact thermal resistance between the base tube and the inner and outer fins. The inner fins are multiple sets of longitudinal fins parallel to the axis of the base tube. The inner fins are symmetrically divided into two groups about the center plane of the base tube, and the hollow area at the center of the base tube forms a flue gas corridor. The outer fins are helical fins. A corrugated plate or turbulence plate is provided axially inside the base tube as an enhanced heat transfer structure. The fin ratio of the outer fins is greater than 100%, and the fin ratio of the inner fins is greater than 100%.

[0006] The base tube, outer wing, inner wing, and base tube are made of extruded aluminum. When the base tube, outer wing, and inner wing are manufactured using casting technology, they are made of high-temperature nickel-based alloy or high-chromium heat-resistant steel, and the base tube, outer wing, and inner wing are cast simultaneously.

[0007] The outer wings have a wing height of 8–16 mm, a wing thickness of 0.2 mm or more, and a wing pitch of 1.6–4 mm; the inner wings have a wing height of 10 mm–30 mm and a wing thickness of 2 mm–6 mm.

[0008] The corrugated plate is a self-twisting corrugated plate that runs through coaxial, conjugate, and oppositely reinforced heat exchange tubes, dividing the flue gas into two streams, with through holes every 10mm to 300mm.

[0009] A corrugated plate is a flat or twisted plate with through holes spaced apart along the axial direction.

[0010] The turbulence plate is a plate-shaped structure with guide grooves that runs through coaxial conjugate anisotropic enhanced heat exchange tubes. Guide grooves are provided every 10mm to 300mm and are distributed on both sides of the turbulence plate. The guide grooves are staggered on both sides of the turbulence plate. The guide grooves include elongated holes and arc-shaped guide plates. Several elongated holes are opened at intervals on the turbulence plate. Arc-shaped guide plates are set at the edges of the elongated holes. The arc-shaped guide plates gradually move away from the root of the turbulence plate. The opening of the arc-shaped guide plates faces the direction of medium entry.

[0011] This invention also provides a method for preparing a coaxial conjugate anisotropic reinforced heat exchange tubular element. First, a heated blank is extruded through a die using an extruder to obtain an inner reinforced tube. The inner reinforced tube consists of a base tube and inner fins. Before the inner reinforced tube cools to room temperature, the outer fins are processed using a roller cutter. The roller cutter and the outer surface of the base tube move relative to each other along the circumference of the inner reinforced tube. The relative movement causes permanent plastic deformation of the outer surface of the base tube, generating an outer fin with its root connected to the base tube. Then, a corrugated plate or turbulence plate is inserted into the hollow area in the center of the base tube.

[0012] During the process of machining the outer fins with a roller cutter, a retractable support plate is inserted inside the base tube; the retractable support plate is a longitudinal plate that runs through the coaxial conjugate anisotropic reinforced heat exchange tube, and the cross section of the retractable support plate is radial or cross-shaped; the retractable support plate includes a central support and a support plate, with the top of the support plate extending to the inner surface of the base tube.

[0013] This invention also provides a hot blast stove, comprising coaxial conjugate anisotropic enhanced heat exchange tubes, a burner, a dilution fan, a furnace, a flame deflector, an oil storage tank, a flue, a chimney, a semiconductor power generation device, and a battery; the coaxial conjugate anisotropic enhanced heat exchange tubes adopt the coaxial conjugate anisotropic enhanced heat exchange tube-shaped element described in this invention; the burner and the flame deflector are surrounded inside the furnace, with the flame deflector located at the rear of the furnace and a circumferential gap between the flame deflector and the furnace; the semiconductor power generation device is located between the furnace and the burner, and is cylindrical, fitted onto the outside of the burner outlet; the dilution fan is located at the head of the furnace; the oil storage tank is located at the bottom of the furnace; the flue is located at the upper part of the furnace and connects to the furnace; and several coaxial... Conjugate anisotropic enhanced heat exchange tubes are installed inside the flue; cold air is introduced into the shell side of the flue; a vertical baffle is installed in the middle of the flue, dividing the flue into at least two heat exchange zones; a composite tube sheet connection method is used when welding the coaxial conjugate anisotropic enhanced heat exchange tubes to the tube sheet; a tube sheet of the same material as the coaxial conjugate anisotropic enhanced heat exchange tubes is added to the conventional steel tube sheet, and the tube sheet is sealed and welded to the coaxial conjugate anisotropic enhanced heat exchange tubes, with the conventional steel tube sheet providing strength support; diffusion welding or bolt connection is used between the conventional steel tube sheets; when the coaxial conjugate anisotropic enhanced heat exchange tubes are used in the heat exchanger, it is a partitioned heat exchanger structure, with the working fluid inside the tubes flowing parallel to the direction of the tube's central axis, and the working fluid outside the tubes flowing perpendicular to the direction of the tube's central axis.

[0014] This invention provides a contoured gas-to-gas heat exchanger, comprising a heat exchange tube bundle. The heat exchange tube bundle employs multiple coaxial, conjugate, anisotropic enhanced heat exchange tube elements as described in this invention. The coaxial, conjugate, anisotropic enhanced heat exchange tubes are located at the tail end of a vertical cylindrical boiler. The central axis of the coaxial, conjugate, anisotropic enhanced heat exchange tubes is parallel to the central axis of the vertical cylindrical boiler. The coaxial, conjugate, anisotropic enhanced heat exchange tubes are arranged along the arc-shaped surface of the flue gas outlet of the vertical cylindrical boiler. An outer shell is provided on the outside of the heat exchange tube bundle, and the entire outer shell is connected to the flue gas duct of the vertical cylindrical boiler. A flue gas outlet is provided on the side of the outer shell, and an air inlet is provided at the bottom. An air outlet is provided at the top; a composite tube sheet connection method is used when welding coaxial conjugate anisotropic enhanced heat exchange tubes to the tube sheet; a tube sheet of the same material as the coaxial conjugate anisotropic enhanced heat exchange tubes is added to the traditional steel tube sheet, and the tube sheet is sealed and welded to the coaxial conjugate anisotropic enhanced heat exchange tubes, with the traditional steel tube sheet providing strength support; diffusion welding or bolt connection is used between the traditional steel tube sheet and the tube sheet; when the coaxial conjugate anisotropic enhanced heat exchange tubes are used in the heat exchanger, it is a partition wall heat exchanger structure, with the working fluid flow direction inside the tube parallel to the tube central axis direction, and the working fluid flow direction outside the tube perpendicular to the tube central axis direction.

[0015] This invention can also provide a shell-and-tube type two-stage gas-to-gas heat exchanger, comprising a first-stage gas-to-gas heat exchanger composed of several vertically arranged coaxial conjugate anisotropic enhanced heat exchange tubes and a second-stage gas-to-gas heat exchanger composed of several horizontally arranged coaxial conjugate anisotropic enhanced heat exchange tubes. The coaxial conjugate anisotropic enhanced heat exchange tubes adopt the coaxial conjugate anisotropic enhanced heat exchange tube element described in this invention. It is connected to a feedwater tube bundle energy-saving condenser, with the first-stage gas-to-gas heat exchanger located on the side of the feedwater tube bundle energy-saving condenser. A baffle is installed between the first-stage gas-to-gas heat exchanger and the feedwater tube bundle energy-saving condenser. The second-stage gas-to-gas heat exchanger is located directly below the feedwater tube bundle energy-saving condenser. A horizontal baffle is installed in the second-stage gas-to-gas heat exchanger to divide it into at least two heat exchangers. The system is structured as follows: the shell side serves as the flue gas passage, and the tube side serves as the cold air passage; the secondary gas-to-gas heat exchanger has a cold air inlet, and the primary gas-to-gas heat exchanger has an air outlet; a composite tube sheet connection method is used when welding coaxial conjugate anisotropic enhanced heat exchange tubes to the tube sheet; an additional tube sheet of the same material as the coaxial conjugate anisotropic enhanced heat exchange tubes is added to the conventional steel tube sheet, and the tube sheet is sealed and welded to the coaxial conjugate anisotropic enhanced heat exchange tubes, with the conventional steel tube sheet providing strength support; diffusion welding or bolted connections are used between the conventional steel tube sheets; when coaxial conjugate anisotropic enhanced heat exchange tubes are used in heat exchangers, they form a partitioned heat exchanger structure, with the working fluid flow direction inside the tubes parallel to the tube's central axis, and the working fluid flow direction outside the tubes perpendicular to the tube's central axis.

[0016] This invention provides a shell-and-tube air preheater. The heat exchanger tube bundle employs multiple conjugate anisotropic enhanced heat exchange tubes. These conjugate anisotropic enhanced heat exchange tubes are coaxial conjugate anisotropic enhanced heat exchange tube elements as described in this invention. The conjugate anisotropic enhanced heat exchange tubes serve as flue gas channels, while the shell side serves as an air channel. A four-pass configuration is provided on the air side, and multiple baffles are arranged along the axial direction of the conjugate anisotropic enhanced heat exchange tubes. The baffles and the air preheater shell provide an S-shaped channel for the air. The coaxial conjugate anisotropic enhanced heat exchange tubes are welded to the tube sheet using... The composite tube sheet connection method involves adding a layer of tube sheet made of the same material as the coaxial conjugate anisotropic enhanced heat exchange tubes to a traditional steel tube sheet. The tube sheet and the coaxial conjugate anisotropic enhanced heat exchange tubes are sealed and welded together, with the traditional steel tube sheet providing strength support. The traditional steel tube sheet is connected to the tube sheet by diffusion welding or bolts. When the coaxial conjugate anisotropic enhanced heat exchange tubes are used in the heat exchanger, it is a partitioned heat exchanger structure. The flow direction of the working fluid inside the tube is parallel to the direction of the tube's central axis, while the flow direction of the working fluid outside the tube is perpendicular to the direction of the tube's central axis.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] 1. The coaxial conjugate anisotropic enhanced heat exchange tube of the present invention couples hot extrusion molding and plastic deformation molding processes, and creatively proposes a high-efficiency heat transfer element with conjugate enhanced heat exchange inside and outside the tube. There is no contact thermal resistance between the inner and outer fins and the base tube, and various in-tube enhanced heat exchange units can be selected. Compared with traditional bare tubes, the heat exchange area of ​​the same length is more than three times that of bare tubes, the average surface heat transfer coefficient is more than twice that of bare tubes, and the comprehensive heat transfer capacity is more than six times that of bare tubes, making the heat exchange device structure more compact and significantly reducing raw material consumption and carbon emissions.

[0019] 2. The present invention provides a coaxial conjugate anisotropic enhanced heat exchange tube for retrofitting traditional carbon steel hot blast stoves. While maintaining the same boiler efficiency, it reduces the weight of the hot blast stove by more than 50%, does not rely on external power supply, and greatly increases the portability of the hot blast stove.

[0020] 3. The present invention provides a coaxial conjugate anisotropic enhanced heat exchange tube, forming a two-stage gas-to-gas heat exchanger structure, which can reduce the flue gas temperature of a steam boiler under feedwater conditions of 20°C to below 50°C, and increase the boiler efficiency to 102% to 105%. Compared with the efficiency of 98% to 100% of traditional steam boilers, the carbon emissions of the steam boiler throughout its entire life cycle can be reduced by more than 3%.

[0021] 4. When the heat exchange capacity of the coaxial conjugate anisotropic enhanced heat exchange tube of the present invention is the same as that of the traditional carbon steel air preheater, its volume is only less than 30% of that of the traditional carbon steel heat exchanger. It can be widely used in various occasions that require gas heating and waste heat recovery, solving the problem of the large size and difficulty in placement of traditional air preheaters, and reducing carbon emissions of related industries by more than 3%.

[0022] 5. The coaxial conjugate anisotropic enhanced heat exchange tube of the present invention is preferably made of aluminum and aluminum alloy materials by extrusion. It can resist the corrosion of low-temperature condensate and can be directly applied to the working conditions of flue gas condensation and recovery of the latent heat of vaporization of water vapor. When used for higher temperature conditions, high melting point metal materials such as copper and steel can be used for extrusion. When used for even higher temperature conditions, nickel-based alloys and other materials can be used and manufactured by casting process. In this case, the base tube 2, outer fin 3, and inner fin 4 are cast simultaneously. When used for very high temperature conditions, non-metallic material powder can also be made into a paste, extruded and then aged, heated or sintered for shaping, such as ceramics, silicon carbide and their synthetic materials. Attached Figure Description

[0023] Figure 1a This is a schematic diagram of a coaxial conjugate anisotropic enhanced heat exchange tube. Figure 1b This is a schematic diagram of the inner reinforced heat exchange tube 13; Figure 1c This is a schematic diagram of a cross-section of a coaxial conjugate anisotropic enhanced heat exchange tube; Figure 1d This is a schematic diagram of a coaxial, conjugate, anisotropic enhanced heat exchange tube connected to a tube sheet.

[0024] Figure 2a This is a schematic diagram of the cross-section of the coaxial conjugate anisotropic enhanced heat exchange tube after torsion; Figure 2b This is a cross-sectional schematic diagram of the assembly of the retractable support plate 5 and the coaxial conjugate anisotropic enhanced heat exchange tubes.

[0025] Figure 3 A schematic diagram of the cross-section of the inner wing 4 with unequal thickness.

[0026] Figure 4a This is a schematic diagram of the cross-section of the fishbone plate 6 in conjunction with the coaxial conjugate anisotropic enhanced heat exchange tube; Figure 4b This is a schematic diagram of the fishbone plate 6.

[0027] Figure 5a This is a schematic diagram of the cross-section of the corrugated plate 7 and the coaxial conjugate anisotropic enhanced heat exchange tubes. Figure 5b This is a schematic diagram of the overall structure of wave plate 7.

[0028] Figure 6a This is a schematic diagram of the cross-section of the turbulence plate 8 and the coaxial conjugate anisotropic enhanced heat exchange tubes. Figure 6b This is a schematic diagram of the overall flow plate 8.

[0029] Figure 7a This is an overall schematic diagram of hot air furnace 9; Figure 7b This is a schematic diagram of the vertical cross-section of hot blast stove 9; Figure 7c This is a schematic diagram of the cross-section of hot blast stove 9.

[0030] Figure 8a This is an overall schematic diagram of the contour-following gas-to-gas heat exchanger 14 and the vertical cylindrical boiler 141; Figure 8bThis is a schematic diagram of the vertical cross-section of the contoured gas-to-gas heat exchanger 14 and the vertical cylindrical boiler 141. Figure 8c This is a schematic cross-sectional view of the contoured gas-to-gas heat exchanger 14 and the vertical cylindrical boiler 141.

[0031] Figure 9a This is a schematic diagram of the combined two-stage gas-to-gas heat exchanger 15 and the feedwater pipe bundle energy-saving condenser 153. Figure 9b This is a schematic diagram of the vertical cross-section of the two-stage gas-to-gas heat exchanger 15 and the water supply pipe bundle energy-saving condenser 153.

[0032] Figure 10 This is a schematic diagram of the vertical cross-section of a traditional four-pass gas-to-gas heat exchanger. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The technical solution of this invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise stated, the exemplary embodiments / exemplifications shown are to be understood as providing exemplary features of various details that provide ways in which the technical concept of the invention can be implemented in practice. Therefore, unless otherwise stated, the features of the various embodiments / exemplifications may be additionally combined, separated, interchanged and / or rearranged without departing from the technical concept of the invention.

[0036] The use of crosshairs and / or shading in the accompanying drawings is generally used to clarify the boundaries between adjacent components. Thus, unless otherwise stated, the presence or absence of crosshairs or shading does not convey or indicate any preference or requirement for the specific material, material properties, dimensions, proportions, commonalities between the illustrated components, or any other characteristics, properties, etc., of the components. Furthermore, in the accompanying drawings, the dimensions and relative dimensions of components may be exaggerated for clarity and / or descriptive purposes. When exemplary embodiments can be implemented differently, a specific process sequence may be performed in a different order than that described. For example, two consecutively described processes may be performed substantially simultaneously or in the reverse order of their description. Furthermore, the same reference numerals denote the same components.

[0037] When a component is referred to as being "on" or "above" another component, "connected to," or "joined to" another component, the component may be directly on, directly connected to, or directly joined to the other component, or there may be intermediate components. However, when a component is referred to as being "directly on" another component, "directly connected to," or "directly joined to" another component, there are no intermediate components. Therefore, the term "connection" can refer to a physical connection, an electrical connection, etc., and may or may not have intermediate components.

[0038] Referring to the accompanying drawings, the present invention provides a coaxial conjugate anisotropic enhanced heat transfer tubular element, comprising an integrally formed base tube 2, outer fins 3, and inner fins 4. The surface of the inner fins 4 is provided with a wave-shaped undulating structure. The base tube 2, outer fins 3, and inner fins 4 are made of the same material, and there is no contact thermal resistance between the base tube 2 and the inner and outer fins 3. The inner fins 4 are multiple sets of longitudinal fins parallel to the axis of the base tube 2. The inner fins 4 are symmetrically divided into two groups about the center plane of the base tube 2, and the hollow area at the center of the base tube 2 forms a flue gas corridor. The outer fins 3 are helical fins. A corrugated plate 7 or a turbulent plate 8 is provided axially inside the base tube 2 as an enhanced heat transfer structure. The fin ratio of the outer fins 3 is greater than 10, and the fin ratio of the inner fins 4 is greater than 3.

[0039] like Figure 1a , Figure 1b , Figure 1c , Figure 1d As shown, the base tube 2, outer fin 3, and inner fin 4 are integrally processed from the same base material, without contact thermal resistance; the inner fin 4 consists of multiple sets of longitudinal fins parallel to the axis of the base tube 2. The inner fin 4 and the base tube 2 are generated simultaneously by extrusion. Due to the limitations of the extrusion process, the inner fin 4 cannot extend to the hollow area in the center of the base tube 2 to form a flue gas corridor; the outer fin 3 is a spiral fin, which is processed on the outer surface of the base tube 2 by processes such as roll forming.

[0040] Because the surface heat transfer coefficient is relatively small when gas exchanges heat with a metal wall, bilateral enhancement is required for gas-to-gas heat exchange. In the illustrated structure, the fin ratio of the outer fin 3 is greater than 10, the fin ratio of the inner fin 4 is greater than 3, the average flow velocity at the outer fin 3 is greater than 8 m / s, the average flow velocity at the inner fin 4 is greater than 10 m / s, and the average heat transfer coefficient of the outer fin 3 is not less than 30 W / (m²). 2 The average heat transfer coefficient of the inner fin 4 is not less than 100 W / (m²). 2 The surface heat transfer coefficients, calculated from the outer and inner sides of the tube to the surface of the base tube 2, can both reach 300 W / (m²). 2 Considering wall thermal resistance and fouling thermal resistance, the overall heat transfer coefficient applied to the surface of base tube 2 is greater than 120 W / (m²). 2 ·K).

[0041] Optionally, the base tube 2, outer wing 3, inner wing 4 and base tube 2 are made of extruded aluminum material; when the base tube 2, outer wing 3 and inner wing 4 are manufactured by casting process, they are made of high-temperature nickel-based alloy or high-chromium heat-resistant steel, and the base tube 2, outer wing 3 and inner wing 4 are cast simultaneously.

[0042] The inner fin 4 consists of multiple sets of longitudinal fins parallel to the axis of the base tube 2. The longitudinal fins are parallel to each other, and the cross-section of each fin perpendicular to the axis of the base tube 2 is a long strip pattern composed of short wavy lines. Due to the limitations of the extrusion process, the height of the inner fin 4 is less than the radius of the base tube 2, resulting in a large central flue gas corridor. When the flue gas velocity is low (less than 8 m / s), a herringbone plate 6, a corrugated plate 7, or a turbulence plate 8 can be installed to enhance the heat transfer inside the base tube 2. When the flue gas velocity is high (greater than 8 m / s), it is not necessary to install herringbone plates 6, corrugated plates 7, or turbulence plates 8 to obtain a high heat transfer coefficient inside the tube. The multiple sets of fins of the inner fin 4 have different lengths. To optimize heat transfer, the long fins can be thickened to maintain the same length-to-diameter ratio for each fin.

[0043] The processing technology of the coaxial conjugate anisotropic reinforced heat exchange tube 1 involves first using an extruder to extrude a heated aluminum rod through a die to obtain an inner reinforced tube 13. The inner reinforced tube 13 includes a base tube 2 and inner fins 4. Before the inner reinforced tube 13 cools to room temperature, an outer fin 3 is processed using a roller cutter. The roller cutter and the outer surface of the base tube 2 move relative to each other along the circumference of the inner reinforced tube 13. This relative movement causes permanent plastic deformation of the outer surface of the base tube 2, generating an outer fin 3 whose root is connected to the base tube 2. The outer fin 3 has a fin height of 8-16 mm, a fin thickness of 0.2 mm or more, and a fin spacing of 1.6-4 mm. The inner fin 4 has a fin height ranging from 10 mm to 30 mm and a fin thickness ranging from 2 mm to 6 mm.

[0044] The coaxial conjugate anisotropic enhanced heat exchange tube 1 is welded to the tube sheet using composite tube sheet technology; a tube sheet 11 of the same material as the coaxial conjugate anisotropic enhanced heat exchange tube 1 is added to the conventional steel tube sheet 12, and the tube sheet 11 and the coaxial conjugate anisotropic enhanced heat exchange tube 1 are connected by a sealed weld. The conventional steel tube sheet 12 is tightly connected to the coaxial conjugate anisotropic enhanced heat exchange tube 1 and provides strength support; the conventional steel tube sheet 12 and the tube sheet 11 are connected by explosive diffusion welding. The steel tube sheet can be made of carbon steel, low alloy steel, medium alloy steel, or ferritic, austenitic, or duplex stainless steel, depending on the temperature level of the different gases on both sides. All heat exchangers of the present invention can be manufactured using the above connection process.

[0045] like Figure 2a , Figure 2bAs shown, the processing technology of the coaxial conjugate anisotropic enhanced heat exchange tube 1 involves first using an extruder to extrude a heated aluminum rod through a die to obtain an inner enhanced tube 13. The inner enhanced tube 13 includes a base tube 2 and inner fins 4. Before the inner enhanced tube 13 cools to room temperature, the outer fins are processed using a roller cutter. The roller cutter and the outer surface of the base tube 2 move relative to each other along the circumference of the inner enhanced tube 13. The relative movement causes permanent plastic deformation of the outer surface of the base tube 2, generating an outer fin 3 connected to the base tube 2 at its root. The relative movement also causes the inner enhanced tube 13 to twist around the central axis with a twist angle greater than 0°. The centers of the two ends of the coaxial conjugate anisotropic enhanced heat exchange tube 1 still coincide, and the planes containing the two end faces are still parallel.

[0046] If a retractable support plate 5 is inserted inside the base tube 2 during the roller cutting process of the outer fin 3, torsional deformation can be prevented. The retractable support plate 5 is a longitudinal plate that runs through the coaxial conjugate anisotropic enhanced heat exchange tube 1. The cross section of the retractable support plate 5 is radial or cross-shaped. The retractable support plate 5 is divided into two parts: a central support 52 and a support plate 51. The support plate 51 is a retractable structure. High-pressure working medium is introduced into the high-pressure filling working medium inlet 53 of the central support 52 to push the support plate 51 to the inner surface of the base tube 2, preventing the base tube 2 from becoming unstable and breaking during the roller pressing process. After the roller pressing process is completed, the high-pressure working medium is removed, and the support plate 51 retracts, making it easy to remove the retractable support plate 5 from the coaxial conjugate anisotropic enhanced heat exchange tube 1.

[0047] like Figure 3 As shown, the multiple sets of fins in the inner fin 4 are of different lengths. To optimize heat exchange, the longer fins can be thickened, and the ratio of the radial dimension of each fin to the diameter of the base tube should be kept close, with the ratio controlled at around 5.

[0048] like Figure 4a , Figure 4b As shown, the fishbone plate 6 is a longitudinal plate that runs through the coaxial conjugate anisotropic enhanced heat exchange tube 1. The cross section of the fishbone plate 6 perpendicular to the axis of the coaxial conjugate anisotropic enhanced heat exchange tube 1 is fishbone shaped. It cooperates with the inner fin 4 to form a gap channel parallel to the axis of the coaxial conjugate anisotropic enhanced heat exchange tube 1. The average width of the gap channel is less than 4mm, forming laminar flow enhanced heat exchange.

[0049] like Figure 5a , Figure 5bAs shown, a corrugated plate 7 is installed in the space between the two rows of inner fins 4. The corrugated plate 7 is a self-twisting corrugated plate that runs through the coaxial conjugate anisotropic enhanced heat exchange tube 1 and divides the flue gas into two streams. Through holes 71 are opened every 10mm to 300mm on the corrugated plate 7. The diameter of the through holes 71 is 10mm, and they are evenly distributed in 4 rows along the transverse direction of the corrugated plate 7. When the working fluid flowing along the axial direction of the coaxial conjugate anisotropic enhanced heat exchange tube 1 encounters the corrugated plate 7, it generates a transverse flow parallel to the fin height direction of the inner fin 3. The flue gas transversely washes the inner fin 3, disturbs the boundary layer on the surface of the inner fin 3, and enhances heat exchange. The through holes 71 can connect the working fluid on both sides of the corrugated plate 7, balance the flow rate of the working fluid on both sides, and further enhance the transverse flow.

[0050] The corrugated plate 7 can also be simplified to a flat plate or various twisted plates with through holes spaced apart along the axial direction.

[0051] like Figure 6a , Figure 6b As shown, a turbulence plate 8 is installed in the space between the two rows of inner fins 4. The turbulence plate 8 is a plate-shaped structure with guide grooves 81 that penetrates the coaxial conjugate anisotropic enhanced heat exchange tube 1. Guide grooves 81 are provided every 10mm to 300mm and are distributed on both sides of the turbulence plate 8. The guide grooves 81 are 50mm high and are arranged at intervals on both sides of the turbulence plate 8. The guide grooves 81 include elongated holes and arc-shaped guide plates. Several elongated holes are opened at intervals on the turbulence plate 8. Arc-shaped guide plates are provided at the edges of the elongated holes. The arc-shaped guide plates gradually move away from the root of the turbulence plate 8. The opening of the arc-shaped guide plates faces the direction of medium entry, separating the flue gas and allowing it to flow on both sides of the turbulence plate 8; guiding the working medium in the tube from one side to the other; and guiding the flue gas on both sides to laterally scour the inner fins 3, disturbing the boundary layer on the surface of the inner fins 3 and enhancing heat transfer.

[0052] like Figure 7a , Figure 7b , Figure 7cAs shown, the present invention provides a hot blast stove 9, which includes coaxial conjugate anisotropic enhanced heat exchange tubes 1, a burner 91, a dilution fan 92, a furnace 93, a flame deflector 94, an oil storage tank 95, a flue 96, a chimney 97, a semiconductor power generation chip 98, and a battery. The burner 91 and the flame deflector 94 are surrounded within the furnace 93. The flame deflector 94 is located at the rear of the furnace 93, with a circumferential gap between it and the furnace 93. The dilution fan 92 is located at the head of the furnace 95. The oil storage tank 95... Located at the bottom of the furnace 93, the flue 96 is located at the top of the furnace 93. Several coaxial conjugate anisotropic enhanced heat exchange tubes 1 are located inside the flue 96. The oil storage tank 95 is located at the bottom of the hot blast stove 9. The bottom of the oil storage tank 95 is equipped with small wheels, and pull rods are provided on both sides to facilitate the movement of the hot blast stove 9. Semiconductor power generation plates 98 are installed on the outside of the burner 91. The combustion of the burner 91 generates high-temperature flue gas, which heats the inside of the semiconductor power generation plates 98. The dilution fan 92 sends in cooling air to cool the semiconductor power generation plates 98 and the burner 91. After the high-temperature flue gas encounters the flame baffle 94, it mixes with the cooling air under the constraint of the furnace 93 to form medium-temperature flue gas with a temperature below 700°C. The medium-temperature flue gas is guided by the flue 96 into the inside of the coaxial conjugate anisotropic enhanced heat exchange tubes 1. After cooling to below 150°C, it leaves the hot blast stove 9 through the chimney 97. There is a continuous heat source inside the semiconductor power generation plates 98. The side-cooled air cooling system enables continuous power generation. When the thermoelectric conversion efficiency is 2%, the 20kW hot air furnace can generate 400W of power per hour, providing power support for the operation of the hot air furnace 9 and charging the battery. The starting power is provided by the battery. Air flows on the outside of the coaxial conjugate anisotropic enhanced heat exchange tube 1, laterally scouring the coaxial conjugate anisotropic enhanced heat exchange tube 1, forming two cross-counterflow heat exchange with the medium-temperature flue gas inside the tube. The air temperature rises from below 20℃ to about 100℃. The air flow rate is adjusted according to the required hot air temperature to control the outlet air temperature. The oil-fired hot air furnace is transformed into a gas-fired hot air furnace by removing the oil tank, replacing the gas burner, and connecting the gas source pipeline. This hot air furnace is lightweight, compact, easy to carry and move, and can be used in mobile homes, barracks, and mobile warehouses in mountainous areas far from urban areas. It can also be used for farmers' homes, districts, or centralized heating using biomass oil or biogas as a source.

[0053] like Figure 8a , Figure 8b , Figure 8cAs shown, the present invention also provides a contoured gas-to-gas heat exchanger 14, which employs 15 coaxial conjugate anisotropic enhanced heat exchange tubes 1. The coaxial conjugate anisotropic enhanced heat exchange tubes 1 are located at the tail of the vertical cylindrical boiler 141. The central axis of the coaxial conjugate anisotropic enhanced heat exchange tubes 1 is parallel to the central axis of the vertical cylindrical boiler 141. The coaxial conjugate anisotropic enhanced heat exchange tubes 1 in the gas-to-gas heat exchanger 14 are arranged along the arc-shaped surface of the flue gas outlet of the vertical cylindrical boiler 141, reducing the footprint of the contoured gas-to-gas heat exchanger 14. The gas-to-gas heat exchanger 14 is provided with an outer shell, which is connected to the flue of the vertical cylindrical boiler 141. The side of the outer shell is provided with a flue gas outlet, the bottom is provided with an air inlet, and the top is provided with an air outlet.

[0054] like Figure 9a , Figure 9b As shown, this invention provides a two-stage gas-to-gas heat exchanger 15 connected to a water supply pipe bundle energy-saving condenser 153. The two-stage gas-to-gas heat exchanger 15 consists of a first-stage gas-to-gas heat exchanger 151 composed of several vertically arranged coaxial conjugate anisotropic enhanced heat exchange tubes 1 and a second-stage gas-to-gas heat exchanger 152 composed of several horizontally arranged coaxial conjugate anisotropic enhanced heat exchange tubes 1. For simplified view, the outer fins 3 of the coaxial conjugate anisotropic enhanced heat exchange tubes 1 are not shown here. The air side of the first-stage gas-to-gas heat exchanger 151 is arranged in a single-pass configuration, while the air side of the second-stage gas-to-gas heat exchanger 152 is arranged in a two-pass configuration. Cold air first enters the tubes of the second-stage gas-to-gas heat exchanger 152, is heated, and then enters the first-stage gas-to-gas heat exchanger 151. The flue gas is cooled by more than 60°C after passing through the first-stage gas-to-gas heat exchanger 151 before entering the water supply. The tube bundle energy-saving condenser 153 cools the flue gas to below 60°C before it enters the secondary gas-to-gas heat exchanger 152. In the secondary gas-to-gas heat exchanger 152, a large amount of flue gas condenses, releasing the latent heat of water vapor to the cold air, resulting in a temperature drop of 3–6°C. The two-stage gas-to-gas heat exchanger 15, connected to the feedwater tube bundle energy-saving condenser 153, can reduce the flue gas temperature of the steam boiler from 20°C to below 50°C under feedwater conditions, increasing the boiler thermal efficiency to over 102% (calculated based on the lower heating value of the fuel gas). This two-stage gas-to-gas heat exchanger 15, as a combined structure, can be arranged at the tail outlet of any vertical or horizontal boiler or heating furnace to deeply recover the sensible heat and latent heat of vaporization of water vapor in the flue gas, reducing fuel consumption and carbon dioxide emissions.

[0055] like Figure 10As shown, the present invention provides an air preheater. When the conjugate anisotropic enhanced heat exchange tube 1 is applied to a conventional air preheater structure, the flue gas flows inside the conjugate anisotropic enhanced heat exchange tube 1, and the air flows outside the tube, with the air side 4 being the return path. Multiple baffles are arranged along the axial direction of the conjugate anisotropic enhanced heat exchange tube 1. The baffles and the air preheater shell provide an S-shaped channel for the air. In order to reduce the resistance on the air side, the number of tube rows along the air flow direction on the air side is less than the number of tube rows on the air side parallel to the air flow direction.

[0056] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A coaxial, conjugate, anisotropic enhanced heat transfer tubular element, characterized in that, The system includes an integrally formed base tube (2), outer fin (3), and inner fin (4). The surface of the inner fin (4) is provided with a wave-shaped undulating structure. The base tube (2), outer fin (3), and inner fin (4) are made of the same material. There is no contact thermal resistance between the base tube (2) and the inner fin (4) and outer fin (3). The inner fin (4) consists of multiple sets of longitudinal fins parallel to the axis of the base tube (2). The inner fin (4) is symmetrically divided into two groups about the center plane of the base tube (2). The hollow area in the center of the base tube (2) forms a flue gas corridor. The outer fin (3) is a spiral fin. A wave plate (7) or a turbulence plate (8) is provided along the axial direction inside the base tube (2) as a heat exchange enhancement structure. The fin ratio of the outer fin (3) is greater than 10, and the fin ratio of the inner fin (4) is greater than 3. The base tube (2), outer fin (3), and inner fin (4) are made of extruded aluminum material. When the base tube (2), outer fin (3), and inner fin (4) are manufactured using a casting process, Made of high-temperature nickel-based alloy or high-chromium heat-resistant steel, the base tube (2), outer fin (3), and inner fin (4) are cast simultaneously; the corrugated plate (7) is a self-twisting corrugated plate that runs through the coaxial conjugate anisotropic enhanced heat exchange tube (1) and divides the flue gas into two streams, with through holes (71) every 10mm to 300mm; the turbulent plate (8) is a plate-shaped structure with guide grooves (81) that runs through the coaxial conjugate anisotropic enhanced heat exchange tube (1), with guide grooves (81) every 10mm to 300mm, the guide grooves (81) are distributed on both sides of the turbulent plate (8), and the guide grooves are staggered on both sides of the turbulent plate (8). The guide grooves (81) include elongated holes and arc-shaped guide plates. Several elongated holes are opened at intervals on the turbulent plate (8), and arc-shaped guide plates are set at the edges of the elongated holes. The arc-shaped guide plates gradually move away from the turbulent plate (8) from the root, and the opening of the arc-shaped guide plates faces the direction of medium entry.

2. The coaxial conjugate anisotropic enhanced heat transfer tubular element according to claim 1, characterized in that, The outer wing (3) has a wing height of 8-16 mm, a wing thickness of more than 0.2 mm, and a wing pitch of 1.6-4 mm; the inner wing (4) has a wing height of 10 mm-30 mm and a wing thickness of 2 mm-6 mm.

3. The method for preparing the coaxial conjugate anisotropic enhanced heat transfer tubular element according to claim 1 or 2, characterized in that, First, the heated blank is extruded through a die to obtain the inner reinforced tube (13). The inner reinforced tube (13) consists of a base tube (2) and an inner fin (4). When the inner reinforced tube (13) has not cooled to room temperature, the outer fin is processed by a roller cutter. The roller cutter and the outer surface of the base tube (2) move relative to each other along the circumference of the inner reinforced tube (13). The relative movement causes permanent plastic deformation of the outer surface of the base tube (2) to generate an outer fin (3) connected to the base tube (2) at the root. Then, a corrugated plate (7) or a turbulent plate (8) is inserted into the hollow area in the center of the base tube (2). During the process of processing the outer fin (3) by the roller cutter, a retractable support plate (5) is inserted inside the base tube (2). The retractable support plate (5) is a longitudinal plate that runs through the coaxial conjugate anisotropic reinforced heat exchange tube. The cross section of the retractable support plate (5) is radial or cross-shaped. The retractable support plate (5) includes a central support (52) and a support plate (51). The support plate (51) reaches the inner surface of the base tube (2).

4. A hot air furnace, characterized in that, The furnace includes a coaxial conjugate anisotropic enhanced heat exchange tube (1), a burner (91), a dilution fan (92), a furnace (93), a flame deflector (94), an oil storage tank (95), a flue (96), a chimney (97), a semiconductor power generation chip (98), and a battery; the coaxial conjugate anisotropic enhanced heat exchange tube (1) adopts the coaxial conjugate anisotropic enhanced heat exchange tube-shaped element as described in claim 1 or 2; the burner (91) and the flame deflector (94) surround the furnace (93) to deflect the flame. The plate (94) is located at the rear of the furnace (93). A circumferential gap is left between the flame deflector (94) and the furnace (93). The semiconductor power generation chip (98) is located between the furnace (93) and the burner (91). The semiconductor power generation chip (98) is cylindrical and is fitted on the outside of the burner (91) outlet. The dilution fan (92) is located at the head of the furnace (93). The oil storage tank (95) is located at the bottom of the furnace (93). The flue (96) is located at the furnace. The upper part of the furnace (93) is connected to the flue (96), and several coaxial conjugate anisotropic enhanced heat exchange tubes (1) are set inside the flue (96); cold air is introduced into the shell side of the flue (96); a vertical baffle is set in the middle of the flue (96) to divide the flue (96) into at least two heat exchange zones; when the coaxial conjugate anisotropic enhanced heat exchange tubes (1) are welded to the tube sheet, a composite tube sheet connection method is adopted; an additional layer of coaxial conjugate anisotropic enhanced heat exchange tubes (1) is added to the conventional steel tube sheet (12). The tube sheet (11) is made of the same material as the heat pipe (1). The tube sheet (11) is sealed and welded to the coaxial conjugate anisotropic enhanced heat exchange tube (1). The conventional steel tube sheet (12) provides strength support. The conventional steel tube sheet (12) and the tube sheet (11) are connected by diffusion welding or bolts. When the coaxial conjugate anisotropic enhanced heat exchange tube (1) is applied to the heat exchanger, it is a partitioned heat exchanger structure. The flow direction of the working fluid inside the tube is parallel to the direction of the tube's central axis, and the flow direction of the working fluid outside the tube is perpendicular to the direction of the tube's central axis.

5. A contour-following gas-to-gas heat exchanger, characterized in that, The system includes a heat exchange tube bundle, which employs multiple coaxial conjugate anisotropic enhanced heat exchange tube elements as described in claim 1 or 2. The coaxial conjugate anisotropic enhanced heat exchange tube (1) is located at the tail of the vertical cylindrical boiler (141). The central axis of the coaxial conjugate anisotropic enhanced heat exchange tube (1) is parallel to the central axis of the vertical cylindrical boiler (141). The coaxial conjugate anisotropic enhanced heat exchange tube (1) is arranged along the arc-shaped surface of the flue gas outlet of the vertical cylindrical boiler (141). An outer shell is provided on the outside of the heat exchange tube bundle. The outer shell is connected to the flue of the vertical cylindrical boiler (141). A flue gas outlet is provided on the side of the outer shell, an air inlet is provided at the bottom, and an air outlet is provided at the top. When the coaxial conjugate anisotropic enhanced heat exchange tube (1) is welded to the tube sheet, a composite tube sheet connection method is adopted; a tube sheet (11) of the same material as the coaxial conjugate anisotropic enhanced heat exchange tube (1) is added on the conventional steel tube sheet (12), and the tube sheet (11) and the coaxial conjugate anisotropic enhanced heat exchange tube (1) are sealed and welded together, and the conventional steel tube sheet (12) provides strength support; the conventional steel tube sheet (12) and the tube sheet (11) are connected by diffusion welding or bolts; when the coaxial conjugate anisotropic enhanced heat exchange tube (1) is applied to the heat exchanger, it is a partition wall heat exchanger structure, the flow direction of the working fluid inside the tube is parallel to the direction of the tube center axis, and the flow direction of the working fluid outside the tube is perpendicular to the direction of the tube center axis.

6. A shell-and-tube two-stage gas-to-gas heat exchanger, characterized in that, A primary gas-to-gas heat exchanger (151) is composed of several vertically arranged coaxial conjugate anisotropic enhanced heat exchange tubes (1), and a secondary gas-to-gas heat exchanger (152) is composed of several horizontally arranged coaxial conjugate anisotropic enhanced heat exchange tubes (1). The coaxial conjugate anisotropic enhanced heat exchange tubes (1) are coaxial conjugate anisotropic enhanced heat exchange tube elements as described in claim 1 or 2. The primary gas-to-gas heat exchanger (151) is located on the side of the energy-saving condenser (153) of the energy-saving condenser (153) of the energy-saving condenser (153) of the energy-saving condenser (151), and a baffle is set between the primary gas-to-gas heat exchanger (151) and the energy-saving condenser (153) of the energy-saving condenser (153). The secondary gas-to-gas heat exchanger (152) is located directly below the energy-saving condenser (153) of the energy-saving condenser (153). A horizontal baffle is set in the secondary gas-to-gas heat exchanger (152) to divide it into at least two heat exchange zones. The shell side is the flue gas passage, and the tube side is the cold air passage; the secondary gas-to-gas heat exchanger (152) is provided with a cold air inlet, and the primary gas-to-gas heat exchanger (151) is provided with an air outlet; when the coaxial conjugate anisotropic enhanced heat exchange tube (1) is welded to the tube sheet, a composite tube sheet connection method is adopted; a tube sheet (11) of the same material as the coaxial conjugate anisotropic enhanced heat exchange tube (1) is added on the conventional steel tube sheet (12), and the tube sheet (11) and the coaxial conjugate anisotropic enhanced heat exchange tube (1) are sealed and welded together, and the conventional steel tube sheet (12) provides strength support; the conventional steel tube sheet (12) and the tube sheet (11) are connected by diffusion welding or bolts; when the coaxial conjugate anisotropic enhanced heat exchange tube (1) is applied to the heat exchanger, it is a partition wall heat exchanger structure, the working fluid inside the tube flows parallel to the direction of the tube's central axis, and the working fluid outside the tube flows perpendicular to the direction of the tube's central axis.

7. A shell-and-tube air preheater, characterized in that, The heat exchange tube bundle adopts multiple coaxial conjugate anisotropic enhanced heat exchange tubes (1). The coaxial conjugate anisotropic enhanced heat exchange tubes (1) are the coaxial conjugate anisotropic enhanced heat exchange tube elements as described in claim 1 or 2. The coaxial conjugate anisotropic enhanced heat exchange tubes (1) are flue gas channels and the shell side is an air channel. The air side is provided with four passes, and multiple baffles are provided along the axial direction of the coaxial conjugate anisotropic enhanced heat exchange tube (1). The baffles and the air preheater shell provide an S-shaped channel for the air. When the coaxial conjugate anisotropic enhanced heat exchange tube (1) is welded to the tube sheet, a composite tube sheet connection method is adopted. A tube sheet (11) of the same material as the coaxial conjugate anisotropic enhanced heat exchange tube (1) is added on the conventional steel tube sheet (12). The tube sheet (11) is sealed and welded to the coaxial conjugate anisotropic enhanced heat exchange tube (1). The conventional steel tube sheet (12) provides strength support. The conventional steel tube sheet (12) and the tube sheet (11) are connected by diffusion welding or bolts. When the coaxial conjugate anisotropic enhanced heat exchange tube (1) is applied to the heat exchanger, it is a partition wall heat exchanger structure. The flow direction of the working fluid inside the tube is parallel to the direction of the tube's central axis, and the flow direction of the working fluid outside the tube is perpendicular to the direction of the tube's central axis.

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