A heat exchanger and method for enhancing vortex heat transfer based on memory alloy

Abstract

The present invention discloses a vortex heat transfer enhanced heat exchanger and method based on memory alloy, which belongs to the field of thermal engineering of heat transfer enhanced heat exchangers. The heat exchanger includes a heat exchange tube, a tube sheet, an outer vortex generator and an inner vortex generator. The vortex generator guides the fluid to form a vortex or vortex structure inside the device, thereby changing the velocity distribution and flow direction of the fluid. The present invention uses memory alloy to manufacture a vortex generator and applies it to the heat exchanger. At the same time, the inner and outer layers of vortex generators are creatively set to make the turbulence of the internal fluid more intense, thereby enhancing heat transfer. When the temperature of the shell-side fluid exceeds the critical temperature of the memory alloy, the shape of the vortex generator changes adaptively, changing the flow state of the fluid and enhancing heat transfer. The vortex heat transfer enhanced heat exchanger designed by the present invention is suitable for a variety of working conditions. At the same time, the heat transfer enhancement method proposed based on the heat exchanger also has good guiding significance for engineering practice.

Description

Technical Field

[0001] The present invention belongs to the field of thermal engineering of heat exchangers with enhanced heat transfer, and in particular relates to a heat exchanger with enhanced vortex heat transfer based on memory alloy and a method thereof. Background Art

[0002] Memory alloys are a class of materials with unique properties, most notably their ability to return to their original shape under specific conditions after undergoing a change in shape. The properties of memory alloys stem from phase transitions in their microstructure, typically changes in the crystal lattice structure. These alloys undergo a solid-state phase transition within a specific temperature range, resulting in different elastic shapes at different temperatures. Furthermore, they can undergo reversible transitions, allowing the material to switch between two shapes at two different temperatures.

[0003] A vortex generator is a device designed to change the flow pattern of a fluid and enhance its kinetic energy. Its basic principle is to change the velocity distribution and flow direction of the fluid by guiding the fluid to form a vortex or eddy structure inside the device. The shape and structure of the vortex generator can vary depending on the application, with common designs including spiral, cut-sheet, and wavy shapes. These structures can guide the fluid to produce rotational or wavy motion, thereby introducing turbulence and vortices into the fluid. The performance of the vortex generator depends on its geometry, installation position, and the flow rate and properties of the fluid. In the field of heat exchange, vortex generators can be used to increase the heat exchange surface area and improve the heat exchange effect between the fluid and the heat exchange surface. Summary of the Invention

[0004] The purpose of the present invention is to combine memory alloy and vortex generator, apply them in the field of enhanced heat transfer, and provide a vortex heat transfer enhanced heat exchanger and method based on memory alloy, which can further improve the heat exchange capacity of the heat exchanger.

[0005] The specific technical solutions adopted in the present invention are as follows:

[0006] In a first aspect, the present invention provides a heat exchanger with enhanced vortex heat transfer based on a memory alloy, comprising a heat exchange tube, a tube sheet, an outer vortex generator, and an inner vortex generator;

[0007] The vortex heat transfer enhanced heat exchanger has a plurality of heat exchange tubes arranged horizontally inside. All heat exchange tubes are fixed by a plurality of tube sheets arranged at intervals along the tube path. The tube sheets divide each heat exchange tube into a plurality of sections. The plate surfaces of all tube sheets are perpendicular to the tube path direction. A flow channel for the shell-side fluid is left between each tube sheet and the inner bottom or inner top of the vortex heat transfer enhanced heat exchanger. The flow channels between two adjacent tube sheets and the vortex heat transfer enhanced heat exchanger are located at different positions, so that the shell-side fluid can flow in an up and down serpentine shape under the guidance of the tube sheets.

[0008] Each section of each heat exchange tube is provided with an outer vortex generator and an inner vortex generator made of memory alloy on the outside; the inner vortex generator is arranged adjacent to the downstream side of the heat exchange tube, and the outer vortex generator is located outside the inner vortex generator; when the temperature is lower than the critical temperature, the inner vortex generator is an arc-shaped structure that can guide the shell-side fluid to the backflow side of the heat exchange tube, and the outer vortex generator is an inclined plate structure with the downstream side inclined inward and its extension surface is tangent to the outer side surface of the heat exchange tube in the adjacent row downstream; when the temperature is higher than the critical temperature, the inner vortex generator and the outer vortex generator are both arc-shaped structures that bend toward the side of the heat exchange tube.

[0009] Preferably, along the tube-side direction, a shell-side inlet and a shell-side outlet are provided at the head end and the tail end located at the top of the vortex heat transfer enhanced heat exchanger, respectively.

[0010] Furthermore, the tube-side fluid inlet of the vortex heat transfer enhanced heat exchanger is located on the shell-side outlet side, and the tube-side fluid outlet is located on the shell-side inlet side, so that the tube-side fluid and the shell-side fluid flow in opposite directions.

[0011] Preferably, the outer vortex generator and the inner vortex generator are both fixed to the tube sheet by threaded connection.

[0012] Preferably, the outer layer vortex generator and the inner layer vortex generator are both cut sheet type vortex generators.

[0013] Preferably, the outer vortex generator and the inner vortex generator are arranged in pairs and are respectively located on both sides of the outside of the heat exchange tube.

[0014] In a second aspect, the present invention provides a method for enhancing vortex heat transfer using any of the memory alloy-based vortex heat transfer enhanced heat exchangers described in the first aspect, specifically as follows:

[0015] The shell-side fluid enters the vortex heat transfer enhanced heat exchanger from the shell-side inlet, contacts the heat exchange tube, the inner vortex generator and the outer vortex generator, and is divided into four types of fluids A to D according to the contact area;

[0016] When the temperature of the shell-side fluid is lower than its critical temperature: the fluid C that is in direct contact with the outer surface of the heat exchange tube directly exchanges heat with the heat exchange tube with a lower temperature, taking away the cold on the upstream side of the heat exchange tube; the fluid B that is in contact with the inner vortex generator is guided by the inner vortex generator to guide the shell-side fluid to the backflow side of the heat exchange tube, making full use of the cold on the backflow side of the heat exchange tube. At the same time, the vortex generated by the inner and outer vortex generators makes the turbulence of the shell-side fluid more intense, thereby enhancing heat exchange and improving the heat transfer coefficient; the fluid A that is in contact with the outer vortex generator is guided by the outer vortex generator to push part of the fluid A into the area where the fluid B is located and then contact the backflow side of the heat exchange tube for heat exchange, and the other part of the fluid A is spun out from the inner vortex generator. The vortex generator flows between the inner and outer vortex generators. Since the extension surface of the outer vortex generator is tangent to the outer surface of the downstream adjacent heat exchange tube, the fluid A passing between the inner and outer vortex generators is accelerated and impacts the downstream adjacent heat exchange tube at a higher speed, thereby enhancing the convective heat transfer on the surface of the downstream adjacent heat exchange tube. Due to the inclined structure of the outer vortex generator, the fluid D passing between the two adjacent outer vortex generators first has a decreased flow velocity at the inlet, and then the fluid velocities on both sides at the outlet are relatively large, thereby forming a transverse flow, and sufficient heat exchange will also be carried out between the shell-side fluids of different temperatures. At the same time, the inner and outer vortex generators will cause longitudinal vortices in the flow direction of the shell-side fluid, and the boundary layer of the heat exchange tube will also change accordingly, thereby improving the heat transfer coefficient.

[0017] When the temperature of the shell-side fluid rises to its critical temperature, the temperature difference between the tube-side fluid and the shell-side fluid increases, and the amount of heat to be transferred also increases. At this time, the shapes of the inner and outer vortex generators automatically change, and their curvatures spontaneously bend toward the direction of the heat exchange tube. Under the guidance of the inner vortex generator, the flow path of fluid B will be closer to the heat exchange tube, and the heat exchange with the backflow side of the heat exchange tube will be more sufficient. Fluid A is also closer to the heat exchange tube, and the heat exchange is more sufficient. At the same time, the lateral relative velocity of fluid A on both sides of the heat exchange tube is also greater. After leaving the inner vortex generator, the liquid turbulence becomes greater, which has a gain effect on the heat transfer of the fluid C in the next layer of heat exchange tubes; at the same time, the vortices generated by the inner and outer vortex generators also enhance heat transfer; when the temperature difference between the shell-side fluid and the tube-side fluid is large, the shape of the inner and outer vortex generators can be adaptively adjusted to improve the heat transfer coefficient of a single pipe by utilizing the characteristic of the memory alloy that it can switch between two shapes at two different temperatures, further enhancing the heat transfer capacity of the vortex heat transfer enhanced heat exchanger;

[0018] When the shell-side fluid passes through each row of heat exchange tubes, it is affected by the inner and outer vortex generators, thereby impacting the downstream heat exchange tubes at a higher flow rate, achieving heat exchange with the tube-side fluid, and then flowing out from the shell-side outlet.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) The present invention uses memory alloy to manufacture the vortex generator, which can automatically change the shape of the vortex generator when the temperature of the medium in the heat exchanger changes, and adapt to different working conditions.

[0021] 2) The vortex generator of the present invention can change the flow of the medium in the heat exchanger, increase the degree of turbulence, enhance the mass transfer and heat transfer between the fluids, and improve the efficiency and performance of the process.

[0022] 3) The present invention combines memory alloys with vortex generators, determines the optimal location and shape of the vortex generators through numerical simulation, and sets up two layers of vortex generators, one inside and one outside, which are suitable for various working conditions and further enhance the heat exchange performance of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the vortex heat transfer enhanced heat exchanger of the present invention;

[0024] Figure 2 Schematic diagram of the shape and position of the inner and outer vortex generators of the present invention when the temperature is lower than the critical temperature;

[0025] Figure 3 Schematic diagram of the shape and position of the inner and outer vortex generators of the present invention when the temperature is higher than the critical temperature;

[0026] The reference numerals in the figure are: 1, shell side inlet; 2, heat exchange tube; 3, tube sheet; 5, shell side outlet; 9, outer vortex generator; 10, inner vortex generator. DETAILED DESCRIPTION

[0027] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention may be combined accordingly, provided that there is no conflict between them.

[0028] like Figure 1 As shown, the present invention provides a heat exchanger with enhanced vortex heat transfer based on a memory alloy. The heat exchanger primarily comprises heat exchange tubes 2, a tube sheet 3, outer vortex generators 9, and inner vortex generators 10. The outer vortex generators 9 are arranged in pairs outside a single heat exchange tube 2, and the inner vortex generators 10 are also arranged in pairs. Multiple vortex generators are positioned between multiple heat exchange tubes to alter the flow of the fluid within the shell side of the heat exchanger. In actual use, the vortex generators guide the fluid to form vortices or eddy currents within the device, thereby changing the velocity distribution and flow direction of the fluid.

[0029] The structure and connection method of each component will be described in detail below.

[0030] In the present invention, a vortex heat transfer enhanced heat exchanger is horizontally arranged with multiple parallel heat exchange tubes 2 arranged with intervals in both the horizontal and vertical directions. Along the tube-pass direction (i.e., along the tube length), all heat exchange tubes 2 are secured by multiple tube sheets 3, which are spaced apart and divide each heat exchange tube 2 into multiple sections. The surfaces of all tube sheets 3 are perpendicular to the tube-pass direction. A flow channel for the shell-side fluid is provided between each tube sheet 3 and the inner bottom or top of the vortex heat transfer enhanced heat exchanger. The flow channels between two adjacent tube sheets 3 and the vortex heat transfer enhanced heat exchanger are located at different positions, allowing the shell-side fluid to flow in an upward and downward serpentine pattern under the guidance of the tube sheets 3. That is to say, along the tube side direction, the flow channels are located in the inner bottom, inner top, inner bottom, inner top, inner bottom... in sequence, and the tube sheet 3 can completely cover the cross section of the interior of the vortex heat transfer enhanced heat exchanger except for the flow channel, so that when the shell side fluid flows through the cross section, it can only flow through the flow channel there and cannot flow from other positions of the tube sheet 3.

[0031] In a preferred embodiment of the present invention, along the tube side direction, the shell side inlet 1 and the shell side outlet 5 are respectively provided at the head end and the tail end of the top of the vortex heat transfer enhanced heat exchanger. At the same time, in order to enhance the heat exchange effect, the tube side fluid inlet of the vortex heat transfer enhanced heat exchanger can be set on the side of the shell side outlet 5, and the tube side fluid outlet can be set on the side of the shell side inlet 1, so that the tube side fluid and the shell side fluid flow in opposite directions. For example Figure 1 As shown, the shell-side inlet 1 of this embodiment is located on the right side of the top of the vortex heat transfer enhanced heat exchanger, and the shell-side outlet 5 is located on the left side of the top of the vortex heat transfer enhanced heat exchanger, that is, the shell-side fluid flows from right to left, and the tube-side fluid flows from left to right, so that the shell-side fluid can better achieve heat exchange with the tube-side fluid.

[0032] In the present invention, each section of each heat exchange tube 2 is equipped with an outer vortex generator 9 and an inner vortex generator 10. Both outer and inner vortex generators are made of a memory alloy. In practice, when they reach a critical temperature, the outer and inner vortex generators 9 and 10 change shape, thereby altering the flow of fluid within the heat exchanger and enhancing heat transfer. The inner vortex generator 10 is positioned adjacent to the downstream side of the heat exchange tube 2, with the outer vortex generator 9 located outside the inner vortex generator 10.

[0033] It should be noted that, unless otherwise specified, the directions indicated by "downstream" and "upstream" in the present invention are the rear and front directions of the shell-side fluid flow direction. Since the shell-side fluid in the present invention flows up and down in a serpentine shape under the guidance of the tube sheet 3, the "downstream" and "upstream" of the vortex heat transfer enhanced heat exchanger are constantly changing in the flow unit between adjacent tube sheets 3. For example, Figure 1As shown in the figure, when the shell-side fluid just enters the vortex heat transfer enhanced heat exchanger from the upper right, the shell-side fluid flows from top to bottom, so "upstream" is top and "downstream" is bottom; when the shell-side fluid flows from bottom to top after passing through the first tube sheet 3, "upstream" is bottom and "downstream" is top.

[0034] It should be noted that, unless otherwise specified, the "inside" and "outside" in the present invention are relative to the "heat exchange tube 2", the side adjacent to the heat exchange tube 2 is the "inside", and the side away from the heat exchange tube 2 is the "outside".

[0035] In a preferred embodiment of the present invention, the outer vortex generator 9 and the inner vortex generator 10 can be arranged in pairs, that is, the two outer vortex generators 9 and the two inner vortex generators 10 of each pair are respectively located on both sides of the exterior of the heat exchange tube 2. Figure 2 and 3 As shown, each section of the outer left side and outer right side of each heat exchange tube 2 is provided with an inner vortex generator 10 and an outer vortex generator 9 from the inside to the outside, that is, there are two inner vortex generators 10 and two outer vortex generators 9. The "left side" and "right side" here refer to Figure 1 The horizontal left and right positions of the structure in the right view.

[0036] In the present invention, when the temperature is below the critical temperature, the inner vortex generator 10 is an arc-shaped structure that directs the shell-side fluid toward the backflow side of the heat exchange tubes 2. The outer vortex generator 9 is an inclined plate structure with the downstream side tilted inward, and its extended surface is tangent to the outer surface of the heat exchange tubes 2 in the immediately adjacent downstream row. When the temperature is above the critical temperature, both the inner vortex generator 10 and the outer vortex generator 9 are arc-shaped structures that bend toward the heat exchange tubes 2.

[0037] In a preferred embodiment of the present invention, when the temperature does not reach the critical temperature, Figure 2 As shown, each pair of inner vortex generators 10 is an arc-shaped structure open to the upstream, that is, the upstream curvature is greater than the downstream curvature, and each outer vortex generator 9 is an inclined plate-shaped structure open to the upstream; when the temperature exceeds the critical temperature, as shown Figure 3 As shown, each pair of inner vortex generators 10 and outer vortex generators 9 are arc-shaped structures bent toward the side of the heat exchange tube 2, and the upstream distance between each pair of inner vortex generators 10 is greater than the downstream distance between the two, and the upstream distance between each pair of outer vortex generators 9 is greater than the downstream distance between the two.

[0038] In a preferred embodiment of the present invention, Figure 2 and 3As shown, the outer vortex generator 9 and the inner vortex generator 10 are both fixed in the middle, and the inner and outer vortex generators are connected to the adjacent tube sheet 3 by threaded connection. A plurality of inner and outer vortex generators are connected to one tube sheet 3. However, in actual use, the position and specific shape of the vortex generator fixed on the tube sheet should be changed according to different working conditions. The working conditions that should be taken into account include the temperature and velocity of the shell-side fluid and the tube-side fluid. When the size and other conditions of the internal components of the heat exchanger change, the position and specific shape of the vortex generator fixed on the tube sheet should also be changed accordingly. In the actual research and development stage, numerical simulation should be used to determine the optimal fixed position and shape of the vortex generator based on the actual working conditions before production and manufacturing, so as to better control the shape of the outer vortex generator 9 and the inner vortex generator 10 when the temperature is below and above the critical temperature, so as to achieve better heat exchange effect.

[0039] In a preferred embodiment of the present invention, the span of the inner and outer vortex generators depends on the design of the heat exchanger and is mainly determined by the distance between adjacent tube sheets 3. When the distance between adjacent tube sheets is small and the shell-side fluid flow rate is small, and the impact force of the flow on the inner and outer vortex generators is small, the inner and outer vortex generators can be fixed to a single tube sheet. In this case, the inner and outer vortex generators can be fixed to the tube sheets on both sides in the fluid turning area. Due to the change in liquid flow direction, the inclination direction of the inner and outer vortex generators is also different. When the distance between adjacent tube sheets is large or the shell-side fluid flow rate is large, and the impact force of the flow on the inner and outer vortex generators is large, the inner and outer vortex generators should be fixed to the tube sheets on both sides to increase stability. In this case, the inner and outer vortex generators are not set in the shell-side fluid turning area.

[0040] In a preferred embodiment of the present invention, the shell-side fluid can be a hot fluid, and the tube-side fluid can be a cold fluid; however, the reverse arrangement can be employed, i.e., the shell-side fluid can be a cold fluid, and the tube-side fluid can be a hot fluid, as desired. Both the outer vortex generator 9 and the inner vortex generator 10 are preferably cut-sheet vortex generators.

[0041] Utilizing the aforementioned vortex heat transfer enhanced heat exchanger based on memory alloy, the present invention also provides a vortex heat transfer enhancement method, which is specifically as follows:

[0042] The shell-side fluid enters the vortex heat transfer enhanced heat exchanger from the shell-side inlet 1, contacts the heat exchange tube 2, the inner vortex generator 10 and the outer vortex generator 9, and is divided into four types of fluids A to D according to the contact area: the part of the shell-side fluid that is in direct contact with the outer surface of the heat exchange tube 2 is fluid C, the part of the shell-side fluid that enters between the inner vortex generator 10 and the heat exchange tube 2 and contacts the inner vortex generator 10 is fluid B, the part of the shell-side fluid that enters between the inner vortex generator 10 and the outer vortex generator 9 is fluid A, and the part of the shell-side fluid that enters between two adjacent outer vortex generators 9 on the outside of different heat exchange tubes is fluid D. Figure 2 and 3 shown.

[0043] When the shell-side fluid temperature is lower than its critical temperature, such as Figure 2 As shown, fluid C, which is in direct contact with the outer surface of the heat exchange tube 2, directly exchanges heat with the lower-temperature heat exchange tube 2, removing the cooling energy from the upstream side of the heat exchange tube 2. Fluid B, which is in contact with the inner vortex generator 10, is guided by the inner vortex generator 10, directing the shell-side fluid to the downstream side of the heat exchange tube 2, fully utilizing the cooling energy from the downstream side of the heat exchange tube 2. At the same time, the vortices generated by the inner vortex generator 10 and the outer vortex generator 9 increase the turbulence of the shell-side fluid, thereby enhancing heat exchange and improving the heat transfer coefficient. Fluid A in contact with the outer vortex generator 9 is guided by the outer vortex generator 9, pushing a portion of fluid A into the area where fluid B is located, thereby contacting the backflow side of the heat exchange tube 2 for heat exchange. The remaining portion of fluid A flows between the inner vortex generator 10 and the outer vortex generator 9. Because the extended surface of the outer vortex generator 9 is tangential to the outer surface of the downstream adjacent heat exchange tube 2, fluid A passing between the inner vortex generator 10 and the outer vortex generator 9 is accelerated and impacts the downstream adjacent heat exchange tube 2 at a higher speed, enhancing convective heat transfer on the surface of the downstream adjacent heat exchange tube 2. Due to the inclined structure of the outer vortex generator 9, the flow velocity of fluid D passing between two adjacent outer vortex generators 9 first decreases at the inlet, and then the fluid velocities on both sides are higher at the outlet, forming a transverse flow, and sufficient heat exchange also occurs between the shell-side fluids of different temperatures. At the same time, the inner vortex generator 10 and the outer vortex generator 9 will cause longitudinal vortex in the shell-side fluid flow direction, and the boundary layer of the heat exchange tube 2 will also change accordingly, thereby improving the heat transfer coefficient.

[0044] When the shell-side fluid temperature rises to its critical temperature, Figure 3As shown, the shapes of the inner vortex generator 10 and the outer vortex generator 9 automatically change, their curvatures spontaneously bending toward the heat exchange tube 2. Under the guiding action of the inner vortex generator 10, fluid B's flow path will be closer to the heat exchange tube 2, allowing for more complete heat exchange with the backflow side of the heat exchange tube 2. Fluid A will also be closer to the heat exchange tube 2, allowing for more complete heat exchange. Simultaneously, the lateral relative velocity of fluid A on both sides of the heat exchange tube 2 is also greater. After exiting the inner vortex generator 10, the liquid turbulence becomes greater, which has a positive effect on the heat exchange with fluid C in the next layer of heat exchange tube 2. At this point, based on the original flow state, fluid B's flow path will be closer to the heat exchange tube 2, allowing for more complete heat exchange with the backflow side of the heat exchange tube 2. Simultaneously, the vortices generated by the inner vortex generator 10 and the outer vortex generator 9 also enhance heat transfer. When the temperature difference between the shell-side fluid and the tube-side fluid is large, the shape of the inner vortex generator 10 and the outer vortex generator 9 can be adaptively adjusted to improve the heat transfer coefficient of a single pipeline by utilizing the property of the memory alloy that it can switch between two shapes at two different temperatures, thereby further enhancing the heat transfer capacity of the vortex heat transfer enhanced heat exchanger.

[0045] When the shell-side fluid passes through each row of heat exchange tubes 2, it is affected by the inner vortex generator 10 and the outer vortex generator 9, thereby impacting the downstream heat exchange tube 2 at a higher flow rate, achieving heat exchange with the tube-side fluid, and then flowing out from the shell-side outlet 6.

[0046] The present invention uses a memory alloy to manufacture a vortex generator, which is then applied to a heat exchanger. The innovative design of two vortex generators, inner and outer, increases the turbulence of the internal fluid, thereby enhancing heat transfer. When the shell-side fluid temperature exceeds the critical temperature of the memory alloy, the vortex generator's shape adaptively changes, altering the fluid flow and enhancing heat transfer. The vortex heat transfer-enhanced heat exchanger designed by the present invention is suitable for a variety of operating conditions, and the heat transfer enhancement method proposed based on this heat exchanger also has valuable practical application in engineering practice.

[0047] The embodiment described above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A vortex heat transfer enhanced heat exchanger based on memory alloy, characterized in that: It comprises a heat exchange tube (2), a tube sheet (3), an outer vortex generator (9) and an inner vortex generator (10); A plurality of heat exchange tubes (2) are horizontally arranged inside the vortex heat transfer enhanced heat exchanger, and all the heat exchange tubes (2) are fixed by a plurality of tube sheets (3) arranged at intervals along the tube path, and the tube sheets (3) divide each heat exchange tube (2) into a plurality of sections; the plate surfaces of all the tube sheets (3) are perpendicular to the tube path direction, and a flow channel for the circulation of the shell-side fluid is reserved between each tube sheet (3) and the inner bottom or inner top of the vortex heat transfer enhanced heat exchanger, and the flow channels between two adjacent tube sheets (3) and the vortex heat transfer enhanced heat exchanger are located at different positions, so that the shell-side fluid can flow in an upward and downward serpentine shape under the guidance of the tube sheets (3); Each section of each heat exchange tube (2) is provided with an outer vortex generator (9) and an inner vortex generator (10) made of memory alloy; the inner vortex generator (10) is arranged adjacent to the downstream side of the heat exchange tube (2), and the outer vortex generator (9) is located outside the inner vortex generator (10); when the temperature is lower than the critical temperature, the inner vortex generator (10) is an arc-shaped structure capable of guiding the shell-side fluid to the backflow side of the heat exchange tube (2), and the outer vortex generator (9) is an inclined plate structure with an inward inclination on the downstream side and its extension surface is tangent to the outer side surface of the heat exchange tube (2) in the adjacent row downstream; when the temperature is higher than the critical temperature, the inner vortex generator (10) and the outer vortex generator (9) are both arc-shaped structures with a curvature bent toward the side of the heat exchange tube (2); The outer vortex generator (9) and the inner vortex generator (10) are both threadedly connected to the tube sheet (3) for fixation; The outer layer vortex generator (9) and the inner layer vortex generator (10) are arranged in pairs and are respectively located on both sides of the exterior of the heat exchange tube (2).

2. The heat exchanger with enhanced vortex heat transfer based on memory alloy according to claim 1, characterized in that: Along the tube side direction, a shell side inlet (1) and a shell side outlet (5) are respectively provided at the head end and the tail end located at the top of the vortex heat transfer enhanced heat exchanger.

3. The heat exchanger with enhanced vortex heat transfer based on memory alloy according to claim 2, characterized in that: The tube-side fluid inlet of the vortex heat transfer enhanced heat exchanger is located on the shell-side outlet (5) side, and the tube-side fluid outlet is located on the shell-side inlet (1) side, so that the tube-side fluid and the shell-side fluid flow in opposite directions.

4. The heat exchanger with enhanced vortex heat transfer based on memory alloy according to claim 1, characterized in that: The outer layer vortex generator (9) and the inner layer vortex generator (10) are both cut sheet type vortex generators.

5. A method for enhancing vortex heat transfer using a heat exchanger having vortex heat transfer enhancement based on a memory alloy according to any one of claims 1 to 4, characterized in that: The details are as follows: The shell-side fluid enters the vortex heat transfer enhanced heat exchanger from the shell-side inlet (1), contacts the heat exchange tube (2), the inner vortex generator (10) and the outer vortex generator (9), and is divided into four types of fluids A to D according to the contact area; When the temperature of the shell-side fluid is lower than its critical temperature: the fluid C directly in contact with the outer surface of the heat exchange tube (2) directly exchanges heat with the heat exchange tube (2) with a lower temperature, taking away the cold on the upstream side of the heat exchange tube (2); the fluid B in contact with the inner vortex generator (10) is guided by the inner vortex generator (10) to guide the shell-side fluid to the downstream side of the heat exchange tube (2), making full use of the cold on the downstream side of the heat exchange tube (2); at the same time, the vortex generated by the inner vortex generator (10) and the outer vortex generator (9) makes the turbulence of the shell-side fluid more intense, thereby enhancing heat exchange and improving the heat transfer coefficient; the fluid A in contact with the outer vortex generator (9) is guided by the outer vortex generator (9) to push a part of the fluid A into the area where the fluid B is located and then contact the downstream side of the heat exchange tube (2) for heat exchange, and the other part of the fluid A is pushed from the inner vortex generator (10) to the downstream side of the heat exchange tube (2). 0) and the outer vortex generator (9). Since the extension surface of the outer vortex generator (9) is tangent to the outer surface of the downstream adjacent heat exchange tube (2), the fluid A passing between the inner vortex generator (10) and the outer vortex generator (9) is accelerated and impacts the downstream adjacent heat exchange tube (2) at a higher speed, thereby enhancing the convective heat transfer on the surface of the downstream adjacent heat exchange tube (2); due to the inclined structure of the outer vortex generator (9), the fluid D passing between the two adjacent outer vortex generators (9) first decreases in velocity at the inlet, and then the fluid velocities on both sides at the outlet are larger, thereby forming a transverse flow, and sufficient heat exchange will also be carried out between the shell-side fluids of different temperatures; at the same time, the inner vortex generator (10) and the outer vortex generator (9) will cause a longitudinal vortex in the flow direction of the shell-side fluid, and the boundary layer of the heat exchange tube (2) will also change accordingly, thereby improving the heat transfer coefficient; When the temperature of the shell-side fluid rises to its critical temperature, the temperature difference between the tube-side fluid and the shell-side fluid increases, and the amount of heat to be transferred also increases. At this time, the shapes of the inner vortex generator (10) and the outer vortex generator (9) automatically change, and their curvatures spontaneously bend toward the direction of the heat exchange tube (2); under the guiding effect of the inner vortex generator (10), the flow path of fluid B will be closer to the heat exchange tube (2), and the heat exchange with the back flow side of the heat exchange tube (2) will be more sufficient; fluid A will also be closer to the heat exchange tube (2), and the heat exchange will be more sufficient. At the same time, the lateral relative velocity of fluid A on both sides of the heat exchange tube (2) will also increase. The turbulence of the liquid is greater after it leaves the inner vortex generator (10), which has a gain effect on the heat transfer of the fluid C in the next layer of heat exchange tube (2); at the same time, the vortices generated by the inner vortex generator (10) and the outer vortex generator (9) also enhance the heat transfer; when the temperature difference between the shell-side fluid and the tube-side fluid is large, the shape of the inner vortex generator (10) and the outer vortex generator (9) can be adaptively adjusted to improve the heat transfer coefficient of a single pipe by utilizing the characteristic that the memory alloy can switch between two shapes at two different temperatures, thereby further enhancing the heat transfer capacity of the vortex heat transfer enhanced heat exchanger; When the shell-side fluid passes through each row of heat exchange tubes (2), it is affected by the inner vortex generator (10) and the outer vortex generator (9), thereby impacting the downstream heat exchange tube (2) at a higher flow rate, achieving heat exchange with the tube-side fluid, and then flowing out from the shell-side outlet (5).

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