A printed circuit board heat exchanger core with bionic airfoil fins

Abstract

This invention discloses a printed circuit board heat exchanger core with biomimetic airfoil fins, comprising: multiple heat exchange plates and multiple biomimetic airfoil fins. The multiple biomimetic airfoil fins adopt a biomimetic whale fin design and are arranged at intervals on each heat exchange plate. The multiple heat exchange plates are stacked on top of each other and have reserved fluid inlets and outlets to form a complete fluid channel. This invention increases the heat exchange area and improves the compactness of the heat exchanger core by designing traditional airfoil fins with a biomimetic whale fin design. At the same time, it can induce strong longitudinal vortices and high-speed jets, reduce the coherence of flow separation at the trailing edge of the airfoil and wake vortex shedding, thereby reducing the flow resistance and flow-induced noise of the heat exchange channel and improving the overall heat exchange performance of the airfoil fins.

Description

Technical Field

[0001] This invention relates to a printed circuit board heat exchanger core with biomimetic airfoil fins, belonging to the technical field of high-efficiency and low-resistance heat exchange devices. Background Technology

[0002] In recent years, Brayton cycle power systems using supercritical CO2 as the working fluid have shown broad application prospects in concentrated solar thermal power generation, new thermal power generation, advanced compressed energy storage, advanced nuclear reactors, and enhanced geothermal systems due to their higher energy density, more compact equipment, and advantages such as modularization, miniaturization, and rapid load changes. These power systems involve numerous heat exchange processes between supercritical CO2 and supercritical CO2 (or molten salt, high-temperature particles, heat transfer oil, and air), with the heat exchanger core cost accounting for over 50% of the overall system cost. Printed circuit board type heat exchanger cores, with their outstanding advantages of high efficiency, compactness, and resistance to high temperatures and pressures, have been widely recommended and adopted by the industry.

[0003] In conventional printed circuit board heat exchanger cores, fluid channels are mostly straight. With further research and optimization, various channel fin structures have been proposed, such as Z-shaped, S-shaped, airfoil-shaped, asymmetric airfoil-shaped, and diamond-shaped fins. Current research suggests that airfoil fins have better overall heat transfer performance. However, due to the influence of fluid flow, traditional smooth, straight airfoil fins often exhibit flow separation at the trailing edge of the apex, forming a tail-separated vortex region. The fluid velocity in the tail region is low, resulting in significant kinetic energy dissipation. Furthermore, the coherence of the tail vortex shedding leads to increased flow resistance and flow-induced noise, thus weakening the overall heat transfer performance of the fins. Therefore, a new technical solution is needed to address these issues. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a printed circuit board heat exchanger core with biomimetic airfoil fins, which solves the problem of increased flow resistance at the trailing edge of the airfoil fins and weakened heat exchange performance caused by flow separation and delamination.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows:

[0006] This invention discloses a printed circuit board heat exchanger core with biomimetic airfoil fins, comprising: multiple heat exchange plates and multiple biomimetic airfoil fins. The multiple biomimetic airfoil fins adopt a biomimetic whale fin design and are arranged at intervals on each heat exchange plate. The multiple heat exchange plates are stacked on each other and have reserved fluid inlets and fluid outlets to form a complete fluid channel.

[0007] Furthermore, the biomimetic airfoil has a symmetrical structure, with a fin width of 1–5 mm, a fin chord length of 4–20 mm, and a fin height that is the same as the height of the fluid channel.

[0008] Furthermore, the leading edge of the biomimetic airfoil is provided with a cosine-distributed concave-convex structure, the number of cycles of the cosine structure is 2 to 6, the top-bottom distance of the cosine concave-convex structure is 1 / 10 to 1 / 6 of the chord length of the airfoil, and the cross-sectional airfoil size of the cosine concave-convex structure is proportional to the airfoil size of the top end face.

[0009] Furthermore, the biomimetic airfoil fin surface is provided with multiple pairs of rectangular longitudinal vortex generators, which are located at the starting position of the trailing edge of the fin.

[0010] Furthermore, the distance between the front end of the rectangular longitudinal vortex generator and the front end of the fin is 1 / 4 to 1 / 3 of the fin chord length. The rectangular longitudinal vortex generator has a length of 0.5 to 3.5 mm, a height of 0.25 to 1.75 mm, a thickness of 0.1 to 2 mm, and an angle of 20° to 40° with the horizontal direction.

[0011] Furthermore, the biomimetic airfoil fins of the adjacent heat exchange plates face opposite directions, and the fluid flow direction in the fluid channel is opposite, so they are used as cold fluid heat exchange plates and hot fluid heat exchange plates, respectively.

[0012] Furthermore, the fluid inlet of the heat exchange plate is located on one side of the leading edge of the bionic airfoil, and the fluid outlet is located on one side of the trailing edge of the bionic airfoil.

[0013] Furthermore, the heat exchange plates are sealed by diffusion welding, the height of the heat exchange plates is 1-8 mm, the height of the fluid channel is 1-12 mm, and the ratio of the height of the heat exchange plates to the height of the fluid channel is 1-2.

[0014] Furthermore, the biomimetic airfoil fins are arranged in a staggered manner on the heat exchange plate, with equal spacing between each row of biomimetic airfoil fins.

[0015] Furthermore, the lateral spacing of the biomimetic airfoil is 0.8 to 4 times the fin width, the staggered spacing of the fins is 0.8 to 2 times the fin chord length, and the longitudinal spacing of the fins is 1.6 to 4 times the fin chord length.

[0016] The technical solutions of the embodiments of the present invention can have the following beneficial effects:

[0017] (1) The leading edge of the airfoil adopts a biomimetic concave-convex structure design, which can induce a rotating longitudinal vortex on the inclined surface of the leading edge of the airfoil, enhance the convective heat transfer capability of the leading edge of the airfoil, and at the same time, the longitudinal vortex enhances the fluid disturbance, strengthens the energy and mass exchange between the boundary layer fluid and the main fluid, provides energy for the continuous adhesion of the boundary layer, and slows down the boundary layer flow separation on the trailing edge of the airfoil, thereby reducing flow resistance and enhancing heat transfer.

[0018] (2) Pairs of rectangular longitudinal vortex generators are set on the trailing edge of the airfoil, which can further enhance the secondary vortex disturbance and enhance the mixing between the fin boundary layer fluid and the main fluid. At the same time, the rectangular longitudinal vortex generator forms a tapered channel on the airfoil surface. The fluid is accelerated in the channel similar to a nozzle and forms a jet impact at the trailing edge of the airfoil. Under the combined effect of the secondary vortex and the jet, the coherence of the flow separation and wake vortex shedding at the trailing edge of the airfoil is further improved, which enhances the boundary layer heat transfer and reduces the flow-induced noise, thereby improving the overall heat transfer performance of the heat exchanger core.

[0019] (3) The concave-convex structure design of the leading edge of the airfoil and the extended surface of the rectangular longitudinal vortex generator increase the heat exchange area and improve the compactness of the heat exchanger core.

[0020] This application provides a printed circuit board heat exchanger core with biomimetic airfoil fins. By designing traditional airfoil fins in a biomimetic whale fin pattern, the heat exchange area is increased, the compactness of the heat exchanger core is improved, and strong longitudinal vortices and high-speed jets are induced. This reduces the coherence of flow separation at the trailing edge of the airfoil and the shedding of the wake vortex, thereby reducing the flow resistance and flow-induced noise of the heat exchange channel and improving the overall heat exchange performance of the airfoil fins. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a printed circuit board heat exchanger core with biomimetic airfoil fins according to an exemplary embodiment.

[0022] Figure 2 This is a schematic diagram of a biomimetic airfoil structure according to an exemplary embodiment;

[0023] Figure 3 This is a top view of a biomimetic airfoil according to an exemplary embodiment;

[0024] Figure 4 This is a side view of a biomimetic airfoil fin shown according to an exemplary embodiment;

[0025] Figure 5 This is a front view of a biomimetic airfoil according to an exemplary embodiment;

[0026] Figure 6 This is a front view of a printed circuit board heat exchanger core with biomimetic airfoil fins, according to an exemplary embodiment.

[0027] Figure 7 This is a top view of a printed circuit board heat exchanger core with biomimetic airfoil fins, according to an exemplary embodiment.

[0028] In the diagram: 1. Heat exchange plate; 2. Cold fluid channel; 3. Hot fluid channel; 4. Bionic airfoil fin; 5. Bionic airfoil fin leading edge concave-convex structure; 6. Rectangular longitudinal vortex generator; where h1 is the height of the heat exchange plate, h2 is the height of the fluid channel, and L... h L is the lateral spacing between the fins. c L represents the fin staggered spacing. z L is the longitudinal spacing between the fins, A is the chord length of the fins, h is the height of the rectangular longitudinal vortex generator, L1 is the distance from the front end of the rectangular longitudinal vortex generator to the front end of the fins, L2 is the length of the rectangular longitudinal vortex generator, and x is the distance to the top of the fins. x Let H be the fin chord length at position x from the top of the fin, H be the fin height, α be the angle between the rectangular longitudinal vortex generator and the horizontal direction, and K be the fin width. x This represents the fin width at a distance x from the top of the fin. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0030] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure of the invention, components and arrangements of specific examples are described below. Furthermore, reference numerals and / or letters may be repeated in different examples. This repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. Descriptions of well-known components, processing techniques, and processes are omitted in this invention to avoid unnecessarily limiting the invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] like Figure 1As shown in the figure, an embodiment of the present invention provides a printed circuit board heat exchanger core with biomimetic airfoil fins, comprising: multiple heat exchange plates 1 and multiple biomimetic airfoil fins 4. The multiple biomimetic airfoil fins 4 adopt a biomimetic whale fin design and are arranged at intervals on each heat exchange plate 1. The multiple heat exchange plates 1 are stacked on top of each other and have reserved fluid inlets and fluid outlets to form a complete fluid channel. Figure 1 The structure shown is only a partial display of the flow channel units of the heat exchange core of the printed circuit board. In actual applications, the number of heat exchange plate layers and the number of biomimetic airfoil fins need to be set according to the actual situation.

[0033] like Figure 2-5 As shown, the biomimetic airfoil 4 has a symmetrical structure, with a fin width K of 1 to 5 mm, a fin chord length L of 4 to 20 mm, and a fin height H that is the same as the fluid channel height h2.

[0034] The biomimetic airfoil 4 adopts a biomimetic whale fin design, simulating the structure of the humpback whale's forefin. The leading edge of the humpback whale's forefin has a special concave-convex nodular structure, which acts as a lift-enhancing disturbance device compared to a smooth flipper of the same size. It can control the water flow over the flipper, maintain fluid adhesion on the trailing edge of the fin, and improve eddy shedding. Therefore, it can also exhibit better heat transfer and aerodynamic performance.

[0035] The biomimetic airfoil fin 4 has a cosine-distributed concave-convex structure 5 at its leading edge. Compared with traditional smooth and straight airfoil fins, the biomimetic airfoil fin adopts a biomimetic concave-convex structure design at its leading edge. When the fluid impacts the fin head-on, the fluid generates a longitudinal secondary vortex perpendicular to the mainstream direction under the induction of the concave-convex inclined surface at the leading edge. This enhances the lateral turbulence of the fluid, strengthens the energy and mass mixing between the boundary layer and the mainstream hot and cold fluids, and enhances the convective impact heat transfer capability of the fin leading edge. At the same time, the longitudinal vortex generated by the concave-convex structure develops downstream of the fin, providing energy for the continuous adhesion of the boundary layer and forming a low-pressure zone. Under the action of the pressure difference between the mainstream high-pressure zone and the vortex low-pressure zone, the fluid on the airfoil surface adheres more closely, thereby delaying and mitigating the flow separation phenomenon around the trailing edge of the airfoil and reducing flow resistance.

[0036] The number of periods of the cosine concave-convex structure 5 on the leading edge of the biomimetic airfoil 4 is 2 to 6. The top-to-bottom distance A of the cosine concave-convex structure is 1 / 10 to 1 / 6 of the chord length of the fin. The airfoil dimensions of the cosine concave-convex structure cross-section are proportional to the airfoil dimensions of the top end face, such as the ratio L of the airfoil chord length at a distance x from the top of the fin. x / L equals the ratio of the airfoil width to K x / K.

[0037] The biomimetic airfoil fin 1 is also provided with multiple pairs of rectangular longitudinal vortex generators 6. The rectangular longitudinal vortex generators 6 are rectangular plate-shaped structures and are set at the starting position of the trailing edge of the fin. When the longitudinal vortex generated by the concave and convex structure flows through the widest part of the fin, the rectangular longitudinal vortex generators arranged in pairs on the trailing edge of the airfoil can further enhance the secondary vortex disturbance and enhance the mixing and heat exchange between the fluid near the fin and the main fluid. At the same time, the inclined arrangement of the rectangular longitudinal vortex generators forms a tapered channel downstream of the airfoil, which accelerates the fluid in a channel similar to a nozzle and forms a jet impact on the trailing edge of the airfoil. Under the combined effect of the longitudinal secondary vortex and the low-pressure zone of the jet, the coherence of the flow separation and wake vortex shedding at the trailing edge of the airfoil is further improved, which enhances the boundary layer heat transfer at the trailing edge of the airfoil and weakens the flow-induced noise generated by the wake vortex, ultimately improving the overall heat exchange performance of the heat exchanger core.

[0038] The distance L1 between the front end of the rectangular longitudinal vortex generator 6 and the front end of the fin 1 is 1 / 4 to 1 / 3 of the fin chord length L. The length L2 of the rectangular longitudinal vortex generator 6 is 0.5 to 3.5 mm, the height h is 0.25 to 1.75 mm, the thickness is 0.1 to 2 mm, and the angle α with the horizontal direction is 20° to 40°.

[0039] The biomimetic airfoil fins of adjacent heat exchange plates face opposite directions, and the fluid flow direction within the fluid channels is opposite, serving as cold fluid heat exchange plates and hot fluid heat exchange plates respectively. That is, if the first heat exchange plate is a hot fluid heat exchange plate, the second heat exchange plate has fins facing opposite directions and the fluid flow direction within the fluid channels, serving as a cold fluid heat exchange plate, and the third layer is still a hot fluid heat exchange plate. Figure 1 The example shows two heat exchange plates, with the lower layer being a cold fluid heat exchange plate and the upper layer being a hot fluid heat exchange plate. Multiple biomimetic airfoil fins 4 on the plate cooperate to form a cold fluid channel 2 and a hot fluid channel 3, respectively.

[0040] The fluid inlet of the heat exchange plate 1 is located on one side corresponding to the leading edge of the biomimetic airfoil fin 4, and the fluid outlet is located on one side corresponding to the trailing edge of the biomimetic airfoil fin 4. The leading edge of the biomimetic airfoil fin 4 is blunt, and the trailing edge is pointed. Fluid enters from the fluid inlet, passes through the fluid channel, and exits from the fluid outlet. Figure 1 The direction indicated by the middle arrow.

[0041] like Figure 6 As shown, the heat exchange plates 1 are sealed by diffusion welding process. The height h1 of the heat exchange plate 1 is 1 to 8 mm, the height h2 of the fluid channels 2 and 3 is 1 to 12 mm, and the ratio of the height h1 of the heat exchange plate 1 to the height h2 of the fluid channels 2 and 3 is 1 to 2.

[0042] like Figure 7As shown, multiple biomimetic airfoil fins 4 are arranged in a staggered manner on the heat exchange plate 1, and the spacing between each row of biomimetic airfoil fins 4 is equal.

[0043] The lateral spacing L of the biomimetic airfoil 4 h The fin width K is 0.8 to 4 times, and the fin stagger spacing L is... c The longitudinal spacing between the fins is 0.8 to 2 times the fin chord length L. z It is 1.6 to 4 times the chord length L of the fin.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A printed circuit board heat exchanger core with biomimetic airfoil fins, characterized in that, include: Multiple heat exchange plates and multiple biomimetic airfoil fins, the multiple biomimetic airfoil fins adopt a biomimetic whale fin design, and are arranged at intervals on each heat exchange plate. The multiple heat exchange plates are stacked on each other and have reserved fluid inlets and fluid outlets to form a complete fluid channel. The biomimetic airfoil has a symmetrical structure, with a fin width of 1-5 mm, a fin chord length of 4-20 mm, and a fin height that is the same as the height of the fluid channel. The biomimetic airfoil has a cosine-distributed concave-convex structure at its leading edge, with a period number of 2 to 6. The distance between the top and bottom of the concave-convex structure is 1 / 10 to 1 / 6 of the chord length of the airfoil. The airfoil dimensions of the concave-convex structure cross section are proportional to the airfoil dimensions of the top end face. The biomimetic airfoil fin surface is provided with multiple pairs of rectangular longitudinal vortex generators, which are located at the starting position of the trailing edge of the fin. The distance between the front end of the rectangular longitudinal vortex generator and the front end of the fin is 1 / 4 to 1 / 3 of the fin chord length. The rectangular longitudinal vortex generator has a length of 0.5 to 3.5 mm, a height of 0.25 to 1.75 mm, a thickness of 0.1 to 2 mm, and an angle of 20° to 40° with the horizontal direction.

2. The printed circuit board heat exchanger core with biomimetic airfoil fins according to claim 1, characterized in that, The biomimetic airfoil fins of adjacent heat exchange plates face opposite directions and the fluid flow direction in the fluid channel, serving as cold fluid heat exchange plates and hot fluid heat exchange plates respectively.

3. The printed circuit board heat exchanger core with biomimetic airfoil fins according to claim 1, characterized in that, The fluid inlet of the heat exchange plate is located on one side of the leading edge of the bionic airfoil, and the fluid outlet is located on one side of the trailing edge of the bionic airfoil.

4. The printed circuit board heat exchanger core with biomimetic airfoil fins according to claim 1, characterized in that, The heat exchange plates are sealed by diffusion welding. The height of the heat exchange plates is 1-8 mm, the height of the fluid channel is 1-12 mm, and the ratio of the height of the heat exchange plates to the height of the fluid channel is 1-2.

5. The printed circuit board heat exchanger core with biomimetic airfoil fins according to claim 1, characterized in that, The biomimetic airfoil fins are arranged in a staggered manner on the heat exchange plate, with equal spacing between each row of biomimetic airfoil fins.

6. A printed circuit board heat exchanger core with biomimetic airfoil fins according to claim 5, characterized in that, The lateral spacing of the biomimetic airfoil fins is 0.8 to 4 times the fin width, the staggered spacing of the fins is 0.8 to 2 times the fin chord length, and the longitudinal spacing of the fins is 1.6 to 4 times the fin chord length.

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