Rib for supercritical working medium printed circuit board heat exchanger

Abstract

The utility model provides a fin for a supercritical working medium printed circuit board heat exchanger, which comprises a plurality of fins arranged on a supercritical working medium heat exchange plate I, the fins are diamond-like, and through holes are arranged on the fins. According to the fin structure, the negative pressure gradient before and after incoming flow of the fins is reduced, incoming flow resistance is reduced, stagnation generated when a fluid working medium impacts the front edges of the fins and fluid separation at the tail parts of the fins are weakened, and the speed, pressure and temperature distribution of the whole fluid is more uniform; therefore, the purposes of improving the stability and efficiency of flow heat exchange of the supercritical fluid with drastic thermophysical property changes, remarkably reducing flow resistance and pressure loss and improving the comprehensive heat exchange capacity of the supercritical working medium printed circuit board heat exchanger are achieved, and the comprehensive heat exchange capacity of the supercritical working medium printed circuit board heat exchanger is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of micro -channel heat exchanger fin, concretely is a kind of fin for supercritical working medium printed circuit board heat exchanger. BACKGROUND

[0002] Printed circuit heat exchanger (PCHE) is a kind of fine channel plate heat exchanger, which is etched with micro cold and hot fluid channels with a diameter of 0.5-2mm on the heat exchange plate by chemical etching method, and then the cold and hot fluid channels are welded into one body by vacuum diffusion technology, which has the characteristics of compact structure, high temperature and high pressure resistance, and is widely used in supercritical carbon dioxide Brayton power generation cycle system, solar thermal power generation cycle system, super-high temperature gas cooled reactor and other fields.

[0003] At present, the common forms of printed circuit board heat exchanger channel structure include Z-shaped continuous type zigzag channel and wing-shaped rib non-continuous channel. The research on the heat transfer and resistance characteristics of printed circuit board heat exchanger with different channel structure forms shows that when the fluid flows through the non-continuous rib, the fluids in adjacent channels are mixed with each other, and the collision with the downstream rib produces turbulence, which is beneficial to destroy the boundary layer, so the wall heat resistance is small, thus the heat transfer performance is stronger, but at the same time, the flow resistance is increased. In addition, when the heat exchange medium of printed circuit board heat exchanger is supercritical fluid, due to the poor stability of the thermophysical properties of supercritical fluid near the critical point, the thermal conductivity, density and dynamic viscosity decrease rapidly with the increase of temperature, and the specific heat capacity at constant pressure increases rapidly first and then decreases.

[0004] In order to adapt to the change characteristics of supercritical fluid heat exchange medium, improve the heat exchange efficiency of heat exchanger, reduce the resistance pressure drop of heat exchanger, and improve the overall performance of heat exchanger, it is necessary to further optimize the channel structure of printed circuit board heat exchanger, such as the Chinese invention patent CN114111393B published on August 29, 2023, which discloses a heat exchange plate, core and printed circuit board heat exchanger based on supercritical working medium, and its technical scheme is as follows: according to the supercritical working medium property change curve, wing-shaped fin area, S-shaped fin area and diamond-shaped fin area are arranged in sequence, and the fins in each fin area are arranged in staggered manner.

[0005] In the above-mentioned prior art, different shaped ribs are arranged in different heat exchange sections of supercritical fluid working medium to improve the comprehensive heat exchange performance of heat exchanger, but there are many fin forms, and the arrangement of fins on the heat exchange plate is complex. UTILITY MODEL CONTENTS

[0006] The utility model provides a rib for supercritical working medium printed circuit board heat exchanger has simple structure, improve supercritical working medium flow heat exchange stability and high efficiency, reduce flow resistance and pressure loss significantly, improve supercritical working medium printed circuit board heat exchanger comprehensive heat exchange capacity's advantage.

[0007] The technical scheme of the present application is:

[0008] A rib for supercritical working medium printed circuit board heat exchanger, including several rib that sets up on supercritical working medium heat exchange board one, the rib is similar to rhombus, be provided with through -hole on the rib.Compared with traditional Z shape and so on continuous type and wing shape rib and so on discontinuous type rib structure's supercritical working medium printed circuit board heat exchanger, the rib structure of the utility model reduces the negative pressure gradient before and after the rib come flow, reduces come flow resistance, weakens the stagnation when fluid working medium impacts the rib leading edge and the fluid separation of rib tail, makes the velocity, pressure and temperature distribution of overall fluid more uniform, thereby reaches the purpose of improving the stability and high efficiency of supercritical fluid flow heat exchange of thermal property change sharply, reduce flow resistance and pressure loss significantly, improve supercritical working medium printed circuit board heat exchanger comprehensive heat exchange capacity, improve supercritical working medium printed circuit board heat exchanger comprehensive heat exchange capacity.

[0009] Further, the rib includes symmetrically arranged similar isosceles triangle structure one and similar isosceles triangle structure two, the bottom edge of the similar isosceles triangle structure one is connected with the similar isosceles triangle structure two, and the through-hole communicates the similar isosceles triangle structure one and the similar isosceles triangle structure two.

[0010] Further, the through-hole is provided with two or more than two along the length direction of the rib.

[0011] Further, the through-hole is symmetrically arranged about the long axis of the rib.

[0012] Further, when the through-hole is provided with two, the port of the through-hole is arranged at the center of the side surface of the rib, so that the flow heat exchange effect is better.

[0013] Further, the aperture d of the through-hole is 0.08mm-0.16mm.

[0014] Further, the length L of the rib is 4.0-16.0mm, the width L of the rib is 0.89-3.56mm, and the height L of the rib is 0.5-2.0mm. c w h

[0015] ​​​Furthermore, each layer of supercritical working fluid heat exchange plate has several rows and columns of fins, with adjacent rows or columns of fins arranged alternately.

[0016] Furthermore, the vertical spacing L between adjacent ribs t The horizontal spacing L between adjacent ribs is 2.11–5.11 mm. z The spacing between adjacent ribs is 4.0–16.0 mm. k The diameter is 4.0 to 16.0 mm.

[0017] Furthermore, a second supercritical working fluid heat exchange plate is provided on the upper surface of the rib, and the lower part of the second supercritical working fluid heat exchange plate and the upper part of the first supercritical working fluid heat exchange plate form a supercritical fluid channel.

[0018] The specific beneficial effects of this utility model include:

[0019] 1. The fin structure of this utility model reduces the negative pressure gradient before and after the incoming flow of the fin, reduces the incoming flow resistance, weakens the stagnation when the fluid working medium impacts the leading edge of the fin and the fluid separation at the tail of the fin, and makes the overall fluid velocity, pressure and temperature distribution more uniform. This achieves the purpose of improving the stability and efficiency of heat transfer of supercritical fluid flow with drastic changes in thermophysical properties, significantly reducing flow resistance and pressure loss, and improving the overall heat transfer capacity of the supercritical working medium printed circuit board heat exchanger.

[0020] 2. The rib structure in this utility model is simple, avoiding the processing of complex curves during production and manufacturing, saving materials and reducing costs. Attached Figure Description

[0021] To more clearly illustrate the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a plan view of the rib of this utility model;

[0023] Figure 2 This is a schematic diagram of the rib formation of this utility model;

[0024] Figure 3 This is a perspective view of the rib in Embodiment 1 of this utility model;

[0025] Figure 4 This is a schematic diagram showing the arrangement of adjacent ribs in this utility model;

[0026] Figure 5This is a schematic diagram of the arrangement of the fins on the supercritical working fluid heat exchange plate of this utility model.

[0027] Figure 6 A three-dimensional view of the core structure of a printed circuit board heat exchanger using the fins of this utility model on the supercritical working fluid side.

[0028] Figure 7 Side view of the core structure of a printed circuit board heat exchanger using the fins of this utility model on the supercritical working fluid side.

[0029] Figure 8 This is a perspective view of the rib in Embodiment 2 of this utility model;

[0030] Figure 9 This is a plan view of the rib in Embodiment 2 of this utility model.

[0031] Explanation of icon numbers:

[0032] 1. Ribs;

[0033] 2. Through hole;

[0034] 3. Supercritical working fluid heat exchange plate one;

[0035] 4. Supercritical working fluid heat exchange plate II;

[0036] 5. Supercritical fluid channel;

[0037] 11. Isosceles triangle-like structure 1;

[0038] 12. Two types of isosceles triangle structures. Detailed Implementation

[0039] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0040] Example 1: A fin for a supercritical working fluid printed circuit board heat exchanger, comprising several fins 1 disposed on a supercritical working fluid heat exchange plate 3. The fins 1 are rhomboid in shape and have through holes 2. This invention's fin structure reduces the negative pressure gradient before and after the incoming flow, decreases the incoming flow resistance, weakens the stagnation when the fluid impacts the leading edge of the fin, and reduces fluid separation at the tail of the fin. This results in a more uniform distribution of overall fluid velocity, pressure, and temperature, thereby improving the stability and efficiency of heat exchange in supercritical fluid flow with drastic changes in thermophysical properties, significantly reducing flow resistance and pressure loss, and enhancing the overall heat exchange capacity of the supercritical working fluid printed circuit board heat exchanger. Furthermore, the fin structure of this invention is simple, avoiding the processing of complex curves during manufacturing, saving materials, and reducing costs.

[0041] Based on the above embodiments, the rib 1 includes a symmetrically arranged isosceles triangle structure 11 and isosceles triangle structure 12, the base of the isosceles triangle structure 11 and the base of the isosceles triangle structure 12 are connected, and the through hole 2 connects the isosceles triangle structure 11 and the isosceles triangle structure 12.

[0042] Specifically, such as Figure 1 , Figure 2 As shown, the rib 1 uses two NACA00 series standard symmetrical airfoil ribs of the same size. The tail portion is crossed and joined along the direction of its axis of symmetry to form a rib with a rhomboid cross section. The outer edge of the cross joint is smooth, forming two symmetrical vertices A of the new rhomboid rib. The two vertices retained at the tail of the original airfoil rib form the other two vertices of the new rhomboid rib.

[0043] Based on the above implementation, two through holes 2 are provided along the length direction of the rib 1 and are symmetrical about the major axis of the rib 1.

[0044] Preferably, the port of the through hole 2 is located at the center of the side of the rib 1, which improves the flow heat transfer effect. Each rib 1 has four sides, and a through hole 2 is provided at the center of each side. Figure 3 As shown, the through hole 2 connects from the left side to the right side along the length of the rib 1.

[0045] Based on the above embodiments, the diameter d of the through hole 2 is 0.08mm to 0.16mm.

[0046] Based on the above implementation method, the length L of the rib 1 c The width L of the rib 1 is 4.0–16.0 mm. w The height L of the rib 1 is 0.89–3.56 mm.h The diameter is 0.5–2.0 mm.

[0047] Based on the above implementation method, each layer of supercritical working fluid heat exchange plate 3 has several rows and columns of ribs 1, with adjacent rows or columns of ribs 1 arranged alternately.

[0048] Based on the above implementation method, the vertical spacing L between adjacent ribs 1 t The horizontal spacing L between adjacent ribs 1 is 2.11–5.11 mm. z The spacing L between adjacent ribs 1 is 4.0–16.0 mm. k The diameter is 4.0 to 16.0 mm.

[0049] Specifically, the symmetrical airfoil ribs adopt NACA0025. Table 1 shows three different structural sizes of rhomboid perforated ribs No.1 to No.3 formed by the standard NACA0025 symmetrical airfoil ribs.

[0050] Table 1. Structural dimensions and distribution dimensions of ribs No. 1 to No. 3 of this utility model on the supercritical working fluid heat exchange plate.

[0051]

[0052]

[0053] Based on the above embodiments, a supercritical working fluid heat exchange plate 2 4 is provided on the upper surface of the rib 1, and the lower part of the supercritical working fluid heat exchange plate 2 4 and the upper part of the supercritical working fluid heat exchange plate 3 form a supercritical fluid channel 5.

[0054] Specifically, tiny supercritical fluid channels 5 and the other side of the fluid channel that exchanges heat with the supercritical working fluid heat exchange plate 3 and 4 are etched between them by chemical etching. These channels are stacked alternately and welded together by vacuum diffusion welding technology. Several discontinuously staggered fins 1 are etched between the supercritical working fluid heat exchange plate 3 and 4 by chemical etching. The heat exchange plate on the other side of the supercritical fluid channel can be selected according to the type of fluid and the heat exchange conditions.

[0055] The pressure loss ΔP, friction factor f, heat transfer factor j, and the ratio j / f (reflecting the overall heat transfer performance of the fluid channel) on the supercritical working fluid side of the printed circuit board heat exchanger with three different structures and distribution characteristic sizes (No.1 to No.3) in Table 1 of this invention were numerically calculated using ANSYS FLUENT flow heat transfer numerical simulation software. The calculation results were compared with the corresponding calculation results on the supercritical working fluid side of the NACA0025 airfoil rib printed circuit board heat exchanger under the same scale conditions.

[0056] Table 2 Numerical Model and Parameter Settings

[0057]

[0058]

[0059] Tables 3, 4, and 5 list the simulated calculation results of the pressure loss ΔP, friction factor f, and the ratio j / f (reflecting the comprehensive heat transfer performance of the fluid channel) of the printed circuit board heat exchanger with fins No.1 to No.3 of this utility model in Table 1 when the inlet Reynolds number Re increases uniformly by 1 / 6 in the range of 12477 to 71705. The results are compared with the corresponding calculation results of the supercritical working fluid side of the NACA0025 airfoil fin printed circuit board heat exchanger under the same scale conditions.

[0060] As can be seen, when the imported Reynolds number Re increases uniformly by 1 / 6 within the range of 12477 to 71705, compared with the NACA0025 airfoil fins of the same scale, the pressure loss ΔP on the supercritical working fluid side of the printed circuit board heat exchanger under the No.1 fin of this utility model in Table 1 is reduced by 10.07% to 15.49%, the friction factor f is reduced by 6.26% to 15.58%, and the ratio j / f, which represents the overall heat transfer performance, is increased by 2.80% to 11.27% (see Table 3). The pressure loss ΔP on the supercritical working fluid side of the printed circuit board heat exchanger under the No.2 fin of this utility model is also reduced. The pressure loss ΔP decreased by 24.07% to 30.96%, the friction factor f decreased by 8.74% to 17.80%, and the ratio j / f, representing the overall heat exchange performance of the channel, increased by 3.70% to 10.75% (see Table 4). In the No. 3 printed circuit board heat exchanger under the fins of this utility model, the pressure loss ΔP on the supercritical working fluid side decreased by 8.58% to 19.27%, the friction factor f decreased by 7.08% to 17.47%, and the ratio j / f, representing the overall heat exchange performance of the channel, increased by 3.33% to 9.29% (see Table 5).

[0061] The data above show that the supercritical working fluid flow heat exchanger with the finned structure of this invention has significantly improved the stability and efficiency of heat exchange on the working fluid side, reduced the flow resistance and pressure loss, and significantly improved the overall heat exchange capacity of the heat exchanger.

[0062] Table 3 compares the supercritical working fluid side flow heat transfer performance of the NACA0025 airfoil finned printed circuit board heat exchanger using the fins of Embodiment No.1 in Table 1 of this utility model and at the same scale.

[0063]

[0064] Table 4 compares the supercritical working fluid side flow heat transfer performance of the NACA0025 airfoil finned printed circuit board heat exchanger with fins of the present invention No. 2 and at the same scale.

[0065]

[0066] Table 5 compares the supercritical working fluid side flow heat transfer performance of the NACA0025 airfoil finned printed circuit board heat exchanger using the fins of Utility Model No. 3 and at the same scale.

[0067]

[0068] Example 2, as a preferred embodiment, differs from Example 1 in that, as follows: Figure 8 , Figure 9 As shown, four through holes 2 are provided along the length of the rib 1. The through holes 2 are symmetrical about the long axis of the rib 1. Two through holes 2 are provided on each side of the long axis of the rib 1, and the spacing between the through holes 2 is equidistant. Numerical calculations were performed according to the numerical simulation method of Example 1 to obtain the pressure loss ΔP, friction factor f, and the ratio j / f of heat transfer factor to friction factor (reflecting the comprehensive heat transfer performance of the fluid channel) of the supercritical working fluid side of the printed circuit board heat exchanger. The results are compared with the calculation results of the supercritical working fluid side of the NACA0025 airfoil rib printed circuit board heat exchanger under the same scale conditions, as shown in Table 6. It can be seen that when the inlet Reynolds number Re increases in the range of 12477 to 71705, compared with the NACA0025 airfoil fin of the same size, the pressure loss ΔP of the fin No.2 of this utility model, which has four through holes 2 along the length direction of the fin 1, is reduced by 21.18% to 33.75%, the friction factor f is reduced by 6.64% to 15.65%, and the ratio j / f, which represents the overall heat transfer performance, is increased by 3.55% to 6.99%.

[0069] Table 6 compares the supercritical working fluid side flow heat transfer performance of the No. 2 finned heat exchanger with four through holes and the NACA0025 airfoil finned printed circuit board heat exchanger with the same scale.

[0070]

[0071] The data above demonstrate that the supercritical working fluid flow heat exchanger using the finned structure of this invention effectively improves the stability and efficiency of heat transfer on the supercritical working fluid side, significantly reduces flow resistance and pressure loss, and significantly enhances the overall heat exchange capacity. Compared with traditional supercritical working fluid printed circuit board heat exchangers with continuous finned structures such as Z-shaped fins and discontinuous finned structures such as airfoil fins, the finned structure of this invention reduces the negative pressure gradient before and after the finned flow, reduces the inflow resistance, weakens the stagnation when the fluid impacts the leading edge of the fins, and reduces fluid separation at the tail of the fins. This results in a more uniform distribution of overall fluid velocity, pressure, and temperature, thereby improving the stability and efficiency of supercritical fluid flow heat transfer under conditions of drastic thermophysical changes, significantly reducing flow resistance and pressure loss, and enhancing the overall heat exchange capacity of the supercritical working fluid printed circuit board heat exchanger.

[0072] Any aspects of this utility model that are not detailed herein are conventional technical means known to those skilled in the art.

[0073] The above content shows and describes the basic principles, main features, and beneficial effects of this utility model. The above description is merely a preferred embodiment of this utility model and is not intended to limit it. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A fin for a supercritical working fluid printed circuit board heat exchanger, characterized in that: It includes several fins (1) disposed on a supercritical working fluid heat exchange plate (3), the fins (1) are rhomboid in shape, and the fins (1) are provided with through holes (2).

2. The fins for a supercritical working fluid printed circuit board heat exchanger according to claim 1, characterized in that: The rib (1) includes a first isosceles triangle structure (11) and a second isosceles triangle structure (12) arranged symmetrically. The first isosceles triangle structure (11) and the second isosceles triangle structure (12) are connected to each other. The through hole (2) connects the first isosceles triangle structure (11) and the second isosceles triangle structure (12).

3. The fins for a supercritical working fluid printed circuit board heat exchanger according to claim 1 or 2, characterized in that: Two or more through holes (2) are provided along the length direction of the rib (1).

4. The fins for a supercritical working fluid printed circuit board heat exchanger according to claim 3, characterized in that: The through hole (2) is symmetrical about the long axis of the rib (1).

5. The fins for a supercritical working fluid printed circuit board heat exchanger according to claim 4, characterized in that: When two through holes (2) are provided, the port of the through hole (2) is located at the center of the side of the rib (1).

6. The fins for a supercritical working fluid printed circuit board heat exchanger according to any one of claims 1-2 and 4-5, characterized in that: The diameter d of the through hole (2) is 0.08 mm to 0.16 mm.

7. The fins for a supercritical working fluid printed circuit board heat exchanger according to any one of claims 1-2 and 4-5, characterized in that: The length L of the rib (1) c The width L of the rib (1) is 4.0–16.0 mm. w The height L of the rib (1) is 0.89–3.56 mm. h The diameter is 0.5–2.0 mm.

8. A heat exchanger for a printed circuit board with a supercritical working fluid, characterized in that: The ribs (1) included in any one of claims 1-7 are arranged in several rows and columns on each layer of supercritical working fluid heat exchange plate (3), with the ribs (1) in adjacent rows or columns being arranged alternately.

9. The heat exchanger for supercritical working fluid printed circuit boards according to claim 8, characterized in that: Vertical spacing L between adjacent ribs (1) t The horizontal spacing L between adjacent ribs (1) is 2.11–5.11 mm. z The spacing L between adjacent ribs (1) is 4.0–16.0 mm. k The diameter is 4.0 to 16.0 mm.

10. The heat exchanger for a supercritical working fluid printed circuit board according to claim 8 or 9, characterized in that: The upper surface of the rib (1) is provided with a supercritical working fluid heat exchange plate two (4), and the lower part of the supercritical working fluid heat exchange plate two (4) and the upper part of the supercritical working fluid heat exchange plate one (3) form a supercritical fluid channel (5).

Images