Claw-type lattice array heat exchange tube for inhibiting heat transfer deterioration effect

Abstract

A claw-type lattice array heat exchange tube capable of inhibiting the heat transfer deterioration effect is characterized in that a basic unit comprises a claw-type lattice structure and an outer tube body, the outer tube body is a smooth round tube, and a refrigerant is circulated in the tube and is carbon dioxide; the claw-type lattice structure is formed by intersecting a plurality of smooth cylinders at one point according to a specific angle, the intersection point is subjected to fillet treatment, fluid resistance is effectively reduced, the other end of each cylinder is completely fused with the inner wall of the outer pipe body, the structural strength is ensured, the claw-type lattice structure is periodically arranged with the inner surface of the outer pipe body as a carrier, and the claw-type lattice array is formed. The array spacing, the number of sections, the structural parameters and the like can be flexibly adjusted according to working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange equipment, and in particular relates to a claw-shaped lattice array heat exchange tube capable of suppressing the deterioration effect of heat transfer. Background Art

[0002] The large-scale grid integration of renewable energy sources like wind power and photovoltaics has significantly exacerbated the intermittent, random, and volatile nature of renewable energy. This high proportion of renewable energy access to the grid poses significant challenges to the security and stability of energy supply. There is an urgent need to transition traditional thermal power units to peak-shaving and frequency-regulating power sources. Traditional Rankine cycle generators have a low ramp rate, making them unable to meet the demands of rapid peak-shaving and frequency-regulating power.

[0003] Brayton cycle power plants based on supercritical CO2 can significantly increase load ramp rates, potentially addressing the rapid peak and frequency regulation requirements of large-scale grid integration of renewable energy. However, supercritical CO2 power plants inevitably experience variable pressure conditions during deep peak and frequency regulation, causing their physical properties to fluctuate dramatically with pressure. This can lead to deteriorated heat transfer, severely impacting the safe and efficient operation of the power plant and even causing overheating and tube bursts. Therefore, suppressing heat transfer degradation is key to the safe, efficient, and stable operation of supercritical CO2 power plants.

[0004] The lattice structure can induce complex local vortices, which not only enhances heat transfer but also has lower pressure drop loss than traditional enhanced tube structures. However, the lattice structure across the cross section occupies the central flow space of the pipe cross section, which can easily cause the central fluid in the tube to rotate, resulting in fluid instability and other problems. Summary of the Invention

[0005] The present invention proposes a claw-shaped lattice array heat exchange tube that suppresses the heat transfer deterioration effect. It is a claw-shaped lattice array that only acts on the fluid in the near-wall area, aiming to improve heat exchange efficiency, avoid heat transfer deterioration and alleviate pipeline vibration problems.

[0006] A claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration effect comprises an outer tube body and a plurality of claw-shaped lattice structures arranged inside the outer tube body.

[0007] Furthermore, the number of cylinders in each claw-shaped lattice structure of the present invention is 1-4, and the angle between the cylinders is 30°-60°.

[0008] Furthermore, the top of each claw-shaped lattice structure of the present invention is processed with a rounded corner process to reduce resistance.

[0009] Furthermore, the claw-shaped lattice structures of the present invention are arranged in an array on the inner surface of the outer tube, are evenly distributed along the circumference of the outer tube, and are periodically arranged along the axial direction of the outer tube.

[0010] Furthermore, one end of the outer tube body of the present invention is an inlet end, and the other end is an outlet end. The inlet end is provided with an insulation section 30 times the length of the tube diameter, and the outlet end is provided with an insulation section of not less than 150 mm in length.

[0011] Furthermore, the claw-shaped lattice structure and the outer tube body of the present invention are manufactured in an integrated manner through selective laser melting technology.

[0012] Furthermore, the refrigerant flowing in the outer tube of the present invention is carbon dioxide.

[0013] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0014] 1. The claw-shaped lattice structure of the present invention can induce the refrigerant to generate a complex vortex system with a strong extension effect, destroy the boundary layer, enhance the disturbance and mixing of the refrigerant, achieve long-term suppression of heat transfer deterioration, and avoid the risk of overheating and tube burst.

[0015] 2. The claw-shaped lattice structure of the present invention only acts on the area near the wall, avoiding occupying the central flow space of the pipeline and avoiding the problem of central fluid rotation instability caused by the existing lattice structure.

[0016] 3. This invention achieves integrated manufacturing through selective laser melting technology, eliminating weaknesses in traditional joining processes and ensuring the structure's tightness and mechanical strength under high pressure and variable operating conditions. Furthermore, the claw-shaped lattice structure features rounded corners at the top, balancing enhanced heat transfer with low flow resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] Figure 1 This is a schematic diagram of a three-dimensional structure of a claw-shaped lattice array heat exchange tube provided in an embodiment of the present application;

[0019] Figure 2 is a three-dimensional diagram of a single claw-shaped lattice structure provided in an embodiment of the present application;

[0020] Figure 3 This is a diagram showing the arrangement of a claw-shaped lattice structure array in a pipeline provided in an example of this application;

[0021] Figure 4 It is a schematic diagram of the vortex structure when the refrigerant flows through the claw-type lattice structure;

[0022] Figure 5This is the flow field diagram of the refrigerant in the claw-type lattice array heat exchange tube;

[0023] Figure 6 This is a comparison chart of the heat exchange tube's effect of suppressing heat transfer deterioration.

[0024] In the accompanying drawings: 1. Claw-type lattice structure; 2. Outer tube body; 1.1. Cylinder; 1.2. Two-claw lattice structure; 1.3. Three-claw lattice structure; 1.4. Four-claw lattice structure; 1.5. Rounded corners; 2.1. Inlet end insulation section; 2.2. Heating section; 2.3. Outlet end insulation section. DETAILED DESCRIPTION

[0025] The present invention will be further described below by way of examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are intended to fall within the scope of protection of the present invention.

[0026] A claw-shaped lattice array heat exchange tube that suppresses the deterioration effect of heat transfer, a claw-shaped lattice array heat exchange tube used in a supercritical state, suitable for a supercritical carbon dioxide Brayton cycle system, and a high-efficiency heat exchange tube used to suppress the deterioration of heat transfer and enhance heat transfer.

[0027] A claw-shaped lattice array heat exchange tube for suppressing heat transfer degradation comprises an outer tube body and a claw-shaped lattice array. The claw-shaped lattice array is arranged on the inner surface of the outer tube body. The claw-shaped lattice array comprises claw-shaped lattice structures uniformly distributed along the circumference of the outer tube body and periodically arranged along the axial direction. Fluid flowing through a single claw-shaped lattice structure generates a complex vortex system, which effectively disturbs the boundary layer and enhances heat transfer. Furthermore, the vortex system exhibits a good extension effect, continuously disturbing the fluid downstream of the claw-shaped lattice structure, thereby continuously suppressing heat transfer degradation.

[0028] Example 1

[0029] like Figure 1-3 As shown, this embodiment provides a claw-shaped lattice array heat exchange tube that suppresses heat transfer degradation. The heat exchange tube comprises an outer tube body 2 and claw-shaped lattice structures 1 uniformly distributed on the inner surface of the outer tube body 2. The claw-shaped lattice structures 1 are arranged in an array on the inner surface of the outer tube body 2, periodically arranged along the axial direction of the outer tube body and evenly distributed along the circumference, forming a complete claw-shaped lattice array. The array spacing is preferably 10 to 11 times the diameter of the outer tube body 2. The number of claw-shaped lattice structures 1 on the cross-section of the outer tube body 2 is preferably 2 to 8. The claw-shaped lattice structures 1 are integrally formed with the outer tube body 2 using selective laser melting technology.

[0030] The outer tube body 2 of the present invention is a smooth circular tube structure, comprising an inlet end insulation section 2.1, a heating section 2.2, and an outlet end insulation section 2.3. Figure 2 As shown, the claw-type lattice structure 1 of the present invention includes a two-claw lattice structure 1.2, a three-claw lattice structure 1.3, and a four-claw lattice structure 1.4. The claw-type lattice structure 1 is based on a cylinder 1.1, which has a diameter of 1 to 2 mm and a height of 3 to 5 mm. The two-claw lattice structure 1.2 is composed of two cylinders 1.1 intersecting at a 60° angle, the three-claw lattice structure 1.3 is composed of three cylinders 1.1 intersecting at a 60° angle, and the four-claw lattice structure 1.2 is composed of two two-claw lattice structures 1.2 intersecting at a 90° angle. All intersections are rounded 1.5.

[0031] Example 2

[0032] like Figure 4-6 This embodiment further illustrates the effectiveness of the claw-shaped lattice array structure in suppressing heat transfer degradation. After the refrigerant flows through the claw-shaped lattice structure 1, a stable vortex structure with a high extension effect is formed in the downstream region. This vortex system effectively disturbs the boundary layer and enhances turbulent mixing, thereby suppressing the occurrence of heat transfer degradation.

[0033] Figure 4 Figure 1 shows the vortex structure formed after the refrigerant flows through the claw-shaped lattice structure 1. Specifically, when the refrigerant flows within the claw-shaped lattice structure, horseshoe vortices, hairpin vortices, and bow vortices are generated in sequence. The generation of these vortices can effectively promote turbulent mixing of the refrigerant, thereby improving the heat exchange effect.

[0034] Figure 5 The flow field distribution of the refrigerant in a smooth circular tube and a claw-shaped lattice array heat exchange tube is shown. In a pipe with a length of 2280 mm, the fluid velocity in the center area of ​​the claw-shaped lattice array heat exchange tube is significantly higher than that in the smooth circular tube, and the high-speed flow area can cover the entire pipe for a long distance. At the same time, the fluid velocity in the mainstream area is higher than the velocity in the boundary layer. This characteristic can effectively optimize the shear stress distribution of the distortion in the pipe, which is conducive to enhancing the heat transfer process. Specifically, when the refrigerant flows through the claw-shaped lattice structure, the flow velocity of the fluid begins to increase at the leading edge of the structure, and shows a significant increasing trend during the process of flowing through the structure. Compared with the leading edge of the structure (z = 2034.5 mm), the tail (z = 2045.5 mm) produces a severe disturbance and forms multiple obvious longitudinal vortices. The above vortices can cause the fluid to impact the wall, thereby significantly reducing the thickness of the local thermal boundary layer, further intensifying the flow mixing, and improving the heat transfer efficiency.

[0035] Figure 6This figure compares the wall temperature of a smooth circular tube and the claw-shaped lattice array heat exchange tube described in the present invention under the same operating conditions. The horizontal axis represents the dimensionless distance along the tube axis, and the vertical axis represents the tube wall temperature. As can be seen from the figure, the claw-shaped lattice array heat exchange tube of the present invention can significantly reduce local wall temperature, preventing deterioration in heat transfer.

[0036] A claw-shaped lattice array heat exchange tube designed to suppress heat transfer degradation is described. The basic unit comprises a claw-shaped lattice structure and an outer tube. The outer tube is a smooth circular tube, and a refrigerant, carbon dioxide, flows through the tube. The claw-shaped lattice structure is composed of multiple smooth cylinders intersecting at a specific angle. The intersection is rounded to effectively reduce fluid resistance. The other ends of the cylinders are fully fused to the inner wall of the outer tube, ensuring structural strength. The claw-shaped lattice structures are arranged periodically on the inner surface of the outer tube, forming the claw-shaped lattice array. The array spacing, number of cross-sections, and structural parameters can be flexibly adjusted according to operating conditions. Selective laser melting is used to integrate the claw-shaped lattice array and the outer tube, avoiding the drawbacks of traditional joining processes and ensuring the reliability of the structure under high-pressure conditions. When the refrigerant flows through the claw-shaped lattice structure, vortices are generated within the tube, disrupting the near-wall boundary layer and enhancing fluid turbulence and mixing. These vortices have a strong extension effect and can persist within the array spacing, significantly improving heat transfer efficiency and preventing heat transfer degradation.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A claw-shaped lattice array heat exchange tube for suppressing the deterioration of heat transfer, characterized in that It comprises an outer tube body (2) and a plurality of claw-shaped lattices (1) arranged inside the outer tube body (2).

2. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: The number of cylinders in each claw-shaped lattice (1) is 1-4, and the angle between the cylinders is 30°-60°.

3. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: The top of the claw-shaped lattice structure is rounded to reduce resistance.

4. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: The claw-shaped lattice structures are arranged in an array on the inner surface of the outer tube body, are evenly distributed along the circumference of the outer tube body, and are periodically arranged along the axial direction of the outer tube body.

5. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: One end of the outer tube body (2) is an inlet end, and the other end is an outlet end. An insulation section with a length of 30 times the tube diameter is provided at the inlet end, and an insulation section with a length of not less than 150 mm is provided at the outlet end.

6. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: The claw-shaped lattice structure and the outer tube are manufactured in an integrated manner through selective laser melting technology.

7. The claw-shaped lattice array heat exchange tube for suppressing heat transfer deterioration according to claim 1, characterized in that: The refrigerant circulating in the outer tube body (2) is carbon dioxide.

Images