A reinforced condenser tube applicable to the microgravity environment

Abstract

The present invention provides a reinforced condenser tube applicable to a microgravity environment, which is used to solve the technical problem of low heat transfer efficiency of the condenser tube in the microgravity environment. The present invention includes an external base tube, a liquid absorption component is coaxially arranged inside the external base tube, and a plurality of V-shaped needle components are arranged between the external base tube and the liquid absorption component. The apex end of the V-shaped needle component is fixed to the liquid absorption component, the tail end of the V-shaped needle component is fixed to the external base tube, and the width of the tail end of the V-shaped needle component is greater than the width of the apex end. The present invention effectively reduces the retention of condensate on the heat transfer wall surface in the microgravity environment, significantly reduces the condensation heat transfer resistance, thereby improving the condensation efficiency of the external base tube and achieving the effect of enhanced condensation.

Description

Technical Field

[0001] The present invention belongs to the technical field of enhanced condensation heat transfer, and particularly relates to an enhanced condensation tube applicable to a microgravity environment. Background Art

[0002] Condensation is an extremely common heat transfer process, which is widely applied to various engineering fields such as petroleum power, energy chemistry, aerospace, etc. Generally, it is considered that there are two different condensation modes when steam contacts a wall surface with a temperature lower than the saturation temperature: filmwise condensation and dropwise condensation. Under normal gravity conditions, the liquid beads generated by dropwise condensation are affected by gravity on a non-horizontal wall surface. After growing to a certain size, they roll down along the wall surface. During the rolling process, they will clear the liquid beads along the way and merge with the encountered liquid beads to form larger liquid drops, thereby enabling the wall surface to repeat the process of liquid bead formation and growth; there is always a continuous liquid film on the wall surface during filmwise condensation, and its thickness continuously increases along the gravity direction. Whether it is filmwise condensation or dropwise condensation, the condensed liquid will prevent the direct contact between the steam and the heat transfer wall surface, enabling the steam to only exchange heat with the surface of the condensed liquid; the more the condensed liquid accumulates and the higher the temperature of the liquid surface, the greater the heat transfer resistance and the smaller the heat transfer temperature difference, and the lower the condensation efficiency.

[0003] With the development of aerospace vehicle manufacturing technology in recent years and the steady progress of lunar exploration projects and deep space exploration projects, China's manned space station has entered the stage of in-orbit construction. The existing traditional condensation tubes have low condensation efficiency in a microgravity environment. Due to the greatly weakened gravity and extremely reduced buoyancy in a microgravity environment, ordinary condensation tubes will face the problem that the condensed liquid cannot be discharged in time and accumulates on the heat transfer wall surface. The accumulated condensed liquid will affect the subsequent direct contact between the steam and the heat transfer wall surface, increase the heat transfer resistance during the condensation process, lead to the deterioration of the condensation process, and reduce the condensation efficiency. Therefore, there is an urgent need for a condensation tube applicable to a microgravity environment to achieve efficient steam condensation.

[0004] Chen Hongxia et al. disclosed an internal liquid-dividing baffle type condensation heat exchange tube for improving the condensation phase change heat exchange efficiency in a tube in Patent CN102278904B. By utilizing the action of liquid surface tension, the invention sucks the condensate into an internal liquid-dividing baffle with a microporous or slit structure arranged in a common external heat exchange tube, thereby realizing the separation of gas-liquid two-phase flow and achieving the purpose of enhancing condensation. However, the effect of the condensation tube of this invention is not good in the initial stage of condensation. Since the specific gravity of the gas is relatively large in the initial stage of condensation, the gas will enter the internal liquid-dividing baffle, resulting in a reduction in the condensation heat exchange efficiency. Minimizing the thickness of the condensate accumulated on the heat exchange wall surface is an effective way to enhance condensation. This purpose can be considered from two aspects: on the one hand, a special-shaped extended surface can be formed on the condensation heat exchange tube, and the surface tension is used to reduce the liquid film thickness and improve the condensation efficiency; on the other hand, the condensation efficiency can also be improved by timely removing the condensate accumulated on the heat exchange wall surface. In view of the fact that in a microgravity environment, the surface tension of the gas-liquid interface plays an important role in the migration of liquid droplets, which provides a new idea for the efficient removal of the liquid accumulated on the heat exchange wall area. Summary of the Invention

[0005] Aiming at the technical problem of low heat exchange efficiency of the condensation tube in a microgravity environment, the present invention proposes a condensation tube for enhancing condensation suitable for a microgravity environment, effectively reducing the retention of condensate on the heat exchange wall surface, significantly reducing the condensation heat transfer resistance, thereby improving the condensation efficiency of the external base tube and achieving the effect of enhancing condensation.

[0006] In order to achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A condensation tube for enhancing condensation suitable for a microgravity environment, comprising an external base tube, an absorbent component is coaxially arranged inside the external base tube, and a plurality of V-shaped needle components are arranged between the external base tube and the absorbent component. The apex end of the V-shaped needle component is fixed to the absorbent component, and the tail end of the V-shaped needle component is fixed to the external base tube. The width of the tail end of the V-shaped needle component is greater than the width of the apex end.

[0008] The absorbent component includes a capillary absorbent core, and an internal shaft is coaxially arranged inside the capillary absorbent core. The apex of the V-shaped needle component is fixed on the capillary absorbent core or the internal shaft.

[0009] The V-shaped needle components are circumferentially distributed along the external base tube to form a V-shaped needle row group. The V-shaped needle components in the V-shaped needle row group can have the same arrangement angle or can be inclined at a certain angle; a plurality of V-shaped needle row groups are axially distributed along the external base tube, and the V-shaped needle row groups can be parallelly distributed or cross-distributed.

[0010] The V-shaped needle component is composed of a metal wire, and the diameter of the metal wire is 0.5 - 2 mm.

[0011] The wire in the V-shaped pin assembly is located in the same plane. It can form a V shape with two wires, or a trident structure with three wires, etc.

[0012] The V-shaped pin assembly is pyramid-shaped. The adjacent two sides of the pyramid form a V-shaped gap. The pyramid can be a triangular pyramid, a quadrangular pyramid, a pentagonal pyramid, etc. The pyramid has multiple sides, which can increase the number of V-shaped gaps. The side apex angles of the pyramid are the same, ensuring that there is no liquid retention at all positions of the condenser tube. In addition, V-shaped gaps can also be formed between adjacent V-shaped pin assemblies at a certain angle.

[0013] The apex angle of the V-shaped gap is 5-20°. A smaller gap apex angle is more conducive to the migration of liquid droplets.

[0014] The V-shaped pin assembly is quadrangular pyramid-shaped, and the side apex angles of the pyramid are the same and the apex angle is 10°.

[0015] There are 10-20 V-shaped pin assemblies in the V-shaped pin row group. Too many V-shaped pin assemblies will increase the steam flow resistance, and too few will be unfavorable for the migration of liquid.

[0016] There are 18 V-shaped pin assemblies in the V-shaped pin row group.

[0017] The internal shaft and the external base tube are made of metal materials with good heat conduction. The diameter of the internal shaft is 2-5 mm. The metal materials can be materials such as copper and aluminum. The capillary wick is a metal wire mesh. Except for using a metal wire mesh, all materials with high water absorption or high porosity can be used.

[0018] The mechanism of enhanced condensation of the present invention is as Figure 5 shown: When steam flows into the metal condenser tube, due to the scouring of the cold fluid outside the tube or the influence of the low-temperature environment, the steam will condense on the heat transfer wall surface (i.e., the inner wall of the external base tube). Many small liquid droplets generated by condensation will adhere to the inner wall of the external base tube. As the condensation process progresses, the small liquid droplets gradually grow and merge into larger liquid droplets, and finally accumulate on the inner wall of the external base tube. When the condensate accumulates to a certain extent, the accumulated liquid will contact the V-shaped pin, and the vapor-liquid interface surface presents a concave meniscus. Under the action of the surface tension at the vapor-liquid interface, the condensate accumulated on the heat transfer wall surface will gradually migrate along the V-shaped gap in the V-shaped pin to the central area of the external base tube. The capillary wick arranged in the central area of the external base tube will timely suck the migrated accumulated liquid. Finally, the condensate will be collected in the capillary wick.

[0019] Advantages of the present invention: Since gravity is greatly weakened in the microgravity environment, as steam continuously flows into the condenser tube, condensate droplets gradually form and grow continuously, and finally accumulate on the inner wall of the outer base tube. During the accumulation of condensate, the accumulated liquid will come into contact with the V-shaped needle assembly, and under the action of its surface tension, it will gradually migrate along the V-shaped gap towards the central region of the outer base tube (i.e., the apex region of the V-shaped gap), and the capillary liquid absorption core filled at the apex of the V-shaped gap will timely absorb the droplets migrating to the central region of the outer base tube, making the steam tend to flow in the region close to the inner wall of the outer base tube, and the condensate tend to flow in the central region of the outer base tube. Furthermore, the process of "steam condensing and accumulating on the wall - condensate droplet migration - condensate absorption" can be repeated effectively, reducing the retention of condensate on the heat transfer wall surface significantly, reducing the condensation heat transfer resistance, thereby improving the condensation efficiency of the outer base tube and achieving the effect of enhanced condensation. In addition, during the condensation process, the condenser tube of the present invention will make the vapor phase tend to be distributed in the region near the inner wall of the outer base tube and the liquid phase tend to be distributed in the central region of the outer base tube, achieving the effect of regulating the two-phase flow pattern, so the present invention also has the characteristics of phase separation. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the structure of the enhanced condenser tube of the present invention.

[0022] Figure 2 Axial sectional view of the enhanced condenser tube of the present invention.

[0023] Figure 3 Schematic cross-sectional view of the enhanced condenser tube of the present invention.

[0024] Figure 4 Schematic diagram of the structure of the V-shaped needle assembly.

[0025] Figure 5 Schematic diagram of the enhanced condensation mechanism of the enhanced condenser tube.

[0026] In the figure: 1. Outer base tube; 2. V-shaped needle assembly; 3. Capillary liquid absorption core; 4. Inner shaft. Detailed Embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1

[0029] A reinforced condenser tube suitable for a microgravity environment, as Figure 1 shown, includes an external base tube 1. An absorbent component is coaxially arranged inside the external base tube 1. A plurality of V-shaped needle components 2 are arranged between the external base tube 1 and the absorbent component. The apex ends of the V-shaped needle components 2 are fixed to the absorbent component, and the tail ends of the V-shaped needle components 2 are fixed to the external base tube 1. The width of the tail ends of the V-shaped needle components 2 is greater than the width of the apex ends.

[0030] Embodiment 2

[0031] A reinforced condenser tube suitable for a microgravity environment, as Figure 1-3 shown, includes an external base tube 1 and an internal shaft 4. The internal shaft 4 is arranged at the central axis of the external base tube 1. The external base tube 1 is placed in a low-temperature environment or flushed by a cold fluid; the outside of the external base tube 1 is a low-temperature environment or a cold fluid, and the inside is a steam side; the inner wall of the external base tube 1 in direct contact with the steam is a smooth hydrophobic surface. The inner wall of the external base tube 1 provides a heat transfer interface for water vapor, and the condensed liquid droplets adhere to the inner wall of the external base tube 1. A capillary absorbent core 3 is sleeved on the internal shaft 4, and the capillary absorbent core 3 can absorb and store the condensed liquid. A plurality of V-shaped needle components 2 are arranged between the external base tube 1 and the internal shaft 4. The apex ends of the V-shaped needle components 2 are fixed to the internal shaft 4, and the tail ends of the V-shaped needle components 2 are fixed to the external base tube 1. The liquid droplets condensed on the external base tube 1 can converge along the V-shaped needle components 2 into the capillary absorbent core 3. The V-shaped needle components 2 are evenly distributed along the circumferential direction of the external base tube 1 to form a V-shaped needle row group, and several V-shaped needle row groups are distributed along the axial direction of the external base tube 1. According to the number of V-shaped needle components 2 in the V-shaped needle row group and the interval between the axial V-shaped needle row groups, the arrangement density of the V-shaped needle components 2 in the condenser tube is controlled. The V-shaped needle components 2 include V-shaped gaps, and the condensed liquid droplets mainly migrate in the V-shaped gaps. By increasing the number of V-shaped gaps, the condensation efficiency can be improved to a certain extent.

[0032] Embodiment 3

[0033] A reinforced condenser tube suitable for a microgravity environment, as Figure 1 shown, the V-shaped needle component 2 is a V-shaped structure and is composed of two metal wires. The V-shaped needle components 2 are evenly distributed along the circumferential direction on the external base tube 1, and the V-shaped needle components 2 in the V-shaped needle row group are on the same flat sheet.

[0034] The other structures are the same as those in Embodiment 2.

[0035] Embodiment 4

[0036] A reinforced condenser tube applicable to a microgravity environment, as Figure 4 shown. The V-shaped needle assembly 2 is a quadrangular pyramid, and can also be a triangular pyramid, a pentagonal pyramid, etc. The edges of the pyramid are made of metal wires with a diameter of 0.5 mm. By using small-diameter metal wires, on the one hand, due to the high strength of the metal wires, the attached liquid can be heavier without breaking. On the other hand, the metal wires can minimize the contact area with the steam, thereby reducing the condensation amount of the steam on the internal structure and facilitating the avoidance of pipe blockage. The adjacent metal wires form a V-shaped gap, and the side vertex angles of the pyramid are the same at 10°. The vertex angle of the V-shaped gap is the side vertex angle of the quadrangular pyramid. The V-shaped needle assembly 2 adopts the shape of a pyramid, which can ensure that multiple V-shaped gaps are provided in one V-shaped needle assembly 2, thereby improving the condensation efficiency.

[0037] The other structures are the same as those in Embodiment 2.

[0038] Embodiment 5

[0039] A reinforced condenser tube applicable to a microgravity environment, as Figure 1-3 shown. 10 V-shaped needle assemblies 2 are evenly distributed in the circumferential direction of the external base tube 1 to form a V-shaped needle row group, and the included angle between two adjacent V-shaped needle assemblies 2 is 36°. In addition, the internal shaft 4 and the external base tube 1 are made of a metal material with good heat conduction, and the heat transfer efficiency is improved through the high heat conductivity of the metal material; the capillary wick 3 is a metal wire mesh, and the metal wire mesh is filled at the vertex angle of the V-shaped needle assembly 2 to achieve efficient absorption and storage of the condensate.

[0040] The other structures are the same as those in Embodiment 2.

[0041] Embodiment 6

[0042] A reinforced condenser tube applicable to a microgravity environment, as Figure 1-4As shown in the figure, it includes an external base tube 1 and an internal shaft 4. The external base tube 1 is a metal tube, and the internal shaft 4 is a thick metal wire or metal rod. The internal shaft 4 is arranged at the central axis of the external base tube 1, and a capillary wick 3 is sleeved on the internal shaft 4. A plurality of V-shaped needle assemblies 2 are arranged between the external base tube 1 and the internal shaft 4. 18 V-shaped needle assemblies 2 are evenly distributed along the circumferential direction of the external base tube 1 to form a V-shaped needle row group, and several V-shaped needle row groups are distributed along the axial direction of the external base tube 1. The V-shaped needle assembly 2 is in a quadrangular pyramid shape and is made of 4 copper wires with a diameter of 1 mm, and the included angle between two copper wires is 10°. The number of rows of the V-shaped needle assemblies 2 distributed along the axial direction of the metal tube depends on the length of the external base tube, and the number of equally spaced distributions along the radial direction of the metal tube in each row is 18. The top angle end of the V-shaped needle assembly 2 is fixed by the internal shaft 4, and the tail end is fixed on the wall of the metal tube. A V-shaped gap can be formed between the V-shaped needle assembly 2 and between two adjacent V-shaped needle assemblies 2. Each V-shaped needle assembly 2 can form 4 V-shaped gaps, and 2 V-shaped gaps are formed between two adjacent V-shaped needle assemblies 2, that is, each V-shaped needle row group can form 108 V-shaped gaps. The top angle of each gap is 10°, and the capillary wick 3 is filled at the top angle.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A reinforced condenser tube applicable to the microgravity environment, characterized in that, It includes an external base tube (1), a liquid absorption component is coaxially arranged inside the external base tube (1), and a plurality of V-shaped needle components (2) are arranged between the external base tube (1) and the liquid absorption component. The apex end of the V-shaped needle component (2) is fixed to the liquid absorption component, the tail end of the V-shaped needle component (2) is fixed to the external base tube (1), and the width of the tail end of the V-shaped needle component (2) is greater than the width of the apex end. The liquid absorption component includes a capillary liquid absorption core (3), and an internal shaft (4) is coaxially arranged inside the capillary liquid absorption core (3). The V-shaped needle components (2) are circumferentially distributed along the external base tube (1) to form a V-shaped needle row group, and a plurality of V-shaped needle row groups are axially distributed along the external base tube (1). The V-shaped needle component (2) is composed of a metal wire. The V-shaped needle component (2) is pyramid-shaped, and adjacent sides of the pyramid form a V-shaped gap.

2. The enhanced condensation tube applicable to the microgravity environment according to claim 1, characterized in that The diameter of the metal wire is 0.5 - 2 mm.

3. The enhanced condensation tube applicable to the microgravity environment according to claim 2, characterized in that, The apex angle of the V-shaped gap is 5 - 20°.

4. The enhanced condensation tube applicable to the microgravity environment according to claim 3, characterized in that, The V-shaped needle component (2) is quadrangular pyramid-shaped, and the side apex angles of the pyramid are the same and the apex angle is 10°.

5. The enhanced condensation tube applicable to the microgravity environment according to any one of claims 1, wherein There are 10 - 20 V-shaped needle components (2) in the V-shaped needle row group.

6. The enhanced condensation tube applicable to the microgravity environment according to claim 5, characterized in that, There are 18 V-shaped needle components (2) in the V-shaped needle row group.

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