Micro-channel combined super-boiling enhanced heat transfer channel structure

Abstract

This invention relates to the field of two-phase flow heat transfer technology under high heat load, and particularly to a supervaporization enhanced heat transfer channel structure combined with microchannels. The shell has a vertical channel and a horizontal channel for the flow of cooling fluid on one side. The inner side of the shell has horizontally arranged ribs. The horizontal channel is located between two adjacent ribs. The vertical channel is located on both sides of the rib. Vertical microchannels are also provided on the vertical channels, and these vertical microchannels flow in the same direction as the cooling mass. The ribs can be discontinuous, wing-shaped, corrugated, etc. Vertical microchannels are also provided on the lower side of the ribs. A horizontal microchannel perpendicular to the cooling mass flow direction is also provided between adjacent ribs. The shapes of the vertical and horizontal microchannels can be rectangular, S-shaped, discontinuous, vein-shaped, gradually expanding, stepped, etc. Sloping structures with different gradients can be added between adjacent ribs.

Description

Technical Field

[0001] This invention relates to the field of two-phase flow heat transfer technology under high heat load, specifically to a supervaporization enhanced heat transfer channel structure combined with microchannels. Background Technology

[0002] In today's booming development of new energy sources, nuclear fusion technology has always been favored due to its ability to provide a stable and continuous energy source without the greenhouse gas emissions risks associated with traditional nuclear energy and fossil fuels. The helical magnetic field within a tokamak device can effectively confine high-temperature plasma, enabling controllable nuclear fusion. However, strong interactions between the high-temperature plasma and the first wall still occur at the tokamak's boundary, causing corrosion and damage to the first wall material and generating a large amount of impurities. This reduces the target plate's sputter resistance and contaminates the plasma. Therefore, a divertor needs to be added at the tokamak's boundary to directly contact the plasma and expel the plasma particle and heat flow. For future fusion reactors, without control, the steady-state heat load of the divertor target plate could reach tens of megawatts per square meter, severely testing the divertor components' heat load-bearing and exhaust capabilities. Conventional heat dissipation techniques are insufficient to ensure the divertor operates normally under such high heat loads; therefore, researching hypervaporization-enhanced heat transfer technology with higher heat transfer coefficients is essential.

[0003] The main characteristic of supervaporization structures is the addition of fins or grooves laterally within the flow channel. This allows the fluid between two adjacent fins to be heated and vaporized by the heating surface. As the vapor bubbles leave the wall and enter the cooling fluid, they rapidly condense in the supercooled liquid, simultaneously refilling the groove between the fins with supercooled fluid. As long as the temperature of the heating surface does not exceed the Leidenfrost temperature, this continuous boiling and condensation process between adjacent fins can significantly enhance heat transfer efficiency and critical heat flux density. Currently, supervaporization-enhanced heat transfer structures are mainly used in the high heat load regions of the first wall of fusion reactors and the dome region of divertors. Compared to other structures, supervaporization-enhanced heat transfer structures have a larger heat transfer area, higher heat transfer efficiency, and advantages such as simple processing and easy maintenance. Supervaporization-enhanced heat transfer typically has a much higher heat transfer coefficient than single-phase heat transfer, making it a crucial method for enhancing heat transfer. However, due to the large number of bubbles generated during supervaporization-enhanced heat transfer, a rapid decrease in the heat transfer coefficient and a sharp rise in wall temperature can occur if the heat flux density exceeds the critical heat flux density, potentially leading to equipment burnout – a safety hazard that is unacceptable in fusion reactor design. Furthermore, the presence of transverse ribs increases the fluid friction resistance, consequently raising the pumping power requirements for the cooling channels. Therefore, to meet the increasingly demanding heat load requirements in the future, the structure of supervaporization-enhanced heat transfer channels needs to be improved and optimized.

[0004] like Figure 1 As shown, the main feature of the traditional supervaporization enhanced heat exchange channel is the fins 2 perpendicular to the fluid flow direction. The shape of the fins 2 is not unique. The surfaces of the vertical channel 1 and the horizontal channel 3 are both smooth surfaces. In this channel of fins 2, the distribution of vaporization nuclei is uneven, and the randomness of the bubble formation position is relatively large, resulting in uneven temperature distribution.

[0005] In the structural research of two-phase flow heat transfer, the use of microchannel phase change cooling technology can achieve a higher specific surface area and exhibit a higher heat transfer coefficient, while maintaining a relatively uniform temperature distribution, effectively compensating for the defect of uneven temperature distribution on the heated surface of the supervaporization channel. This invention combines the unique microscale effect of microchannel phase change cooling technology with the supervaporization heat transfer channel to form a structure with higher heat transfer efficiency and lower pump power. Summary of the Invention

[0006] The purpose of this invention is to provide a supervaporization enhanced heat exchange channel structure that incorporates microchannels, in order to solve the problems of uneven temperature distribution and excessively high inlet and outlet pressure drop in traditional supervaporization heat exchange channels mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A supervaporization-enhanced heat exchange channel structure incorporating microchannels includes a shell, one side of which is a heat load surface, and the other side of which is provided with a vertical channel and a horizontal channel for cooling fluid to flow through. Horizontally arranged ribs are provided on the inner side of the shell, and the horizontal channels are positioned between two adjacent ribs. The vertical channels are located on both sides of the ribs, and vertical microchannels are also provided on the vertical channels, with the vertical microchannels flowing in the same direction as the cooling fluid.

[0009] Furthermore, the ribs can be of the following types: discontinuous, wing-shaped, corrugated, etc.

[0010] Furthermore, the lower side of the rib is also provided with vertical microchannels.

[0011] Furthermore, the lower edge of the rib is also provided with a vertical microchannel in the same direction as the flow of cold mass.

[0012] Furthermore, the shapes of the vertical and horizontal microchannels can be rectangular, S-shaped, discontinuous, leaf vein-shaped, gradually expanding, stepped, or other types.

[0013] Furthermore, inclined structures with different slopes can be added between adjacent ribs, and the transverse microchannels are opened on the inclined structures.

[0014] Furthermore, the overall thickness of the shell ranges from 8mm to 15mm.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] In this invention, based on supervaporization heat transfer technology and combined with microchannel phase change cooling technology, the heat transfer area is increased and the heat transfer efficiency is improved compared to the original technology. The addition of microchannels increases the vaporization nuclei on the heated surface, and the distribution of these nuclei is more uniform, resulting in a more uniform temperature distribution on the heated surface, which better meets the requirements of the workpiece. The microchannels added between the two transverse ribs in this invention help the bubbles to escape to both sides, enhancing boiling and thus improving heat transfer. Finally, the overall thermal stress is enhanced by the addition of microchannels. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a traditional transverse rib supervaporization enhanced heat exchange channel, where Figure (a) is a three-dimensional transparent schematic diagram, and Figures (b) and (c) are its front view and side view, respectively.

[0018] Figure 2 This is a schematic diagram of the supervaporization enhanced heat exchange channel of the present invention after incorporating microchannels, wherein Figure (a) is an overall three-dimensional transparent schematic diagram, and Figures (b) and (c) are its front view and side view, respectively.

[0019] Figure 3 This is a schematic diagram of the supervaporization enhanced heat exchange channel of the present invention, which combines microchannels and adds a sloping structure between two adjacent transverse ribs. Figure (a) is a three-dimensional transparent schematic diagram, and Figures (b) and (c) are its front view and side view, respectively.

[0020] In the diagram: 1. Vertical channel; 1a. Vertical microchannel; 2. Rib; 3. Horizontal channel; 3a. Horizontal microchannel;

[0021] a. Heat load surface; b. Cold mass flow direction. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] Please see Figure 1-2 The present invention provides a technical solution:

[0025] A supervaporization enhanced heat exchange channel structure incorporating microchannels includes a shell 1. One side of the shell 1 is a heat load surface a. The other side of the shell 1 is provided with a vertical channel 1 and a transverse channel 3 for the flow of cooling fluid. The inner side of the shell 1 is provided with transversely arranged ribs 2. The transverse channel 3 is disposed between two adjacent ribs 2. The vertical channel 1 is disposed on both sides of the ribs 2. A vertical microchannel 1a is also provided on the vertical channel 1. The vertical microchannel 1a is in the same direction as the flow of the cooling fluid b.

[0026] Specifically, the aforementioned rib 2 can be of the following types: discontinuous, wing-shaped, corrugated, etc.

[0027] Specifically, the lower side of the aforementioned rib 2 is also provided with a vertical microchannel 1a.

[0028] Specifically, a transverse microchannel 3a perpendicular to the cold mass flow direction b is provided between the two adjacent ribs 2. The transverse microchannel 3a perpendicular to the cold mass flow direction b is added to the transverse channel 3 because the fluid between the two ribs 2 has a transverse velocity, which can better discharge the air bubbles between the two ribs 2.

[0029] Specifically, the shapes of the aforementioned vertical microchannel 1a and horizontal microchannel 3a can be rectangular, S-shaped, discontinuous, leaf-vein-shaped, gradually expanding, stepped, etc. When the overall channel structure and total heat load are determined, the heat transfer coefficient of the super-vaporization enhanced heat exchange channel combined with microchannels is higher than that of traditional channels, the inlet and outlet pressure drop is lower than that of traditional channels, and the temperature uniformity is better than that of traditional channels.

[0030] Example 2

[0031] Please see Figure 1 and Figure 3 The present invention provides a technical solution:

[0032] In this embodiment, the parts that are the same as in Embodiment 1 will not be repeated. The differences are as follows:

[0033] Specifically, an inclined structure is added between the two adjacent ribs 2, and the transverse microchannel 3a is opened on the inclined structure. An inclined structure is added between the two ribs 2, and then the transverse microchannel 3a is processed on the inclined structure.

[0034] Figure 3 The optimized internal structure has rib 2 with a height of 3mm, a width of 3mm, and a slope of 2:5.5. The transverse microchannel 3a has a width of 0.3mm and a height of 0.4mm, and the vertical microchannels 1a on both sides have a width of 1.5mm.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A micro-channel combined super-hydrophobic enhanced heat transfer channel structure comprising a shell (1), characterized in that: One side of the shell (1) is a heat load surface (a), the other side of the shell (1) is provided with vertical channels (1) and horizontal channels (3) for cooling fluid flow, the inner side of the shell (1) is provided with horizontally arranged fins (2), the horizontal channels (3) are arranged between two adjacent fins (2), the vertical channels (1) are arranged on both sides of the fins (2), and vertical microchannels (1a) are further arranged on the vertical channels (1), the vertical microchannels (1a) are the same as the cold mass flow direction (b); The fins (2) are of intermittent, folded fin, and corrugated types. Different slope structures are additionally arranged between adjacent fins (2), and horizontal microchannels (3a) are arranged on the slope structures.

2. The super-hydrophobic enhanced heat transfer channel structure integrated with microchannels according to claim 1, wherein: The lower side of the fins (2) is also provided with vertical microchannels (1a).

3. The super-hydrometallurgical enhanced heat transfer channel structure integrated with microchannels according to claim 2, characterized in that: The fins (2) are also provided with vertical microchannels (1a) which are the same as the cold mass flow direction (b).

4. The super-hydrometallurgical enhanced heat transfer channel structure integrated with microchannels according to claim 3, characterized in that: The shapes of the vertical microchannels (1a) and the horizontal microchannels (3a) are rectangular, S-shaped, intermittent, vein-shaped, gradually expanding, and stepped types.

5. The microchannel-bonded superheat-enhanced heat transfer channel structure of claim 1, wherein: The overall thickness of the shell (1) ranges from 8mm to 15mm.

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