CN107144162B - Gravity assisted heat pipe with annular components - Google Patents

Abstract

The invention relates to a novel high-efficiency heat exchanger gravity heat pipe, in particular to a gravity heat pipe for reducing the thickness of a condensation film by changing the structure of a pipe wall, belonging to the technical field of heat exchange. When the gravity heat pipe works, working medium is heated and evaporated to reach a condensing section, and a thick liquid film is formed on the wall surface, so that the heat resistance is increased, and the heat exchange is seriously hindered. The invention is to add annular components into the tube to change the wall structure so as to thin the liquid film. The evaporation section annular components are added to enable the liquid film of the evaporation section to be uniformly distributed, so that falling film evaporation is realized; the liquid film is thinned by adding the annular component of the condensing section, so that the condensation heat exchange is enhanced. Meanwhile, the heat exchange area of the condensing section and the evaporating section is increased by adding the annular components to strengthen heat transfer, and in addition, the arrangement of the components of the evaporating section can also solve the problem that overflowed liquid returns to the liquid pool again due to the too thick liquid film, so that the heat transfer is prevented from being influenced by cold and hot air flow intersection.

Description

Gravity assisted heat pipe with annular components

Technical Field

The invention relates to a novel high-efficiency heat exchanger gravity heat pipe, in particular to a gravity heat pipe for reducing the thickness of condensation film by changing the pipe wall structure, and belongs to the technical field of heat exchange.

Background

Two major problems faced by the current heat transfer engineering are: high thermal insulation materials and high thermal conductivity materials were investigated. However, the heat conductivity coefficient of the heat conducting material with good heat conductivity can only reach 10 ² The order of W/m.cndot.C is far from meeting the need for rapid heat transfer in some projects. The invention solves the problem that the heat transfer coefficient of the heat pipe is hundreds times to thousands times that of common metal materials, and can transmit a large amount of heat through a small sectional area in a long distance without external power. The gravity assisted heat pipe has the outstanding advantages of high heat transfer efficiency, simple structure, low cost and the like.

However, when the gravity heat pipe works, the heat exchange efficiency is not high due to various factors, for example, the cold and hot air flows relatively move to form opposite flushing, and an unnecessary mixing process of the cold and hot steam is added in the gravity heat pipe, so that the running resistance of the cold and hot air flows is increased to influence the heat transfer. In addition, because the heat exchange area of the inner wall surface of the condensing section is limited, especially when the working medium is heated and evaporated to reach the condensing section, a thick liquid film is formed on the wall surface, so that the heat resistance is increased, and the heat exchange is seriously hindered. Therefore, the key of enhancing heat exchange of the heat pipe is to promote heat exchange of the inner wall of the condensing section and reduce the thickness of a condensate film. The film-like condensation is one of the condensation processes, and is characterized in that the condensate can form a liquid film to completely wet the wall surface, and the thicker the liquid film is, the more the condensate flows down along the wall. Because the inner wall of the heat pipe is always covered with a layer of liquid film, the heat transfer between the wall surface and the condensed vapor encounters resistance, so the heat transfer efficiency is lower than that of drop condensation.

In the disclosed patent, "multi-head spiral groove heat exchange tube" (ZL 00250108.2) belongs to corrugated pipes, the existing screw heat exchange tube enhances heat exchange by enlarging the heat exchange area and enabling the fluid in the tube to generate disturbance, while the heat exchange efficiency is improved, the scale is easy to build, and the manufacturing cost of the spiral element for enhancing heat transfer is relatively high due to lower processing efficiency or complex manufacturing process. The gravity heat pipe enhanced heat transfer structure (CN 203534295U) has the advantages that heat transfer is enhanced by arranging the guide cylinder, the problem of cold and hot air flow opposite flushing in the working process of the gravity heat pipe is reduced by adding the guide cylinder in the inner cavity of the gravity heat pipe, heat transfer efficiency is improved, and the gravity heat pipe enhanced heat transfer structure is simple in structure but not high in heat transfer efficiency. And neither can solve the problem of low heat exchange efficiency due to the liquid film. In view of the liquid resistance caused by liquid films, existing solutions generally utilize longitudinal grooves and corrugations to reduce the thickness of the liquid film. The condensing wall surface concentrates condensate at the bottom of the groove by the tension action of the liquid surface, so that the thickness of the liquid film is thinned. Alternatively, the film-like coagulation may be beaded, with the walls coated with a hydrophobic material or with a small amount of oily additives added to the vapor, but the beaded coagulation may not be maintained for a long period of time. In addition, the gravity heat pipe (CN 104197761A) for enhancing heat transfer has a complex structure and is not beneficial to popularization by adding the liquid sweeping device into the gravity heat pipe for enhancing heat exchange.

Disclosure of Invention

The invention aims at solving the problem that the heat exchange is affected by increasing condensation heat resistance due to accumulation of a liquid film at a condensation section of a gravity heat pipe, and the condensed liquid is timely discharged by adding annular components to the pipe wall of the gravity heat pipe, so that the thickness of a condensed liquid film formed by condensing steam on the pipe wall is reduced, and the purpose of enhancing the heat exchange of the gravity heat pipe is achieved; meanwhile, in order to strengthen the evaporation heat exchange of the evaporation section, an annular component with a liquid distribution function is additionally arranged in the evaporation section, so that liquid flowing down from the condensation section can be uniformly distributed on an evaporation heat exchange surface of the heat pipe evaporation section, and falling film evaporation is realized, thereby strengthening the evaporation heat exchange process.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the gravity heat pipe with the annular components comprises a multi-stage annular component arranged on the inner wall of the gravity heat pipe and a multi-stage annular component arranged on the inner wall of the gravity heat pipe, wherein the inner side of the multi-stage annular component is a falling channel of liquid working medium and a rising channel of working medium vapor from the evaporation section; the outer side of the condensation section multi-stage annular component is in sealing connection with the inner cavity wall of the gravity heat pipe, so that condensate can conveniently flow out from the inner side of the condensation section multi-stage annular component after leaving the wall surface, the condensation section multi-stage annular component can reduce the thickness of a condensate film to enhance condensation heat exchange, and meanwhile, the condensation heat exchange area is expanded, so that the condensation section multi-stage annular component has a dual heat transfer enhancement effect; the gap between the outer side of the evaporation section multi-stage annular component and the inner wall of the gravity heat pipe is reserved to form a liquid distribution gap, so that a liquid film is uniformly distributed on the inner cavity wall of the evaporation section of the heat pipe, falling film evaporation is realized, the inner side of the evaporation section multi-stage annular component is a rising channel of working medium steam, and the evaporation section multi-stage annular component also increases evaporation heat exchange area.

The multistage annular components comprise a condensing stage multistage annular component and an evaporating stage multistage annular component. The condensation wall surface structure is changed by adding a condensation section annular component into the pipe, so that liquid is discharged from the wall surface in time, a liquid film is thinned, and condensation heat exchange is enhanced; the evaporation wall surface structure is changed by adding the evaporation section annular component into the pipe, so that falling film evaporation is realized, and evaporation heat exchange is enhanced. Meanwhile, the heat exchange area of the condensing section and the evaporating section is increased due to the addition of the annular components, so that the heat transfer enhancement effect is achieved. In addition, the annular components and parts of the gravity heat pipe are fixed with the pipe wall through interference fit, so that the problem that welding is difficult to achieve in the heat pipe is solved, the whole manufacturing process is simple, the processing efficiency is high, and the cost is low.

Drawings

Fig. 1 is a schematic diagram of a gravity assisted heat pipe with an annular component according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an evaporation section annular component used in the gravity assisted heat pipe with annular component according to the embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a condensation section ring-shaped component used in the gravity assisted heat pipe with the ring-shaped component according to the embodiment of the present invention.

Detailed Description

The technical scheme of the invention is described below through specific embodiments with reference to the accompanying drawings.

Referring to fig. 1, in combination with fig. 2 and 3, a gravity assisted heat pipe with annular components includes a housing 1, a condensation section 2, an evaporation section 3, a heat preservation section 7, a process port 11, n evaporation section annular components 4 mounted on the evaporation section 3, and n condensation section annular components 8 mounted on the condensation section 2. The evaporation section annular components are arranged in number according to the requirement, the condensation section annular components are arranged in number according to the requirement, and n is an integer greater than or equal to 1. The annular component 10 of the condensing section and the pipe wall of the condensing section 2 are fixed together through interference fit. The center Kong Jishi of the inner side of the condensing section annular component 10 is a descending channel of liquid working medium and is a ascending channel of working medium vapor from the evaporating section 3; the joint of the outer side of the evaporation section annular component 6 and the inner wall of the gravity heat pipe is provided with a liquid distribution gap to form a descending channel of liquid working medium so that a liquid film is uniformly distributed on the inner cavity wall of the evaporation section 3 of the heat pipe, and the central hole of the inner side of the evaporation section annular component 6 is a ascending channel of heat pipe working medium steam. The same result size is adopted for each condensation section annular component 10, and the central hole size of the upper one-stage condensation section annular component 10 slightly larger than that of the lower one-stage condensation section annular component 9 can also be adopted, so that the condensed liquid can not influence the discharge of a liquid film on the next one-stage annular component when flowing down from the next one-stage annular component. Each evaporation stage annular component 6 is slightly smaller than the central hole of the next stage annular component 5 which is close to the previous stage annular component 6, or an overflow hole 12 is arranged on each evaporation stage annular component 6 at the upper part except the bottom stage, so that the liquid working medium in each evaporation stage annular component 6 at the upper part can flow into the evaporation stage annular component 5 at the lower part through overflow.

The liquid working medium evaporates in the evaporation section 3, and reaches the condensation section 2 through the heat preservation section to condense, strengthens condensation heat transfer through the thinned liquid film of the annular component 10 of the condensation section, and condensate relies on gravity to reach the annular component 6 of the evaporation section to accomplish the cloth liquid of the liquid film of the evaporation section, strengthen evaporation heat transfer. The outside of evaporation zone ring components and parts 6 is processed into the cockscomb structure, and evaporation zone ring components and parts 6 is fixed through the surplus cooperation with gravity heat pipe evaporation zone 3 internal wall face, and the clearance between the sawtooth forms the decline passageway of liquid working medium falling film evaporation with the aperture that forms between the gravity heat pipe inner wall to guarantee the evenly distributed of evaporation liquid film, strengthen the heat transfer effect.

Claims (2)

1. A gravity assisted heat pipe enhanced heat transfer structure is characterized in that: the gravity heat pipe comprises a multistage annular component arranged on a condensation section of the inner wall of the gravity heat pipe and a multistage annular component arranged on an evaporation section, wherein n annular components are arranged on the evaporation section according to the requirement, n is an integer greater than or equal to 1, the condensation section annular components are fixed with the wall of the condensation section through interference fit, and the inner side center Kong Jishi of the condensation section annular components is a falling channel of liquid working medium and a rising channel of working medium vapor from the evaporation section; the outer side of the evaporation section annular component is processed into a saw-tooth shape, the evaporation section annular component is fixed with the inner wall surface of the evaporation section of the gravity heat pipe in a interference fit manner, a liquid distribution gap is reserved at the joint of the outer side of the evaporation section annular component and the inner wall of the gravity heat pipe, a descending channel for falling film evaporation of a liquid working medium is formed by a gap between the saw-tooth and a small hole formed between the inner wall of the gravity heat pipe, and a central hole at the inner side of the evaporation section annular component is an ascending channel for working medium steam of the heat pipe; the liquid working medium evaporates in the evaporation section, and reaches the condensation section through the heat preservation section to condense, the liquid film is thinned through the annular components of the condensation section to strengthen the condensation heat exchange, the condensate reaches the annular components of the evaporation section by means of gravity, the liquid distribution of the liquid film of the evaporation section is completed, and the evaporation heat exchange is strengthened; the outside of the evaporation section annular component is processed into a zigzag shape, the evaporation section annular component is fixed with the inner wall surface of the evaporation section of the gravity heat pipe through interference fit, and a descending channel for liquid working medium falling film evaporation is formed by gaps between the zigzag and small holes formed between the inner walls of the gravity heat pipe, so that the uniform distribution of an evaporation liquid film is ensured, and the heat exchange effect is enhanced.

2. The gravity assisted heat pipe enhanced heat transfer structure of claim 1, wherein: the annular components of the condensing section adopt the same structural size, or adopt the central hole size slightly larger than that of the annular components of the condensing section of the upper stage; the annular components of the evaporation section are slightly smaller than the central hole of the annular components of the next stage, or overflow holes are formed in each annular component of the upper stage except the bottom stage.

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