CN215638970U

CN215638970U - Low flow resistance gravity heat pipe heat exchanger

Info

Publication number: CN215638970U
Application number: CN202122200037.7U
Authority: CN
Inventors: 葛明慧; 赵运通; 李振华; 玄志伟; 赵玉龙
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2021-09-13
Filing date: 2021-09-13
Publication date: 2022-01-25
Anticipated expiration: 2031-09-13

Abstract

The utility model relates to a low flow resistance gravity assisted heat pipe exchanger, which comprises a phase change cavity, a cold and hot fluid pipe bundle, a phase change working medium and a variable cross-section channel, wherein the phase change cavity is provided with a first flow passage and a second flow passage; the phase change cavity is a closed cavity, the cold fluid tube bundle is arranged at the upper part in the closed cavity, the hot fluid tube bundle is arranged at the lower part in the closed cavity, and two ends of the cold and hot fluid tube bundles are welded with the wall surfaces at two ends of the phase change cavity; filling a phase change working medium into the phase change cavity, wherein the phase change working medium is immersed in the whole hot fluid tube bundle, the liquid level of the phase change working medium is higher than the whole height of the hot fluid tube bundle, and meanwhile, the liquid level of the phase change working medium is not directly contacted with the cold fluid tube bundle; the variable cross-section channel covers the inlet and outlet of the cold and hot fluid tube bundles at two ends of the phase change cavity respectively in a welding mode. This application cold and hot fluid tube bank disect insertion is in the heat pipe, in the phase transition cavity promptly, and cold and hot fluid flows in the tube bank, and medium boiling condensation takes place outside the tube bank, because there is not the interpolation in the tube bank, and the flow resistance is littleer.

Description

Low flow resistance gravity heat pipe heat exchanger

Technical Field

The utility model relates to the field of efficient heat exchangers applied to waste heat recovery, in particular to a low-flow-resistance gravity heat pipe heat exchanger.

Background

In recent years, the energy industry in China has greatly strengthened the energy-saving technical problem, and energy conservation and consumption reduction continuously obtain new effects. The heat pipe is widely applied to various fields as a high-efficiency heat transfer device capable of transferring more heat in a smaller area. The heat pipe not only has higher heat transfer efficiency than the traditional material, but also has the characteristics of compact structure, small mass, low noise, no transmission element and the like, and the heat pipe heat exchanger constructed based on the high-efficiency heat transfer capacity of the heat pipe also plays an important role in energy conservation and emission reduction.

The heat pipe heat exchanger is usually composed of a cold and hot runner and a heat pipe, wherein the heat pipe is positioned in the cold and hot runner and penetrates through the cold and hot runner, hot fluid in the runner exchanges heat with an evaporation section of the heat pipe on the outer surface of the heat pipe, and heat is transferred to a condensation section of the heat pipe and then is subjected to heat convection with cold fluid on the outer surface of the heat pipe, so that heat is transferred from the hot fluid to the cold fluid. The heat pipe heat exchanger has the advantages of high heat transfer efficiency, compact structure, high reliability and the like, and can be used in heat energy recovery occasions with lower grade. For fluid with higher dust content, the heat pipe heat exchanger can solve the problems of abrasion and dust blockage of the heat exchanger by changing the structure, expanding the heating surface and the like. For example, chinese patent publication No. CN109520336A discloses that the heat pipe is disposed in the flow guide, and the M-shaped flow guide and the S-shaped flow guide are disposed in the flow channel, so as to prolong the heating time of the fluid in the heat pipe and improve the heat exchange efficiency. However, because the flow channel part is bent at a plurality of positions, strong impact can be generated when fluid flows through the bent positions, the flow channel is easy to vibrate, and the service life of the flow channel is influenced. Because the heat pipe is arranged in the cold and hot flow channel, cold and hot fluid flows outside the heat pipe, the flow of the fluid can be blocked to a certain extent by the heat pipe, and the fluid can cause larger flow resistance when flowing through the heat pipe.

SUMMERY OF THE UTILITY MODEL

The utility model aims to develop a low-flow-resistance integrated gravity heat pipe heat exchanger.

In order to achieve the purpose, the utility model adopts the technical scheme that:

a low flow resistance gravity assisted heat pipe exchanger comprises a phase change cavity, a cold and hot fluid pipe bundle, a phase change working medium and a variable cross-section channel; the method is characterized in that:

the phase change cavity is a closed cavity, the upper part in the closed cavity is provided with a cold fluid tube bundle, the lower part in the closed cavity is provided with a hot fluid tube bundle, two ends of the cold and hot fluid tube bundles are welded with the wall surfaces at two ends of the phase change cavity, and the corresponding side surface of the phase change cavity provided with the cold and hot fluid tube bundles is provided with an opening for communicating with the interiors of the cold and hot fluid tube bundles; filling a phase change working medium into the phase change cavity, wherein the phase change working medium is required to immerse the whole hot fluid tube bundle, the liquid level of the phase change working medium is required to be at least 2cm higher than the whole height of the hot fluid tube bundle, and meanwhile, the liquid level of the phase change working medium is not directly contacted with the cold fluid tube bundle so as to ensure that the hot fluid tube bundle is always immersed in the operation process of the equipment; the variable cross-section channel covers the inlet and outlet of the cold and hot fluid tube bundles at two ends of the phase change cavity respectively in a welding mode.

The phase change working medium is immersed in the hot fluid tube bundle and exceeds the highest point of the hot fluid tube bundle by about 2-5 cm, and the distance from the bottom of the cold fluid tube bundle to the liquid level of the phase change working medium is more than 2 cm.

The width of one end of the variable cross-section channel, which is connected with the phase change cavity, is equal to the width of the phase change cavity, and the height of the end is not less than the distance from the lowest point to the highest point in the corresponding cold and hot fluid tube bundles, so that the end of the variable cross-section channel can completely cover the corresponding tube bundle, corresponding fluid can enter each tube of the cold and hot fluid tube bundles at the corresponding position through the variable cross-section channel, and the flowing direction of the cold and hot fluid in the cold and hot fluid tube bundles is defined as the length direction.

The end of the variable cross-section channel, which is far away from the phase change cavity, is in a flange shape, so that the variable cross-section channel is convenient to apply in the later period. One end of the variable cross-section channel, which is far away from the phase change cavity, is a circular cross section, and the interface position of the variable cross-section channel and the phase change cavity is a rectangular cross section or a circular cross section, so that the variable cross-section channel can cover the tube bundles which are correspondingly arranged.

The whole phase change cavity can be regarded as a heat pipe, the cold fluid pipe bundle and the hot fluid pipe bundle can directly carry out heat transfer with a phase change working medium in the heat pipe, the flow state of corresponding fluid in the pipe bundle can not be influenced due to the increase of the number of the cold fluid pipe bundle and the hot fluid pipe bundle, the flow resistance is small, and the heat exchange efficiency of the phase change working medium in the heat pipe can be increased.

The heat exchange area of the cold side and the hot side of the heat exchanger in the heat pipe can adjust the number of corresponding pipe bundles according to the parameters of cold and hot fluid, and can save materials to the maximum extent, reduce the manufacturing cost and realize high-efficiency heat exchange under the same condition.

The operation flow of the low flow resistance gravity heat pipe heat exchanger provided by the utility model is as follows: in a heat pipe (phase change cavity), a phase change working medium soaks a thermal fluid pipe bundle to wrap all pipes of the whole thermal fluid pipe bundle, the thermal fluid enters the thermal fluid pipe bundle in the heat pipe through a bottom variable cross-section channel to form the largest heat exchange area, each thermal fluid pipe exchanges heat with a liquid phase working medium at the bottom of the cavity, and the phase change working medium absorbs heat and is evaporated into a gas phase. Cold fluid enters the cold fluid tube bundle through an upper variable cross-section channel in the hot tube, a gas phase working medium which absorbs heat and evaporates wraps the outer surfaces of all the tubes of the cold fluid tube bundle in the phase change cavity, each cold fluid tube is in direct contact with the gas phase working medium for heat exchange, the cold fluid tubes can be condensed on the surfaces of the cold fluid tube bundles to the maximum extent, heat is transferred to the cold fluid in all the cold fluid tubes, and the condensed working medium flows into the bottom of the phase change cavity again under the action of gravity to complete circulation; the flow of the corresponding fluid in the cold and hot fluid tube bundle is not influenced in the process, so the flow resistance state is low. The cold and hot fluid adopts a counter-flow mode.

The phase-change working medium used by the low flow resistance gravity heat pipe heat exchanger provided by the utility model can select working media such as water, a heat conducting medium heat exchanger, sodium and the like according to the working temperature.

The shape of the phase change cavity of the low flow resistance gravity heat pipe exchanger provided by the utility model can be adjusted according to the specific installation space, but the horizontal arrangement of the phase change cavity is ensured, the cold fluid pipe bundle is higher than the hot fluid pipe bundle, and the phase change working medium can be completely immersed in the hot fluid pipe bundle and exceeds at least 2 cm.

The cold and hot fluid tube bundle of the low flow resistance gravity heat pipe heat exchanger provided by the utility model can respectively adjust the diameter and the number of the tubes in the heat pipe according to specific working conditions, and the arrangement mode of the tube bundle can be selected from a linear shape, a U-shaped shape, a return shape and the like.

Compared with the prior art, the utility model has the beneficial effects that:

the prominent substantive features of the utility model are:

the interfaces of the cold fluid and the hot fluid are integrally connected with the corresponding tube bundles, the installation is convenient, the number and the diameter of the tube bundles are adjusted on the premise of not changing the structure of a flow channel in the tube bundles, and the turbulence of the fluid in the pipeline can not be increased, so that the flow resistance of the fluid can be reduced to the greatest extent under the same condition, the heat exchange area of the fluid tube bundles can be increased by the form that the tube bundles are completely wrapped by the phase-change working medium, all pipeline wall surfaces of the tube bundles can play a heat exchange effect, the heat exchange area is maximized, and the heat exchange efficiency of the heat pipe exchanger is improved. The defect that in the prior art, the heat pipe is arranged outside the runner, only the runner exchanges heat with the part in contact with the wall surface of the heat pipe, and the heat exchange efficiency of other parts is low, so that the heat exchange effect is obviously poor is overcome, the defect that in the prior art, the fins are simply added outside the heat pipe is also avoided, but the effective heat exchange area is not obviously increased, and the heat exchange effect is not ideal.

The utility model has the remarkable advantages that:

1) this application cold and hot fluid tube bank disect insertion is in the heat pipe, in the phase transition cavity promptly, and cold and hot fluid flows in the tube bank, and medium boiling condensation takes place outside the tube bank, because there is not the interpolation in the tube bank, and the flow resistance is littleer.

2) The cold and hot fluid tube bundle directly serves as a condensation section and an evaporation section of the heat pipe, the cold and hot fluid flows in the tube bundle, heat is transferred to the phase-change working medium outside the pipe, and heat transfer is achieved.

3) The gravity heat pipe exchanger provided by the utility model has the advantages of simple structure, small flow resistance and high heat exchange efficiency. The amount of the tube bundle is adjusted according to the specific parameters (such as required flow, inlet and outlet temperature and the like) of the cold and hot fluid, so that the purposes of reasonably utilizing the tube materials and reducing the cost are achieved.

4) The utility model can be quickly installed on various pipelines due to the variable cross-section channel, and can be directly applied to the waste heat recovery and transformation of the existing equipment due to the low resistance characteristic, and the normal operation of the equipment cannot be influenced.

Drawings

Fig. 1 is a schematic front view of a low flow resistance gravity heat pipe heat exchanger according to an embodiment of the present invention.

FIG. 2 is a schematic side view of a low flow resistance gravity assisted heat pipe exchanger according to an embodiment of the present invention.

FIG. 3 is a schematic top view of a low flow resistance gravity assisted heat pipe exchanger according to an embodiment of the present invention.

Detailed Description

For a further understanding of the contents, features and effects of the present invention, reference is made to the following embodiments, which are illustrated in the accompanying drawings:

as shown in fig. 1-3, the low flow resistance gravity assisted heat pipe heat exchanger of the present invention comprises a phase change cavity 1, a flange type interface 2, a variable cross-section channel 3, a cold fluid pipe bundle 4, a phase change working medium 5 and a hot fluid pipe bundle 6. The phase change cavity 1 is a closed cavity and is divided into an upper part and a lower part, the upper part is provided with a cold fluid tube bundle 4, the lower part is provided with a hot fluid tube bundle 6, and two ends of the cold and hot fluid tube bundle are welded with the wall surfaces at two ends of the phase change cavity 1. The wall surface of the phase change cavity at the connecting position of the tube bundle and the phase change cavity is provided with a plurality of through holes, so that the tube bundle in the phase change cavity is communicated with the outside through the through holes, and each pipeline in the tube bundle enables corresponding fluid to enter and exit the pipeline through the corresponding through hole.

The phase change cavity 1 is filled with a liquid phase change working medium 5, and the liquid level of the phase change working medium 5 is ensured to be completely immersed in the thermal fluid tube bundle 6 and exceed about 2 cm. The distance between the bottom of the cold fluid tube bundle and the liquid level of the phase change working medium is more than 3 cm. The cold fluid tube bundle 4 and the hot fluid tube bundle 6 can be arranged in the phase change cavity 1 in a linear mode, a U-shaped mode, a return mode and the like. Two variable cross-section channels 3 are respectively arranged at the upper and lower positions of two ends of the phase change cavity, and each variable cross-section channel 3 is connected with the phase change cavity 1 and the flange type interface 2 in a welding mode. The large port area of the variable cross-section channel 3 can correspondingly cover the integral inlet and outlet of the cold fluid tube bundle 4 and/or the hot fluid tube bundle 6.

In the low flow resistance gravity heat pipe exchanger, the number and the type of the cold fluid pipe bundle 4 and the hot fluid pipe bundle 6 can be freely arranged, the heat transfer area can be increased by increasing the diameter of the pipe bundles or the diameter of the pipes, all the pipe wall surfaces of the cold fluid pipe bundle are surrounded by vaporized gaseous working media in the heat pipe (phase change cavity 1) and directly exchange heat with the cold fluid, all the pipe wall surfaces of the hot fluid pipe bundle are soaked by liquid working media and directly exchange heat with the hot fluid, the effective contact area between the pipe bundle diameter increase or the pipe diameter increase and the corresponding working media can be increased, the heat exchange efficiency is greatly improved, and the fluid flow resistance can be reduced.

In the low flow resistance gravity heat pipe heat exchanger, different phase change working media 5 can be selected according to different working temperatures to improve the applicability and safety of the heat pipe heat exchanger.

In the low flow resistance gravity heat pipe heat exchanger, the variable cross-section channel 3 has the function of ensuring that corresponding fluid uniformly enters and exits the fluid pipe bundle, and can be conveniently installed and used in subsequent actual engineering. During installation, a layer of filter screen can be added at the flange type interface 2 to avoid the influence of impurities in the fluid on the normal operation of the heat exchanger.

When the cold fluid tube bundle and the hot fluid tube bundle are arranged on the side surface of the phase change cavity in a circular array mode, the shape of the connecting position of the variable cross-section channel 3 and the phase change cavity can be circular, the whole shape of the phase change cavity can be a cuboid, and the circular area of the variable cross-section channel can cover all the pipeline cross sections in the corresponding tube bundle, so that fluid enters each pipeline in the tube bundle through the variable cross-section channel. When the tube bundles are arranged in a rectangular array, the shape of the connecting position of the variable cross-section channel and the phase change cavity is rectangular, the width of the rectangle is the same as that of the phase change cavity, and the height of the rectangle is not less than the total height of all the thermal fluid tube bundles. The phase change cavity and the variable cross-section pipeline are arranged in a cuboid or a rectangle to enhance the heat exchange effect to the maximum extent, and the areas of the upper cavity half and the lower cavity half in the phase change cavity are fully utilized to improve the heat exchange efficiency.

The low flow resistance gravity heat pipe heat exchanger can be used for waste heat recovery and transformation of existing thermodynamic equipment, for example, two variable cross-section channels at the bottom of a phase change cavity are connected with an inlet and an outlet of a flue through a flange type interface in boiler exhaust smoke to form a flow path of hot fluid; the cold fluid channel can supply water for heating and is used for supplying indoor heat, or the air is supplied for preheating, and the like, so that the waste heat is recovered, the increase of the back pressure of the thermal equipment cannot be caused, and the normal operation of the thermal equipment is ensured.

The heat pipe exchanger emphasizes an integrated structural form, the whole heat pipe exchanger is equivalent to a heat pipe, the hot runner pipe bundle and the cold runner pipe bundle are respectively used as an evaporation side and a condensation side, and cold and hot fluid flows in the heat pipe exchanger, so that the flow resistance is reduced to a great extent, and the heating area is also increased. The common heat pipe heat exchanger consists of two structures, namely a plurality of heat pipes and a cold and hot flow passage, wherein an evaporation section and a condensation section of each heat pipe are respectively inserted into the cold and hot fluid passage, heat transfer is realized by heat exchange between the heat pipes and fluid in the cold and hot fluid passage, and the flow resistance is larger due to the existence of the heat pipe insertion section in the flow passage. The heat pipe can be regarded as a whole, the cold and hot fluid pipe bundle is respectively used as a condensation section and an evaporation section, and the fluid directly transfers heat to working media in the phase change cavity when flowing in the heat pipe, so that the heat transfer is realized. The fluid has small flow resistance and large heat exchange area in the tube bundle, and the heat exchange efficiency is improved.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A low flow resistance gravity assisted heat pipe exchanger comprises a phase change cavity, a cold and hot fluid pipe bundle, a phase change working medium and a variable cross-section channel; the method is characterized in that:

the phase change cavity is a closed cavity, the cold fluid tube bundle is arranged at the upper part in the closed cavity, the hot fluid tube bundle is arranged at the lower part in the closed cavity, and two ends of the cold and hot fluid tube bundles are welded with the wall surfaces at two ends of the phase change cavity; filling a phase change working medium into the phase change cavity, wherein the phase change working medium is immersed in the whole hot fluid tube bundle, the liquid level of the phase change working medium is higher than the whole height of the hot fluid tube bundle, and meanwhile, the liquid level of the phase change working medium is not directly contacted with the cold fluid tube bundle; the variable cross-section channel respectively covers the inlet and outlet of the cold and hot fluid tube bundles at two ends of the phase change cavity.

2. The low flow resistance gravity assisted heat pipe exchanger of claim 1, wherein the phase change working medium is to be immersed in the hot fluid tube bundle and to exceed the highest point of the hot fluid tube bundle by 2-5 cm, and the distance from the bottom of the cold fluid tube bundle to the liquid level of the phase change working medium is more than 2 cm.

3. The low flow resistance gravity heat pipe exchanger of claim 1, wherein the width of the end of the variable cross-section channel connecting the phase change cavity is equal to the width of the phase change cavity, and the height of the end is not less than the distance from the lowest point to the highest point in the corresponding cold and hot fluid tube bundles, so that the end of the variable cross-section channel can completely cover the corresponding tube bundle.

4. The low flow resistance gravity heat pipe heat exchanger of claim 1, wherein an end of the variable cross-section channel away from the phase change cavity is in a flange shape; one end of the variable cross-section channel, which is far away from the phase change cavity, is a circular cross section, and the interface position of the variable cross-section channel and the phase change cavity is a rectangular cross section or a circular cross section, so that the variable cross-section channel can cover the tube bundles which are correspondingly arranged.

5. The low flow resistance gravity heat pipe heat exchanger of claim 1, wherein the phase change working medium is water, a thermite heat exchanger, or sodium; the phase change cavity is horizontally arranged, and the cold fluid tube bundle is higher than the hot fluid tube bundle; the arrangement mode of the tube bundles is in a shape like a Chinese character ' yi ', a shape like a U ' or a shape like a Chinese character ' hui '.

6. The low flow resistance gravity heat pipe exchanger of claim 1, wherein the low flow resistance gravity heat pipe exchanger can be used for waste heat recovery retrofit of existing thermodynamic equipment.