Dry-wet integrated falling film heat transfer unit

Abstract

The utility model discloses a dry and wet integrated falling film heat transfer unit which is composed of a base tube (1), fins (2) and falling film channels (3). According to the dry and wet integrated falling film heat transfer unit, the falling film channel in the longitudinal direction of the base tube is created on the annular finned tube, the problem that a liquid film cannot be formed due to the annular finned tube is solved in the field of longitudinal falling film heat transfer, the finned tube is used for replacing a light tube, and the heat transfer efficiency is improved. Longitudinal finned tubes which are high in machining difficulty and low in finned coefficient are replaced with the annular finned tubes which are easy to machine and higher in finned coefficient, and the annular finned tubes are particularly suitable for falling film heat transfer of gravity assisted heat tubes and vertical heat exchange tubes.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange technology, specifically a dry-wet integrated falling film heat transfer unit. Background Technology

[0002] Falling film heat transfer is a highly efficient wet heat exchange method that utilizes a liquid to form a thin film on the heat exchange wall, through which heat is transferred. Its heat transfer coefficient is much higher than that of conventional dry heat exchange. Falling film heat transfer is generally divided into two operating conditions: falling film evaporation and falling film condensation. Falling film evaporation is particularly suitable for the heating and humidification process of gaseous substances, while falling film condensation is suitable for the cooling and condensation dehydration process of gaseous substances.

[0003] Conventional falling film heat transfer units are mostly bare tubes or horizontally arranged annular finned tubes. When gravity heat pipes or vertically arranged heat exchange tubes are used as heat transfer units, conventional annular finned tubes will affect the formation of the liquid film, resulting in a decrease in the heat transfer coefficient. Longitudinal finned tubes are mostly made of steel-aluminum composite materials, which are difficult to process, have a low finning coefficient, and will increase the steel consumption of the equipment. They are also difficult to adapt to high-temperature application scenarios. Summary of the Invention

[0004] To address the challenges of annular finned tubes being difficult to adapt to vertical heat transfer units and the low finning coefficient of longitudinal finned tubes in falling film heat transfer, this utility model discloses a dry-wet integrated falling film heat transfer unit.

[0005] The dry and wet integrated falling film heat transfer unit of this utility model consists of a base tube 1, fins 2, and falling film channels 3. The fins 2 are arranged in a ring on the outer wall of the base tube 1 and are tightly connected to the base tube 1. Falling film channels 3 are intermittently arranged at the annular intersections where the fins 2 and the base tube 1 contact each other. The falling film channels 3 are close to the base tube 1 and run through all the fins 2 at the annular intersections along the length of the base tube 1. The width h of the falling film channel 3 is smaller than the width B of the fin 2.

[0006] Compared with the prior art, the present invention has the following beneficial effects:

[0007] 1. A falling film channel was created for the vertically arranged annular finned tubes, enabling the annular finned tubes to meet the longitudinal falling film heat transfer requirements, thus increasing the application scenarios of the annular finned tubes. Through falling film heat transfer, the heat transfer coefficient and the heat exchange density per unit space between gravity heat pipes and conventional vertical heat exchange tubes and gas phase substances can be further improved, effectively reducing the steel consumption of the equipment.

[0008] 2. The use of annular finned tubes, which are easy to process and have a high finning coefficient, replaces conventional bare tubes or longitudinal finned tubes. This enhances heat transfer while increasing the density of the heated surface area per unit space, thereby increasing the compactness and layout flexibility of the equipment. Attached Figure Description

[0009] Figure 1 This is a typical structural diagram of the dry and wet integrated falling film heat transfer unit of this utility model.

[0010] Figure 2 for Figure 1 The J-direction view.

[0011] Figure 3 This is Embodiment 1 of the present invention.

[0012] Figure 4 This is Embodiment 2 of the present invention.

[0013] Explanation of figure numbers and symbols:

[0014] 1-Base tube; 2-Fin; 3-Falling film channel; 4-First type of high temperature medium channel; 5-First type of low temperature medium channel; 6-High temperature medium distribution device; 7-Low temperature medium distribution device; 8-Second type of high temperature medium channel; 9-Second type of low temperature medium channel;

[0015] h - Falling film channel width; B - Fin width; M - High temperature medium inlet; N - High temperature medium outlet; P - Low temperature medium inlet; Q - Low temperature medium outlet. Detailed Implementation

[0016] The present invention and its embodiments will be further described in detail below with reference to the accompanying drawings. It should be noted that the following description is intended to facilitate the understanding of the present invention and does not constitute any limitation thereof.

[0017] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0018] Combination Figure 1 :

[0019] The dry-wet integrated falling film heat transfer unit of this utility model consists of a base tube 1, fins 2, and falling film channels 3. The fins 2 are arranged in a ring on the outer wall of the base tube 1 and are tightly connected to the base tube 1. Falling film channels 3 are intermittently arranged at the annular intersections where the fins 2 and the base tube 1 contact each other. The falling film channels 3 run along the length of the base tube 1 and penetrate all the fins 2 at the annular intersections. The width h of the falling film channels 3 is smaller than the width B of the fins 2. The falling film channels 3 are close to the base tube 1 and guide the falling film liquid to the outer surface of the base tube 1. Under the action of gravity, the falling film liquid forms a liquid film along the outer surface of the base tube 1, thereby enhancing the heat transfer effect.

[0020] The fins 2 are flat steel, spirally wound around the outer wall of the base tube 1, or are several annular steel plates welded one by one to the outer wall of the base tube 1. The fins 2 and the base tube 1 are connected by conventional welding or snap rings, which is simple in structure and easy to produce.

[0021] One or both ends of the base tube 1 have a light tube area. The light tube area is used for connecting the dry and wet integrated falling film heat transfer unit of this utility model with adjacent elements, or for partially changing the fin type.

[0022] Combination Figure 2 :

[0023] Figure 2 yes Figure 1 The J-direction view is also a vertical projection schematic diagram of the relative positions of the base tube 1, fins 2 and falling film channel 3 of the dry-wet integrated falling film heat transfer unit of this utility model.

[0024] The fins 2 surround the outer wall of the base tube 1, and the falling film channel is close to the outer wall of the base tube 1, penetrating all the fins 2 along the longitudinal direction of the base tube 1.

[0025] The outer edges of the fins 2 and 1 after forming are circular, triangular, square, pentagonal or hexagonal.

[0026] The falling film channel (3) is arranged circumferentially along the base tube (1), and the falling film channel (3) is triangular, arc-shaped or square notch.

[0027] The outer edge shapes of the fins 2 and 1 after forming, and the shape of the falling film channel 3, can be freely combined and used in the structure.

[0028] Combination Figure 3 :

[0029] Figure 3 This is an embodiment of the dry and wet integrated falling film heat transfer unit described in this utility model applied to a gravity heat pipe.

[0030] The dry-wet integrated falling film heat transfer unit of this invention is prepared as a gravity heat pipe by filling the base tube 1 with a phase change medium. The gravity heat pipe is installed inside a heat pipe heat exchanger, with the evaporation section arranged inside the first high-temperature medium channel 4 and the condensation section arranged inside the first low-temperature medium channel 5. The high-temperature medium enters the heat pipe heat exchanger through the high-temperature inlet M, carrying heat that is transferred to the low-temperature medium via the gravity heat pipe. After being cooled, it exits the heat pipe heat exchanger through the high-temperature medium outlet N. The low-temperature medium enters the heat pipe heat exchanger through the low-temperature medium inlet P, is heated by the heat from the high-temperature medium transferred from the gravity heat pipe, and exits the heat pipe heat exchanger through the low-temperature medium outlet Q.

[0031] To enhance the heat transfer between the high-temperature medium and the gravity heat pipe, and to further reduce the temperature and humidity of the high-temperature medium, a high-temperature medium distribution device 6 is partially or completely arranged inside the first high-temperature medium channel 4 of the gravity heat pipe. The high-temperature medium distribution device 6 uses a liquid with a temperature lower than that of the high-temperature medium to form a low-temperature liquid film on the gravity heat pipe, thereby enhancing the heat transfer process between the high-temperature medium and the gravity heat pipe and reducing the temperature of the high-temperature medium. When the temperature of the liquid is lower than the dew point temperature of the high-temperature medium, the temperature of the high-temperature medium can be reduced below its dew point temperature, completing the cooling and condensation dehydration of the high-temperature medium. This process is the falling film condensation process of the high-temperature medium.

[0032] The gravity heat pipe is located inside the first high-temperature medium channel 4, in the area without the rain distribution device 6, where the heat transfer is dry, and is partially or entirely a bare tube or a conventional finned tube.

[0033] To enhance the heat transfer between the cryogenic medium and the gravity heat pipe, and to increase the temperature and humidity of the cryogenic medium, a cryogenic medium distribution device 7 is partially or completely arranged inside the first cryogenic medium channel 5 of the gravity heat pipe. A liquid film is formed on the gravity heat pipe, enhancing the heat transfer process between the gravity heat pipe and the cryogenic medium, and efficiently increasing the temperature and humidity of the cryogenic medium. This process is also a falling film evaporation process of the liquid. The temperature of the liquid is lower than the phase change temperature of the gravity heat pipe.

[0034] The dry and wet integrated falling film heat transfer unit of this invention can adapt to both dry and wet heat transfer processes in the gravity heat pipe embodiment.

[0035] Combination Figure 4 :

[0036] Figure 4 This is an embodiment of the dry-wet integrated falling film heat transfer unit of this utility model applied to a conventional vertical heat exchange tube. A typical device in this embodiment is a heat exchanger with a low-temperature medium of gas. The high-temperature medium of the heat exchanger is flue gas, air, water vapor, water, oil, or a flowable solid; the low-temperature medium of the heat exchanger is one or a mixture of air, flue gas, and fuel gas.

[0037] The high-temperature medium enters the high-temperature medium channel of the heat exchanger from the high-temperature medium inlet M, i.e., the second type of high-temperature medium channel 8 shown in the figure. It flows through the inside of the base tube 1 of the dry-wet integrated falling film heat transfer unit of this invention. During the flow, it transfers heat to the low-temperature medium through the dry-wet integrated falling film heat transfer unit of this invention. After being cooled, the high-temperature medium leaves the heat exchanger from the high-temperature medium outlet N. The low-temperature medium enters the low-temperature medium channel of the heat exchanger from the low-temperature medium inlet P, i.e., the second type of low-temperature medium channel 9 shown in the figure. After being heated by the heat transferred from the high-temperature medium by the dry-wet integrated falling film heat transfer unit of this invention, it leaves the heat exchanger from the low-temperature medium outlet Q.

[0038] To enhance the heat transfer effect between the low-temperature medium and the dry-wet integrated falling film heat transfer unit of this invention, the dry-wet integrated falling film heat transfer unit of this invention is partially or completely equipped with a low-temperature medium distribution device 7 inside the second low-temperature medium channel 9, using liquid to form a liquid film on the gravity heat pipe, thereby enhancing the heat transfer process between the gravity heat pipe and the low-temperature medium and efficiently improving the temperature and humidity of the low-temperature medium. The process is also the falling film evaporation process of the liquid.

[0039] The dry and wet integrated falling film heat transfer unit of this utility model can adapt to both dry and wet heat transfer processes in conventional vertical heat exchange tube embodiments.

[0040] The above description is merely an application example of the present invention and does not limit the scope of protection of the present invention. Any equivalent structures made using the content of this specification and drawings, whether directly or indirectly applied to related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A dry and wet integrated falling film heat transfer unit, which is composed of a base pipe (1), a fin (2), and a falling film channel (3), characterized in that: The fin (2) is arranged in a ring on the outer wall of the base pipe (1), the fin (2) is tightly connected with the base pipe (1), the fin (2) is discontinuously arranged with falling film channels (3) at the annular intersection lines where the fin (2) contacts the base pipe (1), the falling film channels (3) are tightly attached to the base pipe (1), the falling film channels (3) run along the length direction of the base pipe (1), penetrate through the fin (2) at all the annular intersection lines, and the width h of the falling film channels (3) is less than the width B of the fin (2).

2. The falling film heat transfer unit of claim 1, wherein: The base pipe (1) is a gravity heat pipe or a conventional heat exchange pipe.

3. The falling film heat transfer unit of claim 1, wherein: The fin (2) is flat steel, is spirally wound on the outer wall of the base pipe (1), or is several ring-shaped steel plates which are tightly connected on the outer wall of the base pipe (1), and the outer edge shape of the fin (2) after being connected with the base pipe (1) is circular, triangular, square, pentagonal or hexagonal.

4. The falling film heat transfer unit of claim 1, wherein: The falling film channels (3) are arranged along the circumference of the base pipe (1), and the falling film channels (3) are triangular, arc-shaped or square notches in shape.

5. The falling film heat transfer unit of claim 1, wherein: The head of one end or both ends of the base pipe (1) is left as a light pipe area.

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