Shell-and-tube heat exchanger and refrigerating unit

Abstract

The invention provides a shell-and-tube heat exchanger and a refrigerating unit. The shell-and-tube heat exchanger comprises a barrel, a heat exchange tube bundle, two fluid chambers, a partition plate and a flow control component. A partition plate is arranged in at least one fluid chamber and divides the fluid chamber where the partition plate is located into different cavities so that the heat exchange tube bundle can form a plurality of heat exchange tube sets of a plurality of tube passes. A flow control component is arranged in at least one cavity and located between the two heat exchange tube sets communicated with the cavity where the flow control component is located. The flow control component comprises a flow equalizing structure communicating with the two heat exchange tube sets and / or a flow guide structure guiding tube pass fluid of an outlet of the upstream heat exchange tube set in the two heat exchange tube sets to an inlet of the downstream heat exchange tube set in the two heat exchange tube sets. By arranging the flow control component comprising the flow equalizing structure and / or the flow guide structure, the flow of the fluid of each tube pass is more uniform, and the temperature and flow distribution volatility is smaller.

Description

Technical Field

[0001] The present application relates to the technical field of heat exchangers, and particularly relates to a shell-and-tube heat exchanger and a refrigeration unit. Background Art

[0002] A shell-and-tube heat exchanger is a common heat exchanger, mainly composed of two parts: a tube side and a shell side. Two non-communicating materials, namely, tube-side fluid and shell-side fluid, flow in the tube side and the shell side respectively to achieve the function of heat exchange between the materials.

[0003] When the temperature of the tube-side fluid in the shell-and-tube heat exchanger is relatively low, although the operating parameters of the tube-side fluid in the heat exchange tubes are above the solidification temperature, ice formation may still occur, which may seriously affect the operation of the shell-and-tube heat exchanger.

[0004] Taking the falling film evaporator of a refrigeration unit using a shell-and-tube heat exchanger as the process chilled water as an example, when the refrigerant as the shell-side fluid filled in the shell side of the falling film evaporator cools the process chilled water as the tube-side fluid in the heat exchange tubes, although the temperature requirement for the process chilled water product is above the freezing point, ice formation still exists in the heat exchange tubes. In severe cases, it will cause blockage or cracking of the heat exchange tubes, and further lead to the failure of the refrigeration unit where the falling film evaporator is located.

[0005] The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. Summary of the Invention

[0006] The purpose of the present application is to provide a shell-and-tube heat exchanger and a refrigeration unit, aiming to solve the problem that ice may form when the operating temperature of the tube-side fluid in the heat exchange tubes is relatively low.

[0007] To achieve the above purpose, the first aspect of the present application provides a shell-and-tube heat exchanger, including: a cylinder body; a heat exchange tube bundle located inside the cylinder body for the flow of tube-side fluid; two fluid chambers respectively located at the axial two ends of the cylinder body and communicating with the heat exchange tube bundle; a partition, at least one fluid chamber is provided with a partition, and the partition divides the fluid chamber where it is located into different chambers so that the heat exchange tube bundle forms multiple heat exchange tube groups with multiple tube sides; and a flow control component, at least one chamber is provided with a flow control component, the flow control component is located between two heat exchange tube groups communicating with the chamber where it is located, and the flow control component includes a flow equalizing structure for connecting the two heat exchange tube groups and / or a diversion structure for guiding the tube-side fluid at the outlet of the upstream heat exchange tube group among the two heat exchange tube groups towards the inlet of the downstream heat exchange tube group among the two heat exchange tube groups.

[0008] In some embodiments, the flow control component includes a baffle, the baffle is installed on the chamber wall of the chamber where it is located and / or installed on the partition separating the chamber where it is located, and the flow equalizing structure and / or the diversion structure is arranged on the baffle.

[0009] In some embodiments, the flow equalizing structure includes flow holes formed in the baffle; and / or the flow guiding structure includes a flow guiding section of the baffle, and the flow guiding section inclines from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups towards the inlet of the downstream heat exchange tube group of the two heat exchange tube groups in a direction away from the outlet.

[0010] In some embodiments, the included angle between the flow guiding section and the extending direction of the heat exchange tube bundle is between 20 degrees and 70 degrees.

[0011] In some embodiments, the baffle further includes an axial section that extends along the axial direction of the cylinder body, and the flow guiding section is connected to one end of the axial section that is far from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups.

[0012] In some embodiments, a plurality of flow holes are evenly distributed in at least one area of the baffle.

[0013] In some embodiments, the flow holes are round holes with a diameter between 6 mm and 15 mm.

[0014] In some embodiments, there is a gap between the end of the flow guiding section that is far from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups and the chamber wall of the fluid chamber.

[0015] In some embodiments, the shell-and-tube heat exchanger has more than three tube passes; and / or partition plates are arranged in each fluid chamber; and / or flow control components are arranged in other chambers except for the chamber that receives the tube-pass fluid from outside the shell-and-tube heat exchanger and the chamber that outputs the tube-pass fluid to the outside of the shell-and-tube heat exchanger.

[0016] In some embodiments, the shell-and-tube heat exchanger further includes a tube-pass fluid input pipe and a tube-pass fluid output pipe, wherein the tube-pass fluid input pipe and the tube-pass fluid output pipe communicate with different chambers of the same fluid chamber; and / or the tube-pass fluid input pipe is located below the tube-pass fluid output pipe.

[0017] In some embodiments, the shell-and-tube heat exchanger is a falling film evaporator.

[0018] According to another aspect of the embodiments of the present disclosure, a refrigeration unit is provided, including the shell-and-tube heat exchanger according to any one of the above embodiments.

[0019] In the shell-and-tube heat exchanger of the present disclosure, by providing a flow control component including a flow equalizing structure and / or a flow guiding structure, the flow of the tube-pass fluid is made more uniform, so that the temperature and flow distribution fluctuations of the fluid in the heat exchange tubes are smaller, which is beneficial to preventing the low-temperature tube-pass fluid from locally supercooling and generating ice crystal phenomena due to uneven temperature, thus being beneficial to preventing the heat exchange tubes from freezing and blocking or freezing and cracking, and being beneficial to reducing the flow dead zone and preventing temperature stratification and icing caused by the existence of the flow dead zone. When the shell-and-tube heat exchanger is used in a refrigeration unit, it can reduce the failure of the refrigeration unit caused by the icing of the tube-pass fluid in the heat exchange tubes.

[0020] Other features and advantages of the present application will become clear through the following detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings. Description of the Drawings

[0021] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0022] Figure 1 It is a schematic structural diagram of a shell-and-tube heat exchanger according to some embodiments of the present application.

[0023] Figure 2 is Figure 1 a schematic structural diagram of the fluid chamber at the left end of the shell-and-tube heat exchanger in , where the head at the left end is not shown to display the internal structure of the fluid chamber at the left end.

[0024] Figure 3 is Figure 1 a schematic structural diagram of the fluid chamber at the right end of the shell-and-tube heat exchanger in , where the head at the right end is not shown to display the internal structure of the fluid chamber at the right end.

[0025] Figure 4 is Figure 1 a schematic structural diagram of the first baffle of the shell-and-tube heat exchanger in .

[0026] Figure 5 is Figure 1 a schematic structural diagram of the third baffle of the shell-and-tube heat exchanger in .

[0027] Figures 1 to 5 In , each reference numeral represents:

[0028] 1, shell; 2, fluid chamber; 3, partition; 4, flow control component; 41, baffle; 41A, first baffle; 41B, second baffle; 41C, third baffle; 411, axial section; 412, diversion section; 413, flow-through hole; 5, head; 6, tube sheet; 7, tube-side fluid output pipe; 8, tube-side fluid input pipe; 9, heat exchange tube bundle; A, first angle; B, second angle. Detailed Embodiments

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes a limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0030] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0031] In the description of the present application, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without further statement, these terms have no special meaning, and thus cannot be construed as limiting the scope of protection of the present application.

[0032] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] In the description of the present application, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the scope of protection of the present application; the orientation words "inner, outer" refer to the inside and outside relative to the contour of each component itself.

[0034] In addition, when an element is referred to as being "on" another element, it can be directly on the other element, or it can be indirectly on the other element with one or more intermediate elements interposed therebetween. Additionally, when an element is referred to as being "connected to" another element, it can be directly connected to the other element, or it can be indirectly connected to the other element with one or more intermediate elements interposed therebetween. In the following text, the same reference numerals denote the same elements.

[0035] Unless the context requires otherwise, throughout the following specification, the word "comprising" and its variations, such as "including" and "having", will be interpreted in an open, inclusive sense, i.e., as "including but not limited to".

[0036] In this application, "a plurality of" means two or more (including two), and similarly, "a plurality of groups" means two or more groups (including two groups).

[0037] Regarding the problem that the operating temperature of the tube-side fluid in the shell-and-tube heat exchanger mentioned in the background art is relatively low and prone to icing, the inventors found that the reasons for the icing of the tube-side fluid are as follows: the process chilled water temperature in the heat exchange tubes is uneven, and there is a phenomenon that the tube-side fluid in some heat exchange tubes is supercooled and ice crystals are generated. If it continues to develop, icing will occur. In addition, there may be flow dead zones in the tube-side fluid of the shell-and-tube heat exchanger, resulting in uneven heating and temperature stratification, and finally icing.

[0038] Based on this, the embodiments of the present disclosure provide a shell-and-tube heat exchanger.

[0039] As Figures 1 to 3 shown, the shell-and-tube heat exchanger of the embodiments of the present application includes a cylinder body 1, a heat exchange tube bundle 9, two fluid chambers 2, a partition plate 3, and a flow control component 4. The heat exchange tube bundle 9 is located inside the cylinder body 1 and is used for the flow of the tube-side fluid. The two fluid chambers 2 are respectively located at the axial two ends of the cylinder body 1 and are communicated with the heat exchange tube bundle 9. At least one partition plate 3 is arranged in one of the fluid chambers 2, and the partition plate 3 divides the fluid chamber 2 where it is located into different chambers so that the heat exchange tube bundle 9 forms a plurality of heat exchange tube groups with a plurality of tube passes. At least one flow control component 4 is arranged in one of the chambers. The flow control component 4 is located between two heat exchange tube groups communicated with the chamber where it is located, and the flow control component 4 includes a flow equalizing structure for communicating the two heat exchange tube groups and / or a flow guiding structure for guiding the tube-side fluid at the outlet of the heat exchange tube group upstream in the two heat exchange tube groups to the inlet of the heat exchange tube group downstream in the two heat exchange tube groups.

[0040] Based on the shell-and-tube heat exchanger provided by this application, during the operation of the shell-and-tube heat exchanger, the tube-side fluid flowing out of the outlet of the upstream heat exchange tube group and entering the cavity flows into the inlet of the downstream heat exchange tube group after passing through the flow equalizing structure and / or the flow guiding structure of the flow control component 4. Among them, the flow equalizing structure of the flow control component 4 makes the distribution of the tube-side fluid more uniform, making the flow of the tube-side fluid more uniform, and the fluctuations in temperature and flow rate smaller. The flow guiding structure of the flow control component 4 plays a role in guiding the tube-side fluid from the tube-side fluid at the outlet of the upstream heat exchange tube group towards the inlet of the downstream heat exchange tube group among the two heat exchange tube groups. During the process of guiding the fluid, it also helps the tube-side fluid to flow more uniformly, making the fluctuations in the temperature and flow rate of the tube-side fluid smaller. Therefore, it is beneficial to prevent the low-temperature tube-side fluid from generating ice crystal phenomena due to uneven temperature and local supercooling, thus facilitating the prevention of ice blockage or freezing and cracking of the heat exchange tubes. After the tube-side fluid passes through the flow equalizing of the flow equalizing structure and / or the guiding of the flow guiding structure, it is beneficial to reduce the flow dead zone and prevent icing caused by temperature stratification due to the existence of the flow dead zone. When the shell-and-tube heat exchanger is used in a refrigeration unit, it can reduce the failures of the refrigeration unit caused by the icing of the tube-side fluid in the heat exchange tubes. In addition, since the installation of the flow control component 4 is beneficial to increasing the average flow velocity of the tube-side fluid in the shell-and-tube heat exchanger, it is beneficial to increasing the turbulence degree of the tube-side fluid in the heat exchange tubes, enhancing the heat transfer on the tube-side fluid, and facilitating the improvement of the heat transfer efficiency of the shell-and-tube heat exchanger. Further, the flow guiding structure is also beneficial to reducing the impact of the tube-side fluid on the cavity wall of the fluid chamber 2, reducing the flow resistance of the tube-side fluid, and reducing the energy consumption of the shell-and-tube heat exchanger.

[0041] As Figures 1 to 5 shown, in the shell-and-tube heat exchanger of some embodiments, the flow control component 4 includes a baffle 41. The baffle 41 is installed on the cavity wall of the cavity where it is located and / or installed on the partition plate 3 that divides the cavity where it is located. The flow equalizing structure and / or the flow guiding structure are arranged on the baffle 41.

[0042] By arranging partition plates and baffles in the fluid chamber, the flow path of the tube-side fluid is divided into multiple tube sides, and the flow equalizing and / or guiding are carried out between the heat exchange tube groups of the two tube sides in the cavity separated by the partition plates through the baffle 41, which can increase the flow velocity of the tube-side fluid (such as process chilled water) in the shell-and-tube heat exchanger, increase the turbulence degree of the tube-side fluid in the heat exchange tubes, thereby enhancing the heat transfer on the tube-side fluid and facilitating the improvement of the heat transfer efficiency of the shell-and-tube heat exchanger. Through the combination of the partition plate and the baffle, the flow space of the tube-side fluid in the fluid chamber is partitioned, and each flow region becomes smaller. The tube-side fluid can be fully mixed in each flow region, which is beneficial to making the flow rate and temperature of the tube-side fluid in the heat exchange tubes more uniform and with small fluctuations, facilitating the elimination of temperature stratification. On the one hand, it is beneficial to prevent icing due to too low local temperature, and on the other hand, it is beneficial to melting the ice crystals existing in some heat exchange tubes by heat, thereby preventing icing in the heat exchange tubes and further preventing the failures of the unit where the shell-and-tube heat exchanger is located due to icing of the heat exchange tubes. Using the baffle 41 as the flow control component 4 also has the advantages of simple processing and manufacturing and stable flow control effect.

[0043] The flow control component is not limited to the form of a baffle. For example, in a shell-and-tube heat exchanger of some embodiments not shown, the flow control component may include a grate-like or mesh-like structure, etc.

[0044] As Figures 3 to 4 shown, in some embodiments, the flow equalizing structure includes flow holes 413 provided on the baffle 41; and / or the flow guiding structure includes a flow guiding section 412 of the baffle 41, and the flow guiding section 412 inclines from the outlet of the heat exchange tube group in the upstream of the two heat exchange tube groups towards the inlet of the heat exchange tube group in the downstream of the two heat exchange tube groups in a direction away from the outlet.

[0045] Providing the flow holes 413 on the baffle 41 as the flow equalizing structure can make the flow of the tube-side fluid at the outlets of the heat exchange tube groups in each tube pass more uniform and the temperature distribution less volatile.

[0046] The flow guiding section 412 inclines from the outlet of the heat exchange tube group in the upstream of the two heat exchange tube groups towards the inlet of the heat exchange tube group in the downstream of the two heat exchange tube groups in a direction away from the outlet, and has the function of guiding the tube-side fluid at the outlet of the heat exchange tube group in the upstream of the two heat exchange tube groups towards the inlet of the heat exchange tube group in the downstream of the two heat exchange tube groups, so as to facilitate more uniform flow of the tube-side fluid, and also facilitate reducing the impact of the tube-side fluid on the cavity wall of the fluid chamber 2, reducing the resistance of the tube-side fluid flow, and reducing the energy consumption of the shell-and-tube heat exchanger.

[0047] As Figure 1 、 Figure 4 and Figure 5 shown, in a shell-and-tube heat exchanger of some embodiments, the second angle B between the flow guiding section 412 and the extending direction of the heat exchange tube bundle 9 is between 20 degrees and 70 degrees, and the second angle B can be, for example, 30 degrees, 40 degrees, 50 degrees, or 60 degrees.

[0048] Reasonably setting the second angle B between the flow guiding section 412 and the extending direction of the heat exchange tube bundle 9 is conducive to guiding the reasonable change of the flow direction of the tube-side fluid and giving play to the flow guiding function of the flow guiding section 412. The size of the second angle B is related to the shape and size of the fluid chamber 2 and the position of the baffle 41.

[0049] As Figures 4 to 5 shown, in a shell-and-tube heat exchanger of some embodiments, the baffle 41 further includes an axial section 411. The axial section 411 extends along the axis of the cylinder 1. The flow guiding section 412 is connected to one end of the axial section 411 far from the outlet of the heat exchange tube group in the upstream of the two heat exchange tube groups.

[0050] The angle between the axial section 411 and the flow guiding section 412 of the baffle 41 is the first angle A. The second angle B between the flow guiding section 412 and the extending direction of the heat exchange tube bundle 9 is complementary to the first angle A.

[0051] The arrangement of the axial section 411 helps to extend the flow distance of the tube-side fluid in the chamber where it is located, thereby helping to increase the average flow path length of the tube-side fluid in the chamber from the outlet of the upstream heat exchange tube group to the inlet of the downstream heat exchange tube group, which is conducive to more uniform flow of the tube-side fluid and smaller fluctuations in temperature distribution.

[0052] In some embodiments, the axial section 411 and the diversion section 412 are transitionally connected through an arc section.

[0053] In some embodiments not shown, the entire baffle can be set as the diversion section, and the entire baffle is inclined from the outlet of the upstream heat exchange tube group in the two heat exchange tube groups towards the inlet of the downstream heat exchange tube group in the two heat exchange tube groups in a direction away from the outlet. The angle between the entire baffle and the extension line direction of the heat exchange tube bundle can be between 20 degrees and 70 degrees, and this angle can be, for example, 30 degrees, 40 degrees, 50 degrees, or 60 degrees.

[0054] Figures 1 to 5 In the illustrated embodiment, the diversion section is a flat plate. In some embodiments not shown, the diversion section can also be a curved plate, a folded plate, or a combination of a curved plate and a flat plate, etc.

[0055] As Figures 4 to 5 As shown, in the shell-and-tube heat exchanger of some embodiments, a plurality of flow holes 413 are evenly distributed in at least one area of the baffle 41.

[0056] The uniform distribution of the flow holes 413 in at least one area of the baffle 41 helps the tube-side fluid to mix more evenly.

[0057] In the shell-and-tube heat exchanger of some embodiments, the flow holes 413 are round holes. The diameter of the round holes is between 6 mm and 15 mm, such as 8 mm, 10 mm, 12 mm, or 14 mm.

[0058] The flow holes 413 are round holes, and by reasonably setting the diameter of the flow holes 413, it is beneficial to reasonably control the flow rate and velocity of the tube-side fluid passing through the flow holes 413 through the flow holes 413, thereby facilitating improving the flow equalizing effect of the flow holes 413 on the tube-side fluid. The size of the diameter of the flow holes 413 is related to the size of the tube-side fluid flow rate. The flow holes 413 are manufactured into a circular shape, which is simple to process, has less resistance to the tube-side fluid, and reduces the stress concentration generated on the baffle 41 due to the processing of the flow holes 413, which is beneficial to improving the service life of the baffle 41.

[0059] In some embodiments not shown, the flow holes 413 can also be oval or square holes or special-shaped holes, etc.

[0060] As Figure 1As shown, in the shell-and-tube heat exchanger of some embodiments, one end of the diversion section 412 away from the outlet of the upstream heat exchange tube group among the two heat exchange tube groups has a gap with the chamber wall of the fluid chamber 2.

[0061] One end of the diversion section 412 away from the outlet of the upstream heat exchange tube group among the two heat exchange tube groups has a gap with the chamber wall of the fluid chamber 2, which is conducive to at least part of the tube-side fluid entering the inlet of the downstream heat exchange tube group through the gap under the guidance of the diversion section 412, thereby reducing the impact of the tube-side fluid on the chamber wall of the fluid chamber 2.

[0062] As Figure 1 shown, in the shell-and-tube heat exchanger of some embodiments, the shell-and-tube heat exchanger has more than three tube passes. In some embodiments, a partition 3 is provided in each fluid chamber 2. In some embodiments, flow control components 4 are provided in other chambers except for the chamber that receives the tube-side fluid from outside the shell-and-tube heat exchanger and the chamber that outputs the tube-side fluid to the outside of the shell-and-tube heat exchanger.

[0063] By providing more than three tube passes, it helps the tube-side fluid in the shell-and-tube heat exchanger to have a higher flow rate. The greater the flow rate of the tube-side fluid, the more conducive it is to the temperature uniformity of the tube-side fluid in the heat exchange tubes, thereby helping to reduce the icing phenomenon. At the same time, providing more than three tube passes is conducive to improving the heat exchange efficiency of the shell-and-tube heat exchanger.

[0064] Providing a partition 3 in each fluid chamber 2 is conducive to increasing the number of tube passes, thereby helping to reduce the icing phenomenon and improve the heat exchange efficiency of the shell-and-tube heat exchanger.

[0065] Flow control components 4 are provided in other chambers except for the chamber that receives the tube-side fluid from outside the shell-and-tube heat exchanger and the chamber that outputs the tube-side fluid to the outside of the shell-and-tube heat exchanger, so that the tube-side fluid can be evenly distributed and / or diverted when entering the downstream tube pass inlet from each upstream tube pass outlet, thereby being conducive to improving the temperature uniformity of the fluid in the heat exchange tubes and achieving the effect of reducing the icing phenomenon of the tube-side fluid.

[0066] As Figure 1 shown, in the shell-and-tube heat exchanger of some embodiments, the shell-and-tube heat exchanger further includes a tube-side fluid input pipe 8 and a tube-side fluid output pipe 7. The tube-side fluid input pipe 8 and the tube-side fluid output pipe 7 are communicated with different chambers of the same fluid chamber 2; and / or the tube-side fluid input pipe 8 is located below the tube-side fluid output pipe 7.

[0067] The tube-side fluid input pipe 8 and the tube-side fluid output pipe 7 are communicated with different chambers of the same fluid chamber 2, which is convenient for the tube-side fluid input pipe 8 and the tube-side fluid output pipe 7 to be respectively connected to external fluid pipelines, thereby saving installation space.

[0068] Since the temperature of the tube-side fluid is the highest at the tube-side fluid inlet pipe 8 and the lowest at the tube-side fluid outlet pipe 7, when the shell-and-tube heat exchanger is used as a falling-film evaporator, the temperature of the shell-side fluid (such as refrigerant) remains basically unchanged. Therefore, the temperature difference between the tube-side fluid and the shell-side fluid is the smallest at the tube bundle heat exchange tube group located in the upper part of the heat exchange tube bundle and closest to the tube-side fluid outlet pipe 7, and the largest at the tube bundle heat exchange tube group located in the lower part of the heat exchange tube bundle and closest to the tube-side fluid inlet pipe 8. When the tube-side fluid inlet pipe 8 is located below the tube-side fluid outlet pipe 7, since the liquid film on the surface of the heat exchange tube group in the upper part of the heat exchange tube bundle is relatively thin, and the temperature difference between the tube-side fluid and the shell-side fluid is the smallest here, the liquid film on the surface of the heat exchange tube is not easily evaporated and dried to cause the phenomenon of "dry burning", so it is not easy to produce the phenomenon that the heat exchange efficiency of the heat exchange tube drops sharply due to dry burning, the tube-side fluid temperature is uneven, and the temperature fluctuates greatly; at the same time, the heat exchange tube group located in the lower part of the heat exchange tube bundle is immersed in the shell-side fluid in the full liquid area, and the temperature difference between the tube-side fluid and the shell-side fluid is the largest here. Therefore, the heat transfer coefficient of the heat exchange tube group below the full liquid area liquid level is relatively high, so that the shell-and-tube heat exchanger has uniform heat exchange, small temperature fluctuation, and high heat exchange efficiency.

[0069] In the shell-and-tube heat exchanger of some embodiments, the shell-and-tube heat exchanger is a falling-film evaporator.

[0070] The falling-film evaporator of the refrigeration unit can be used to produce process chilled water. The falling-film evaporator using a shell-and-tube heat exchanger has the advantages of high efficiency, less refrigerant charge, and excellent heat transfer performance under low temperature difference conditions. If the shell-and-tube heat exchanger of the above embodiments of the present application is used as a falling-film evaporator, it can effectively prevent the process chilled water in the heat exchange tube from freezing, thus solving the related problems caused by the freezing of the process chilled water.

[0071] The embodiments of the present disclosure also provide a refrigeration unit, including the shell-and-tube heat exchanger according to any one of the above embodiments.

[0072] The refrigeration unit of the embodiments of the present disclosure has the advantages of the shell-and-tube heat exchanger of the embodiments of the present disclosure.

[0073] The following combines Figures 1 to 5 to describe the shell-and-tube heat exchanger of an embodiment of the present application in more detail.

[0074] As Figures 1 to 5 shown, the shell-and-tube heat exchanger of the embodiment of the present application includes a cylinder body 1, a heat exchange tube bundle 9, two fluid chambers 2, two end heads 5, two tube sheets 6, a plurality of partitions 3, a plurality of baffles 41, a tube-side fluid inlet pipe 8, and a tube-side fluid outlet pipe 7.

[0075] The two end heads 5 and the two tube sheets 6 are respectively arranged on the axial direction of the cylinder body 1 ( Figure 1At both ends in the left - right direction), and a fluid chamber 2 is formed at each axial end of the cylinder body 1, that is, the end head 5 and the tube sheet 6 form the chamber walls of the fluid chamber 2.

[0076] The heat - exchange tube bundle 9 is located inside the cylinder body 1, and both ends of each heat - exchange tube are inserted into the tube holes of the tube sheet 6, thereby being in communication with both fluid chambers 2, so that the heat - exchange tube bundle 9 and the two fluid chambers 2 are both used for the flow of the tube - side fluid.

[0077] The tube - side fluid inlet pipe 8 and the tube - side fluid outlet pipe 7 are arranged on the end head 5 of the fluid chamber 2 at the right end. And, the tube - side fluid inlet pipe 8 is located below the tube - side fluid outlet pipe 7.

[0078] A partition plate 3 is arranged in the fluid chamber 2 at the left end. The partition plate 3 divides the fluid chamber 2 at the left end into two different chambers, and two partition plates 3 are arranged in the fluid chamber 2 at the right end. The two partition plates 3 divide the fluid chamber 2 at the right end into three different chambers, so that the heat - exchange tube bundle 9 forms four heat - exchange tube groups for four tube passes.

[0079] Except for the two chambers in the fluid chamber 2 at the right end that are directly connected to the tube - side fluid inlet pipe 8 and the tube - side fluid outlet pipe 7, a baffle 41 is arranged in each of the other chambers. The baffle 41 is arranged between the outlet of the heat - exchange tube group upstream and the inlet of the heat - exchange tube group downstream in the two heat - exchange tube groups that are in communication in the chamber where the baffle 41 is located.

[0080] As Figure 2 and Figure 3 shown, the multiple baffles 41 are respectively the first baffle 41A, the second baffle 41B, and the third baffle 41C. The first baffle 41A (refer to Figure 4 ), the second baffle 41B, and the third baffle 41C (refer to Figure 5 ) all include an axial section 411 and a diversion section 412. The axial section 411 extends along the axial direction of the cylinder body 1. The axial section 411 is connected to the tube sheet 6 or the partition plate 3 forming the chamber where the baffle is located. The diversion section 412 is connected to one end of the axial section 411 that is far from the outlet of the heat - exchange tube group upstream in the two heat - exchange tube groups. There is a gap between one end of the diversion section 412 that is far from the outlet of the heat - exchange tube group upstream in the two heat - exchange tube groups and the end head 5 of the fluid chamber 2 where the diversion section 412 is located. The gap between each baffle 41 and the end head 5 is used for part of the tube - side fluid guided by the diversion section 412 of the baffle 41 to pass through. The tube - side fluid passing through the gap flows to the inlet of the downstream heat - exchange tube group, which can reduce the impact of this part of the tube - side fluid on the chamber wall of the fluid chamber 2. For example, the end face of the end of the diversion section 412 far from the axial section 411 can be set as a plane, and the inner surface of the end head 5 opposite to this end face is an arc surface, then a gap is formed between the arc surface and the plane.

[0081] The diversion section 412 inclines from the outlet of the upstream heat exchange tube group among the two heat exchange tube groups towards the inlet of the downstream heat exchange tube group among the two heat exchange tube groups in a direction away from the outlet. The second included angle B between the diversion section 412 and the extending direction of the heat exchange tube bundle 9 is approximately 40 degrees.

[0082] A plurality of flow-through holes 413 are provided on the diversion section 412 and the axial section 411 of the baffle 41. The plurality of flow-through holes 413 are evenly distributed on the baffle 41. In this embodiment, the flow-through holes 413 are round holes with a diameter of 10 mm. When the tube-side fluid flows out from the outlet of the upstream heat exchange tube group and flows towards the inlet of the downstream heat exchange tube group, part of the tube-side fluid passes through the baffle 41 with the flow-through holes 413, which has the effect of equalizing the flow of the tube-side fluid.

[0083] During the flow of the spaced tube-side fluid towards the inlet of the downstream heat exchange tube group, it will converge and mix evenly with the tube-side fluid passing through the flow-through holes 413, which is beneficial to improving the temperature uniformity of the tube-side fluid entering the downstream heat exchange tube group and achieving the effect of reducing the icing phenomenon of the tube-side fluid.

[0084] The flow-through area formed by the intervals and the total flow-through area of the plurality of flow-through holes 413 can be set according to the proportion of the tube-side fluid flowing through the intervals in the tube-side fluid flowing out from the outlet of the upstream heat exchange tube group as needed. For example, the proportion of the tube-side fluid flowing through the intervals in the tube-side fluid flowing out from the outlet of the upstream heat exchange tube group can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc. The larger the flow-through area formed by the intervals, the smaller the fluid resistance, and the larger the total flow-through area of the flow-through holes 413, the better the flow equalizing effect.

[0085] The baffle 41 can be installed in the chamber where it is located by welding to at least one of the partition plate 3, the tube sheet 6, and the head 5. When the baffle 41 is welded to any one of the partition plate 3, the tube sheet 6, and the head 5, it can be full welding or partial welding. When it is partial welding, there will probably be a certain gap between the baffle 41 and any one of the partition plate 3, the tube sheet 6, and the head 5 due to the loose fit, and this gap does not need to be completely sealed. Although when there is a gap, a small part of the tube-side fluid can flow through the gap, but due to the small gap, the fluid flow rate is small and it is not the main part of the fluid. Through simulation and actual measurement, the fluid flowing through the gap has little influence on the mass flow rate and temperature fluctuation degree of the tube-side fluid in the corresponding cavity.

[0086] The cylinder 1, the baffle 41, the partition plate 3, the tube sheet 6, and the head 5 can be made of metal materials, such as stainless steel. Stainless steel has the advantages of corrosion resistance and high strength. In some embodiments, a protective layer can be sprayed on the outside of the cylinder 1 and the head 5 to isolate from the air and prevent oxidation.

[0087] The working process of the shell-and-tube heat exchanger according to an embodiment of the present application will be described below by taking the falling film evaporator of a refrigeration unit as an example. In the falling film evaporator, the tube-side fluid is process chilled water, and the shell-side fluid is refrigerant.

[0088] As Figures 1 to 3 shown, when the falling film evaporator works, the process chilled water as the tube-side fluid enters from the tube-side fluid input pipe 8 of the fluid chamber 2 at the right end, flows through the heat exchange tube group of the first tube side to the outlet of the heat exchange tube group of the first tube side in the fluid chamber 2 at the left end ( Figure 2 the front side part of the middle and lower part of the pipe orifice), passes through the flow-through holes 413 on the first baffle 41A in the lower chamber in the fluid chamber 2 at the left end and enters the inlet of the heat exchange tube group of the second tube side through the guiding section 412 and the interval between the guiding section 412 and the corresponding head 5 after being guided by the guiding section 412 ( Figure 2 the rear side part of the middle and lower part of the pipe orifice); the process chilled water flows out from the outlet of the heat exchange tube group of the second tube side ( Figure 3 the front side part of the middle and lower part of the pipe orifice) and enters the lower part of the fluid chamber 2 at the right end. The process chilled water flows upward, passes through the flow-through holes 413 on the second baffle 41B and enters the inlet of the heat exchange tube group of the third tube side through the guiding section 412 and the interval between the guiding section 412 and the corresponding head 5 after being guided by the guiding section 412 ( Figure 3 the middle part of the upper and lower directions of the pipe orifice); the process chilled water comes to the outlet of the heat exchange tube group of the third tube side in the left fluid chamber 2 after being transported by the heat exchange tube group of the third tube side ( Figure 2 the middle part of the upper and lower directions of the pipe orifice); the process chilled water flows upward through the flow-through holes 413 of the third baffle 41C and enters the inlet of the heat exchange tube group of the fourth tube side through the guiding plate 412 and the interval between the guiding plate 412 and the corresponding head 5 after being guided by the guiding plate 412 ( Figure 2 the upper part of the pipe orifice); finally, the process chilled water comes to the upper chamber of the fluid chamber 2 at the right end after being transported by the fourth heat exchange tube group, enters the tube-side fluid output pipe 7 to complete the multi-tube-side flow process of the process chilled water. During the multi-tube-side flow process of the process chilled water, it continuously exchanges heat with the refrigerant flowing from top to bottom as the shell-side fluid to complete the cooling process, and the process chilled water meeting the temperature requirements is output from the tube-side fluid output pipe 7.

[0089] The liquid refrigerant enters the shell-side space of the falling film evaporator from the refrigerant inlet of the falling film evaporator, is evenly distributed by the liquid distributor located above the heat exchange tube bundle 9, and the evenly distributed liquid refrigerant flows downward to the heat exchange tube bundle 9 to form a film-like liquid refrigerant on the surface of the heat exchange tube bundle 9. After the film-like liquid refrigerant exchanges heat with the process chilled water in the heat exchange tube bundle 9, it absorbs heat and evaporates to form gaseous refrigerant, which then flows out from the refrigerant outlet at the top of the falling film evaporator.

[0090] In this embodiment, through the arrangement of the baffle 41, the flow uniformity and temperature consistency of the tube-side fluid at the outlet of the corresponding heat exchange tube group are improved. The following table shows the simulation calculation statistical values of the flow rate and temperature fluctuation of the tube-side fluid at the outlet of each heat exchange tube group of the four-tube-pass falling film evaporator.

[0091] Degree of flow rate fluctuation Degree of temperature fluctuation Outlet of the second tube pass heat exchange tube group 0.036154267 0.000349415 Outlet of the third tube pass heat exchange tube group 0.024375669 0.000485023 Outlet of the fourth tube pass heat exchange tube group 0.005270524 0.00030716

[0092] The degree of fluctuation refers to the average value of the difference between the flow rate or temperature at the outlet of each heat exchange tube and the average flow rate or average temperature of all the heat exchange tubes in this tube pass; the smaller the fluctuation value, the smaller the difference from the average value, and the more uniform the flow rate or temperature. The calculation formula is:

[0093] Flow rate fluctuation degree

[0094]

[0095] Temperature fluctuation degree

[0096]

[0097] n represents the number of heat exchange tubes in the heat exchange tube group of this tube pass; q and T are respectively the average flow rate and average temperature of the heat exchange tube group of this tube pass; q i 、T i are respectively the flow rate and temperature of each heat exchange tube in the heat exchange tube group of this tube pass.

[0098] For the shell-and-tube heat exchanger provided with the baffle 41, after the baffle 41 equalizes the flow and guides the flow, the flow rate and temperature of the tube-side fluid at the outlet of the heat exchange tube group of each tube pass are more uniformly distributed and have a very small degree of fluctuation compared with the shell-and-tube heat exchanger under the same conditions except without the baffle 41.

[0099] The descriptions of the above embodiments tend to emphasize the differences between the embodiments. Their similarities or similarities can be referred to each other. For the sake of brevity, they will not be elaborated in this article.

[0100] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: still modifications can be made to the specific implementation manners of the present application or equivalent replacements can be made to some technical features, and they should all be covered within the scope of the technical solutions claimed in the present application.

Claims

1. A shell-and-tube heat exchanger, comprising a shell (1); a heat exchange tube bundle (9) located inside the shell (1) for the flow of the tube-side fluid; two fluid chambers (2) respectively located at two axial ends of the shell (1) and communicating with the heat exchange tube bundle (9); a partition plate (3), at least one of the fluid chambers (2) is provided with the partition plate (3), and the partition plate (3) divides the fluid chamber (2) where it is located into different chambers so that the heat exchange tube bundle (9) forms multiple heat exchange tube groups with multiple tube passes; and a flow control component (4), at least one of the chambers is provided with the flow control component (4), the flow control component (4) is located between two heat exchange tube groups communicating with the chamber where it is located, and the flow control component (4) includes a flow equalizing structure connecting the two heat exchange tube groups and / or a flow guiding structure for guiding the tube-side fluid at the outlet of the heat exchange tube group upstream among the two heat exchange tube groups towards the inlet of the heat exchange tube group downstream among the two heat exchange tube groups.

2. The shell-and-tube heat exchanger according to claim 1, wherein, The flow control component (4) includes a baffle plate (41), the baffle plate (41) is installed on the chamber wall of the chamber where it is located and / or installed on the partition plate (3) separating the chamber where it is located, and the flow equalizing structure and / or the flow guiding structure is arranged on the baffle plate (41).

3. The shell-and-tube heat exchanger according to claim 2, characterized in that the flow equalizing structure includes flow holes (413) arranged on the baffle plate (41); and / or the flow guiding structure includes a flow guiding section (412) of the baffle plate (41), and the flow guiding section (412) inclines from the outlet of the heat exchange tube group upstream among the two heat exchange tube groups towards the inlet of the heat exchange tube group downstream among the two heat exchange tube groups in a direction away from the outlet.

4. The shell-and-tube heat exchanger according to claim 3, characterized in that, The second included angle (B) between the flow guiding section (412) and the extending direction of the heat exchange tube bundle (9) is between 20 degrees and 70 degrees.

5. The shell-and-tube heat exchanger according to claim 3, wherein, The baffle plate (41) further includes an axial section (411), the axial section (411) extends along the axis of the shell (1), and the flow guiding section (412) is connected to one end of the axial section (411) away from the outlet of the heat exchange tube group upstream among the two heat exchange tube groups.

6. The shell-and-tube heat exchanger according to claim 3, wherein, The multiple flow holes (413) are uniformly distributed in at least one area of the baffle plate (41).

7. The shell-and-tube heat exchanger according to claim 3, wherein The flow holes (413) are round holes with a diameter between 6 mm and 15 mm.

8. The shell-and-tube heat exchanger according to claim 3, wherein, One end of the flow guiding section (412) away from the outlet of the heat exchange tube group upstream among the two heat exchange tube groups has a gap with the chamber wall of the fluid chamber.

9. The shell-and-tube heat exchanger according to claim 1, characterized in that the shell-and-tube heat exchanger has three or more tube passes; and / or, each of the fluid chambers (2) is provided with the partition plate (3); and / or the flow control component (4) is provided in each of the other chambers except the chamber receiving the tube-side fluid from outside the shell-and-tube heat exchanger and the chamber discharging the tube-side fluid to the outside of the shell-and-tube heat exchanger.

10. The shell-and-tube heat exchanger according to claim 1, characterized in that, The shell-and-tube heat exchanger further includes a tube-side fluid inlet pipe (8) and a tube-side fluid outlet pipe (7), wherein, The tube-side fluid inlet pipe (8) and the tube-side fluid outlet pipe (7) communicate with different chambers of the same fluid chamber (2); and / or The tube-side fluid inlet pipe (8) is located below the tube-side fluid outlet pipe (7).

11. The shell-and-tube heat exchanger according to any one of claims 1 to 10, characterized in that, The shell-and-tube heat exchanger is a falling-film evaporator.

12. A refrigeration unit, characterized in that, It includes the shell-and-tube heat exchanger according to any one of claims 1 to 11.

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