Shell-and-tube heat exchanger and refrigerating unit

Abstract

The utility model 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] This application relates to the field of heat exchanger technology, and in particular to a shell-and-tube heat exchanger and a refrigeration unit. Background Technology

[0002] Shell-and-tube heat exchangers are a common type of heat exchanger, mainly composed of two parts: the tube side and the shell side. Two different materials—the tube-side fluid and the shell-side fluid—flow in the tube side and the shell side respectively, achieving the function of heat exchange.

[0003] When the temperature of the fluid in the tubes of a shell-and-tube heat exchanger is low, even if the operating parameters of the fluid in the tubes are above the solidification temperature, icing may still occur, which can have an adverse effect on the operation of the shell-and-tube heat exchanger in severe cases.

[0004] Taking the falling film evaporator of a refrigeration unit that uses shell-and-tube heat exchangers to produce process chilled water as an example, when the refrigerant, which is the shell-side fluid, is charged on the shell side of the falling film evaporator to cool the process chilled water, which is the tube-side fluid, in the heat exchange tube bundle, although the temperature requirement for the process chilled water product is above the freezing point, there is still icing inside the heat exchange tubes. In severe cases, this can lead to blockage or cracking of the heat exchange tubes, which in turn can cause malfunctions in the refrigeration unit where the falling film evaporator is located.

[0005] The above statements are for the purpose of providing background information in relation to this application only, and do not necessarily constitute prior art. Utility Model Content

[0006] The purpose of this application is to provide a shell-and-tube heat exchanger and a refrigeration unit, which aims to solve the problem of icing that may occur when the fluid in the tubes of the heat exchanger is at a low operating temperature.

[0007] To achieve the above objectives, a first aspect of this application provides a shell-and-tube heat exchanger, comprising: a shell; a heat exchange tube bundle located within the shell for tube-side fluid flow; two fluid chambers located at opposite axial ends of the shell and communicating with the heat exchange tube bundle; a baffle plate disposed in at least one fluid chamber, the baffle plate dividing the fluid chamber into different chambers to allow the heat exchange tube bundle to form multiple heat exchange tube groups with multiple tube sides; and a flow control component disposed in at least one chamber, the flow control component being located between two heat exchange tube groups communicating within the chamber, the flow control component including a flow equalization structure communicating between the two heat exchange tube groups and / or a flow guiding structure guiding the tube-side fluid at the outlet of the upstream heat exchange tube group toward the inlet of the downstream heat exchange tube group.

[0008] In some embodiments, the flow control component includes a baffle mounted on the cavity wall of the chamber and / or on a partition separating the chamber, with a flow equalization structure and / or a flow guiding structure disposed on the baffle.

[0009] In some embodiments, the flow equalization structure includes flow holes disposed on the baffle; and / or the flow guiding structure includes a flow guiding section of the baffle, the flow guiding section being inclined from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups toward 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 angle between the flow guide section and the extension 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 extending axially along the cylinder, and a flow guide section connected to the end of the axial section away 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 uniformly distributed in at least one region of the baffle.

[0013] In some embodiments, the flow passage is a circular hole with a diameter between 6 mm and 15 mm.

[0014] In some embodiments, the end of the guide section away from the outlet of the upstream heat exchanger tube group of the two heat exchanger tube groups is spaced from the chamber wall of the fluid chamber.

[0015] In some embodiments, the shell-and-tube heat exchanger has three or more tube passes; and / or each fluid chamber is provided with a baffle; and / or each chamber other than the chamber that receives tube pass fluid from outside the shell-and-tube heat exchanger and the chamber that outputs tube pass fluid to outside the shell-and-tube heat exchanger is provided with a flow control component.

[0016] In some embodiments, the shell-and-tube heat exchanger further includes a tube-side fluid inlet pipe and a tube-side fluid outlet pipe, wherein the tube-side fluid inlet pipe and the tube-side fluid outlet pipe are in communication with different chambers of the same fluid chamber; and / or the tube-side fluid inlet pipe is located below the tube-side fluid outlet pipe.

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

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

[0019] In the shell-and-tube heat exchanger disclosed herein, by incorporating flow control components including flow equalization and / or flow guiding structures, the flow of the fluid in the tubes is made more uniform. This results in smaller fluctuations in the temperature and flow rate distribution of the fluid within the heat exchange tubes, which helps prevent ice crystal formation due to localized overcooling of the low-temperature fluid in the tubes caused by uneven temperature distribution. This, in turn, helps prevent icing, blockage, or cracking of the heat exchange tubes, and reduces flow dead zones, preventing temperature stratification and icing caused by these dead zones. When the shell-and-tube heat exchanger is used in refrigeration units, it can reduce refrigeration unit malfunctions caused by icing of the fluid in the heat exchange tubes.

[0020] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a schematic diagram of the structure of a shell-and-tube heat exchanger according to some embodiments of this application.

[0023] Figure 2 for Figure 1 A schematic diagram of the fluid chamber at the left end of a shell-and-tube heat exchanger, where the end cap at the left end is not shown to illustrate the internal structure of the fluid chamber.

[0024] Figure 3 for Figure 1 The diagram shows the structure of the fluid chamber at the right end of the shell-and-tube heat exchanger, where the end cap at the right end is not shown to illustrate the internal structure of the fluid chamber.

[0025] Figure 4 for Figure 1 A schematic diagram of the structure of the first baffle of the shell-and-tube heat exchanger.

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

[0027] Figures 1 to 5 In the figures, the labels represent:

[0028] 1. Shell; 2. Fluid chamber; 3. Baffle; 4. Flow control component; 41. Baffle; 41A. First baffle; 41B. Second baffle; 41C. Third baffle; 411. Axial section; 412. Guide section; 413. Flow passage; 5. End cap; 6. Tube sheet; 7. Tube-side fluid outlet pipe; 8. Tube-side fluid inlet pipe; 9. Heat exchanger tube bundle; A. First included angle; B. Second included angle. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0031] In the description of this application, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0032] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0033] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0034] Furthermore, when an element is referred to as being "on" another element, the element may be directly on the other element, or it may be indirectly on the other element with one or more intermediate elements inserted between them. Additionally, when an element is referred to as being "connected" to another element, the element may be directly connected to the other element, or it may be indirectly connected to the other element with one or more intermediate elements inserted between them. In the following drawings, the same reference numerals denote the same elements.

[0035] Unless otherwise required by the content, throughout the following description, the word “including” and its variations, such as “comprising” and “having”, will be interpreted in an open-ended, inclusive sense, that is, as “including but not limited to”.

[0036] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two).

[0037] Regarding the problem mentioned in the background art that the low operating temperature of the tube-side fluid in shell-and-tube heat exchangers easily leads to icing, the inventors discovered that the cause of icing in the tube-side fluid is: uneven temperature of the process chilled water in the heat exchange tubes, resulting in some tube-side fluids being undercooled and producing ice crystals, which can lead to icing if it continues to develop. In addition, the tube-side fluid in the shell-and-tube heat exchanger may have flow dead zones, leading to uneven heating and temperature stratification, which ultimately results in icing.

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

[0039] like Figures 1 to 3 As shown, the shell-and-tube heat exchanger of this embodiment includes a shell 1, a heat exchange tube bundle 9, two fluid chambers 2, a baffle 3, and a flow control component 4. The heat exchange tube bundle 9 is located inside the shell 1 and is used for tube-side fluid flow. The two fluid chambers 2 are located at opposite axial ends of the shell 1 and communicate with the heat exchange tube bundle 9. At least one fluid chamber 2 is provided with a baffle 3, which divides the fluid chamber 2 into different chambers so that the heat exchange tube bundle 9 forms multiple heat exchange tube groups with multiple tube passes. At least one chamber is provided with a flow control component 4. The flow control component 4 is located between the two heat exchange tube groups connected to the chamber, and the flow control component 4 includes a flow equalization structure connecting the two heat exchange tube groups and / or a flow guiding structure that guides the tube-side fluid from the outlet of the upstream heat exchange tube group toward the inlet of the downstream heat exchange tube group.

[0040] Based on the shell-and-tube heat exchanger provided in 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 enters the cavity and then flows into the inlet of the downstream heat exchange tube group after passing through the flow equalization structure and / or flow guiding structure of the flow control component 4. The flow equalization structure of the flow control component 4 makes the tube-side fluid distribution more uniform, resulting in more uniform fluid flow and smaller fluctuations in temperature and flow rate. The flow guiding structure of the flow control component 4 guides the tube-side fluid from the outlet of the upstream heat exchange tube group towards the downstream heat exchange tube group. The inlet guide of the heat pipe assembly facilitates more uniform fluid flow in the tubes, resulting in smaller fluctuations in temperature and flow rate distribution. This helps prevent ice crystal formation due to localized overcooling caused by uneven temperature in the low-temperature tubes, thus preventing icing, blockage, or cracking of the heat exchange tubes. After the fluid passes through the flow equalization structure and / or is guided by the flow guiding structure, dead zones are reduced, preventing temperature stratification and icing caused by these zones. When shell-and-tube heat exchangers are used in refrigeration units, this reduces refrigeration unit malfunctions caused by icing of the tube fluid within the heat exchange tubes. Furthermore, the flow control component 4 increases the average flow velocity of the tube fluid within the shell-and-tube heat exchanger, thereby increasing turbulence and enhancing heat transfer on the tube side, improving the heat exchange efficiency of the shell-and-tube heat exchanger. Further, the flow guiding structure reduces the impact of the tube fluid on the fluid chamber 2 wall, lowering the resistance to fluid flow and reducing the energy consumption of the shell-and-tube heat exchanger.

[0041] like Figures 1 to 5 As shown, in some embodiments of the shell-and-tube heat exchanger, the flow control component 4 includes a baffle 41. The baffle 41 is mounted on the cavity wall of the chamber and / or on the partition 3 separating the chamber. A flow equalization structure and / or flow guiding structure are provided on the baffle 41.

[0042] By installing baffles and partitions within the fluid chamber, the flow path of the tube-side fluid is divided into multiple tube passes. Baffles 41 then even out and / or guide the flow between the heat exchanger tube groups in the two tube passes within the baffle-separated chambers. This increases the flow velocity of the tube-side fluid (such as process chilled water) within the shell-and-tube heat exchanger, enhances turbulence, and thus improves heat exchange on the tube-side fluid side, thereby increasing the heat exchange efficiency of the shell-and-tube heat exchanger. The combination of baffles and partitions further divides the flow space of the tube-side fluid within the fluid chamber, reducing the size of each flow region. This allows for thorough mixing of the tube-side fluid in each flow region, resulting in more uniform flow rate and temperature within the heat exchanger tubes, minimizing fluctuations and eliminating temperature stratification. This helps prevent localized freezing due to excessively low temperatures and also allows some ice crystals within the heat exchanger tubes to melt, preventing icing and thus preventing unit malfunctions caused by icing in the heat exchanger tubes. Using 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 some shell-and-tube heat exchangers of embodiments not shown, the flow control component may include a grate or mesh structure, etc.

[0044] like Figures 3 to 4 As shown, in some embodiments, the flow equalization structure includes a flow passage 413 disposed on the baffle 41; and / or the flow guiding structure includes a flow guiding section 412 of the baffle 41, the flow guiding section 412 being inclined from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups toward the inlet of the downstream heat exchange tube group of the two heat exchange tube groups in a direction away from the outlet.

[0045] By setting flow holes 413 on the baffle 41 as a flow equalization structure, the flow of fluid in the tube side at the outlet of each heat exchange tube group can be more uniform and the temperature distribution fluctuation is smaller.

[0046] The flow guide section 412 is inclined from the outlet of the upstream heat exchange tube group to the inlet of the downstream heat exchange tube group, away from the outlet. It guides the tube-side fluid from the outlet of the upstream heat exchange tube group to the inlet of the downstream heat exchange tube group, thereby promoting more uniform tube-side fluid flow, reducing the impact of tube-side fluid on the wall of fluid chamber 2, reducing the resistance of tube-side fluid flow, and reducing the energy consumption of the shell-and-tube heat exchanger.

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

[0048] By appropriately setting the second included angle B between the flow guiding section 412 and the extension direction of the heat exchange tube bundle 9, it is beneficial to guide the flow direction of the fluid in the tube side to change reasonably, and to give full play to the flow guiding function of the flow guiding section 412. The size of the second included angle B is related to the shape and size of the fluid chamber 2 and the position of the baffle 41.

[0049] like Figures 4 to 5 As shown, in some embodiments of the shell-and-tube heat exchanger, the baffle 41 further includes an axial section 411. The axial section 411 extends axially along the shell 1. A flow guide section 412 is connected to the end of the axial section 411 away from the outlet of the upstream heat exchange tube bundle of the two heat exchange tube bundles.

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

[0051] The axial section 411 helps to extend the distance the tube-side fluid flows in the chamber, thereby increasing the average flow path length of the tube-side fluid from the outlet of the upstream heat exchange tube assembly to the inlet of the downstream heat exchange tube assembly, which is conducive to more uniform tube-side fluid flow and less temperature distribution fluctuation.

[0052] In some embodiments, the axial segment 411 and the guide segment 412 are connected by a circular arc segment.

[0053] In some embodiments not shown, the entire baffle can be configured as a flow guide section, with the entire baffle inclined from the outlet of the upstream heat exchanger bundle toward the inlet of the downstream heat exchanger bundle in a direction away from the outlet. The angle between the entire baffle and the extension direction of the heat exchanger bundle can be between 20 degrees and 70 degrees, for example, 30 degrees, 40 degrees, 50 degrees, or 60 degrees.

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

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

[0056] The flow holes 413 are evenly distributed in at least one area of ​​the baffle 41, which helps to mix the fluid in the tube more evenly.

[0057] In some embodiments of the shell-and-tube heat exchanger, the flow passage 413 is a circular orifice. The diameter of the circular orifice is between 6 mm and 15 mm, for example, 8 mm, 10 mm, 12 mm, or 14 mm.

[0058] The flow passage 413 is a circular hole, and its diameter is appropriately set to facilitate the control of the flow rate and velocity of the fluid passing through it, thereby improving the flow uniformity of the fluid in the pipe. The diameter of the flow passage 413 is related to the flow rate of the fluid in the pipe. Manufacturing the flow passage 413 as a circle simplifies machining, reduces resistance to the fluid in the pipe, and minimizes stress concentration in the baffle 41 caused by machining the flow passage 413, thus extending the service life of the baffle 41.

[0059] In some embodiments not shown, the flow passage 413 may also be an elliptical or square hole or an irregularly shaped hole.

[0060] like Figure 1As shown, in some embodiments of the shell-and-tube heat exchanger, the end of the guide section 412 away from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups is spaced from the chamber wall of the fluid chamber 2.

[0061] The end of the guide section 412 that is away from the outlet of the upstream heat exchanger tube group of the two heat exchanger tube groups is spaced from the wall of the fluid chamber 2, which facilitates that at least part of the tube-side fluid can enter the inlet of the downstream heat exchanger tube group through the gap under the guidance of the guide section 412, thereby reducing the impact of the tube-side fluid on the wall of the fluid chamber 2.

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

[0063] By incorporating three or more tube passes, it is beneficial to achieve a higher flow velocity of the fluid in the tube passes of a shell-and-tube heat exchanger. A higher flow velocity promotes more uniform temperature distribution within the tubes, thus reducing icing. Furthermore, having three or more tube passes improves the heat exchange efficiency of the shell-and-tube heat exchanger.

[0064] Each fluid chamber 2 is equipped with a baffle 3, which helps to increase the number of tubes, thereby reducing icing and improving the heat exchange efficiency of the shell-and-tube heat exchanger.

[0065] In addition to the chambers that receive tube-side fluid from the outside of the shell-and-tube heat exchanger and the chambers that output tube-side fluid to the outside of the shell-and-tube heat exchanger, each other chamber is equipped with a flow control component 4. This ensures that the tube-side fluid is evenly distributed and / or guided when it enters the downstream tube-side inlet at each upstream tube outlet. This helps to improve the temperature uniformity of the fluid inside the heat exchange tubes and reduce the freezing phenomenon of the tube-side fluid.

[0066] like Figure 1 As shown, in some embodiments of the shell-and-tube heat exchanger, the shell-and-tube heat exchanger further includes a tube-side fluid inlet pipe 8 and a tube-side fluid outlet pipe 7. The tube-side fluid inlet pipe 8 and the tube-side fluid outlet pipe 7 are in communication 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.

[0067] The tube-side fluid inlet pipe 8 and the tube-side fluid outlet pipe 7 are connected to different chambers of the same fluid chamber 2, which facilitates the connection of the tube-side fluid inlet pipe 8 and the tube-side fluid outlet pipe 7 to external fluid pipelines, thereby saving installation space.

[0068] Since the temperature of the tube-side fluid is highest at the tube-side fluid inlet pipe 8 and 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 (e.g., refrigerant) remains basically constant. Therefore, the temperature difference between the tube-side fluid and the shell-side fluid is smallest at the 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 largest at the 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, the liquid film on the surface of the heat exchange tube bundle at the top of the heat exchange tube bundle is relatively thin, and the temperature difference between the tube-side fluid and the shell-side fluid is minimal at this point. Therefore, the liquid film on the surface of the heat exchange tubes at this point is less likely to evaporate and cause "dry burning," thus reducing the likelihood of a sharp decrease in heat exchange efficiency, uneven tube-side fluid temperature, and large temperature fluctuations due to dry burning. Simultaneously, the heat exchange tube bundle at the bottom of the heat exchange tube bundle is immersed in the shell-side fluid in the full liquid zone, where the temperature difference between the tube-side fluid and the shell-side fluid is greatest. Therefore, the heat transfer coefficient of the heat exchange tube bundle below the full liquid level is higher, resulting in uniform heat exchange, minimal temperature fluctuations, and high heat exchange efficiency in the shell-and-tube heat exchanger.

[0069] In some embodiments of the shell-and-tube heat exchanger, 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 advantages such as high efficiency, low refrigerant charge, and excellent heat transfer performance under low temperature difference conditions. In the above embodiments of this application, the shell-and-tube heat exchanger, as a falling film evaporator, can effectively prevent the process chilled water inside the heat exchange tubes from freezing, thereby solving the related problems caused by the freezing of process chilled water.

[0071] This disclosure also provides a refrigeration unit, including a shell-and-tube heat exchanger as described in any of the above embodiments.

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

[0073] The following combination Figures 1 to 5 A shell-and-tube heat exchanger according to an embodiment of this application will be described in more detail.

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

[0075] The two end caps 5 and the two tube sheets 6 are respectively arranged axially on the cylinder 1. Figure 1The fluid chamber 2 is formed at both ends of the cylinder 1 in the left and right directions, and at each end of the cylinder 1 in the axial direction. The end cap 5 and the tube sheet 6 form the cavity wall of the fluid chamber 2.

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

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

[0078] A baffle 3 is installed in the fluid chamber 2 at the left end. The baffle 3 divides the fluid chamber 2 at the left end into two different chambers. Two baffles 3 are installed in the fluid chamber 2 at the right end. The two baffles 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 with four tube passes.

[0079] Except for the two chambers of 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, each of the other chambers is equipped with a baffle 41. The baffle 41 is located between the outlet of the upstream heat exchange tube group and the inlet of the downstream heat exchange tube group of the two connected heat exchange tube groups in the chamber.

[0080] like Figure 2 and Figure 3 As shown, the multiple baffles 41 are respectively a first baffle 41A, a second baffle 41B, and a third baffle 41C. The first baffle 41A (reference) Figure 4 ), second baffle 41B and third baffle 41C (reference) Figure 5 Each of the two heat exchanger tube bundles includes an axial section 411 and a guide section 412. The axial section 411 extends axially along the tube sheet 6 or the partition 3 forming the chamber containing the baffle. The guide section 412 is connected to the end of the axial section 411 away from the outlet of the upstream heat exchanger tube bundle. There is a gap between the end of the guide section 412 away from the outlet of the upstream heat exchanger tube bundle and the end cap 5 of the fluid chamber 2 containing the guide section 412. The gap between each baffle 41 and the end cap 5 is used for a portion of the tube-side fluid guided by the guide section 412 through the baffle 41 to flow to the inlet of the downstream heat exchanger tube bundle, which can reduce the impact of this portion of the tube-side fluid on the chamber wall of the fluid chamber 2. For example, the end face of the guide section 412 away from the axial section 411 can be set as a plane, while the inner surface of the end cap 5 opposite to this end face is an arc surface, thus forming a gap between the arc surface and the plane.

[0081] The guide section 412 slopes from the outlet of the upstream heat exchanger tube bundle towards the inlet of the downstream heat exchanger tube bundle, moving away from the outlet. The second angle B between the guide section 412 and the extension direction of the heat exchanger tube bundle 9 is approximately 40 degrees.

[0082] Multiple flow-through holes 413 are provided on the flow-guiding section 412 and the axial section 411 of the baffle 41. These flow-through holes 413 are evenly distributed on the baffle 41. In this embodiment, the flow-through holes 413 are circular holes with a diameter of 10 mm. When the tube-side fluid flows from the outlet of the upstream heat exchanger tube assembly to the inlet of the downstream heat exchanger tube assembly, a portion of the tube-side fluid passes through the baffle 41 with the flow-through holes 413, thus achieving the function of evenly distributing the tube-side fluid.

[0083] During the flow of the tube-side fluid through the gaps to the inlet of the downstream heat exchanger tube assembly, it will merge and mix with the tube-side fluid passing through the flow holes 413, which helps to improve the temperature uniformity of the tube-side fluid entering the downstream heat exchanger tube assembly and reduce the phenomenon of tube-side fluid icing.

[0084] The flow area formed by the intervals and the total flow area of ​​the multiple flow holes 413 can be set according to the proportion of the tube-side fluid flowing through the intervals to the tube-side fluid flowing out of the outlet of the upstream heat exchanger tube assembly, as needed. For example, the proportion of the tube-side fluid flowing through the intervals to the tube-side fluid flowing out of the outlet of the upstream heat exchanger tube assembly 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 area formed by the intervals, the smaller the fluid resistance; the larger the total flow area of ​​the flow holes 413, the better the flow uniformity effect.

[0085] The baffle 41 can be installed in the cavity by welding it to at least one of the partition 3, tube sheet 6, and end cap 5. When welding the baffle 41 to any of the partition 3, tube sheet 6, or end cap 5, it can be a full weld or a partial weld. During partial welding, a certain gap is likely to form between the baffle 41 and any of the partition 3, tube sheet 6, or end cap 5 due to imperfect fit; this gap does not need to be completely sealed. Although a small portion of the tube-side fluid can flow through the gap, the flow rate is small and not the mainstream fluid flow. Simulations and actual measurements show that the fluid flowing through the gap has minimal impact on the mass flow rate and temperature fluctuations of the tube-side fluid in the corresponding cavity.

[0086] The cylinder 1, baffle 41, partition 3, tube sheet 6, and end cap 5 can be made of metallic materials, such as stainless steel. Stainless steel has advantages such as corrosion resistance and high strength. In some embodiments, the cylinder 1 and end cap 5 can be coated with a protective layer to isolate them from the air and prevent oxidation.

[0087] The following describes the operation of a shell-and-tube heat exchanger according to an embodiment of this application, using a 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] like Figures 1 to 3 As shown, when the falling film evaporator is working, the process chilled water, which is the tube-side fluid, enters from the tube-side fluid inlet 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 of the fluid chamber 2 at the left end. Figure 2 The lower front part of the tube opening), through the flow hole 413 on the first baffle 41A in the lower chamber of the fluid chamber 2 on the left end, and after being guided by its guide section 412, enters the inlet of the heat exchange tube group of the second tube pass through the gap between the guide section 412 and the corresponding end cap 5. Figure 2 (Lower middle rear section of the pipe opening); Process chilled water is transported through the second-pass heat exchanger tube assembly and exits from the outlet of the second-pass heat exchanger tube assembly ( Figure 3 The lower part of the front section of the middle and lower part of the pipe) flows out into the lower part of the fluid chamber 2 on the right end. The process chilled water flows upward and passes through the flow hole 413 on the second baffle 41B and is guided by its guide section 412. After passing through the gap between the guide section 412 and the corresponding end cap 5, it enters the inlet of the heat exchange tube group of the third tube pass. Figure 3 The middle section of the tube in the upper and lower direction); the process chilled water is transported through the heat exchange tube group of the third pass to the outlet of the heat exchange tube group of the third pass located in the left fluid chamber 2. Figure 2 The middle section of the pipe opening in the vertical direction); the process chilled water flows upward through the flow hole 413 of the third baffle 41C and is guided by its guide plate 412, then passes through the gap between the guide plate 412 and the corresponding end cap 5, and arrives at the inlet of the heat exchange tube group in the fourth tube pass ( Figure 2 (Upper and middle pipe opening); Finally, the process chilled water is transported through the fourth heat exchange tube group to the upper chamber of the fluid chamber 2 located at the right end, and enters the tube-side fluid outlet pipe 7 to complete the multi-pass flow process of the process chilled water. During the multi-pass flow process, the process chilled water continuously exchanges heat with the refrigerant, which is the shell-side fluid flowing downwards, to complete the cooling process, and outputs process chilled water that meets the temperature requirements from the tube-side fluid outlet pipe 7.

[0089] Liquid refrigerant enters the shell-side space of the falling film evaporator through the refrigerant inlet and is then evenly distributed through a liquid equalizer located above the heat exchange tube bundle 9. After being evenly distributed, the liquid refrigerant flows downward to the heat exchange tube bundle 9 and forms a film of liquid refrigerant on the surface of the heat exchange tube bundle 9. The film of liquid refrigerant exchanges heat with the process chilled water in the heat exchange tube bundle 9, 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, the arrangement of baffles 41 improves the flow uniformity and temperature consistency of the tube-side fluid at the outlet of the corresponding heat exchanger tube group. The table below shows the simulation calculation statistics of the flow rate and temperature fluctuation of the tube-side fluid at the outlet of each heat exchanger tube group in the four-tube falling film evaporator.

[0091] Traffic fluctuation level Temperature fluctuation Second pass heat exchanger tube assembly outlet 0.036154267 0.000349415 Third pass heat exchanger tube outlet 0.024375669 0.000485023 Fourth pass heat exchanger tube outlet 0.005270524 0.00030716

[0092] Fluctuation level refers to the average difference between the flow rate or temperature at the outlet of each heat exchanger tube and the average flow rate or temperature of all heat exchanger tubes in that tube pass. A smaller fluctuation value indicates a smaller difference from the average value, and a more uniform flow rate or temperature. The calculation formula is:

[0093] Traffic fluctuation level

[0094]

[0095] Temperature fluctuation

[0096]

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

[0098] The flow rate and temperature of the tube-side fluid at the outlet of each tube-side heat exchanger after the flow is uniformly distributed and the fluctuation is very small compared to a shell-and-tube heat exchanger under the same conditions except for one without baffle 41, after the flow is uniformly distributed and guided by the baffle 41.

[0099] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

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

Claims

1. A shell-and-tube heat exchanger, comprising: Cylinder (1); The heat exchange tube bundle (9) is located inside the cylinder (1) and is used for tube-side fluid flow; Two fluid chambers (2) are located at the two axial ends of the cylinder (1) and are connected to the heat exchange tube bundle (9); A partition (3) is provided in at least one of the fluid chambers (2), the partition (3) dividing the fluid chamber (2) 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) is provided in at least one of the chambers. The flow control component (4) is located between two heat exchange tube groups connected to the chamber. The flow control component (4) includes a flow equalization structure connecting the two heat exchange tube groups and / or a flow guiding structure that guides the tube-side fluid at the outlet of the upstream heat exchange tube group toward the inlet of the downstream heat exchange tube group.

2. The shell-and-tube heat exchanger according to claim 1, characterized in that, The flow control component (4) includes a baffle (41), which is installed on the cavity wall of the chamber and / or on the partition (3) separating the chamber. The flow equalization structure and / or the flow guiding structure are disposed on the baffle (41).

3. The shell-and-tube heat exchanger according to claim 2, characterized in that, The flow equalization structure includes flow holes (413) disposed on the baffle (41); and / or The flow guiding structure includes a flow guiding section (412) of the baffle (41), which is inclined from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups toward the inlet of the downstream heat exchange tube group of 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 angle (B) between the flow guide section (412) and the extension 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, characterized in that, The baffle (41) further includes an axial section (411) that extends along the axial direction of the cylinder (1), and the guide section (412) is connected to the end of the axial section (411) away from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups.

6. The shell-and-tube heat exchanger according to claim 3, characterized in that, The plurality of flow holes (413) are evenly distributed in at least one region of the baffle (41).

7. The shell-and-tube heat exchanger according to claim 3, characterized in that, The flow passage (413) is a circular hole with a diameter between 6 mm and 15 mm.

8. The shell-and-tube heat exchanger according to claim 3, characterized in that, The end of the guide section (412) away from the outlet of the upstream heat exchange tube group of the two heat exchange tube groups is spaced from the 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 (3); and / or The flow control component (4) is provided in each of the other chambers except for the chamber that receives the tube-side fluid from the outside of 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.

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) are in communication with different chambers of the same fluid chamber (2); and / or The tubular fluid inlet pipe (8) is located below the tubular 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, Includes the shell-and-tube heat exchanger according to any one of claims 1 to 11.

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