Spray falling film evaporator and method of using the same

Abstract

The present invention discloses a spray falling film evaporator and a method for using the same, comprising a shell, a refrigerant liquid inlet pipe and a refrigerant vapor outlet pipe arranged on the shell, a liquid collector, a first refrigerant distribution unit, a first heat transfer tube group, a second refrigerant distribution unit and a second heat transfer tube group; wherein the refrigerant liquid inlet pipe and the refrigerant vapor outlet pipe are both arranged on the top of the shell, the liquid collector, the first refrigerant distribution unit, the first heat transfer tube group, the second refrigerant distribution unit and the second heat transfer tube group are sequentially arranged in the shell from top to bottom, and the refrigerant liquid inlet pipe, the liquid collector and the first refrigerant distribution unit are sequentially connected, which can improve the heat exchange efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of refrigeration and air conditioning, and in particular relates to a spray falling film evaporator and a method of using the same. Background Art

[0002] In a vapor compression chiller, the evaporator is a heat exchange device with a built-in heat transfer tube assembly that cools the flowing fluid. During the vapor compression cycle, liquid refrigerant from the condenser is throttled by a throttling mechanism before flowing into the evaporator. There, it contacts a portion of the heat transfer tube assembly, exchanges heat, and absorbs heat, vaporizing into refrigerant vapor.

[0003] In order to prevent liquid refrigerant from being sucked into the compressor, causing "wet compression" and damaging the internal structural components of the compressor, a gas-liquid separator is generally designed and installed at the evaporator outlet to ensure the normal operation of the compressor.

[0004] Based on the degree of refrigerant filling within the evaporator and the evaporation process, current evaporators are mainly divided into dry evaporators and flooded evaporators. In dry evaporators, the refrigerant flows through the heat transfer tubes, while the cold water flows outside the tubes. This results in a relatively low heat exchange efficiency, only about twice that of a bare tube. A flooded evaporator, on the other hand, operates in the opposite manner: cold water flows through the heat transfer tubes, completely submerging them in the refrigerant. This allows the entire heat transfer surface to come into contact with the liquid refrigerant, creating a boiling heat exchange state. This results in a heat exchange efficiency that is approximately five times higher than that of a bare tube.

[0005] However, the refrigerant charge volume of the flooded evaporator is large, and due to the influence of the static pressure of the liquid, the evaporation temperature of the bottom liquid will increase, thereby reducing the heat transfer temperature difference of the evaporator and reducing the heat exchange efficiency. Summary of the Invention

[0006] The object of the present invention is to provide a spray falling film evaporator and a method of using the same, which can improve heat exchange efficiency.

[0007] A first aspect of the present invention discloses a spray falling film evaporator, comprising a shell, a refrigerant liquid inlet pipe and a refrigerant vapor outlet pipe arranged on the shell, a liquid collector, a first refrigerant distribution unit, a first heat transfer tube group, a second refrigerant distribution unit, and a second heat transfer tube group; wherein the liquid collector, the first refrigerant distribution unit, the first heat transfer tube group, the second refrigerant distribution unit, and the second heat transfer tube group are sequentially arranged in the shell from top to bottom, and the refrigerant liquid inlet pipe, the liquid collector, and the first refrigerant distribution unit are sequentially connected.

[0008] In one embodiment, the system further includes a first supporting component and a second supporting component, wherein the upper end of the first supporting component is connected to the first refrigerant distribution unit and the lower end is connected to the wall of the shell, and the upper end of the second supporting component is connected to the second refrigerant distribution unit and the lower end is connected to the base of the shell.

[0009] In one embodiment, the first supporting member and the first heat transfer tube group are arranged perpendicular to each other, and the second supporting member and the second heat transfer tube group are arranged perpendicular to each other.

[0010] In one embodiment, the shell is a cylinder, and the first heat transfer tube group, the second heat transfer tube group, the first refrigerant distribution unit, and the second refrigerant distribution unit are respectively arranged along the length direction of the cylinder.

[0011] In one embodiment, baffles are respectively provided on both sides of the first refrigerant distribution unit in the width direction, and the upper ends of the baffles are fixedly connected to the first refrigerant distribution unit, and the lower ends of the baffles are fixedly connected to the first supporting component.

[0012] In one embodiment, a gas-liquid separator is fixedly installed in the cavity formed by the baffle and the upper wall of the shell.

[0013] In one embodiment, the gas-liquid separator is fixedly connected to the shell via a third supporting component.

[0014] In one embodiment, both the first refrigerant spreading unit and the second refrigerant spreading unit are provided with spreading holes.

[0015] In one embodiment, the distribution holes are unevenly distributed.

[0016] A second aspect of the present invention discloses a method for using the spray falling film evaporator disclosed in the first aspect, comprising:

[0017] Controlling the refrigerant liquid to flow from the refrigerant liquid inlet pipe into the shell, and then forming a certain liquid level in the liquid accumulator and flowing into the first refrigerant distribution unit;

[0018] The first refrigerant distributing unit distributes the refrigerant liquid onto the surface of the first heat transfer tube group, so that part of the refrigerant liquid evaporates through heat exchange in the first heat transfer tube group and becomes part of the refrigerant vapor that flows out from the refrigerant vapor outlet pipe;

[0019] Another portion of the refrigerant liquid that has not evaporated flows into the second refrigerant distribution unit;

[0020] The second refrigerant distribution unit distributes another portion of the refrigerant liquid to the surface of the second heat transfer tube group, so that the other portion of the refrigerant liquid evaporates through heat exchange in the second heat transfer tube group and becomes another portion of refrigerant vapor flowing out from the refrigerant vapor outlet pipe.

[0021] The spray falling film evaporator and the method of using the same provided by the present invention are such that, during use, refrigerant liquid flows from the refrigerant liquid inlet pipe into the interior of the shell, forms a certain liquid level in the accumulator, and then flows into the first refrigerant distribution unit. The refrigerant liquid is distributed by the first refrigerant distribution unit to the first heat transfer tube group. The refrigerant liquid contacts the surface of the first heat transfer tube group, undergoes heat exchange with the cooled fluid flowing in the first heat transfer tube group, and evaporates, becoming part of the refrigerant vapor and flowing out from the refrigerant vapor outlet pipe. Then, part of the refrigerant liquid that has not evaporated flows into the second refrigerant distribution unit, is distributed to the second heat transfer tube group via the second refrigerant distribution unit, undergoes heat exchange with the cooled fluid flowing in the second heat transfer tube group, and evaporates, becoming another part of the refrigerant vapor and flowing out from the refrigerant vapor outlet pipe.

[0022] In this way, the two-stage refrigerant distribution unit and the two-stage heat transfer tube groups facilitate the formation of a film-like heat exchange pattern for the refrigerant liquid, effectively utilizing the heat transfer tube groups for refrigerant evaporation and heat exchange, ensuring more complete evaporation of the refrigerant liquid, thereby improving heat exchange efficiency. Furthermore, by providing two-stage heat transfer tube groups for evaporation heat exchange, each heat transfer tube group is covered with a film of refrigerant liquid, preventing the heat transfer tube group from drying out and preventing lubricating oil contained in the refrigerant liquid from adhering to the surface of the heat transfer tube group, thereby further improving heat exchange efficiency.

[0023] Moreover, the existing flow-type heat exchange of dry evaporators and immersion-type heat exchange of flooded evaporators are abandoned, and falling film heat exchange is adopted. The refrigerant liquid forms a thin refrigerant liquid film on the heat transfer tube group, which can reduce the static liquid level pressure of the refrigerant liquid during boiling and evaporation heat exchange, thereby further improving the heat exchange efficiency. In addition, through film heat exchange, the refrigerant charge amount can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein illustrate specific examples of the technical solutions described in the present invention, and together with the specific implementation methods constitute a part of the specification, and are used to explain the technical solutions, principles and effects of the present invention.

[0025] Unless otherwise specified or defined, the same reference numerals in different drawings represent the same or similar technical features, and the same or similar technical features may also be represented by different reference numerals.

[0026] Figure 1is a schematic cross-sectional view of a spray falling film evaporator disclosed in an embodiment of the present invention;

[0027] Figure 2 2 is a schematic diagram of the longitudinal direction of the spray falling film evaporator disclosed in an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the distribution holes of the refrigerant distribution unit disclosed in an embodiment of the present invention;

[0029] Figure 4 The present invention is a flowchart of a method for using a spray falling film evaporator disclosed in an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1. Refrigerant liquid inlet pipe; 2. Refrigerant vapor outlet pipe; 3. Liquid collector; 4. First refrigerant distribution unit; 401. Distribution hole; 5. First heat transfer tube group; 6. Second refrigerant distribution unit; 7. Second heat transfer tube group; 8. First support component; 9. Second support component; 10. Baffle; 11. Gas-liquid separator; 12. Third support component. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0033] Unless otherwise specified or defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art. In conjunction with the technical solutions of the present invention and in real-world scenarios, all technical and scientific terms used herein may also have meanings corresponding to the purpose of implementing the technical solutions of the present invention.

[0034] Unless otherwise specified or defined, the "first, second..." used herein is merely used to distinguish names and does not represent a specific quantity or order. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0035] It should be noted that when an element is considered to be "fixed to" another element, it can be directly fixed to the other element or there can be an intermediate element; when an element is considered to be "connected to" another element, it can be directly connected to the other element or there can be an intermediate element; when an element is considered to be "mounted on" another element, it can be directly mounted on the other element or there can be an intermediate element. When an element is considered to be "provided on" another element, it can be directly provided on the other element or there can be an intermediate element.

[0036] Unless otherwise specified or defined, the “said” and “the” used in this document refer to the technical features or technical contents mentioned or described before the corresponding position, and the technical features or technical contents may be the same as or similar to the technical features or technical contents mentioned therein.

[0037] There is no doubt that technical contents or technical features that are contrary to the purpose of the present invention or are obviously contradictory should be excluded.

[0038] like Figures 1 to 2 As shown, an embodiment of the present invention discloses a spray falling film evaporator, comprising a shell, a refrigerant liquid inlet pipe 1 and a refrigerant vapor outlet pipe 2 arranged on the shell, a liquid collector 3, a first refrigerant distribution unit 4, a first heat transfer tube group 5, a second refrigerant distribution unit 6, and a second heat transfer tube group 7; wherein the liquid collector 3, the first refrigerant distribution unit 4, the first heat transfer tube group 5, the second refrigerant distribution unit 6, and the second heat transfer tube group 7 are sequentially arranged in the shell from top to bottom, and the refrigerant liquid inlet pipe 1, the liquid collector 3, and the first refrigerant distribution unit 4 are sequentially connected, for example, by a fixed connection method such as welding, hinged connection, or threaded connection.

[0039] During use, the refrigerant liquid flows into the shell from the refrigerant liquid inlet pipe 1, and after the liquid is collected and steadily flows to form a certain liquid level in the accumulator 3, it flows into the first refrigerant distribution unit 4. The refrigerant liquid is distributed to the first heat transfer tube group 5 by the first refrigerant distribution unit 4. The refrigerant liquid contacts the surface of the first heat transfer tube group 5, and evaporates through heat exchange with the cooled fluid flowing in the first heat transfer tube group 5, and becomes part of the refrigerant vapor and flows out from the refrigerant vapor outlet pipe 2. Then, part of the refrigerant liquid that has not evaporated flows into the second refrigerant distribution unit 6, and is distributed to the second heat transfer tube group 7 through the second refrigerant distribution unit 6. It evaporates through heat exchange with the cooled fluid flowing in the second heat transfer tube group 7, and becomes another part of the refrigerant vapor and flows out from the refrigerant vapor outlet pipe 2.

[0040] In this way, the two-stage refrigerant distribution unit and the two-stage heat transfer tube groups facilitate the formation of a film-like heat exchange pattern for the refrigerant liquid, effectively utilizing the heat transfer tube groups for refrigerant evaporation and heat exchange, and ensuring more complete evaporation of the refrigerant liquid, thereby improving heat exchange efficiency. Furthermore, by providing two-stage heat transfer tube groups for evaporation and heat exchange, each heat transfer tube group is covered with a film of refrigerant liquid, preventing the heat transfer tube group from drying out and preventing lubricating oil contained in the refrigerant liquid from adhering to the surface of the heat transfer tube group, thereby further improving heat exchange efficiency.

[0041] Moreover, the existing flow-type heat exchange of dry evaporators and immersion-type heat exchange of flooded evaporators are abandoned, and falling film heat exchange is adopted. The refrigerant liquid forms a thin refrigerant liquid film on the heat transfer tube group, which can reduce the static liquid level pressure of the refrigerant liquid during boiling and evaporation heat exchange, thereby further improving the heat exchange efficiency. In addition, through film heat exchange, the refrigerant charge amount can be reduced.

[0042] According to theoretical calculations, the heat exchange efficiency of the embodiment of the present invention is improved by about 5 times compared with that of a flooded evaporator, and the refrigerant charge is reduced by about 30% compared with that of a flooded evaporator.

[0043] Optionally, the refrigerant liquid inlet pipe 1 is arranged at the top of the shell, so that the refrigerant liquid can flow downward at high speed under the action of pressure difference and gravity.

[0044] The refrigerant vapor outlet pipe 2 may also be arranged at the top of the shell. Preferably, the refrigerant liquid inlet pipe 1 and the refrigerant vapor outlet pipe 2 are arranged parallel to each other at the top of the shell.

[0045] Further optionally, the refrigerant liquid inlet pipe 1 is arranged at the top center of the shell, and the refrigerant vapor outlet pipe 2 is arranged on the left or right side of the top center of the shell.

[0046] Optionally, the inlet of the accumulator 3 can be set at the top and connected to the refrigerant liquid inlet pipe 1, and the outlet of the accumulator 3 is set at the bottom of the side and has a certain distance from the bottom of the accumulator 3, so that when the refrigerant liquid flows into the interior of the shell from the refrigerant liquid inlet pipe 1, it first flows into the interior of the accumulator 3 through the inlet of the accumulator 3, and after a certain liquid level is formed in the interior of the accumulator 3, it flows out from the outlet set at the bottom of the side to the first refrigerant distribution unit 4.

[0047] Optionally, the shell of the spray falling film evaporator can be cylindrical, with the first heat transfer tube group 5, the second heat transfer tube group 7, the first refrigerant distribution unit 4, and the second refrigerant distribution unit 6 arranged along the length of the cylinder. Multiple pipe support devices are provided within the shell, oriented toward the center of gravity, to support the first and second refrigerant distribution units 4 and 6. A certain distance exists between adjacent pipe support devices. Each pipe support device includes a first support component 8 and a second support component 9. The first support component 8 supports the first refrigerant distribution unit 4, while the second support component 9 supports the second refrigerant distribution unit 6. The first support component 8 is perpendicular to the first heat transfer tube group 5, and the second support component 9 is perpendicular to the second heat transfer tube group 7.

[0048] like Figure 1In the shaded area shown, the horizontal sides of the first support member 8 and the second support member 9 are fixedly connected to the shell, and the first support member 8 and the second support member 9 are parallel to the cross section of the cylinder. The upper end of the first support member 8 is connected to the first refrigerant distribution unit 4, and the lower end is connected to the wall of the shell. The upper end of the second support member 9 is connected to the second refrigerant distribution unit 6, and the lower end is connected to the base of the shell. Figure 2 As shown, viewed from the length direction of the housing, the thickness of the first support member 8 and the second support member 9 are both relatively small, and do not affect the spraying of refrigerant liquid by the first refrigerant distribution unit 4 and the second refrigerant distribution unit 6. In addition to support plates, the first support member 8 and the second support member 9 can also be support rods.

[0049] Preferably, the first supporting member 8 and the second supporting member 9 are both welded to the wall surface of the housing.

[0050] Alternatively, as Figure 1 As shown, baffles 10 may be further provided on both sides of the first refrigerant distribution unit 4 in the width direction. The upper end of the baffle 10 is fixedly connected to the first refrigerant distribution unit 4, and the lower end is fixedly connected to the first support member 8, thereby preventing the refrigerant liquid from flashing during the process of being distributed from the first refrigerant distribution unit 4 to the first heat transfer tube group 5, thereby avoiding waste.

[0051] Preferably, the upper end of the baffle 10 is welded to the first refrigerant distribution unit 4 and the lower end is welded to the first support component 8 ; the upper end of the first support component 8 is welded to the first refrigerant distribution unit 4 and the lower end is welded to the wall of the shell.

[0052] Optionally, a gas-liquid separator 11 is fixedly installed in the cavity formed by the baffle 10 and the upper wall of the shell. The gas-liquid separator 11 is fixedly connected to the shell via a third support member 12. The gas-liquid separator removes misted refrigerant and separates the refrigerant gas after evaporation and heat exchange. This prevents liquid refrigerant from being drawn into the compressor, resulting in "wet compression," thereby improving the system's heat exchange efficiency and equipment life.

[0053] Optionally, both the first refrigerant dispersing unit 4 and the second refrigerant dispersing unit 6 are provided with dispersing holes, and the size, number, and spacing of the dispersing holes can be determined by model simulation. For example, theoretical simulations can be performed using fluid software and model simulations based on dimensional analysis to determine the size, number, and spacing of the dispersing holes. Based on this, the dispersing holes can be set to achieve more uniform dispersal, a more stable liquid film, and further improve heat exchange efficiency. The dispersing holes can be evenly distributed or unevenly distributed. Figure 3As shown, the first refrigerant distribution unit 4 is provided with unevenly distributed distribution holes 401 .

[0054] Optionally, a diffusion nozzle is provided on each scattering hole, and the spraying direction of the diffusion nozzle is downward, that is, toward the corresponding heat transfer tube group, so that the sprayed refrigerant can cover a larger area on the surface of the heat transfer tube group.

[0055] like Figure 4 As shown, the embodiment of the present invention discloses a method for using a spray falling film evaporator, which is applied to Figures 1 to 2 The spray falling film evaporator shown, the method of using includes:

[0056] S401 , controlling the refrigerant liquid to flow from the refrigerant liquid inlet pipe into the shell, and then flowing into the first refrigerant distribution unit after a certain liquid level is formed in the liquid collector.

[0057] S402: The first refrigerant distributing unit distributes the refrigerant liquid to the surface of the first heat transfer tube group, so that part of the refrigerant liquid evaporates through heat exchange in the first heat transfer tube group and becomes part of the refrigerant vapor flowing out from the refrigerant vapor outlet pipe.

[0058] S403 , another portion of the refrigerant liquid that has not evaporated flows into the second refrigerant distribution unit.

[0059] S404: The second refrigerant distribution unit distributes another portion of the refrigerant liquid to the surface of the second heat transfer tube group, so that the other portion of the refrigerant liquid evaporates through heat exchange in the second heat transfer tube group and becomes another portion of refrigerant vapor flowing out from the refrigerant vapor outlet pipe.

[0060] The purpose of the above embodiments is to exemplify and deduce the technical solution of the present invention, and to fully describe the technical solution, purpose and effect of the present invention. Its purpose is to enable the public to have a more thorough and comprehensive understanding of the disclosed content of the present invention, and it does not limit the scope of protection of the present invention.

[0061] The above embodiments are not exhaustive and may include many other embodiments not listed above. Any replacements and improvements made without violating the concept of the present invention are within the scope of protection of the present invention.

Claims

1. Spray falling film evaporator, characterized in that: The heat exchanger comprises a shell, a refrigerant liquid inlet pipe and a refrigerant vapor outlet pipe arranged on the shell, a liquid collector, a first refrigerant spreading unit, a first heat transfer tube group, a second refrigerant spreading unit and a second heat transfer tube group; wherein the liquid collector, the first refrigerant spreading unit, the first heat transfer tube group, the second refrigerant spreading unit and the second heat transfer tube group are sequentially arranged in the shell from top to bottom, and the refrigerant liquid inlet pipe, the liquid collector and the first refrigerant spreading unit are sequentially connected; The shell is a cylinder, the first heat transfer tube group, the second heat transfer tube group, the first refrigerant distribution unit and the second refrigerant distribution unit are arranged along the length direction of the cylinder respectively, a plurality of pipe support devices are arranged in the gravity center direction of the shell for supporting the first refrigerant distribution unit and the second refrigerant distribution unit, and a certain distance is provided between each two adjacent pipe support devices; each pipe support device comprises a first support component and a second support component, the upper end of the first support component is connected to the first refrigerant distribution unit and the lower end is connected to the wall surface of the shell, the upper end of the second support component is connected to the second refrigerant distribution unit and the lower end is connected to the base of the shell; the first support component and the first heat transfer tube group are arranged perpendicular to each other, and the second support component and the second heat transfer tube group are arranged perpendicular to each other; Baffles are respectively arranged on both sides of the first refrigerant distribution unit in the width direction, the upper ends of the baffles are fixedly connected to the first refrigerant distribution unit, and the lower ends of the baffles are fixedly connected to the first supporting component; a gas-liquid separator is fixedly arranged in the cavity formed by the baffles and the upper wall surface of the shell, and the gas-liquid separator is fixedly connected to the shell through a third supporting component.

2. The spray falling film evaporator according to claim 1, characterized in that: The first refrigerant spreading unit and the second refrigerant spreading unit are both provided with spreading holes.

3. The spray falling film evaporator according to claim 2, characterized in that: The distribution holes are unevenly distributed.

4. The method for using the spray falling film evaporator according to any one of claims 1 to 3, characterized in that: include: Controlling the refrigerant liquid to flow from the refrigerant liquid inlet pipe into the shell, and then flowing into the first refrigerant distribution unit after a certain liquid level is formed in the liquid collector; The first refrigerant distributing unit distributes the refrigerant liquid to the surface of the first heat transfer tube group, so that part of the refrigerant liquid evaporates through heat exchange in the first heat transfer tube group and becomes part of the refrigerant vapor flowing out from the refrigerant vapor outlet pipe; Another part of the refrigerant liquid that has not evaporated flows into the second refrigerant distribution unit; The second refrigerant distributing unit distributes another part of the refrigerant liquid to the surface of the second heat transfer tube group, so that the other part of the refrigerant liquid evaporates through heat exchange in the second heat transfer tube group and becomes another part of refrigerant vapor flowing out from the refrigerant vapor outlet pipe.

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