Refrigerant distributor, evaporator and distribution method

Abstract

The present invention discloses a refrigerant distributor, an evaporator and a distribution method. The refrigerant distributor comprises a refrigerant distribution box and a plurality of cyclone nozzles connected at intervals on the horizontal circumferential side of the refrigerant distribution box; the cyclone nozzle comprises an outer cylinder and an inner cylinder disposed in the outer cylinder, a filter assembly and a combined nozzle; the combined nozzle comprises a plurality of vertical conical nozzles arranged at intervals in a concentric circumferential direction; the refrigerant distribution box is connected to the space directly contained by the inner wall of the outer cylinder through a tangential inlet; the liquid inlet of each conical nozzle of the combined nozzle is connected to the space. The present invention can fully separate gas and liquid through pressure difference separation and cyclone separation; thereby avoiding the problem caused by the large volume flow of flashed gaseous refrigerant; and avoiding the subsequent impact on the pressure difference problem of the falling film evaporator. It is applicable to R1233zd (E) refrigerant.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial refrigeration and heat exchange, and in particular relates to a refrigerant distributor and a distribution method used in a falling film evaporator. Background Art

[0002] Falling film evaporator is widely used in the field of refrigeration and air conditioning due to its high heat exchange efficiency and small amount of refrigerant. In the falling film evaporator, whether the refrigerant can be evenly distributed has a great influence on the heat exchange efficiency of the evaporator. Most of the refrigerants used in the existing chillers are R134a, and the falling film evaporator is also designed based on the physical parameters of the refrigerant R134a. However, the refrigerant R134a has the disadvantages of high GWP and environmental pollution. Negative pressure refrigerants, such as R1233zd (E), are favored by people because of their environmental protection and high efficiency. Compared with the refrigeration system using R134a as the refrigerant, the refrigeration system using the negative pressure refrigerant R1233zd (E) has the characteristics of small pressure difference between the condenser and the evaporator, and large volume flow of gaseous refrigerant flashed by the refrigerant throttling, so higher requirements are put forward for the uniform distribution of the refrigerant in the falling film evaporator.

[0003] The volume flow of gaseous refrigerant flashed after refrigerant throttling is large. If gas-liquid separation is not performed, it will affect the uniform distribution of refrigerant in the distributor. The pressure difference between the condenser and the evaporator is small, and the existing distributors that use pressure difference distribution for R134a refrigerant cannot meet the demand. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a refrigerant distributor and distribution method for a falling film evaporator, which is mainly used in the case where R134a refrigerant is distributed using a pressure difference, to solve the urgent problem that the volume flow of the flashed gaseous refrigerant after refrigerant throttling is large and requires gas-liquid separation.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A refrigerant distributor applied to a falling film evaporator, characterized in that it includes a refrigerant distribution box, and a plurality of cyclone nozzles connected at intervals on the horizontal circumferential side surfaces of the refrigerant distribution box; the cyclone nozzle includes an outer cylinder and an inner cylinder disposed in the outer cylinder, a filter assembly and a combined nozzle, and in the vertical direction, the inner cylinder is disposed between the filter assembly and the combined nozzle, and the inner cylinder and the outer cylinder are arranged concentrically and spaced apart; the combined nozzle includes a plurality of vertical conical nozzles arranged concentrically and spaced apart; the refrigerant distribution box is connected to the space directly contained by the inner wall of the outer cylinder through a tangential inlet; and the liquid inlet of each conical nozzle of the combined nozzle is connected to the space.

[0007] Furthermore, the refrigerant distribution box is connected to the space directly contained by the inner wall of the outer cylinder in the horizontal direction through the tangential inlet.

[0008] Furthermore, the main body of the combined nozzle is a cylindrical column, the upper end face is the liquid inlet of each nozzle arranged concentrically and circumferentially at intervals, the lower end face is the liquid outlet corresponding to the upper end face in sequence, and the diameter of the liquid outlet is smaller than the liquid inlet, so that each nozzle forms a conical pipe section extending in the vertical direction.

[0009] Furthermore, the height of the combined nozzle is equal to the height of the tapered pipe section.

[0010] Furthermore, the refrigerant distributor applied to the falling film evaporator is arranged in the cylinder of the falling film evaporator and placed above the heat exchange tube bundle of the falling film evaporator; the refrigerant inlet on the cylinder of the falling film evaporator is connected to the top inlet of the refrigerant distribution box.

[0011] Furthermore, the refrigerant distributor applied to the falling film evaporator is suitable for R1233zd(E) refrigerant.

[0012] An evaporator or system is characterized by using the above-mentioned refrigerant distributor applied to the falling film evaporator.

[0013] A refrigerant distribution method, characterized in that: the above-mentioned refrigerant distributor applied to a falling film evaporator is used, after the refrigerant enters the falling film evaporator, it enters the refrigerant distributor from the top of the refrigerant distribution box, and pressure difference distribution is performed in the distribution box to ensure uniform distribution in the axial direction of the falling film evaporator cylinder, the gas-liquid mixed gas distributed from the distribution box enters the cyclone nozzle to first undergo gas-liquid separation, and then is sprayed from each nozzle of the cyclone nozzle onto the heat exchange tube bundle of the falling film evaporator, thereby achieving uniform distribution of the refrigerant in the radial direction of the falling film evaporator.

[0014] Furthermore, the gas-liquid mixed gas coming out of the distribution box enters the inner wall of the outer cylinder of the cyclone nozzle along the tangential direction to form a rotational motion, and the gas-liquid separation is carried out under the action of centrifugal force. The gas is discharged from the upper gas outlet of the cyclone nozzle. The density of the droplets is large, and they are thrown to the wall of the outer cylinder 4 under the action of the larger centrifugal force. The droplets contact the wall of the outer cylinder and lose their inertial force. Relying on the momentum of the downward axial velocity near the wall of the device, they fall along the wall of the outer cylinder and enter the inlet of the combined nozzle.

[0015] Therefore, the working principle of the cyclone separator used for gas-liquid two-phase separation is that the gas-liquid two-phase fluid enters the cylinder tangentially to form a rotational motion. The density of the droplets is large, and they are thrown to the wall of the vessel under the action of a large centrifugal force. The droplets lose their inertial force when in contact with the wall, and rely on the momentum of the downward axial velocity near the wall to fall along the wall and enter the bottom of the cylinder. The rotating and descending external swirling airflow continuously flows into the center of the separator during the descent process, forming a centripetal radial airflow, and flows downward along the outer side of the inner cylinder. When it reaches the lower end of the inner cylinder, it enters the inner cylinder, and the gas moves upward under the action of buoyancy, and the liquid refrigerant contained in the gas is further filtered out through the filter screen, and finally the refrigerant gas is discharged from the top of the cyclone separator. The greater the density difference between the gas and liquid phases, the better the cyclone separation effect. Studies have shown that at the same temperature, the density difference between the gas and liquid phases of refrigerant R1233zd(E) is greater than that of refrigerant R134a. Therefore, the effect of gas-liquid separation of refrigerant R1233zd(E) using a cyclone separator is better than that of refrigerant R134a.

[0016] Compared with the prior art, the refrigerant coming out of the condenser in the present invention can be fully separated into gas and liquid through pressure difference separation and cyclone separation; thereby avoiding the problems caused by the large volume flow of flashed gaseous refrigerant; and avoiding the subsequent impact on the pressure difference problem of the falling film evaporator.

[0017] At the same time, since the structure and method are more suitable for R1233zd (E) refrigerant, since the density difference between the gas phase and the liquid phase of R1233zd (E) refrigerant is large at the same temperature, a cyclone nozzle is used to separate the gas and liquid of R1233zd (E), and the separation effect is obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a schematic diagram of the structure of a refrigerant distributor applied to a falling film evaporator according to the present invention.

[0019] Figure 2 It is a perspective view of a cyclone nozzle (the filter assembly 3 is not shown in the figure).

[0020] Figure 3 Schematic diagram of the split structure of the cyclone nozzle.

[0021] Figure 4 It is a perspective view of the nozzle structure of the cyclone nozzle.

[0022] Figure 5 This is a structure in which the cyclone nozzle 2 of the present invention is combined with a falling film evaporator. DETAILED DESCRIPTION

[0023] According to the refrigerant distributor applied to the falling film evaporator implemented in the present invention, Figure 1-5 shown.

[0024] The falling film evaporator using negative pressure refrigerant R1233zd (E) as refrigerant has the problem of small pressure difference between condenser and evaporator, and large volume flow rate of gaseous refrigerant caused by refrigerant throttling flash. Studies have shown that the density difference between gas and liquid phase of refrigerant R1233zd (E) is greater than that of refrigerant R134a at the same temperature. In view of this feature, the present invention proposes a refrigerant distributor scheme applied to negative pressure refrigerant falling film evaporator. Figure 1 As shown, the refrigerant distributor is composed of a refrigerant distribution box and a plurality of cyclone nozzles 2 connected at intervals on the circumferential side of the refrigerant distribution box. The liquid refrigerant after throttling from the condenser enters from the top inlet 1 of the refrigerant distribution box, and under the action of the pressure difference, the refrigerant is evenly distributed along the horizontal cylinder direction of the refrigerant distribution box. After even distribution, the refrigerant flows out from the side of the refrigerant distribution box, and the outflowing refrigerant enters the plurality of cyclone nozzles 2 connected laterally, and enters the inner wall of the outer cylinder 4 of the cyclone nozzle 2 along the tangential direction. Because the refrigerant distribution box is distributed by pressure difference, the liquid refrigerant flowing out from the side of the distribution box contains a part of flash gas. Figure 2 A schematic diagram of the cyclone nozzle is shown. Figure 2 It can be seen that the gas-liquid two-phase mixed refrigerant enters the inner wall of the outer cylinder 4 of the cyclone nozzle 2 along the tangential inlet 2.1, and is separated into gas and liquid under the action of centrifugal force. The gas is discharged from the upper gas outlet 2.2 of the cyclone nozzle. The filter assembly 3 should be placed above the upper gas outlet 2.2 ( Figure 2 The filter assembly 3 is a conventional filter or similar component, and the liquid refrigerant contained in the gas can be further filtered out after passing through the filter assembly 3; the liquid is discharged from the combined nozzle 6 at the bottom.

[0025] Figure 2-3 The schematic diagram of the structure of the cyclone nozzle 2 is shown. The cyclone nozzle 2 is composed of a filter assembly 3, an inner cylinder 5, an outer cylinder 4, and a combined nozzle 6. The gas-liquid two-phase fluid enters the inner wall of the outer cylinder 4 along the tangential direction to form a rotational motion. The droplets have a large density and are thrown toward the wall of the outer cylinder 4 under the action of a large centrifugal force. The droplets contact the wall of the outer cylinder 4 and lose their inertial force. Relying on the momentum of the downward axial velocity near the wall, they fall along the wall of the outer cylinder 4 and enter the inlet of the combined nozzle 6. The outer cylinder 4 of the cyclone nozzle 2 has an internal thread at the bottom, and the combined nozzle 6 and the outer cylinder are connected as a whole by a threaded connection.

[0026] The perspective view of the combined nozzle 6 is as follows Figure 4 As shown, the combined nozzle 6 is composed of several small nozzles 6.1 concentrically spaced from each other; Figure 4As shown, the main body of the combined nozzle 6 is a solid cylindrical column, the upper end face is the liquid inlet of each small nozzle 6.1 that is evenly spaced and concentrically distributed in the circumferential direction, and the lower end face is the liquid outlet that corresponds to the upper end face in sequence. The diameter of the liquid outlet is smaller than the diameter of the liquid inlet, so that each small nozzle 6.1 forms a tapered pipe section extending in the vertical direction; the height of the combined nozzle 6 is roughly equal to the height of the tapered pipe section. Preferably, the horizontal cross-section of each small nozzle 6.1 is circular, the diameter of the liquid inlet is equal, and the diameter of the liquid outlet is also equal; so that the distribution is uniform. The liquid refrigerant is sprayed onto the heat exchange tube bundle of the falling film evaporator through the small nozzle 6.1, realizing the uniform distribution of the refrigerant in the radial direction of the falling film evaporator.

[0027] While the liquid is being distributed, the outer swirling airflow continuously flows into the central part of the cyclone nozzle 2 during the descent process, forming a centripetal radial airflow, which flows downward along the outer side of the inner cylinder 5. When it reaches the lower end of the inner cylinder 5, it enters the inner side of the inner cylinder 5. The gas moves upward under the action of the buoyancy force, and the liquid refrigerant contained in the gas is further filtered out after passing through the filter assembly 3. Finally, the refrigerant gas is discharged from the top of the cyclone separation nozzle 2. Figure 2 shown.

[0028] At the same temperature, the density difference between the gas phase and the liquid phase of R1233zd(E) is large. The cyclone nozzle is used to separate the gas and liquid of R1233zd(E), and the separation effect is obvious.

[0029] Figure 5 The present invention is a structure combining a cyclone nozzle 2 and a falling film evaporator. The refrigerant distributor composed of the cyclone nozzle 2 is arranged in the barrel of the falling film evaporator. The refrigerant inlet on the barrel enters the top inlet 1 of the refrigerant distribution box. The R1233zd (E) refrigerant is distributed by pressure difference in the distribution box to ensure uniform distribution in the axial direction of the barrel of the falling film evaporator. The gas-liquid mixed gas coming out of the distribution box enters the cyclone nozzle 2 and is first separated into gas and liquid before being sprayed out from the small nozzle 6.1 to ensure uniform distribution in the radial direction of the barrel of the falling film evaporator. This distribution scheme of the refrigerant distributor ensures that the refrigerant is evenly distributed in the falling film evaporator, so that the evaporator has a higher heat exchange efficiency. There is a certain pressure difference between the upper and lower inlets and outlets of the combined nozzle 6. The liquid after cyclone separation is sprayed out through the liquid outlet below each small nozzle 6.1 under the action of the pressure difference, and is evenly sprayed onto the outer wall of the evaporator heat exchange tube 7 after atomization, ensuring uniform distribution of the refrigerant in the evaporator.

Claims

1. A refrigerant distributor for a falling film evaporator, characterized in that: It includes a refrigerant distribution box, and a plurality of cyclone nozzles connected at intervals on the horizontal circumferential side surfaces of the refrigerant distribution box; the cyclone nozzle includes an outer cylinder and an inner cylinder arranged in the outer cylinder, a filter assembly and a combined nozzle, and along the vertical direction, the inner cylinder is arranged between the filter assembly and the combined nozzle, and the inner cylinder and the outer cylinder are arranged concentrically and spaced apart; the combined nozzle includes a plurality of vertical conical nozzles arranged concentrically and spaced apart; the refrigerant distribution box is connected to the space directly contained by the inner wall of the outer cylinder through a tangential inlet; the liquid inlet of each conical nozzle of the combined nozzle is connected to the space.

2. The refrigerant distributor for a falling film evaporator according to claim 1, characterized in that: The refrigerant distribution box is connected to the space directly contained by the inner wall of the outer cylinder in the horizontal direction through the tangential inlet.

3. The refrigerant distributor for a falling film evaporator according to claim 1, characterized in that: The main body of the combined nozzle is a cylindrical column, the upper end face is the liquid inlet of each nozzle arranged concentrically and circumferentially, and the lower end face is the liquid outlet corresponding to the upper end face in sequence. The diameter of the liquid outlet is smaller than the liquid inlet, so that each nozzle forms a conical pipe section extending in the vertical direction.

4. The refrigerant distributor for a falling film evaporator according to claim 3, characterized in that: The height of the combined nozzle is equal to the height of the tapered pipe section.

5. The refrigerant distributor for a falling film evaporator according to claim 1, characterized in that: The refrigerant distributor applied to the falling film evaporator is arranged in the cylinder of the falling film evaporator and placed above the heat exchange tube bundle of the falling film evaporator; the refrigerant inlet on the cylinder of the falling film evaporator is communicated with the top inlet of the refrigerant distribution box.

6. The refrigerant distributor for a falling film evaporator according to claim 1, characterized in that: The refrigerant distributor for falling film evaporator is suitable for R1233zd(E) refrigerant.

7. An evaporator, characterized in that: Use the refrigerant distributor applied to a falling film evaporator as described in any one of claims 1 to 6.

8. A refrigerant distribution method, characterized in that: The refrigerant distributor applied to the falling film evaporator as described in any one of claims 1 to 6 is used. After the refrigerant enters the falling film evaporator, it enters the refrigerant distributor from the top of the refrigerant distribution box, and pressure difference distribution is performed in the distribution box to ensure uniform distribution in the axial direction of the falling film evaporator cylinder. The gas-liquid mixed gas coming out of the distribution box enters the cyclone nozzle for gas-liquid separation first, and then is sprayed from each nozzle of the cyclone nozzle onto the heat exchange tube bundle of the falling film evaporator, thereby realizing uniform distribution of the refrigerant in the radial direction of the falling film evaporator.

9. The refrigerant distribution method according to claim 8, characterized in that: The gas-liquid mixed gas coming out of the distribution box enters the inner wall of the outer cylinder of the cyclone nozzle along the tangential direction to form a rotational motion, and the gas-liquid separation is carried out under the action of centrifugal force. The gas is discharged from the upper gas outlet of the cyclone nozzle. The density of the droplets is large, and they are thrown to the 4 walls of the outer cylinder under the action of the larger centrifugal force. The droplets lose inertia when they contact the wall of the outer cylinder, and rely on the momentum of the downward axial velocity near the wall to fall along the wall of the outer cylinder and enter the inlet of the combined nozzle.

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