Flooded evaporator

Abstract

The utility model relates to a flooded evaporator which comprises an evaporator cylinder, a refrigerant distributor, a heat exchange tube bundle and a refrigerant gas-liquid separator are sequentially arranged in the evaporator cylinder from bottom to top, the refrigerant distributor comprises a bottom plate, an inner partition plate, a flow guide plate, an accelerator plate, a speed reducing plate and an end plate, and a plurality of accelerator plate holes are evenly distributed in the accelerator plate. The inner partition plate, the flow guide plate and the two end plates form a flow guide cavity, the flow guide plate, the acceleration plate and the two end plates form an acceleration cavity, the flow guide cavity is communicated with the acceleration cavity, and the acceleration plate, the speed reducing plate and one end plate form a deceleration cavity. A refrigerant is processed by the refrigerant distributor to form a gas-liquid two-phase mixture with an intermittent flow or an annular flow, the gas-liquid two-phase mixture forms a thin liquid film on the surface of the heat exchange tube bundle, and turbulent flow falling film evaporation is carried out. Flow enhancement is achieved, the heat transfer performance is improved, the refrigerant filling amount is greatly reduced, and erosion abrasion of the refrigerant to a heat exchange tube bundle is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of heat exchange and refrigeration, in particular to a flooded evaporator. Background Art

[0002] Most of the refrigerants in water chillers are synthetic products. Their emissions are being required to limit the potential impact on atmospheric ozone depletion (ODP) or reduce the impact on global greenhouse effect (GWP). The synthetic production process of refrigerants consumes a large amount of energy and is considered to increase a large amount of carbon emissions. Therefore, green or energy-saving building certifications including those in China, as well as the LEED certification in the United States, have put forward restrictive requirements on the refrigerant filling amount of water chillers, attempting to directly and indirectly reduce carbon emissions by reducing the refrigerant filling amount.

[0003] For traditional flooded evaporators of water chillers, people have continuously pursued ways to increase the surface area contact, such as adding fins to the surface of heat exchange tubes, to improve the heat exchange efficiency. Currently, the development limit has been reached in the direction of increasing the heat exchange area contact. However, there are still problems such as unsatisfactory heat exchange effect, large refrigerant filling amount (for example, the unit refrigerant filling amount of a traditional high-efficiency flooded evaporator is generally 0.4 - 0.8 kg / KW), the evaporator product equipment is easily eroded by the refrigerant, and it is difficult to repair in the later stage. Summary of the Utility Model

[0004] The purpose of the utility model is to overcome the above deficiencies and provide a flooded evaporator. After being processed by a refrigerant distributor, the refrigerant forms a two-phase mixture with a flow pattern of intermittent flow or annular flow, changing the Prandtl number of the pure liquid into a Prandtl number of a mixture close to the gas phase. The gas-liquid two-phase mixture flows out uniformly within a fan-shaped angle range, the fluid flow field is uniform, and the gas-liquid two-phase mixture forms a thinner liquid film on the surface of the heat exchange tube bundle for turbulent falling film evaporation, realizing flow strengthening to improve the heat transfer performance (tests show that the overall heat transfer coefficient is increased by 20 - 30% compared with falling film type and traditional flooded type), greatly reducing the refrigerant filling amount (tests show that the unit refrigerant filling amount is reduced by 30 - 60% compared with traditional flooded type), and reducing the erosion and wear of the refrigerant on the heat exchange tube bundle.

[0005] The purpose of the utility model is achieved as follows:

[0006] A flooded evaporator includes an evaporator cylinder body. Inside the evaporator cylinder body, a refrigerant distributor, a heat exchange tube bundle, and a refrigerant gas-liquid separator are sequentially arranged from bottom to top. The refrigerant distributor includes a bottom plate, an inner partition plate, a guide plate, an acceleration plate, a deceleration plate, and end plates. Between the two end plates arranged left and right, a bottom plate, an inner partition plate, a guide plate, an acceleration plate, and a deceleration plate are sequentially arranged from bottom to top. The bottom plate is in the shape of an arc coaxial with the evaporator cylinder body and completely fits the bottom of the evaporator cylinder body. The deceleration plate is fixedly connected to the heat exchange tube bundle support plate through a clamp. A number of acceleration plate holes are evenly distributed on the acceleration plate, and a number of deceleration plate holes are evenly distributed on the deceleration plate. The inner partition plate, the guide plate, and the two end plates form a guide cavity. The guide plate, the acceleration plate, and the two end plates form an acceleration cavity. The guide cavity and the acceleration cavity are communicated. The acceleration plate, the deceleration plate, and one end plate form a deceleration cavity. The inner partition plate, the guide plate, the acceleration plate, and the deceleration plate are all in the shape of ∧ and are integrally bent and formed with the same bending angle.

[0007] Preferably, one end of the guide plate is welded to the corresponding end plate, and the other end has a fluid turning gap with the corresponding end plate to communicate the upper and lower acceleration cavities and the guide cavity, and the fluid in the guide cavity turns and flows into the acceleration cavity.

[0008] Preferably, the guide cavity and the acceleration cavity are distributed at unequal intervals, and the cavity intervals between them decrease sequentially from bottom to top.

[0009] Preferably, the bending angles of the inner partition plate, the guide plate, the acceleration plate, and the deceleration plate are 45°, 60°, 90°, or 120°.

[0010] Preferably, the acceleration plate holes and the deceleration plate holes are arranged in a staggered manner.

[0011] Preferably, both ends of the heat exchange tube bundle are fixed by tube plates, and the middle of the heat exchange tube bundle is supported by a heat exchange tube bundle support plate. The tube plates are welded and fixed on the left and right sides of the evaporator cylinder body. The left tube plate is connected to the left water chamber head, and the right tube plate is connected to the right water chamber head. The left water chamber head is connected to a chilled water outlet pipe and a chilled water inlet pipe. An intermediate partition plate for guiding the fluid is arranged inside the left water chamber head. The intermediate partition plate divides the left water chamber head into upper and lower chambers, and the chilled water outlet pipe and the chilled water inlet pipe arranged up and down correspond to the two chambers respectively.

[0012] Preferably, the evaporator cylinder body is provided with a refrigerant inlet pipe corresponding to the refrigerant distributor, and the evaporator cylinder body is provided with an evaporator outlet pipe corresponding to the refrigerant gas-liquid separator.

[0013] Preferably, a flow equalizing pipe is further arranged inside the evaporator cylinder body. The flow equalizing pipe is arranged in the blank area of the heat exchange tube area inside the evaporator cylinder body and is parallel to the heat exchange tube bundle so as to further mix the gas evaporated in the tube bundle with the remaining liquid, further create a low Prandtl number, and strengthen the flow and enhance heat transfer.

[0014] Preferably, a row of flow equalizing pipes is provided in the middle of the heat exchange tube area inside the evaporator cylinder. The solid flow equalizing pipes are welded to the tube sheets at both ends, and the mixing orifice plate is placed on the row of flow equalizing pipes.

[0015] Preferably, baffles (such as L-shaped) are provided at multiple positions on the inner wall of the evaporator cylinder to force the evaporated gas to flow through the heat exchange tube bundle, strengthen the mixing of liquid and gas between the tube bundles, and at the same time reduce the risk of liquid droplets being carried into the gas-liquid separator by the gas flow.

[0016] Preferably, a gas-liquid separator is provided at the top of the evaporator. There are small liquid return holes at the bottom of the gas-liquid separator to guide the refrigerant along the axial flow direction of the cylinder, prevent liquid from being carried out with the evaporator outlet gas, and realize the management of the position where high-concentration refrigeration oil accumulates.

[0017] The beneficial effects of the present utility model are as follows:

[0018] After being processed by the refrigerant distributor, the refrigerant forms a two-phase mixture with a flow pattern of intermittent flow or annular flow, changing the Prandtl number of the pure liquid to a Prandtl number of the mixture close to the gas phase (taking R134a with a saturation temperature of 5°C as an example, the Prandtl number of the pure liquid is 3.77, the Prandtl number of the pure gas is 0.84, and the Prandtl number of the gas-liquid two-phase flow created by the distributor and the flow equalizing pipes / mixing orifice plates in the tube bundle is between 1.47 and 0.88), increasing the overall heat transfer coefficient by 20%-30%. Compared with traditional flooded and falling film evaporators, the flooded evaporator has significantly improved heat transfer performance;

[0019] When the gaseous refrigerant after heat exchange and evaporation is sucked out, it will carry a small amount of liquid refrigerant. When passing through the gas-liquid separator installed at the top of the evaporator cylinder, the liquid refrigerant will be re-separated and applied;

[0020] The created low Prandtl number mixture also significantly reduces its density (taking R134a with a saturation temperature of 5°C as an example, the density of the pure liquid is 1278.1 kg / m 3 , the density of the pure gas is 17.1 kg / m 3 , and the density of the gas-liquid two-phase flow created by the distributor and the flow equalizing pipes / mixing orifice plates in the tube bundle may be between 81.3 and 19.0). Under the condition of a certain refrigerant filling volume in the evaporator, the refrigerant filling amount can be significantly reduced by up to 30%-60%. The significant reduction in the refrigerant filling amount indirectly reduces carbon emissions and refrigerant consumption, and reduces the product cost by 15%-20% while ensuring the same refrigeration capacity;

[0021] The refrigerant is filled in an ∧-type all-round filling form, making the flow pattern of the refrigerant flow field more uniform and stable, and reducing the erosion hazard of the refrigerant to the evaporator tube bundle and internal structure;

[0022] The heat exchange tube bundle adopts a straight-through type, which saves materials compared with the traditional U-shaped tube bundle and reduces the product cost. Brief Description of the Drawings

[0023] Figure 1 This is a schematic structural diagram of a flooded evaporator of the present utility model.

[0024] Figure 2 It is Figure 1 a side view of.

[0025] Figure 3 It is a schematic assembly structure diagram of the refrigerant distributor.

[0026] Figure 4 It is a front view of the refrigerant distributor.

[0027] Figure 5 It is Figure 4 an A-A cross-sectional view of.

[0028] Figure 6 It is Figure 5 a B-B cross-sectional view of.

[0029] Figure 7 It is Figure 6 a partial enlarged view of.

[0030] Figure 8 It is Figure 2 a partial enlarged view of.

[0031] Figure 9 It is a schematic diagram of the position distribution of the flow equalizing pipe and the mixing orifice plate.

[0032] Wherein:

[0033] Evaporator cylinder body 1; refrigerant distributor 2; bottom plate 2.1; bottom plate hole 2.1.1; inner partition plate 2.2; inner partition plate with hole section 2.2.1; guide plate 2.3; acceleration plate 2.4; acceleration plate hole 2.4.1; deceleration plate 2.5; deceleration plate hole 2.5.1; end plate 2.6; guide partition plate 2.7; guide cavity 2.8; acceleration cavity 2.9; deceleration cavity 2.10; spacer block 2.11; heat exchange tube bundle 3; refrigerant gas-liquid separator 4; refrigerant inlet pipe 5; evaporator outlet gas pipe 6; tube sheet 7; heat exchange tube bundle support plate 8; left water chamber head 9; right water chamber head 10; chilled water outlet pipe 11; chilled water inlet pipe 12; intermediate partition plate 13; flow equalizing pipe 14; mixing orifice plate 15; gas baffle 16. Detailed Embodiment

[0034] See Figures 1-9, the utility model relates to a flooded evaporator, which comprises an evaporator cylinder body 1. A refrigerant distributor 2, a heat exchange tube bundle 3 and a refrigerant gas-liquid separator 4 are arranged in the evaporator cylinder body 1. The refrigerant distributor 2 is arranged at the bottom of the evaporator cylinder body 1, and the refrigerant gas-liquid separator 4 is arranged at the top of the evaporator cylinder body 1. The evaporator cylinder body 1 is provided with a refrigerant inlet pipe 5 corresponding to the refrigerant distributor 2, and the evaporator cylinder body 1 is provided with an evaporator outlet pipe 6 corresponding to the refrigerant gas-liquid separator 4. A plurality of heat exchange tube bundles 3 are arranged between the refrigerant distributor 2 and the refrigerant gas-liquid separator 4. The heat exchange tube bundles 3 are distributed in the lower half of the evaporator cylinder body 1, close to the refrigerant distributor. Both ends of the heat exchange tube bundle 3 are fixed by tube plates 7, and the middle part of the heat exchange tube bundle 3 is supported by a heat exchange tube bundle support plate 8. The tube plates 7 are welded and fixed on the left and right sides of the evaporator cylinder body 1. The left tube plate 7 is connected to a left water chamber head 9, and the right tube plate 7 is connected to a right water chamber head 10. The left water chamber head 9 is connected to a chilled water outlet pipe 11 and a chilled water inlet pipe 12. A middle partition plate 13 for guiding the fluid is arranged in the left water chamber head 9. The middle partition plate 13 divides the left water chamber head into two chambers arranged up and down. The upper chamber is the left water outlet chamber, and the lower chamber is the left water inlet chamber. The chilled water outlet pipe 11 and the chilled water inlet pipe 12 arranged up and down correspond to the two chambers respectively, so that the chilled water adopts the same-side lower-in and upper-out mode. The heat exchange tube bundle 3 communicated with the left water outlet chamber is used for discharging water, and the heat exchange tube bundle 3 communicated with the left water inlet chamber is used for inlet water.

[0035] The refrigerant distributor 2 is fixedly connected with the heat exchange tube bundle support plate through a clamp, and comprises a bottom plate 2.1, an inner partition plate 2.2, a flow guide plate 2.3, an acceleration plate 2.4, a deceleration plate 2.5, an end plate 2.6 and a flow guide partition plate 2.7. A bottom plate 2.1, an inner partition plate 2.2, a flow guide plate 2.3, an acceleration plate 2.4 and a deceleration plate 2.5 are sequentially arranged from bottom to top between two left and right end plates 2.6. A plurality of acceleration plate holes 2.4.1 are evenly distributed on the acceleration plate 2.4, and a plurality of deceleration plate holes 2.5.1 are evenly distributed on the deceleration plate 2.5. The inner partition plate 2.2, the flow guide plate 2.3 and the two end plates 2.6 form a flow guide cavity 2.8. The flow guide plate 2.3, the acceleration plate 2.4 and the two end plates form an acceleration cavity 2.9. The flow guide cavity 2.8 and the acceleration cavity 2.9 are communicated. The acceleration plate 2.4, the deceleration plate 2.5 and one end plate 2.6 form a deceleration cavity 2.10.

[0036] An equalizing tube 14 is further arranged in the evaporator cylinder body 1. The equalizing tube 14 is arranged at the blank of the heat exchange tube area in the evaporator cylinder body 1. The equalizing tube 14 is parallel to the heat exchange tube bundle 2, so as to further mix the gas evaporated in the tube bundle with the remaining liquid, further create a low Prandtl number, and strengthen the flow and heat transfer enhancement. Such as Figure 2 , Figure 8 and Figure 9As shown in the figure, a row of flow equalizing pipes 14 is provided in the middle of the heat exchange tube area inside the evaporator cylinder body 1. The solid flow equalizing pipes 14 are welded to the tube sheets 7 at both ends, and the mixing orifice plate 15 is placed on the row of flow equalizing pipes 14.

[0037] As Figure 8 shown, at an appropriate position on the inner wall of the evaporator cylinder body 1 along the length direction of the evaporator cylinder body, a gas baffle plate 16 is provided, and the gas baffle plate 16 is fixedly welded to the tube bundle support plate 8 and the evaporator cylinder body 1.

[0038] There are liquid return small holes at the bottom of the gas-liquid separator to guide the refrigerant to flow along the axial direction of the cylinder body, prevent liquid from being carried out with the evaporator outlet gas, and realize the management of the position where high-concentration refrigeration oil accumulates.

[0039] The deceleration chamber 2.10 is open, enabling the distributor to have an oil concentration management function. As Figure 4 and Figure 5 shown, the deceleration chamber 2.10 is composed of an acceleration plate 2.4, a deceleration plate 2.5 and an end plate 2.6 on the right side to form the deceleration chamber 2.10. There is a gap between the end plate 2.6 on the left side and the deceleration plate 2.5. Through this design, a high oil concentration is accumulated on the side far from the evaporator outlet, facilitating the recovery of refrigeration oil from the evaporator.

[0040] The bottom plate 2.1, the inner partition plate 2.2 and the flow guiding partition plates 2.7 arranged on the left and right form a feed chamber. The two flow guiding partition plates 2.7 are arranged inside the end plates 2.6. A bottom plate hole 2.1.1 is provided at the bottom of the feed chamber formed by the bottom plate 2.1, and the bottom plate hole 2.1.1 is used to connect the refrigerant liquid inlet pipe. An inner partition plate perforated section 2.2.1 is provided at the top of the feed chamber formed by the inner partition plate 2.2. Since the flow velocity and impact pressure of the newly entered refrigerant are very high, the refrigerant entering the feed chamber from the refrigerant liquid inlet pipe passes through the inner partition plate perforated section 2.2.1 under the constraint of the flow guiding partition plates 2.7 on the left and right sides. Applying Bernoulli's equation principle: , the velocity of the fluid passing through the orifice is inversely proportional to the size of the orifice. The increase in velocity causes the pressure of the fluid at this place to decrease and the height to decrease. By reducing the pressure and height, the erosion and deformation effects of the refrigerant on the flow guiding plate 7 in the acceleration chamber are reduced, and the service life of the distributor is prolonged.

[0041] One end of the flow guide plate 2.3 is welded to the end plate 2.6 on the corresponding side, and there is a fluid turning gap between the other end and the end plate 2.6 on the corresponding side, so that the flow guide chambers 2.8 and the acceleration chamber 2.9 arranged up and down are conducted. The fluid in the flow guide chamber turns and flows into the acceleration chamber. The flow guide chambers 2.8 and the acceleration chambers 2.9 are distributed at unequal intervals, and the chamber spacing decreases sequentially from bottom to top. The change from 18.5 mm to 15.7 mm makes the refrigerant flow rate increase, enhancing the engineering turbulence effect and achieving the complete mixing of the velocities of the gas-liquid two-phase media. By reasonably calculating and setting the plate gap (chamber spacing) between the flow guide chamber and the acceleration chamber, the flow guide chamber realizes intermittent flow or annular flow, and the fluid is evenly distributed to each acceleration plate hole, so that the acceleration chamber maintains a certain pressure drop (which should not be less than 100 KPA), and the fluid is ejected from the acceleration plate hole evenly and at high speed. According to the Reynolds number formula , ( Fluid density, V average flow velocity, D hole diameter, Fluid dynamic viscosity), the Reynolds number is related to the macroscopic flow velocity, fluid geometric structure and fluid physical properties. This chamber increases the turbulent flow of the two-phase body, achieving the purpose of making the refrigerant mix more evenly and forming a low-density two-phase mixture with a Prandtl number much lower than that of the liquid phase.

[0042] All the plate parts of the refrigerant distributor need to have a smooth surface and burrs removed. The bottom plate 2.1 is in an arc shape coaxial with the evaporator cylinder and can be completely attached to the bottom of the evaporator cylinder. The inner partition plate 2.2, the flow guide plate 2.3, the acceleration plate 2.4 and the deceleration plate 2.5 are all in a ∧ shape, and the distributor as a whole is triangular, having a stable characteristic. The inner partition plate 2.2, the flow guide plate 2.3, the acceleration plate 2.4 and the deceleration plate 2.5 are all formed by one-piece bending, and the bending angles are kept consistent. The bending angle can be 45°, 60°, 90° or 120°. The refrigerant is filled in a fan-shaped omnidirectional filling form, making the flow form of the refrigerant flow field more uniform and stable, and reducing the erosion hazard of the refrigerant to the evaporator tube bundle and the internal structure.

[0043] According to the usage conditions and the requirements of the process processing form, the shapes of the bottom plate holes 2.1.1, the acceleration plate holes 2.4.1 and the deceleration plate holes 2.5.1 can be circular, square, diamond-shaped, hexagonal, oval, etc., and the total cross-sectional area of the corresponding hole diameters satisfies . Among them, the acceleration plate holes 2.4.1 and the deceleration plate holes 2.5.1 are arranged in a staggered manner, that is, the projections of the acceleration plate holes 2.4.1 and the deceleration plate holes 2.5.1 on the bottom plate 2.1 do not overlap, preventing the refrigerant from directly running away from the deceleration plate holes 2.5.1 after being accelerated by the acceleration chamber 2.8 and the acceleration plate 2.4. The deceleration plate holes 2.5.1 play a role in increasing resistance and reducing the injection force.

[0044] The spoiler 2.5 is in close contact with the heat exchange tube support plate inside the evaporator cylinder. The refrigerant entering the distributor from the bottom plate hole 2.1.1 is evenly distributed by the distributor and then comes into full area contact with the heat exchange tubes inside the evaporator cylinder for efficient heat exchange.

[0045] There are also spacer blocks 2.10 between the inner partition plate 2.2 and the deflector plate 2.3, between the deflector plate 2.3 and the acceleration plate 2.4, and between the acceleration plate 2.4 and the spoiler 2.5. The adjacent plate members are supported by the spacer blocks so that each chamber can obtain sufficient rigidity.

[0046] The refrigerant enters the refrigerant distributor from the bottom plate hole 2.1.1, passes through the perforated section 2.2.1 of the inner partition plate under the constraint of the left and right deflector partitions 2.7, and sequentially enters the deflector chamber 2.8 and the acceleration chamber 2.9. After being deflected and accelerated to increase the turbulence, it passes through the acceleration plate 2.4 and the acceleration plate hole 2.4.1 to achieve uniform mixing of gas and liquid at the same speed, creating a low Prandtl number medium with a Prandtl number much lower than that of the liquid phase and as close as possible to that of the gas phase, which can greatly improve the heat transfer performance. Under the condition of ensuring the same heat exchange amount, the heat exchange efficiency is increased; then it flows through the deceleration chamber 2.10 and stably flows out from the spoiler hole 2.5.1. The refrigerant passing through the acceleration chamber 2.9 and the acceleration plate 2.4 in the early stage has a very high flow rate. Directly flowing into the evaporator cylinder and exchanging heat with the heat exchange tubes is likely to cause the problem of erosion of the heat exchange tubes due to excessive flow rate. At the same time, the excessive flow rate of the refrigerant will lead to insufficient heat exchange and cause waste. The application of the deceleration chamber 2.10 and the spoiler 2.5 in the low Prandtl number distributor enables the refrigerant to flow out evenly and stably, improves the heat exchange performance of the product, and enables the efficient utilization of the refrigerant.

[0047] The chilled water entering from the chilled water inlet pipe 12 passes through the heat exchange tubes 3 and flows through the evaporator cylinder 1, and conducts full heat exchange with the refrigerant that enters through the refrigerant distributor and is evenly split and flows out. Before the refrigerant exchanges heat with the heat exchange tubes, it is processed by the distributor to form a gas-liquid two-phase mixture with the same moving speed and low density. The mixture is pushed by the gas phase to drive the liquid phase, greatly increasing the flow rate of the refrigerant. Compared with the traditional refrigerant, the fluidity of this gas-liquid two-phase mixture inside the heat exchange tubes is much greater than the original laminar flow form of gas-liquid two-phase separation. According to the mixture density volume formula, the low density of this mixture makes the thickness of the condensation film on the outer surface of the tubes relatively thin, changing the heat exchange form on the tube surface from the traditional laminar falling film to turbulent falling film. The thin film turbulent falling film evaporation form increases the total heat transfer coefficient by 20%-30% while ensuring that the heat exchange area remains unchanged. Compared with the traditional evaporator, the flooded evaporator greatly improves the heat transfer performance.

[0048] When the gaseous refrigerant after heat exchange and evaporation is sucked out, it will carry a small amount of liquid refrigerant. When passing through the gas-liquid separator installed on the top of the evaporator cylinder, the liquid refrigerant will be re-separated and applied.

[0049] The heat exchange tube bundle 3 adopts a direct-through type, and both ends of the heat exchange tube bundle 3 are respectively communicated with the left water chamber and the right water chamber, saving materials compared with the traditional U-shaped tube bundle and reducing the product cost.

[0050] The gas-liquid two-phase mixture formed by the refrigerant after being processed by the distributor, according to the volume formula of the mixture (where is the average density of the gas-liquid two-phase mixture, is the total mass of the two-phase mixture, is the total volume of the two-phase mixture), the intermolecular force of the gas is weak and the molecular arrangement is sparse. Therefore, under the condition of the same filling volume of the gas-liquid two-phase mixed refrigerant, that is, when the volume of the evaporator cylinder is certain, the refrigerant filling amount can be reduced by up to 30%-50%, realizing green energy conservation, indirectly reducing carbon emissions and refrigerant consumption, and reducing the product operation cost by 15%-20% while ensuring the refrigeration capacity remains unchanged.

[0051] The flow route of the chilled water: chilled water inlet pipe → left water inlet chamber → heat exchange tube bundle for water inlet → right water chamber → heat exchange tube bundle for water outlet → left water outlet chamber → chilled water outlet pipe;

[0052] The flow route of the refrigerant: refrigerant inlet pipe → refrigerant distributor → refrigerant gas-liquid separator → evaporator outlet pipe.

[0053] The refrigerant turbulently mixes through the refrigerant distributor and then flows out in the form of a gas-liquid two-phase mixture along the flow field direction within the ∧-type angle range, exchanges heat with the chilled water entering the heat exchange tube bundle. The gas-liquid two-phase mixture forms a turbulent film on the surface of the heat exchange tube bundle, realizing a significant increase in the evaporation heat transfer coefficient outside the tube. The evaporated refrigerant may carry a small amount of liquid refrigerant, which is separated by the refrigerant gas-liquid separator. The liquid refrigerant is collected, and the evaporated gaseous refrigerant is discharged from the evaporator outlet pipe and enters the cycle.

[0054] In addition to the above embodiments, the present utility model also includes other implementation manners. Any technical solutions formed by equivalent transformation or equivalent substitution shall fall within the protection scope of the claims of the present utility model.

Claims

1. A flooded evaporator, characterized in that: The evaporator cylinder comprises an evaporator cylinder, wherein a refrigerant distributor, a heat exchange tube bundle and a refrigerant gas-liquid separator are sequentially arranged in the evaporator cylinder from bottom to top, the refrigerant distributor comprises a bottom plate, an inner partition, a guide plate, an acceleration plate, a deceleration plate and an end plate, and between two end plates arranged on the left and right sides, a bottom plate, an inner partition, a guide plate, an acceleration plate and a deceleration plate are sequentially arranged from bottom to top, the bottom plate is in an arc shape coaxial with the evaporator cylinder, and is completely fitted to the bottom of the evaporator cylinder, the deceleration plate is fixedly connected to the heat exchange tube bundle support plate through a clamp, a plurality of acceleration plate holes are evenly distributed on the acceleration plate, a plurality of deceleration plate holes are evenly distributed on the deceleration plate, the inner partition, the guide plate and the two end plates form a guide cavity, the guide plate, the acceleration plate and the two end plates form an acceleration cavity, the guide cavity and the acceleration cavity are connected, the acceleration plate, the deceleration plate and an end plate form a deceleration cavity, the inner partition, the guide plate, the acceleration plate and the deceleration plate are all in a ∧ shape, and are formed by integral bending, and the bending angle is consistent.

2. A flooded evaporator according to claim 1, characterized in that: One end of the guide plate is welded to the end plate on the corresponding side, and the other end leaves a fluid turning gap with the end plate on the corresponding side, so that the acceleration chamber and the guide chamber arranged above and below are connected, and the fluid in the guide chamber turns and flows to the acceleration chamber.

3. A flooded evaporator according to claim 1, characterized in that: The guide cavity and the acceleration cavity are distributed at unequal intervals, and the cavity intervals between the two decrease from bottom to top.

4. A flooded evaporator according to claim 1, characterized in that: The bending angles of the inner partition, guide plate, acceleration plate and deceleration plate are 45°, 60°, 90° or 120°.

5. A flooded evaporator according to claim 1, characterized in that: The holes of the acceleration plate and the holes of the deceleration plate are staggered.

6. A flooded evaporator according to claim 1, characterized in that: The two ends of the heat exchange tube bundle are fixed by tube sheets, and the middle part of the heat exchange tube bundle is supported by a heat exchange tube bundle support plate. The tube sheets are welded and fixed to the left and right sides of the evaporator cylinder. The tube sheet on the left side is connected to the left water chamber head, and the tube sheet on the right side is connected to the right water chamber head. The left water chamber head is connected to the chilled water outlet pipe and the chilled water inlet pipe. A middle partition for guiding the fluid is provided in the left water chamber head. The middle partition divides the left water chamber head into two upper and lower chambers. The chilled water outlet pipe and the chilled water inlet pipe are provided in the upper and lower parts, which correspond to the two chambers one by one respectively.

7. A flooded evaporator according to claim 1, characterized in that: The evaporator cylinder is provided with a refrigerant liquid inlet pipe corresponding to the refrigerant distributor, and the evaporator cylinder is provided with an evaporator gas outlet pipe corresponding to the refrigerant gas-liquid separator.

8. The flooded evaporator according to claim 1, characterized in that: The evaporator cylinder is also provided with a flow balancing tube, which is arranged in a blank area of ​​the heat exchange tube area in the evaporator cylinder, and is parallel to the heat exchange tube bundle.

9. A flooded evaporator according to claim 8, characterized in that: A row of flow balancing tubes is arranged in the middle of the heat exchange tube area in the evaporator cylinder. Both ends of the solid flow balancing tubes are welded to the tube sheet, and the mixing orifice plates are placed on the rows of flow balancing tubes.

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