Tubular evaporator and flow distribution device

Abstract

The present invention relates to a tubular evaporator and a flow distribution device, wherein the flow distribution device comprises a main body with an arched curved surface; a first water flow area and a second water flow area are distributed on the main body; a plurality of first water flow holes are distributed in the first water flow area, and a plurality of second water flow holes are distributed in the second water flow area, wherein the aperture of the first water flow hole is smaller than the aperture of the second water flow hole; the size of the second water flow hole increases from the middle of the main body to the outside, so as to distribute the flow of the liquid flowing through the flow distribution device and make it flow evenly. A flow distribution device is added to the inner side of the lower head of the heat exchanger to realize the uniform flow of the coolant under a complex flow field, optimize the heat transfer efficiency, and strengthen the rigidity and stability of the internal components under the action of fluid excitation, so as to realize the functions of stirring, flow distribution, optimizing heat transfer, and supporting. By setting the non-uniform water flow holes of the flow distribution device, the flow of the coolant inside the evaporator is optimized to avoid damage to the heat transfer tubes.

Description

Technical Field

[0001] The present invention relates to the field of evaporators, and more particularly to a tubular evaporator and a flow distribution device. Background Art

[0002] In the compact spiral tube evaporator, a fluid flow channel is formed by the inner and outer sleeves of the tube bundle and the evaporator cylinder.

[0003] The high-temperature coolant from the reactor enters the upper rising annular cavity between the outer sleeve of the tube bundle and the container cylinder through a short sleeve. After reaching the upper chamber, it turns back and flows downward, heating the fluid in the heat transfer tube to become superheated steam, which is then collected at the upper head to drive the turbine to do work.

[0004] The cooled high-temperature fluid continues to flow downward, turns back at the lower head of the container, and then flows upward through the lower rising chamber between the outer sleeve of the tube bundle and the container, enters the main pump from the outlet, and the fluid pressurized by the main pump enters the pressure vessel and returns to the core for reheating.

[0005] However, due to the complex structure and uneven flow resistance in the lower head area of ​​the steam generator, the general heat exchanger design does not add relevant flow field stirring components to achieve the purpose of optimizing the flow. Usually, the fluid flow at the lower head of the heat exchanger will flow along the area with small flow resistance in an unexpected path, causing the fluid to bypass the lower chamber and directly enter the lower rising section, causing uneven flow in the lower head and a dead water area, causing unexpected flow of the coolant and uneven heat transfer.

[0006] The once-through steam generator turbulent zone is not equipped with a flow distribution device, which brings the following disadvantages:

[0007] 1. Due to the complex structure and uneven flow resistance in the lower head area of ​​the steam generator, the coolant will flow along the area with small flow resistance in an unexpected path, bypassing the lower chamber, causing uneven flow and forming a local dead water area.

[0008] 2. Uneven coolant flow will further lead to uneven heat transfer and affect the efficiency of the heat exchanger.

[0009] 3. Failure to provide a lower flow distribution device will weaken the overall rigidity of the sleeve structure and result in poor stability under fluid excitation. Summary of the invention

[0010] The technical problem to be solved by the present invention is to provide a tubular evaporator and a flow distribution device in view of the above-mentioned defects of the prior art.

[0011] The technical solution adopted by the present invention to solve the technical problem is: constructing a flow distribution device, including a main body with an arched curved surface;

[0012] The main body is provided with a first water flow area and a second water flow area;

[0013] The first water flow area is distributed with a plurality of first water flow holes, the second water flow area is distributed with a plurality of second water flow holes, and the aperture of the first water flow hole is smaller than the aperture of the second water flow hole;

[0014] The size of the second water flow holes increases gradually from the middle of the body to the outside, so as to distribute the flow of the liquid passing through the flow distribution device and make it flow evenly.

[0015] Preferably, a lock hole is provided at the center of the body for the locking piece to pass through and be locked and fixed.

[0016] Preferably, a plurality of rows of the second water flow holes are provided on the main body along the circumferential direction, and the apertures of the water flow holes in each row are the same.

[0017] Preferably, the diameters of the water flow holes in each row increase from the inside to the outside.

[0018] Preferably, the body is hemispherical or bowl-shaped.

[0019] Preferably, the outer ring of the body is provided with a positioning groove.

[0020] Preferably, a plurality of the positioning grooves are distributed on the outer ring of the body, and the positioning grooves are evenly spaced along the outer ring of the body.

[0021] Preferably, the outer ring of the body is provided with a positioning flange protruding outwards.

[0022] Preferably, the positioning groove is arranged on the positioning flange.

[0023] A tubular evaporator comprises an inner tube bundle, an outer tube bundle and a cylinder which are sequentially sleeved from the inside to the outside, an upper rising annular cavity and a lower rising annular cavity which are isolated from each other are formed between the cylinder and the outer tube bundle, a descending channel is arranged between the inner tube bundle and the outer tube bundle, the upper and lower ends of the descending channel are respectively connected to the upper rising annular cavity and the lower rising annular cavity, a lower end of the cylinder is provided with a lower head, a sleeve is provided on the side wall of the cylinder, an inlet and an outlet which are respectively connected to the upper rising annular cavity and the lower rising annular cavity are formed in the sleeve, and the flow distribution device is also included, the flow distribution device is arranged at the lower end of the outer tube bundle, the body is arched downward, and the second water flow hole is close to the side where the sleeve is located, so as to distribute the water to the descending channel.

[0024] The implementation of the tubular evaporator and flow distribution device of the present invention has the following beneficial effects: a flow distribution device is added to the inner side of the lower head of the heat exchanger to achieve uniform flow of coolant under complex flow fields, optimize heat transfer efficiency, and strengthen the rigidity and stability of internal components under fluid excitation to achieve stirring, flow distribution, optimized heat transfer, support, etc. The setting of non-uniform water flow holes on the flow distribution device optimizes the flow of coolant inside the evaporator, eliminates dead water areas formed by flow stratification, optimizes heat transfer, reduces flow velocity in turbulent areas, and avoids damage to heat transfer tubes caused by fluid elastic instability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 is a schematic structural diagram of a tubular evaporator in an embodiment of the present invention when a flow distribution device is installed;

[0027] Figure 2 yes Figure 1 Schematic diagram of the top view of the flow distribution device. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a tubular evaporator in a preferred embodiment of the present invention comprises an inner tube bundle 1, an outer tube bundle 2, and a cylinder 3 which are sequentially arranged from the inside to the outside, and a lower end of the cylinder 3 is provided with a lower head 4.

[0030] An upper rising annular cavity A and a lower rising annular cavity B which are isolated from each other are formed between the cylinder 3 and the outer tube bundle 2. A descending channel C is provided between the inner tube bundle 1 and the outer tube bundle 2. The upper and lower ends of the descending channel C are connected to the upper rising annular cavity A and the lower rising annular cavity B respectively.

[0031] A sleeve 5 is provided on the side wall of the cylinder 3, and an inlet D and an outlet E are formed in the sleeve 5, which are connected to the upper rising annular cavity A and the lower rising annular cavity B respectively. The high-temperature liquid flows into the upper rising annular cavity A through the inlet D, and then flows into the descending channel C.

[0032] The tube evaporator further comprises a flow distribution device 6, which is arranged at the lower end of the outer tube bundle 2. The flow distribution device 6 comprises a body 61 in the shape of an arched curved surface, and the body 61 arches downward.

[0033] The main body 61 is provided with a first water flow area 61a and a second water flow area 61b. The first water flow area 61a is provided with a plurality of first water flow holes 611 , and the second water flow area 61b is provided with a plurality of second water flow holes 612 . The aperture of the first water flow hole 611 is smaller than that of the second water flow hole 612 .

[0034] The aperture size of the second water flow hole 612 increases from the middle of the main body 61 to the outside. Since the flow path close to the sleeve 5 is short and the flow resistance is small, in order to increase the flow away from the outlet E of the sleeve 5, the second water flow hole 612 is away from the side where the sleeve 5 is located, so that the liquid flowing through the flow distribution device 6 can be distributed and flowed evenly, and then the liquid flowing down the descending channel C can be distributed and flowed through the water flow hole.

[0035] A flow distribution device 6 is added to the inner side of the lower head 4 of the heat exchanger to achieve uniform flow of the coolant under complex flow fields, optimize heat transfer efficiency, and strengthen the rigidity and stability of the internal components under fluid excitation to achieve stirring, flow distribution, optimized heat transfer, support, etc. The setting of non-uniform water flow holes on the flow distribution device 6 optimizes the flow of coolant inside the evaporator, eliminates the "dead water zone" formed by flow stratification, optimizes heat transfer, reduces the flow velocity in the turbulent zone, and avoids the damage of the heat transfer tube caused by fluid elastic instability.

[0036] After adding the flow distribution device 6, the local flow resistance is adjusted by the size of the openings on the distribution device, wherein the aperture of the water flow hole is obtained based on hydraulic calculations, so that the overall flow resistance of the fluid flowing from the lower head 4 to the outlet E is equivalent, and the local resistance is equivalent to the sum of the resistance along the way, so that the flow at the lower head 4 is uniform, thereby eliminating dead water areas and optimizing heat transfer.

[0037] Specifically in the heat exchanger structure, since the area closer to the outlet E has a smaller resistance along the way and the liquid path is a curve, the aperture of the water flow holes in the middle is set smaller to increase the local resistance. The area farther from the outlet E has a larger resistance along the way, so the aperture of the water flow holes in the outer circle is set larger to reduce the local resistance, so that the resistance from different areas to the outlet E is equivalent, thereby optimizing the flow.

[0038] The flow distribution device 6 is suitable for ellipsoidal flow distribution in complex flow fields, and can also be used for flow distribution, turbulence, heat transfer optimization and support in industrial fields such as petrochemicals and water conservancy.

[0039] Preferably, the body 61 is hemispherical or bowl-shaped, satisfying the characteristics of streamlined flow of liquid.

[0040] In some embodiments, a plurality of rows of second water flow holes 612 are disposed on the body 61 along the circumferential direction, and the apertures of each row of water flow holes are the same, so that the apertures of paths with the same distance are the same.

[0041] Furthermore, the diameters of the water flow holes in each row increase from the inside to the outside, so that the flow rate in the outer circle with large resistance increases.

[0042] In some embodiments, a locking hole 613 is provided at the center of the body 61 for the locking piece 62 to pass through and lock and fix. Preferably, the flow distribution device 6 can be fixed to the lower head 4 through the locking piece 62 to improve the stability of the flow distribution device 6.

[0043] Furthermore, the outer ring of the body 61 is provided with a positioning groove 614 , and the positioning groove 614 can be engaged with the outer tube bundle 2 to prevent the flow distribution device 6 from rotating and shaking.

[0044] Preferably, a plurality of positioning grooves 614 are distributed on the outer ring of the body 61 , and the positioning grooves 614 are evenly spaced along the outer ring of the body 61 so as to be engaged with the outer tube bundle 2 in the circumferential direction to improve stability.

[0045] In this embodiment, the outer ring of the body 61 is provided with a positioning flange 615 protruding outward, and the positioning groove 614 is provided on the positioning flange 615 to facilitate the locking of the positioning groove 614 .

[0046] The lower locking piece 62 of the flow distribution device 6 is connected to the lower end cap 4 of the container to enhance stability, and after the positioning groove 614 of the flow distribution device 6 is engaged with the outer tube bundle 2, it is assembled with the lower part of the sleeve of the outer tube bundle 2 to form an integral structure, thereby enhancing the rigidity and stability of the outer tube bundle 2 and avoiding displacement and deformation of the outer tube bundle 2 under fluid excitation. In addition, since the flow distribution device 6 is installed at the lower part of the sleeve of the outer tube bundle 2, the rigidity and stability of the sleeve of the outer tube bundle 2 are enhanced.

[0047] Due to the setting of the flow distribution device 6, the flow velocity in the lower head 4 area is reduced, so that the fluid flow velocity at the tube bundle is lower than the critical flow velocity for triggering flow-induced vibration, thereby avoiding damage to the tube caused by flow-elastic instability.

[0048] The present invention has the following advantages:

[0049] 1. Through the design of non-uniform water flow holes, the final flow and heat transfer balance can be achieved in complex and smooth flow.

[0050] 2. Make the fluid inside the steam generator flow evenly and optimize the heat transfer efficiency of the evaporator.

[0051] 3. Make the fluid inside the steam generator flow along the expected path and eliminate the dead water area inside the evaporator.

[0052] 4. By adding a locking piece 62 to the flow distribution device 6, deformation and displacement under fluid excitation are avoided, and the multifunctional structure and the sleeve of the outer tube bundle 2 are combined into an integral structure, thereby enhancing the overall rigidity and structural stability.

[0053] 5. Reduce the local flow velocity of the flow field and avoid flow-induced vibration of the tube bundle.

[0054] It can be understood that the above-mentioned technical features can be used in any combination without limitation.

[0055] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A flow distribution device, characterized in that: A body (61) comprising an arched curved surface; A first water flow area (61a) and a second water flow area (61b) are distributed on the main body (61); The first water flow area (61a) is distributed with a plurality of first water flow holes (611), the second water flow area (61b) is distributed with a plurality of second water flow holes (612), and the aperture of the first water flow holes (611) is smaller than the aperture of the second water flow holes (612); The size of the second water flow holes (612) gradually increases from the middle of the body (61) toward the outside, so as to distribute the flow of the liquid passing through the flow distribution device (6) so that the liquid flows evenly; The flow distribution device is applied to a tubular evaporator, the tubular evaporator comprising an inner tube bundle (1), an outer tube bundle (2), and a cylinder (3) which are sequentially sleeved from the inside to the outside, an upper rising annular cavity (A) and a lower rising annular cavity (B) which are isolated from each other are formed between the cylinder (3) and the outer tube bundle (2), a descending channel (C) is provided between the inner tube bundle (1) and the outer tube bundle (2), the upper and lower ends of the descending channel (C) are respectively connected to the upper rising annular cavity (A) and the lower rising annular cavity (B), and a lower end cap (4) is provided at the lower end of the cylinder (3). A sleeve (5) is provided on the side wall of the cylinder (3), and an inlet (D) and an outlet (E) are formed in the sleeve (5) and are respectively connected to the upper ascending annular cavity (A) and the lower ascending annular cavity (B). The tube evaporator further comprises the flow distribution device (6) described above, and the flow distribution device (6) is arranged at the lower end of the outer tube bundle (2). The body (61) is arched downward, and the second water flow hole (612) is away from the side where the sleeve (5) is located, so as to distribute the liquid flowing down the descending channel (C) and then flow through the water flow hole.

2. The flow distribution device according to claim 1, characterized in that: The center of the body (61) is provided with a lock hole (613) for the locking piece (62) to pass through and be locked and fixed.

3. The flow distribution device according to claim 1, characterized in that: A plurality of rows of the second water flow holes (612) are provided on the body (61) along the circumferential direction, and the hole diameters of the water flow holes in each row are the same.

4. The flow distribution device according to claim 3, characterized in that: The diameters of the water flow holes in each row increase from the inside to the outside.

5. The flow distribution device according to any one of claims 1 to 4, characterized in that: The body (61) is hemispherical or bowl-shaped.

6. The flow distribution device according to claim 1, characterized in that: The outer ring of the body (61) is provided with a positioning groove (614).

7. The flow distribution device according to claim 6, characterized in that: A plurality of positioning grooves (614) are distributed on the outer ring of the body (61), and the positioning grooves (614) are evenly spaced along the outer ring of the body (61).

8. The flow distribution device according to claim 6 or 7, characterized in that: The outer ring of the body (61) is provided with a positioning flange (615) protruding outwards.

9. The flow distribution device according to claim 8, characterized in that: The positioning groove (614) is arranged on the positioning flange (615).

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