阅读说明：本技术 一种非圆形截面双管程螺旋式换热器管束结构 (Non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure ) 是由 张小波 郭雅琼 韩健 张东 杨军 唐卉 张福君 国金莲 刘博� 章岱超 李凤梅 于 2021-07-14 设计创作，主要内容包括：一种非圆形截面双管程螺旋式换热器管束结构,涉及螺旋式换热器领域。本发明是为了解决如何在极其有限的空间内达到最大的换热面积,同时满足管内水动力和热力过程的问题。本发明所述的一种非圆形截面双管程螺旋式换热器管束结构包括管板、外壳、换热器管束、多片隔板和多组拉杆定距管；所述的换热器管束的两端均插入到管板上,构成双管程螺旋式管束结构；所述的换热器管束的横截面为非圆形结构；多片隔板上下并列设置并套装在换热器管束上,相邻的两片隔板之间设置有一组拉杆定距管；所述的外壳套在换热器管束外。本发明主要用于铅铋堆主容器中蒸发器的换热。(A non-circular section double-tube-pass spiral heat exchanger tube bundle structure relates to the field of spiral heat exchangers. The invention aims to solve the problem of how to reach the maximum heat exchange area in an extremely limited space and simultaneously meet the requirements of hydrodynamic and thermodynamic processes in a pipe. The invention relates to a non-circular section double-tube-pass spiral heat exchanger tube bundle structure which comprises a tube plate, a shell, a heat exchanger tube bundle, a plurality of partition plates and a plurality of groups of pull rod distance tubes, wherein the shell is provided with a plurality of groups of pull rod distance tubes; both ends of the heat exchanger tube bundle are inserted into the tube plates to form a double-tube-pass spiral tube bundle structure; the cross section of the heat exchanger tube bundle is of a non-circular structure; a plurality of partition plates are arranged in parallel up and down and sleeved on the heat exchanger tube bundle, and a group of pull rod distance pipes are arranged between every two adjacent partition plates; the shell is sleeved outside the heat exchanger tube bundle. The invention is mainly used for heat exchange of the evaporator in the lead bismuth stack main container.)

1. The utility model provides a two tube side spiral heat exchanger tube bank structures of non-circular cross-section which characterized in that: the heat exchanger comprises a tube plate (1), a shell (2), a heat exchanger tube bundle (3), a plurality of partition plates and a plurality of groups of pull rod spacing tubes (6);

both ends of the heat exchanger tube bundle (3) are inserted into the tube plate (1) to form a double-tube-pass spiral tube bundle structure; the cross section of the heat exchanger tube bundle (3) is of a non-circular structure;

a plurality of partition plates are arranged in parallel up and down and sleeved on the heat exchanger tube bundle (3), and a group of pull rod distance tubes (6) are arranged between two adjacent partition plates; the shell (2) is sleeved outside the heat exchanger tube bundle (3).

2. A non-circular cross-section, double-tube-pass, spiral heat exchanger tube bundle structure according to claim 1, wherein:

the heat exchanger tube bundle (3) comprises a plurality of central straight tube sections (3-1), a plurality of end bending sections (3-2), a coil tube section (3-3) and a plurality of coil leading-out straight tube sections (3-4), one end of the central straight tube section (3-1) is led out from the middle of the tube plate (1) and is vertically arranged, the other end of the central straight tube section (3-1) is fixedly connected with one end of the end bending sections (3-2), the other end of the end bending sections (3-2) is connected with one end of the coil tube section (3-3), the other end of the coil tube section (3-3) is connected with one end of the coil leading-out straight tube section (3-4), and the other end of the coil leading-out straight tube section (3-4) is vertically inserted into the tube plate (1);

the coil pipe section (3-3) and the coil pipe leading-out straight pipe sections (3-4) surround the central straight pipe sections (3-1).

3. A non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure according to claim 2, characterized in that:

the plurality of partition plates are divided into a plurality of inner partition plates (4) and a plurality of outer partition plates (5); the inner baffles (4) are arranged in parallel up and down and are sleeved on the central straight pipe sections (3-1) in the surrounding area of the coil pipe sections (3-3); the plurality of outer partition plates (5) are arranged in parallel up and down and are sleeved on the plurality of central straight pipe sections (3-1) and the plurality of coil leading-out straight pipe sections (3-4).

4. A non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure according to claim 3, wherein: an inner baffle plate (4) is arranged on the central straight pipe section (3-1) close to the connection part of the central straight pipe section (3-1) and the end bending section (3-2); an outer partition plate (5) is arranged on the coil leading-out straight pipe section (3-4) and the central straight pipe section (3-1) close to the joint of the coil leading-out straight pipe section (3-4) and the coil section (3-3).

5. A non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure according to claim 4, characterized in that: the central straight pipe section (3-1), the end bending section (3-2), the coil pipe section (3-3) and the coil leading-out straight pipe section (3-4) are integrally formed.

6. A non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure according to claim 5, characterized in that: a plurality of central straight pipe sections (3-1) of the heat exchanger pipe bundle (3) are arranged on the pipe plate (1) in an array form; the coil pipe section (3-3) is formed by spirally winding a plurality of heat exchange pipes around a plurality of central straight pipe sections (3-1) along the axial direction of the central straight pipe sections (3-1), and at least one layer of coil pipe section (3-3) formed by the heat exchanger pipe bundle (3); the straight pipe sections (3-4) led out by the plurality of coil pipes are divided into two groups and distributed on two sides of the central straight pipe sections (3-1).

7. A non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure according to claim 6, characterized in that: the cross section of the coil section (3-3) coiled by the heat exchanger tube bundle (3) is oval, racetrack-shaped or rectangular.

8. A non-circular cross-section, double-tube-pass, spiral heat exchanger tube bundle structure according to claim 7, wherein: when the coil pipe sections (3-3) formed by the heat exchanger pipe bundle (3) are multilayer, cross-flow arrangement is adopted between two adjacent layers of coil pipe sections (3-3).

9. A non-circular cross-section, double-tube-pass, spiral heat exchanger tube bundle structure according to any one of claims 1 to 8, wherein: the straight pipe section structure is characterized by further comprising a plurality of sealing sleeves (7), wherein the plurality of sealing sleeves (7) are sleeved outside the central straight pipe sections (3-1), one sealing sleeve (7) is arranged between two adjacent inner baffles (4), and a closed space is formed between the two adjacent inner baffles (4) and the sealing sleeve (7); a sealing sleeve (7) is arranged between two adjacent outer partition plates (5), and a closed space is formed between the two adjacent outer partition plates (5) and the sealing sleeve (7).

Technical Field

The invention relates to the field of spiral heat exchangers, in particular to a tube bundle structure of a spiral heat exchanger with a double tube pass and a non-circular section.

Background

The development of a novel nuclear energy system is a fundamental way to solve the problem of nuclear energy safety. Compared with a large nuclear power station, the nuclear power small-scale reactor has the advantages of flexible and controllable investment, short construction time, good adaptability to plant sites and wider application, and is developed by the nuclear power countries in the world. The development of Small Modular Reactor (SMR) reactors is a new trend of international nuclear energy application development, and becomes an important way for diversification of nuclear energy application markets. The international atomic energy agency believes that SMR has significant advantages over other energy sources and large reactors in terms of safety, economy, nuclear nondiffusion capability, and the ability to be charged on-site. SMR is flexible and simple to construct, has wide application, can effectively solve the problem of power grid transmission in areas with insufficient power, and is regarded as a turning point of the nuclear energy industry. Therefore, the fourth generation lead-cooled fast neutron reactor lead bismuth stack has received much attention from all countries around the world. The energy density of the nuclear fuel of the lead-bismuth pile is improved by 100 to 300 times, and the existing nuclear waste can be utilized to generate electricity. The half-life period of nuclear waste generated by the lead-bismuth pile is obviously shortened, the system structure is reasonable, the operation safety is greatly improved, and the problem of nuclear fuel shortage in China can be solved.

However, the diameter of the main container of the lead-bismuth reactor is only 1.9 meters, the height of the main container is 2 meters, the overall size of the lead-bismuth reactor is greatly reduced relative to that of a conventional nuclear reactor, the width of an arrangement area of an evaporator is only about 200mm, and the structure is extremely compact; because of the height limitation, only one tube plate can be arranged, and the heat exchanger tube bundle can not be moved downwards and upwards but can be moved upwards and downwards; the heat load of the evaporator is high, the heat load of a single machine is designed to be 1.5MW, the heat load of 4 evaporators is 6MW, if the heat exchange area is small, the heat load per unit area is large, the heat transfer deterioration in the evaporation process can be caused by overhigh heat load, and therefore, the larger the heat exchange area is, the better the heat transfer area is; meanwhile, the process of preheating, evaporation, overheating water power and heating power in the pipe is required to be met, and finally, the feasibility, economy and safety of actual production and manufacturing are considered. Therefore, the maximum heat exchange area is realized in a very limited space, and the technical difficulty that the hydrodynamic force and the thermodynamic process in the pipe are the lead-bismuth stack evaporator is met.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: how to reach the maximum heat exchange area in the extremely limited space and simultaneously meet the problems of hydrodynamic force and thermodynamic process in the pipe; further provides a tube bundle structure of the spiral heat exchanger with a non-circular section and double tube passes.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the non-circular section double-tube-pass spiral heat exchanger tube bundle structure comprises a tube plate, a shell, a heat exchanger tube bundle, a plurality of partition plates and a plurality of groups of pull rod distance tubes; both ends of the heat exchanger tube bundle are inserted into the tube plates to form a double-tube-pass spiral tube bundle structure; the cross section of the heat exchanger tube bundle is of a non-circular structure; a plurality of partition plates are arranged in parallel up and down and sleeved on the heat exchanger tube bundle, and a group of pull rod distance pipes are arranged between every two adjacent partition plates; the shell is sleeved outside the heat exchanger tube bundle.

Furthermore, the heat exchanger tube bundle comprises a plurality of central straight tube sections, a plurality of end bending sections, coil pipe sections and a plurality of coil pipe leading-out straight tube sections, wherein one end of each central straight tube section is led out from the middle of the tube plate and is vertically arranged, the other end of each central straight tube section is fixedly connected with one end of each end bending section, the other end of each end bending section is connected with one end of each coil pipe section, the other end of each coil pipe section is connected with one end of each coil pipe leading-out straight tube section, and the other end of each coil pipe leading-out straight tube section is vertically inserted into the tube plate; the coil pipe section and the coil pipe lead-out straight pipe section surround the central straight pipe section.

Furthermore, the plurality of partition plates are divided into a plurality of inner partition plates and a plurality of outer partition plates; the inner baffles are arranged in parallel up and down and are sleeved on the central straight pipe sections in the surrounding area of the coil pipe section; the outer partition plates are arranged in parallel up and down and sleeved on the central straight pipe sections and the coil pipe leading-out straight pipe sections.

Furthermore, an inner baffle plate is arranged on the central straight pipe section close to the joint of the central straight pipe section and the end bending section; an outer partition plate is arranged on the coil pipe leading-out straight pipe section and the central straight pipe section close to the joint of the coil pipe leading-out straight pipe section and the coil pipe section.

Furthermore, the central straight pipe section, the end bending sections, the coil pipe section and the coil pipe leading-out straight pipe section are integrally formed.

Furthermore, a plurality of central straight pipe sections of the heat exchanger pipe bundle are arranged on the pipe plate in an array form; the coil pipe section is formed by spirally winding a plurality of heat exchange pipes around a plurality of central straight pipe sections along the axial direction of the central straight pipe sections, and the coil pipe section formed by the heat exchanger pipe bundle is at least one layer; the plurality of coil pipe leading-out straight pipe sections are divided into two groups and distributed on two sides of the plurality of central straight pipe sections.

Furthermore, the cross section of the coil section coiled by the heat exchanger tube bundle is oval, racetrack-shaped or rectangular.

Further, when the coil pipe sections formed by the heat exchanger pipe bundle are in multiple layers, cross-flow arrangement is adopted between two adjacent layers of coil pipe sections.

The device further comprises a plurality of sealing sleeves, wherein the sealing sleeves are sleeved outside the central straight pipe sections, a sealing sleeve is arranged between two adjacent inner baffles, and a closed space is formed between the two adjacent inner baffles and the sealing sleeve; a sealing sleeve is arranged between the two adjacent outer partition plates, and a closed space is formed between the two adjacent outer partition plates and the sealing sleeve.

Compared with the prior art, the invention has the following beneficial effects:

1. the heat exchange tube bundle adopts a runway-shaped, double tube pass-spiral structure, so that the evaporator has the characteristics of extremely compact structure, large heat exchange area and high heat transfer coefficient, and also meets the thermal performance requirements of high thermal load, hydrodynamic force limitation, large flow velocity change, various heat transfer processes and the like.

2. By arranging and canceling the sealing sleeve, two heat transfer modes of pure countercurrent and mixed forward and reverse can be realized to meet the requirements of different scenes.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a cross-sectional view taken at A-A of FIG. 1;

fig. 3 is a cross-sectional view at B-B in fig. 1.

Detailed Description

The technical solution of the present invention is further explained by the specific embodiments with the attached drawings:

as shown in fig. 1, the non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure comprises a tube plate 1, a shell 2, a heat exchanger tube bundle 3, a plurality of inner partition plates 4, a plurality of outer partition plates 5 and a plurality of groups of pull rod distance tubes 6;

the heat exchanger tube bundle 3 consists of a plurality of heat exchange tubes, the heat exchanger tube bundle 3 comprises a plurality of central straight tube sections 3-1, a plurality of end bending sections 3-2, coil tube sections 3-3 and a plurality of coil leading-out straight tube sections 3-4, one end of the central straight pipe section 3-1 is led out from the middle of the pipe plate 1 and is vertically arranged, the other end of the central straight pipe section 3-1 is fixedly connected with one end of the end part bent section 3-2, the other end of the end bending section 3-2 is connected with one end of the coil pipe section 3-3, the other end of the coil pipe section 3-3 is connected with one end of the coil pipe leading-out straight pipe section 3-4, the other end of the coil pipe leading-out straight pipe section 3-4 is vertically inserted into the pipe plate 1, and the coil pipe section 3-3 and the coil pipe leading-out straight pipe section 3-4 surround the central straight pipe section 3-1;

the central straight pipe section 3-1, the end bent section 3-2, the coil pipe section 3-3 and the coil pipe leading-out straight pipe section 3-4 are integrally formed to form a heat exchange pipe, and the heat exchanger pipe bundle 3 and the pipe plate 1 form a double-pipe-pass (lower flow and upper flow) spiral pipe bundle structure;

under the condition that the arrangement spaces of the evaporators are the same, in order to maximize the heat exchange area, the maximum heat exchange area needs to be arranged in the arrangement spaces, and the central straight pipe sections 3-1 of the heat exchanger pipe bundle 3 are arranged on the pipe plate 1 in an array form; the coil pipe section 3-3 is formed by spirally winding a plurality of heat exchange pipes around a plurality of central straight pipe sections 3-1 along the axial direction of the central straight pipe sections 3-1, the number of the coil pipe sections formed by the heat exchanger pipe bundle 3 is at least one layer, and the number of the layers of the coil pipe sections is determined according to the size of a shell space; when the coil pipe sections formed by the heat exchanger pipe bundle 3 are multilayer, in order to achieve better heat transfer effect, cross flow arrangement is adopted between two adjacent layers of coil pipe sections, and when the heat exchange pipe starts to spiral after being bent at the end bending section 3-2, the coil pipe sections lead out the heat exchange pipe layer by layer according to the sequence from the inner layer to the outer layer; compared with the traditional U-tube type double-tube-pass heat exchanger (although the space utilization rate is higher, the upper flow and the lower flow respectively account for 50% of the total heat exchange area), the upper flow real-distributed heat exchange area proportion in the embodiment is greatly improved (accounting for about 80% of the total heat exchange area), all heat exchange tubes can participate in heat exchange at the moment, and the heat exchange area is maximized.

Because the tube bundle and the tube plate have the functions of force (such as gravity, pressure and scouring force of media outside the tube in the tube) and temperature difference stress (the temperature in the heat exchange tube is much higher than that of the rest of the tube), the quality of a bent tube and the forming precision of the tube bundle are poor when the coil section of the heat exchange tube is manufactured, the coil is led out from the coil section 3-3 and led out of the straight tube section 3-4, the led-out length of the coil led-out straight tube section 3-4 can be adjusted according to the integral structure of the evaporator, and the coil led-out straight tube sections 3-4 are divided into two groups and are uniformly distributed on two sides of the central straight tube sections 3-1, so that the tube bundle and the tube plate are uniformly stressed, and obviously, compared with the condition that the tube bundle is intensively led out from the tube plate, the stress is more uniform.

Because the main container of the lead bismuth pile is also provided with structures such as a pump, a flow channel and the like, the quantity of the arranged evaporators is limited, the lead bismuth pile engineering can only be provided with 4 evaporators, and in order to utilize the space of the main container of the lead bismuth pile to the maximum, the cross section of a coil section coiled by the heat exchanger tube bundle 3 is oval, racetrack-shaped or rectangular; the main container of the lead-bismuth pile is preferably in a runway shape, and has larger arrangement space (a circular spiral pipe is arranged around the main container and a solid column is arranged in the middle) compared with the traditional circular spiral heat exchanger; the shell 2 is sleeved outside the heat exchanger tube bundle 3.

Because the spiral coil has large elasticity and poor rigidity, the heat exchange tube is unsupported and has larger span, the heat exchange tube is easy to vibrate under the medium flushing, and the heat exchanger is easy to damage, a certain number of partition plates and pull rod distance tubes are arranged according to the specification of the heat exchange tube and medium parameters (density, flow rate, flushing direction and the like);

the inner baffles 4 are arranged in parallel up and down and are sleeved on the central straight pipe sections 3-1 in the surrounding area of the coil pipe sections 3-3, and a gap is reserved between the inner baffles 4 and the innermost coil pipe section, so that the inner baffles 4 not only play a role in restraining the central straight pipe sections 3-1, but also can prevent a large leakage channel from being formed between the coil pipe sections 3-3 and the central straight pipe sections 3-1;

the outer clapboards 5 are arranged in parallel up and down and are sleeved on the central straight pipe sections 3-1 and the coil pipe leading-out straight pipe sections 3-4; the outer side walls of the outer partition plates 5 are in contact with the inner wall of the shell 2, and the whole tube bundle is restrained through reaction force, so that the vibration of the tube bundle is reduced.

A group of pull rod distance pipes 6 are arranged between two adjacent inner partition plates 4, and a group of pull rod distance pipes 6 are arranged between two adjacent outer partition plates 5; an inner baffle plate 4 is arranged on the central straight pipe section 3-1 near the joint of the central straight pipe section 3-1 and the end bent section 3-2; an outer partition plate 5 is arranged on the coil leading-out straight pipe section 3-4 and the central straight pipe section 3-1 near the joint of the coil leading-out straight pipe section 3-4 and the coil section 3-3. Each group of the pull rod distance pipes 6 has 4 pull rod distance pipes 6 in total, the 4 pull rod distance pipes 6 are arranged in a 2 x 2 array mode, and the 4 pull rod distance pipes 6 are arranged at the outer edge of the partition board but close to the heat exchange pipe and are connected through threads or welding to ensure that the partition board can be fixed. The arrangement between the inner partition plate 4 and the pull rod distance tube 6 and the arrangement between the outer partition plate 5 and the pull rod distance tube 6 ensure the rigidity of the heat exchange tube bundle and support the tube bundle.

Example 2, different from example 1, the non-circular cross-section double-tube-pass spiral heat exchanger tube bundle structure further comprises a plurality of sealing sleeves 7, in the hydrodynamic process of preheating, evaporation and overheating in the tube, in order to avoid backflow of vapor and water in the tube, a method of shielding a central straight tube section 3-1 is adopted to set an actual heat transfer section of the heat exchange tube into pure countercurrent, namely, a plurality of sealing sleeves 7 are sleeved outside a plurality of central straight pipe sections 3-1, one sealing sleeve 7 is arranged between two adjacent inner baffles 4, the sealing sleeve 7 is of a three-section structure, two arc-shaped parts are arranged at two sections, the other section is two oppositely-arranged plate pieces, the two arc-shaped parts are respectively welded at two sides of the 4 pull rod distance tubes 6, the two plate pieces are welded between the two pull rod distance tubes 6, and a closed space is formed between the two adjacent inner partition plates 4 and the sealing sleeve 7 as well as between the two adjacent pull rod distance tubes 6;

a sealing sleeve 7 is arranged between two adjacent outer partition plates 5, the sealing sleeve 7 is an annular piece, the shape of the sealing sleeve 7 is the same as that of the cross section of the coil section 3-3, and a closed space is formed between the two adjacent outer partition plates 5 and the sealing sleeve 7. At the moment, only the coil pipe is led out of the straight pipe sections 3-4 and the coil pipe sections 3-3 to exchange heat with a shell side medium, so that a pure countercurrent structure can be formed, the steam is ensured to flow upwards all the time, and the backflow of the steam and the water is avoided.

In the lead bismuth pile, the partition plate and the pull rod distance tube can also be used for fixing the sealing sleeve to form a stable sealing space, so that the collision between the sealing sleeve and the heat exchange tube is avoided.

The process in the tube of the lead-bismuth pile evaporator is preheating-evaporation-overheating (preheating fluid is water, evaporation is steam water, and overheating is steam). Since the evaporation process is the transformation of water into steam, the fluid is a steam-water mixture. If the evaporation process fluid flows downwards, the gas in the evaporation process fluid can run upwards due to the action of gravity, namely, the gas flows reversely (or can not flow reversely, and the gas cannot flow reversely under the condition that the medium flow rate is extremely high). According to the thermodynamic characteristics of the evaporator, the heat exchange area required by preheating-evaporation-overheating accounts for about 2% -45% -53%, so that the preheating area is small, the evaporation area is large, and the upper flow area must be maximized, which is the thermodynamic process requirement. However, as is known from the above, the hydrodynamic process cannot be realized because the area occupied by the lower flow path is still about 20% after the new structure is adopted, and if the lower flow path is not shielded, the lower flow path is evaporated. Therefore, a sealing sleeve with a certain length is arranged on the lower flow path, most area is sealed to form a flow dead zone, only a little bottom is left (as shown in figure 1), and the requirements of hydrodynamic and thermodynamic processes are met (the lower flow path area is only less than 2%, so that a pure inverse heat exchange structure is basically formed).

It can be seen that the design parameter requirements, the structural parameter requirements, the hydrodynamic force requirements and the thermodynamic requirements of the whole machine are mutually matched, and the actual production and manufacturing can be carried out only when all the requirements are met, rather than the requirement of one point being met by random arrangement. At present, the existing tube bundle structure can not meet all the requirements of a lead-bismuth pile system.

The sealing sleeve is arranged according to the technical characteristics of the lead-bismuth stack, and when the process in the tube does not need to meet the hydrodynamic and thermodynamic processes of preheating, evaporation and overheating, the sealing sleeve is not needed, so that the maximum heat exchange area can be obtained. The sealing sleeve is selected to be arranged according to specific requirements, but is not required to be arranged.