CN110008579B - Design method of vertical fin tube type heat exchanger - Google Patents

Design method of vertical fin tube type heat exchanger Download PDF

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CN110008579B
CN110008579B CN201910256472.6A CN201910256472A CN110008579B CN 110008579 B CN110008579 B CN 110008579B CN 201910256472 A CN201910256472 A CN 201910256472A CN 110008579 B CN110008579 B CN 110008579B
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vertical fin
tube
heat exchanger
exchange tubes
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CN110008579A (en
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朱丽娜
叶原武
杨红义
申凤阳
余华金
宋广懂
武志广
龚雪婷
侯斌
杜丽岩
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China Institute of Atomic of Energy
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Abstract

The invention provides a design method of a vertical fin tube type heat exchanger, which comprises the following steps: a. determining the total heat exchange capacity of the vertical fin-tube heat exchanger; b. determining the total heat exchange area according to the total heat exchange amount; c. determining the arrangement mode of the vertical fin heat exchange tubes of the vertical fin tube type heat exchanger according to the total heat exchange area; d. determining the air side heat transfer coefficient and the resistance coefficient of the vertical fin-tube heat exchanger through experiments according to the total heat exchange area of the vertical fin-tube heat exchanger, the parameters of the vertical fin heat exchange tubes of the determined arrangement mode and the flow direction of air; e. checking and calculating the heat exchange area and the resistance coefficient of the vertical fin-tube type heat exchanger according to the air side heat transfer coefficient and the resistance coefficient; and f, shaping the vertical fin tube type heat exchanger according to the checking calculation result so as to obtain a shaped product.

Description

Design method of vertical fin tube type heat exchanger
Technical Field
The invention relates to the field of waste heat discharge of fast reactor accidents, in particular to a design method of an air heat exchanger.
Background
At present, the basic principle of passive residual heat removal is natural circulation, namely, the principles of gravity, inertia, natural convection, diffusion, evaporation, condensation and the like of fluid are utilized to take out the residual heat of a reactor core under the accident condition. The corresponding system can simplify the special safety facilities, reduce the equipment and parts, reduce the possible misoperation caused by the intervention of personnel, improve the man-machine relationship and improve the inherent safety of the nuclear power station. Therefore, technically, passive technology is the current advanced safety technology, and represents the development trend of new generation nuclear power.
In order to meet the passive requirement, the large fast reactor accident waste heat discharge system is designed into a natural circulation mode. The design of the air heat exchanger which is an important device of the accident waste heat discharge system must simultaneously take the principles of strong heat exchange capacity, small flow resistance, compact structure and the like into consideration. The air heat exchangers of the prior structural forms such as a vertical light pipe type, a serpentine fin pipe type, a light pipe spiral pipe type and the like are proved to be proved by demonstration and analysis, and the pipe type structures can not meet the design requirements. Therefore, there is a need in the art to provide an air heat exchanger with a new structure or a design method thereof to meet the design requirements of large fast reactor equipment on an accident residual heat removal system.
Disclosure of Invention
In order to solve at least one of the above technical problems, an embodiment of the present invention provides a design method of a vertical fin-tube heat exchanger, including the steps of:
a. determining the total heat exchange capacity of the vertical fin-tube heat exchanger;
b. determining the total heat exchange area according to the total heat exchange amount;
c. determining the arrangement mode of the vertical fin heat exchange tubes of the vertical fin tube type heat exchanger according to the total heat exchange area;
d. determining the air side heat transfer coefficient and the resistance coefficient of the vertical fin-tube heat exchanger through experiments according to the total heat exchange area of the vertical fin-tube heat exchanger, the parameters of the vertical fin heat exchange tubes of the determined arrangement mode and the flow direction of air;
e. checking and calculating the heat exchange area and the resistance coefficient of the vertical fin-tube type heat exchanger according to the air side heat transfer coefficient and the resistance coefficient; and
f. and shaping the vertical fin tube type heat exchanger according to the checking calculation result so as to obtain a shaped product.
According to an embodiment of the method for designing a vertical fin-tube heat exchanger of the present invention, the step a includes determining the total heat exchange amount according to basic operation parameters of the vertical fin-tube heat exchanger, wherein the basic operation parameters include an air side flow rate, an air side temperature, a sodium side flow rate and a sodium side temperature.
In another embodiment of the method of designing a vertical fin and tube heat exchanger according to the present invention, said step b comprises providing an assumed overall heat transfer coefficient K and determining the heat exchange area according to the following formula:
Figure BDA0002012282340000021
wherein A is the heat exchange area of the vertical fin-tube heat exchanger, K is the assumed total heat transfer coefficient, and Delta TmIs the log mean temperature difference between sodium and air.
According to still another embodiment of the design method of the vertical fin-tube heat exchanger of the present invention, the step c includes determining the number of heat exchange tubes according to the total heat exchange area, and determining the arrangement manner of the heat exchange tubes according to the number of the heat exchange tubes.
In yet another embodiment of the design method of the vertical fin-tube heat exchanger according to the present invention, the determining the arrangement manner of the heat exchange tubes according to the number of the heat exchange tubes includes determining the number of the arrangement layers of the heat exchange tubes according to the size of the heat exchanger, determining the number of the first layer of the heat exchange tubes according to the number of the arrangement layers, and determining the number of each layer of the heat exchange tubes according to the pitch of the heat exchange tubes.
According to yet another embodiment of the method of designing a vertical fin and tube heat exchanger of the present invention, the number of the first layer of heat exchange tubes is determined by the following equation:
Figure BDA0002012282340000031
wherein N1 is the number of the first layer of heat exchange tubes; NG is the number of layers of the heat exchange tubes, and NN is the total number of the heat exchange tubes.
In another embodiment of the method for designing a vertical fin-tube heat exchanger according to the present invention, the following step c1 is further included after the step c:
c1. and calculating the total heat transfer coefficient K 'of the vertical fin-tube type heat exchanger according to the arrangement mode of the vertical fin-tube type heat exchange tubes, correcting the assumed total heat transfer coefficient K according to the difference between the total heat transfer coefficient K' and the assumed total heat transfer coefficient K, and repeatedly executing the steps b-c 1 until the difference is within a preset range.
According to yet another embodiment of the method of designing a vertical fin-tube heat exchanger of the present invention, the step of calculating the overall heat transfer coefficient K' comprises:
calculating the sodium side heat transfer coefficient h of the vertical fin tube heat exchanger by the following formulai：
Figure BDA0002012282340000032
Wherein λ isiIs the thermal conductivity of sodium, diThe inner diameter of the heat exchange tube, Pe is the Bekery number;
calculating the air side heat transfer coefficient h of the vertical fin tube heat exchanger by0：
Figure BDA0002012282340000033
Wherein λ is0Is the air heat conductivity coefficient, d0Is the external diameter of the heat exchange tube, Re is Reynolds number, Pr is Plantt number, SfThe distance between fins of the heat exchange tube is H, and the height of the fins of the heat exchange tube is H;
the overall heat transfer coefficient K' was calculated by the following formula:
Figure BDA0002012282340000034
wherein, lambda is the heat conductivity coefficient of the heat exchange tube.
In yet another embodiment of the method of designing a vertical fin and tube heat exchanger according to the present invention, modifying the assumed overall heat transfer coefficient K comprises replacing the value of K with a value of K'.
According to another embodiment of the design method of the vertical fin tube heat exchanger of the present invention, the step of experimentally determining the air side heat transfer coefficient and the drag coefficient of the vertical fin tube heat exchanger in step d comprises the steps of:
d1. selecting and designing experimental working conditions according to the operating parameters of the vertical fin tube type heat exchanger;
d2. selecting the type of equipment adopted by the experiment according to the experimental working condition so as to form an experimental platform for the experiment;
d3. performing systematic heat transfer and resistance characteristic experiments on the experiment platform, testing the influence of temperature, air flow rate and scouring angle on the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle, and obtaining effective experiment data of the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle under different working conditions; and
d4. and processing and analyzing the experimental data to obtain a calculation formula of the heat transfer coefficient and the resistance coefficient of the air side when the air scours the vertical fin heat exchange tubes at different angles.
In another embodiment of the method of designing a vertical fin-tube heat exchanger according to the present invention, the air-side heat transfer coefficient is calculated by the formula:
when air scours the vertical fin heat exchange tubes at an angle of 90 degrees, the air side heat transfer coefficient of each row of vertical fin heat exchange tubes is calculated by the following formula:
the 1 st row of vertical fin heat exchange tubes:
Nu1＝5.63296Re0.45096Pr1/3
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝12.62348Re0.38424Pr1/3
the 3 rd row and the 4 th row of vertical fin heat exchange tubes:
Nu3、4＝4.02015Re0.49126Pr1/3
the 5 th row and the 6 th row of vertical fin heat exchange tubes:
Nu5、6＝3.28158Re0.51712Pr1/3
and 7, a 7 th row of vertical fin heat exchange tubes:
Nu7＝2.39323Re0.54398Pr1/3
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝2.6135Re0.53097Pr1/3
when air scours the vertical fin heat exchange tubes at an angle of 30 degrees, the air side heat transfer coefficient of each row of vertical fin heat exchange tubes is calculated by the following formula:
the 1 st row of vertical fin heat exchange tubes:
Nu1＝1.60875Re0.54165Pr1/3
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝5.80394R e0.43639Pr1/3
and the 3 rd row, the 4 th row and the 5 th row of vertical fin heat exchange tubes:
Nu3、4、5＝2.73359Re0.50906Pr1/3
the 6 th row and the 7 th row of vertical fin heat exchange tubes:
Nu6、7＝2.12396Re0.54129Pr1/3
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝250646Re0.51349Pr1/3
wherein Re is Reynolds number, and Pr is Plantt number.
According to yet another embodiment of the method of designing a vertical fin-tube heat exchanger of the present invention, the resistance coefficient is calculated as:
when the air scours the vertical fin heat exchange tube at an angle of 90 degrees, the resistance coefficient f is as follows:
f＝18.16112Re-0.35282(1000≤Re≤8000)
f＝3.72999Re-0.17235(8000＜Re≤24000)
when air scours the vertical fin heat exchange tube at an angle of 30 degrees, the resistance coefficient f is as follows:
f＝2597.24548Re-1.00785(900≤Re≤5000)
f＝3.34691Re-0.21965(5000＜Re≤24000)，
wherein Re is Reynolds number.
In yet another embodiment of the method of designing a vertical fin and tube heat exchanger according to the present invention, said step e comprises the steps of:
e1. dividing heat exchange areas according to the experimental result;
e2. measuring the temperature and flow of an air inlet, the temperature and flow of an air outlet, the temperature and flow of a sodium inlet and the temperature and flow of a sodium outlet according to the determined total heat exchange area of the vertical fin tube type heat exchanger;
e3. selecting heat transfer coefficients obtained through experiments from different positions of each divided heat exchange area; and
e4. the heat exchange amount of each heat exchange area is calculated to obtain the total heat exchange amount and the total resistance.
According to yet another embodiment of the method of designing a vertical fin and tube heat exchanger of the present invention, the heat transfer coefficients include a sodium side heat transfer coefficient, an air side heat transfer coefficient, and a tube wall heat transfer coefficient of the heat exchange tubes.
Compared with the prior art, the invention has at least one of the following beneficial effects:
(1) according to the design method of the vertical fin tube type heat exchanger, the design operation of the vertical fin tube type heat exchanger can be realized in a theoretical modeling and experimental verification mode, a safer and more reliable design method is provided, and the problem that the design of a vertical fin tube type heat radiator cannot be met by the existing design method of the heat exchanger is solved.
(2) The design method of the invention determines the calculation problem of the heat transfer characteristic and the resistance characteristic of the air side of the heat exchanger and provides a corresponding calculation formula, thereby providing a more reliable theoretical basis for the design and the experiment of the heat exchanger.
Drawings
Other objects and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings, and may assist in a comprehensive understanding of the invention.
Fig. 1 is a design flow diagram of a method of designing a vertical fin-tube heat exchanger according to the present invention.
It is noted that the drawings are not necessarily to scale and are merely illustrative in nature and not intended to obscure the reader.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention. It should be apparent that the described embodiment is one embodiment of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
The vertical fin tube heat exchanger is different from the traditional heat exchanger, the washing angle of air to the heat exchange tube is different along with the difference of positions, and the heat transfer characteristic and the resistance characteristic of the heat exchange tube are also changed along with the difference of the washing angles, so the design method of the heat exchange tube heat exchanger can not adopt the design method of the traditional fin tube heat exchanger.
The inventor provides a design method of a vertical fin tube type heat exchanger through theoretical analysis, and the vertical fin tube type heat exchanger designed by the method has smaller flow resistance and more compact structure when meeting the same heat exchange quantity, so that the vertical fin tube type heat exchanger is very suitable for discharging the waste heat of a large fast reactor accident. Much more attention has been devoted to the design of such vertical fin and tube heat exchangers than to prior art heat exchanger design methods.
The method comprises the following steps of firstly determining working parameters of the air heat exchanger, structural parameters of finned tubes, air flowing direction and other factors according to system working conditions and a structural scheme of the vertical finned tube heat exchanger; then, primarily determining the heat exchange area according to a calculation formula of the heat transfer coefficient of the existing finned tube; then, performing heat transfer and resistance characteristic experiments of the high-temperature finned tube heat exchanger to determine calculation formulas of the heat transfer characteristic and the resistance characteristic of the air side; then, establishing a design method of the vertical fin-tube heat exchanger according to a heat transfer characteristic and resistance characteristic calculation formula determined by an experiment and a tube distribution model of the vertical fin heat exchange tube; and finally, checking and calculating the vertical fin tube type heat exchanger according to the experimental result to determine whether the heat exchange quantity and the flow resistance meet the requirements or not.
The following describes a design method of a vertical fin tube heat exchanger according to the present invention with reference to the accompanying drawings, the specific implementation process of the design method is divided into a theoretical modeling stage and an experimental research stage, the structural design of the vertical fin tube heat exchanger is realized through the theoretical modeling stage, and the trial production of samples can be performed accordingly, and the evaluation and improvement of the samples can be realized through the experimental research stage.
First, the total heat exchange capacity of the vertical fin-tube heat exchanger is determined. The total heat exchange amount can be determined according to basic working parameters of the vertical fin tube type heat exchanger, and the basic working parameters can comprise parameters of two heat exchange media of the heat exchanger, namely air side flow, air side temperature, sodium side flow and sodium side temperature.
The total heat exchange area required can then be determined from the total heat exchange amount. An assumed overall heat transfer coefficient K can be provided here and the overall heat transfer area can be determined according to the following equation (1):
Figure BDA0002012282340000081
in formula (1), A is the total heat exchange area of the vertical fin-tube heat exchanger, K is the assumed total heat transfer coefficient, Δ TmIs the logarithmic mean temperature difference across the heat exchanger.
Then, the arrangement mode of the vertical fin heat exchange tubes of the vertical fin tube type heat exchanger is determined according to the total heat exchange area. Specifically, the number of the heat exchange tubes can be determined according to the total heat exchange area, and the arrangement mode of the heat exchange tubes can be determined according to the number of the heat exchange tubes. After the total heat exchange area is determined, the number of the heat exchange tubes can be obtained according to the ratio of the total heat exchange area to the area of a single heat exchange tube; the number of the tube arrangement layers of the heat exchange tubes is preliminarily determined according to the size requirement of the heat exchanger (mainly the layout requirement of a factory building). Further, the number of the first layer of heat exchange tubes can be determined according to the arrangement layer number, and the number of each layer of heat exchange tubes can be determined according to the space between the heat exchange tubes. Wherein, the number of the first layer of heat exchange tubes is determined by the following formula (2):
Figure BDA0002012282340000082
in the formula (2), N1 is the number of the first layer of heat exchange tubes; NG is the number of layers of the heat exchange tubes, and NN is the total number of the heat exchange tubes.
After the arrangement mode of the vertical finned heat exchange tube is determined, the method further comprises the following steps of calculating the total heat transfer coefficient K ' of the vertical finned tube type heat exchanger according to the arrangement mode of the vertical finned heat exchange tube, then correcting the assumed total heat transfer coefficient K according to the difference value between the total heat transfer coefficient K ' and the assumed total heat transfer coefficient K, and repeatedly executing the steps before the step until the difference value between the total heat transfer coefficient K ' and the assumed total heat transfer coefficient K is within a preset range.
Wherein, calculating the total heat transfer coefficient K' comprises the following steps:
first, the sodium-side heat transfer coefficient h of the vertical fin-tube heat exchanger was calculated by the following formula (3)i：
Figure BDA0002012282340000091
In formula (3), λiIs the thermal conductivity of sodium, diThe inner diameter of the heat exchange tube is Pe is the Bekery number.
Then, the air-side heat transfer coefficient h of the vertical fin-tube heat exchanger was calculated by the following formula (4)0：
Figure BDA0002012282340000092
In formula (4), λ0Is the air heat conductivity coefficient, d0Is the external diameter of the heat exchange tube, Re is Reynolds number, Pr is Plantt number, SfIs the space between the fins of the heat exchange tube, and H is the height of the fins of the heat exchange tube.
Finally, the total heat transfer coefficient K' is calculated by the following formula (5):
Figure BDA0002012282340000093
in the formula (5), λ is a thermal conductivity of the heat exchange tube.
Here, the step of correcting the assumed total heat transfer coefficient K includes performing the recalculation of the total heat exchange area a in equation (1) and the associated subsequent steps using the value of K 'instead of the value of K until the obtained difference between the value of K' and the value of K is within a predetermined range, for example, the difference is less than 0.01.
The step of experimentally determining the air side heat transfer coefficient and the drag coefficient of the vertical fin and tube heat exchanger may comprise the steps of:
selecting and designing experimental working conditions according to the operating parameters of the vertical fin tube type heat exchanger; selecting the type of equipment adopted by the experiment according to the experimental working condition so as to form an experimental platform for the experiment; performing systematic heat transfer and resistance characteristic experiments on the experiment platform, testing the influence of temperature, air flow rate and scouring angle on the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle, and obtaining effective experiment data of the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle under different working conditions; and processing and analyzing the experimental data to obtain a calculation formula of the heat transfer coefficient and the resistance coefficient of the air side when the air scours the vertical fin heat exchange tubes along different angles. The heat exchanger designed according to the above design method can be verified experimentally and improved according to the verification result.
Based on experimental data, data processing and theoretical analysis are carried out, and a calculation formula of the heat transfer coefficient and the resistance coefficient of the air scouring finned tubes along different angles, which can guide the design method of the vertical finned tube type heat exchanger, is provided, and is concretely as follows.
The heat transfer coefficients of the different tube rows obtained when air scours the vertical finned heat exchange tubes at an angle of 90 degrees are found in the calculated relationships (6) to (11):
the 1 st row of vertical fin heat exchange tubes:
Nu1＝5.63296Re0.45096Pr1/3 (6)
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝12.62348Re0.38424Pr1/3 (7)
the 3 rd row and the 4 th row of vertical fin heat exchange tubes:
Nu3、4＝4.02015Re0.49126Pr1/3 (8)
the 5 th row and the 6 th row of vertical fin heat exchange tubes:
Nu5、6＝3.28158Re0.51712Pr1/3 (9)
and 7, a 7 th row of vertical fin heat exchange tubes:
Nu7＝2.39323Re0.54398Pr1/3 (10)
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝2.6135Re0.53097Pr1/3 (11)
the experimental calculation of the resistance coefficients when air scours the vertical finned heat exchange tubes at a 90 degree angle are given by the following equations (12) - (13):
f＝18.16112Re-0.35282(1000≤Re≤8000) (12)
f＝3.72999Re-0.17235(8000＜Re≤24000) (13)
the heat transfer coefficients of different tube rows obtained by experiments when air scours the vertical finned heat exchange tubes at an angle of 30 degrees are calculated by the following relations (14) to (18):
the 1 st row of vertical fin heat exchange tubes:
Nu1＝1.60875Re0.54165Pr1/3 (14)
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝5.80394Re0.43639Pr1/3 (15)
and the 3 rd row, the 4 th row and the 5 th row of vertical fin heat exchange tubes:
Nu3、4、5＝2.73359Re0.50906Pr1/3 (16)
the 6 th row and the 7 th row of vertical fin heat exchange tubes:
Nu6、7＝2.12396Re0.54129Pr1/3 (17)
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝2.50646Re0.51349Pr1/3 (18)
when air washes the vertical fin heat exchange tube at an angle of 30 degrees, the calculated resistance coefficients obtained by experiments are the following relations (19) to (20):
f＝2597.24548Re-1.00785(900≤Re≤5000) (19)
f＝3.34691Re-0.21965(5000＜Re≤24000) (20)
and finally, checking and calculating the heat exchange area and the resistance coefficient of the vertical fin tube type heat exchanger according to the air side heat transfer coefficient and the resistance coefficient, dividing the heat exchange area according to an experimental result when checking and calculating, and measuring the temperature and the flow of an air inlet, the temperature and the flow of an air outlet, the temperature and the flow of a sodium inlet and the temperature and the flow of a sodium outlet according to the preliminarily designed heat exchange area of the heat exchanger, for example, dividing three rows of heat exchange tubes into three heat exchange areas. And then selecting heat transfer coefficients obtained through experiments at different positions of each region in different heat exchange regions, wherein the heat transfer coefficients comprise a sodium side heat transfer coefficient, an air side heat transfer coefficient and a pipe wall heat conduction coefficient of a heat exchange pipe, calculating the heat exchange quantity of each heat exchange region, and finally obtaining the total heat exchange quantity and the total resistance.
The structure of the vertical fin tube type heat exchanger is greatly different from the traditional heat exchanger, and the air heat transfer characteristic and the resistance characteristic of the heat exchanger with the structure can change along with the different scouring angles of air on the vertical fin heat exchange tube. However, the air-side heat transfer resistance characteristics of the finned tubes in the existing literature are mostly directed at the situation that air vertically scours the finned tubes, and are not completely suitable for the design calculation of the vertical fin heat exchange tubes of the vertical fin tube type heat exchanger. The air heat exchanger is used as an important heat exchange device of a passive natural circulation accident waste heat discharge system, and the design of the air heat exchanger needs to meet the requirements of heat exchange quantity and small resistance, so that a test needs to be carried out to determine the heat transfer resistance characteristic when a design method of the vertical fin tube type heat exchanger is established.
According to the design method of the vertical fin tube type heat exchanger, the vertical fin heat exchange tube is designed through two aspects of theoretical modeling and experimental verification, and the problem that the existing design method of the fin heat exchange tube in the prior art is not suitable for a vertical fin tube type radiator is solved. The design method according to the invention also provides corresponding calculation formulas by determining the calculation problems of the heat transfer characteristic and the resistance characteristic of the air side of the heat exchanger, thereby providing more reliable theoretical basis for the design and the improvement of the heat exchanger.
It should also be noted that, in the case of the embodiments of the present invention, features of the embodiments and examples may be combined with each other to obtain a new embodiment without conflict.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and the scope of the present invention is subject to the scope of the claims.

Claims (14)

1. A design method of a vertical fin tube heat exchanger comprises the following steps:
a. determining the total heat exchange capacity of the vertical fin-tube heat exchanger;
b. determining the total heat exchange area according to the total heat exchange amount;
c. determining the arrangement mode of the vertical fin heat exchange tubes of the vertical fin tube type heat exchanger according to the total heat exchange area;
d. determining an air side heat transfer coefficient and a resistance coefficient of the vertical fin tube type heat exchanger through experiments according to the total heat exchange area of the vertical fin tube type heat exchanger, the parameters of the vertical fin heat exchange tubes of the determined arrangement mode and the flow direction of air, wherein a calculation formula of the air side heat transfer coefficient and the resistance coefficient when air scours the vertical fin heat exchange tubes at different angles is obtained through systematic heat transfer and resistance characteristic experiments;
e. checking and calculating the heat exchange area and the resistance coefficient of the vertical fin-tube type heat exchanger according to the air side heat transfer coefficient and the resistance coefficient; and
f. and shaping the vertical fin tube type heat exchanger according to the checking calculation result so as to obtain a shaped product.
2. The method of designing a vertical fin-tube heat exchanger as recited in claim 1 wherein said step a includes determining the total heat exchange based on basic operating parameters of said vertical fin-tube heat exchanger, said basic operating parameters including air side flow, air side temperature, sodium side flow and sodium side temperature.
3. The method of designing a vertical fin-tube heat exchanger as recited in claim 1 wherein said step b includes providing an assumed overall heat transfer coefficient, K, and determining an overall heat exchange area according to the formula:
Figure FDA0002778120670000011
wherein Q is the total heat exchange amount, A is the total heat exchange area of the vertical fin-tube heat exchanger, K is the assumed total heat transfer coefficient, and Delta TmIs the logarithmic mean temperature difference across the heat exchanger.
4. The design method of a vertical fin-tube heat exchanger as recited in claim 1 wherein said step c includes determining the number of heat exchange tubes based on said total heat exchange area and determining the arrangement of said heat exchange tubes based on the number of said heat exchange tubes.
5. The design method of a vertical fin-tube heat exchanger as recited in claim 4 wherein determining the arrangement of the heat exchange tubes based on the number of heat exchange tubes includes determining the number of layers of heat exchange tubes based on the size of the heat exchanger, determining the number of first layers of heat exchange tubes based on the number of layers, and determining the number of layers of heat exchange tubes based on the spacing between heat exchange tubes.
6. The method of designing a vertical fin and tube heat exchanger as recited in claim 5 wherein the number of said first layer of heat exchange tubes is determined by the formula:
Figure FDA0002778120670000021
wherein N1 is the number of the first layer of heat exchange tubes; NG is the number of layers of the heat exchange tubes, and NN is the total number of the heat exchange tubes.
7. The design method of a vertical fin-tube heat exchanger as recited in claim 1 further comprising the following step c1 after said step c:
c1. and calculating the total heat transfer coefficient K 'of the vertical fin-tube type heat exchanger according to the arrangement mode of the vertical fin-tube type heat exchange tubes, correcting the assumed total heat transfer coefficient K according to the difference between the total heat transfer coefficient K' and the assumed total heat transfer coefficient K, and repeatedly executing the steps b-c 1 until the difference is within a preset range.
8. The method of designing a vertical fin-tube heat exchanger of claim 7 wherein the step of calculating the overall heat transfer coefficient K' comprises:
calculating the sodium side heat transfer coefficient h of the vertical fin tube heat exchanger by the following formulai：
Figure FDA0002778120670000022
Wherein λ isiIs the thermal conductivity of sodium, diThe inner diameter of the heat exchange tube, Pe is the Bekery number;
calculating the air side heat transfer coefficient h of the vertical fin tube heat exchanger by0：
Figure FDA0002778120670000023
Wherein λ is0Is the air heat conductivity coefficient, d0Is the external diameter of the heat exchange tube, Re is Reynolds number, Pr is Plantt number, SfThe distance between fins of the heat exchange tube is H, and the height of the fins of the heat exchange tube is H;
the overall heat transfer coefficient K' was calculated by the following formula:
Figure FDA0002778120670000031
wherein, lambda is the heat conductivity coefficient of the heat exchange tube.
9. The method of designing a vertical fin-tube heat exchanger of claim 7 or 8 wherein the modifying the assumed overall heat transfer coefficient K includes replacing the value of K with a value of K'.
10. The method of designing a vertical fin and tube heat exchanger as recited in claim 1 wherein the step of experimentally determining the air side heat transfer coefficient and drag coefficient of the vertical fin and tube heat exchanger in step d comprises the steps of:
d1. selecting and designing experimental working conditions according to the operating parameters of the vertical fin tube type heat exchanger;
d2. selecting the type of equipment adopted by the experiment according to the experimental working condition so as to form an experimental platform for the experiment;
d3. performing systematic heat transfer and resistance characteristic experiments on the experiment platform, testing the influence of temperature, air flow rate and scouring angle on the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle, and obtaining effective experiment data of the actual heat exchange quantity and flow resistance of the vertical fin heat exchange tube bundle under different working conditions; and
d4. and processing and analyzing the experimental data to obtain a calculation formula of the heat transfer coefficient and the resistance coefficient of the air side when the air scours the vertical fin heat exchange tubes at different angles.
11. The method of claim 10, wherein the air side heat transfer coefficient is calculated by the formula:
when air scours the vertical fin heat exchange tubes at an angle of 90 degrees, the air side heat transfer coefficient of each row of vertical fin heat exchange tubes is calculated by the following formula:
the 1 st row of vertical fin heat exchange tubes:
Nu1＝5.63296Re0.45096Pr1/3
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝12.62348Re0.38424Pr1/3
the 3 rd row and the 4 th row of vertical fin heat exchange tubes:
Nu3、4＝4.02015Re0.49126Pr1/3
the 5 th row and the 6 th row of vertical fin heat exchange tubes:
Nu5、6＝3.28158Re0.51712Pr1/3
and 7, a 7 th row of vertical fin heat exchange tubes:
Nu7＝2.39323Re0.54398Pr1/3
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝2.6135Re0.53097Pr1/3
when air scours the vertical fin heat exchange tubes at an angle of 30 degrees, the air side heat transfer coefficient of each row of vertical fin heat exchange tubes is calculated by the following formula:
the 1 st row of vertical fin heat exchange tubes:
Nu1＝1.60875Re0.54165Pr1/3
and the 2 nd row of vertical fin heat exchange tubes:
Nu2＝5.80394Re0.43639Pr1/3
and the 3 rd row, the 4 th row and the 5 th row of vertical fin heat exchange tubes:
Nu3、4、5＝2.73359Re0.50906Pr1/3
the 6 th row and the 7 th row of vertical fin heat exchange tubes:
Nu6、7＝2.12396Re0.54129Pr1/3
and (3) the 8 th row of vertical fin heat exchange tubes:
Nu8＝2.50646Re0.51349Pr1/3
wherein Re is Reynolds number, and Pr is Plantt number.
12. The method of designing a vertical fin-tube heat exchanger as recited in claim 10 wherein the drag coefficient is calculated by the formula:
when the air scours the vertical fin heat exchange tube at an angle of 90 degrees, the resistance coefficient f is as follows:
f＝18.16112Re-0.35282，1000≤Re≤8000，
f＝3.72999Re-0.17235，8000<Re≤24000，
when air scours the vertical fin heat exchange tube at an angle of 30 degrees, the resistance coefficient f is as follows:
f＝2597.24548Re-1.00785，900≤Re≤5000，
f＝3.34691Re-0.21965，5000<Re≤24000，
wherein Re is Reynolds number.
13. The method of designing a vertical fin-tube heat exchanger as recited in claim 1 wherein said step e comprises the steps of:
e1. dividing heat exchange areas according to the experimental result;
e2. measuring the temperature and flow of an air inlet, the temperature and flow of an air outlet, the temperature and flow of a sodium inlet and the temperature and flow of a sodium outlet according to the determined total heat exchange area of the vertical fin tube type heat exchanger;
e3. selecting heat transfer coefficients obtained through experiments from different positions of each divided heat exchange area; and
e4. the heat exchange amount of each heat exchange area is calculated to obtain the total heat exchange amount and the total resistance.
14. The method of designing a vertical fin and tube heat exchanger of claim 13 wherein the heat transfer coefficients include sodium side heat transfer coefficient, air side heat transfer coefficient, and tube wall heat transfer coefficient of the heat exchange tubes.
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