CN116244849B - Optimal design method and system for incomplete pipe-distribution floating head heat exchanger - Google Patents

Optimal design method and system for incomplete pipe-distribution floating head heat exchanger Download PDF

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CN116244849B
CN116244849B CN202310106100.1A CN202310106100A CN116244849B CN 116244849 B CN116244849 B CN 116244849B CN 202310106100 A CN202310106100 A CN 202310106100A CN 116244849 B CN116244849 B CN 116244849B
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tube
bending stress
tube plate
area
maximum radial
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CN116244849A (en
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朱国栋
宋利滨
苏厚德
龚雪茹
康昊源
宋策
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China Special Equipment Inspection and Research Institute
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/0229—Double end plates; Single end plates with hollow spaces
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Abstract

The invention discloses an optimal design method and system of an incomplete pipe-distribution floating head heat exchanger, wherein the tube plate is divided into a region A, a region B and a region C by taking non-uniformity caused by incomplete pipe distribution into consideration; calculating maximum radial bending stress for different areas respectively; and safety analysis and parameter adjustment are carried out based on the maximum radial bending stress of each region, so that the efficient and optimal design of the incomplete pipe-distribution floating head heat exchanger is realized.

Description

Optimal design method and system for incomplete pipe-distribution floating head heat exchanger
Technical Field
The invention relates to the technical field of incomplete tube-distribution floating head heat exchangers, in particular to an optimization design method and system of an incomplete tube-distribution floating head heat exchanger.
Background
The floating head heat exchanger can bear high temperature and high pressure, is convenient to clean, and becomes one of main choices of large-scale shell-and-tube heat exchangers in petrochemical devices. The floating head heat exchanger consists of a front end tube plate (namely a fixed end tube plate), a rear end tube plate (namely a floating end tube plate) and an intermediate tube bundle, wherein the typical structure of the floating head heat exchanger is shown in fig. 1, the most common tube plate connecting structure is that the front end tube plate is clamped by a flange, and the rear end tube plate is connected by a hook ring structure. The design and calculation of the tube plate are key contents of the design and safety evaluation of shell-and-tube heat exchangers such as floating head heat exchangers. The current standard requires the tube sheet to be fully laid, forming a circular laying area 2-1 and a peripheral annular non-laying area 2-2, see fig. 2.
Due to the requirements of arranging a wash-resistant plate, an evaporation space and the like on the shell side, the tube plates of part of the heat exchangers cannot be completely distributed, as shown in fig. 3. For incomplete management, simulation calculation is generally carried out through finite element modeling, which takes a few months, and it is difficult to meet the requirements of efficient design and safety evaluation.
Disclosure of Invention
The invention aims to provide an optimal design method and system for an incomplete pipe-distribution floating head heat exchanger, so as to realize efficient optimal design of the incomplete pipe-distribution floating head heat exchanger.
In order to achieve the above object, the present invention provides the following solutions:
an optimization design method of a non-complete tube-distribution floating head heat exchanger comprises the following steps:
dividing the tube plate into a region A, a region B and a region C; wherein the region A is a linear region comprising a tube distribution region and a non-tube distribution region between the center of the tube plate and the maximum support diameter of the tube plate along the horizontal direction, the region B is a linear region between the center of the tube plate and the furthest open hole of the tube plate along the vertical direction, and the region C is a region between the outer edge of the furthest open hole row of the tube plate and the calculated radius of the tube plate along the vertical direction; the tube plates are fixed end tube plates and/or floating end tube plates;
calculating the maximum radial bending stress of the area A according to the actual tube distribution quantity of the incomplete tube distribution floating head heat exchanger;
calculating the maximum radial bending stress of the area B according to the required tube distribution quantity when the incomplete tube distribution floating head heat exchanger is used for completely distributing tubes;
calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is subjected to uniform pressure;
and adjusting the material and thickness of the tube plate according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, and returning to the step of calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions.
Optionally, calculating the maximum radial bending stress of the area a according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger specifically includes:
according to the thickness and the diameter of the tube plate, calculating the radial bending moment and the circumferential bending moment born by the tube plate, (the calculation can be carried out according to a complete tube distribution calculation model in a patent CN 110619141B, and the specific calculation mode is not repeated here);
according to the radial bending moment and the circumferential bending moment born by the tube plate, the formula is utilizedCalculating the maximum radial bending stress of the area A;
wherein delta is the thickness of the tube plate, mu is the bending weakening coefficient, M r (x) And M θ (x) The radial bending moment and the circumferential bending moment born by the tube plate are respectively.
Alternatively, when the tube sheet is a fixed end tube sheet, the formula for calculating the maximum radial bending stress of the region C is:
wherein,maximum radial bending stress, p, for zone C of the fixed end tubesheet c For pressure, V is the distance between the center of the fixed end tube plate and the furthest opening of the tube plate in the vertical direction, H is the distance between the center of the fixed end tube plate and the furthest opening of the tube plate in the horizontal direction, delta 1 For the thickness of the fixed end tube sheet, U represents the non-uniformity coefficient of the fixed end tube sheet, u=v/H.
Alternatively, when the tubesheet is a floating end tubesheet, the formula for calculating the maximum radial bending stress for region C is:
wherein,maximum radial bending stress, p, for zone C of the floating end tubesheet c Is the pressure, V FL H being the distance between the centre of the floating end tube plate and the furthest opening of the tube plate in the vertical direction FL Delta is the distance between the center of the floating end tube plate and the furthest opening of the tube plate in the horizontal direction 2 To the thickness of the floating end tube plate, U FL Indicating the non-uniformity coefficient of the floating end tube plate, U FL ＝V FL /H FL 。
Optionally, when the tube plate is a fixed end tube plate, the preset conditions are:
and->Are all less than or equal to 1.5[ sigma ] 1 ]And->Less than or equal to [ sigma ] 1 ]；
Wherein,and->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the fixed end tubesheet 1 ]Allowable stress values at temperature are designed for the material of the fixed end tube sheet.
Optionally, when the tube plate is a floating-end tube plate, the preset conditions are:
and->Are all less than or equal to 1.5[ sigma ] 2 ]And->Less than or equal to [ sigma ] 2 ]；
Wherein,and->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the floating end tubesheet 2 ]Allowable stress values at temperature are designed for the material of the floating end tube sheet.
Optionally, when the tube plates are a fixed end tube plate and a floating end tube plate, the preset conditions are:
and->Are all less than or equal to 1.5[ sigma ] 1 ]And->Less than or equal to [ sigma ] 1 ]And->And->Are all less than or equal to 1.5[ sigma ] 2 ]And->Less than or equal to [ sigma ] 2 ]；
Wherein,and->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the fixed end tubesheet 1 ]Allowable stress value at the designed temperature for the fixed end tube sheet material,/-, for the tube sheet material>And->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the floating end tubesheet 2 ]Allowable stress values at temperature are designed for the floating end tube sheet material.
An optimization design system of a non-complete tube-distribution floating head heat exchanger, wherein the system is applied to the method, and the system comprises:
the zone dividing module is used for dividing the tube plate into a zone A, a zone B and a zone C; wherein the region A is a linear region comprising a tube distribution region and a non-tube distribution region between the center of the tube plate and the maximum support diameter of the tube plate along the horizontal direction, the region B is a linear region between the center of the tube plate and the furthest open hole of the tube plate along the vertical direction, and the region C is a region between the outer edge of the furthest open hole row of the tube plate and the calculated radius of the tube plate along the vertical direction; the tube plates are fixed end tube plates and/or floating end tube plates;
the maximum radial bending stress calculation module of the area A is used for calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger;
the maximum radial bending stress calculation module of the area B is used for calculating the maximum radial bending stress of the area B according to the required pipe distribution quantity when the incomplete pipe distribution floating head heat exchanger is used for completely distributing pipes;
the maximum radial bending stress calculation module of the region C is used for calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is subjected to uniform pressure;
and adjusting the material and thickness of the tube plate according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, and returning to the step of calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions.
An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method described above when executing the computer program.
A computer readable storage medium having stored thereon a computer program which when executed implements the method described above.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention discloses an optimal design method and system of an incomplete pipe-distribution floating head heat exchanger, wherein the tube plate is divided into a region A, a region B and a region C by taking non-uniformity caused by incomplete pipe distribution into consideration; the maximum radial bending stress is calculated for different areas respectively, so that the problem that the stress is completely axisymmetrically distributed due to the lack of an incomplete pipe distribution structure is solved, the existing complete pipe distribution calculation model can only be incorporated according to the actual pipe distribution quantity, and the stress difference of different areas is ignored, so that the calculation is incomplete and is deviated from the actual calculation. The calculation result deviation caused by the non-complete pipe distribution structure is larger. Based on stress research of an actual incomplete tube distribution tube plate structure, the stress of different areas of the tube plate is calculated respectively, and finite element verification shows that the stress is more in accordance with a real stress state; and safety analysis and parameter adjustment are carried out based on the maximum radial bending stress of each region, so that the efficient and optimal design of the incomplete pipe-distribution floating head heat exchanger is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a floating head heat exchanger according to the background art;
FIG. 2 is a schematic diagram of a complete piping arrangement according to the background of the invention;
FIG. 3 is a schematic diagram of a non-complete piping structure according to the background of the invention;
FIG. 4 is a flow chart of an optimization design method of a non-complete pipe-distributing floating head heat exchanger provided by an embodiment of the invention;
FIG. 5 is a schematic view of zoning a tubesheet according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of specific dimensional parameters of the incomplete pipe-laying floating head heat exchanger according to embodiment 2 of the present invention;
FIG. 7 is a diagram showing a stress cloud for finite element computation according to example 2 of the present invention;
FIG. 8 is a graph of bending stress in the A region at different U values provided in example 2 of the present invention;
FIG. 9 is a graph showing the bending stress in the B region at different U values provided in example 2 of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide an optimal design method and system for an incomplete pipe-distribution floating head heat exchanger, so as to realize efficient optimal design of the incomplete pipe-distribution floating head heat exchanger.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
In the floating head heat exchanger, heat exchange tubes are used as elastic supports of tube plates and are key parameters influencing calculation results, and in the calculation of a tube plate system, the number of the heat exchange tubes is the stress size and distribution of the tube plates and the tube bundles. To illustrate the effect of the number of heat exchange tubes on the tube sheet calculation, examples are as follows:
when the tube plate stress is calculated, firstly, the elastic basic coefficient N, the effective pressure combination p and other series parameters are calculated according to the number of the heat exchange tubes, and the following formula is calculated:
w+w fl for the displacement sum of two tube plates and N as an elastic basic coefficient, other parameters in the formula are defined, and the complete calculation flow is carried out when the tubes are completely distributed according to national standard GB/T151-2014 or JB4732-1995, the number of the heat exchange tubes finally influences the tube plate to calculate bending moment and tube plate stress through the parameters, and different tube plate numbers can obtain different calculation results.
The non-complete pipe distribution has the advantages that the stress does not meet the characteristic of axisymmetric distribution of the stress of the pipe plate when the pipe is completely distributed due to the existence of the blank pipe distribution area, the areas are different, the actual structure is not in accordance with the assumption of the existing complete pipe distribution calculation model, and the invention provides the following scheme for solving the following problems.
As shown in fig. 4, an optimization design method of a non-complete tube-distribution floating head heat exchanger comprises the following steps:
step 401, dividing the tube plate into a region A, a region B and a region C; as shown in fig. 5, the region a is a linear region including a tube distribution region and a non-tube distribution region between the center of the tube sheet and the maximum support diameter of the tube sheet in the horizontal direction, the region B is a linear region between the center of the tube sheet and the furthest-away opening of the tube sheet in the vertical direction, and the region C is a region between the outer edge of the furthest-away opening row of the tube sheet and the calculated radius of the tube sheet in the vertical direction; the tube plates are fixed end tube plates and/or floating end tube plates.
Step 402, calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger.
For example, in embodiment 2 of the present invention, an asymmetric distribution characteristic coefficient U is introduced at the maximum radial bending stress of the region a, where U represents the uniformity of distribution, and its value is equal to the ratio of the half length V of the longitudinal distribution region to the half length H of the transverse distribution region of the tube sheet (see fig. 5), i.e., u=v/H (see fig. 5), where U is equal to or greater than 0.5.
Setting the thickness of a fixed end tube plate of the floating head heat exchanger as delta 1 Thickness delta of floating end tube sheet 2 The number of the heat exchange tubes is calculated according to the actual tube distribution number N1, the effective pressure combination p of the related tube plates, the elastic basic coefficient N and other intermediate parameters are calculated according to the following formulas, and other parameters in the formulas define national standard GB/T151-2014 of China:
according to patent CN 110619141B, paper ZhuG,Qian C,MD Xue.A New Analytical Theory for the Strength Calculation ofthe Two Different Tubesheets in Floating-Head Heat Exchangers[J]In the calculation process of Journal of Pressure Vessel Technology,2020,142 (5) or standard JB4732-1995, the elastic basic coefficient N, the effective pressure combination p and the like are calculated through the number N of heat exchange tubes, and finally the bending stress and thickness of the tube plate are obtained. It can be seen that in analytical calculations of the heat exchanger, the number of heat exchange tube arrangements n will directly influence the bending stress M (x) or M of the tube sheet f1 (x) Thereby influencing the calculated thickness of the tube plate, and calculating the radial or circumferential bending moment M (x) suffered by the fixed end tube plate and the radial or circumferential bending moment M suffered by the floating end tube plate f1 (x) The method specifically comprises the following steps:
calculating an axial displacement relation of the heat exchange tube by using the following formula:
displacement at fixed end:
displacement at the floating end:
and determining the relationship between bending moment and displacement of the tube plate according to the following formula:
fixed end tube plate:
floating end tube sheet:
wherein C is 1 、C 2 、C 3 、C 4 Is constant, ber (x), bei (x) is Thomson function, D is fixed end tube plate bending rigidity, D f1 For the bending rigidity of the tube plate at the floating end, eta is the bending rigidity weakening coefficient of the perforated area of the tube plate, and f 1 (x)、f 2 (x)、f 3 (x)、f 4 (x) Poisson's ratio, M, for x-variant expression, v for tubesheet material r Is the radial bending moment M of the fixed end tube plate θ Is the circumferential bending moment of the fixed end tube plate,radial bending moment of tube plate of floating end>And k is a dimensionless parameter, and is a circumferential bending moment of the floating end tube plate.
M (x) and M at each position f1 (x) Take maximum values and respectively bring the maximum values into stress equationIn the method, the corresponding maximum bending stress value sigma on the upper surface and the lower surface of the fixed end tube plate under the condition of setting the tube plate thickness is calculated p And the corresponding maximum bending stress values on the upper and lower surfaces of the floating end tube sheet +.>
At this time, the maximum radial bending stress of the region A of the fixed end tube sheet
Maximum radial bending stress of zone A of the floating end tube sheet
Step 403, calculating the maximum radial bending stress of the area B according to the required tube distribution quantity when the incomplete tube distribution floating head heat exchanger is used for completely distributing tubes.
Firstly, according to the limitation of R=L, according to the standard GB/T151 structure requirement, completely distributing the tubes to obtain the complete tube distribution number n2, namely the required tube distribution number, replacing the tube distribution number n1 in the step 402, and according to the step 402, recalculating to obtain the maximum radial bending stress of the region B of the tube plate (comprising the maximum radial bending stress of the region B of the tube plate with the fixed end)And maximum radial bending stress of zone B of the floating-end tube sheet +.>)。
Step 404, calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is uniformly stressed.
The embodiment of the invention adopts a bending stress theoretical formula that the local equivalent circle is uniformly distributed with pressure, and respectively applies the local radial bending stress sigma to the tube plate area C according to the reduction coefficient of 0.85 times of material stress of engineering habit p And (5) performing calculation.
For the fixed end tube sheet, calculating the maximum radial bending stress of the region C of the fixed end tube sheet according to the formula (1)
For the floating end tube sheet, the maximum stress of the region C of the floating end tube sheet is calculated according to the formula (2)Wherein V is FL Corresponding to the V values, H shown in FIG. 5 FL Corresponding to the H values shown in fig. 5.
And 405, adjusting the material and thickness of the tube plate according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, and returning to the step of calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions.
(1) If it isGreater than 1.5[ sigma ] 1 ]Or->Greater than 1.5[ sigma ] 2 ]Increase delta 1 Or delta 2 Either the material of the fixed end tube sheet or the material of the floating end tube sheet is replaced, the calculation according to steps 401 to 405 is repeated until +.>Less than or equal to 1.5[ sigma ] 1 ]Or (I)>Less than or equal to 1.5[ sigma ] 2 ]；
(2) If it isGreater than [ sigma ] 1 ]Or->Greater than [ sigma ] 2 ]Increase delta 1 Or delta 2 Either the material of the fixed end tube sheet or the material of the floating end tube sheet is changed until +.>Less than or equal to [ sigma ] 1 ]Or->Less than or equal to [ sigma ] 2 ]；
If the above condition (1) and the condition (2) are satisfied at the same time, the tube sheet satisfies the design requirement.
Example 2
Example 2 of the present invention provides a specific embodiment of the method of example 1, specifically as follows:
the parameters of the table apparatus are shown in FIG. 6, and the pressure p is calculated c Material properties of the key elements of the floating head heat exchanger are shown in table 1 =3.0 MPa. According to the calculation of different correction models and finite element methods in the invention, the stress cloud diagram of the finite element calculation is shown in fig. 7 to verify the accuracy of the method, and various stress comparison trend results are shown in fig. 8, wherein the maximum stress peak value of the tube plate in the area A is basically consistent with that of the tube plate in the complete tube distribution (U=1).
Table 1 mechanical Properties of the materials (Normal temperature)
Based on the parameters of this example, the values of U (let u= 0.52,0.59,0.68,0.77, and u=1, respectively (the values of the a area of the present invention are taken as values for complete tube distribution) were continuously changed to obtain a stress curve of the horizontal fixed tube sheet, see fig. 8, where R is the distance (mm) of the stress point from the center of the tube sheet, and R is the calculated diameter (mm) of the tube sheet.
Calculation model error for region a: fig. 8 shows that different U straight lines, the maximum stress in the a region is around u=1. The maximum deviation is 247.45MPa when U=0.52, the calculated result of the maximum radial bending stress finite element is 274MPa when corrected according to the invention (when U=1), the deviation is 9.6%, and the actual calculation error is about 15% relative to the GB/T151 standard, so that the engineering requirement can be met.
Calculation model error for region B: FIG. 9 shows the comparison of bending stress curves in the region B, and the maximum bending stress is almost uniform when the number n of heat exchange tubes is corrected according to the present invention with different U values.
Calculation model error analysis for region C: taking u=0.52 as an example, at this time, h=700 mm, v=364 mm, δ=90 mm, the diameter d=h-v=336 mm of the equivalent circle Φd, and the center distance from the tube plate center is R-0.5d= 709.5-336×0.5= 541.5mm. R/r= 541.5/709.5 =0.76 at the center of the equivalent circle Φd.
The stress 139.3MPa calculated according to the formula (1) of the present invention, the finite element result in FIG. 8 is 149MPa, and the error is about 6.4%.
Example 3
The embodiment 3 of the invention provides an optimal design system of a non-complete pipe-distributing floating head heat exchanger, which is applied to the method, and comprises the following steps:
the zone dividing module is used for dividing the tube plate into a zone A, a zone B and a zone C; wherein the region A is a linear region comprising a tube distribution region and a non-tube distribution region between the center of the tube plate and the maximum support diameter of the tube plate along the horizontal direction, the region B is a linear region between the center of the tube plate and the furthest open hole of the tube plate along the vertical direction, and the region C is a region between the outer edge of the furthest open hole row of the tube plate and the calculated radius of the tube plate along the vertical direction; the tube plates are fixed end tube plates and/or floating end tube plates;
the maximum radial bending stress calculation module of the area A is used for calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger;
the maximum radial bending stress calculation module of the area B is used for calculating the maximum radial bending stress of the area B according to the required pipe distribution quantity when the incomplete pipe distribution floating head heat exchanger is used for completely distributing pipes;
the maximum radial bending stress calculation module of the region C is used for calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is subjected to uniform pressure;
and adjusting the material and thickness of the tube plate according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, and returning to the step of calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions.
The system provided by the embodiment of the present invention is similar to the method of the embodiment 1, and the working principle and the beneficial effects thereof are similar, so that details will not be described herein, and the specific content can be referred to the description of the embodiment of the method.
Example 4
Embodiment 4 of the present invention provides an electronic device including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor implements the foregoing method when executing the computer program.
Furthermore, the computer program in the above-described memory may be stored in a computer-readable storage medium when it is implemented in the form of a software functional unit and sold or used as a separate product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk.
Example 5
Embodiment 5 of the present invention provides a computer-readable storage medium having stored thereon a computer program which, when executed, implements the foregoing method.
In summary, compared with the prior art, the method provided by the embodiment of the invention has the beneficial effects that:
(1) The prior art can only calculate complete pipe distribution, and has no basis for incomplete pipe distribution. Because of the existence of a large blank pipe distribution area, the stress of the incomplete pipe distribution area also does not meet the characteristic of axisymmetric distribution of the stress of the pipe plate when the complete pipe distribution is performed, each area is different, and the actual structure is not in accordance with the assumption of the existing complete pipe distribution calculation model. The embodiment of the invention mainly aims at the problems that when the tube plate of the floating head heat exchanger with the connecting structure is used for incompletely distributing the tubes, the stress distribution of the tube plate is not in accordance with axisymmetric distribution any more, and the transverse stress and the longitudinal stress of the tube plate are different from the stress of the tube plate which is completely distributed. In the embodiment of the invention, the tube plate is divided into three areas (see the area A, the area B and the area C in fig. 5) for calculation and analysis respectively.
(2) According to the embodiment of the invention, based on a stress calculation result of complete tube distribution and on tube distribution characteristics of incomplete tube distribution, an asymmetric tube distribution characteristic coefficient U is introduced, wherein a parameter U represents tube distribution uniformity, the value of the parameter U is equal to the ratio of the half length L of a longitudinal tube distribution area of a tube plate to the half length R of a transverse tube distribution area (see figure 4), namely U=V/H, and the parameter U is more than or equal to 0.5;
(3) According to the embodiment of the invention, the maximum stress of the area A is calculated according to the actual pipe distribution quantity n 1; the maximum stress of the region B is calculated according to the corrected tube distribution quantity n2, namely the quantity required by complete tube distribution; the local bending stress of region C is calculated according to the formula provided by the present invention. The design and safety rating method of the incomplete pipe-distribution floating head heat exchanger is formed together, so that the engineering problem is effectively solved, and the method can be conveniently programmed.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.

Claims (7)

1. The optimization design method of the incomplete pipe-distribution floating head heat exchanger is characterized by comprising the following steps of:
dividing the tube plate into a region A, a region B and a region C; wherein the area A is an area comprising a pipe distribution area and a non-pipe distribution area between the center of the tube plate and the maximum supporting diameter of the tube plate along the horizontal direction, the area B is an area between the center of the tube plate and the furthest distance hole row of the tube plate along the vertical direction, and the area C is an area between the outer edge of the furthest distance hole row of the tube plate and the calculated radius of the tube plate along the vertical direction; the tube plate is a fixed end tube plate or a floating end tube plate; calculating the maximum radial bending stress of the area A according to the actual tube distribution quantity of the incomplete tube distribution floating head heat exchanger;
calculating the maximum radial bending stress of the area B according to the required tube distribution quantity when the incomplete tube distribution floating head heat exchanger is used for completely distributing tubes;
calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is subjected to uniform pressure;
according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, adjusting the material and the thickness of the tube plate, and returning to the execution step of calculating the maximum radial bending stress of the area A and the subsequent step according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions;
when the tube plate is a fixed end tube plate, the preset conditions are as follows:
and->Are all less than or equal to 1.5[ sigma ] 1 ]And->Less than or equal to [ sigma ] 1 ]；
Wherein,and->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the fixed end tubesheet 1 ]Designing allowable stress values at the temperature for the fixed end tube plate material;
when the tube plate is a floating end tube plate, the preset conditions are as follows:
and->Are all less than or equal to 1.5[ sigma ] 2 ]And->Less than or equal to [ sigma ] 2 ]；
Wherein,and->Maximum radial bending stress, [ sigma ] for zone A, zone B and zone C, respectively, of the floating end tubesheet 2 ]Allowable stress values at temperature are designed for the floating end tube sheet material.
2. The method for optimizing design of an incomplete pipe-laying floating head heat exchanger according to claim 1, wherein calculating the maximum radial bending stress of the area a according to the actual pipe-laying number of the incomplete pipe-laying floating head heat exchanger specifically comprises:
according to the thickness and the diameter of the tube plate, calculating the radial bending moment and the circumferential bending moment born by the tube plate;
according to the radial bending moment and the circumferential bending moment born by the tube plate, the formula is utilizedCalculating the maximum radial bending stress of the area A;
wherein,is the maximum radial bending stress of the region A, delta is the thickness of the tube plate, mu is the bending weakening coefficient, M r (x) And M θ (x) The radial bending moment and the circumferential bending moment born by the tube plate are respectively.
3. The method for optimizing design of a non-fully distributed tube floating head heat exchanger according to claim 1, wherein when the tube sheet is a fixed end tube sheet, the formula for calculating the maximum radial bending stress of the area C is:
wherein,maximum radial bending stress, p, for zone C of the fixed end tubesheet c For pressure, V is the distance between the center of the fixed end tube plate and the furthest opening of the tube plate in the vertical direction, H is the distance between the center of the fixed end tube plate and the furthest opening of the tube plate in the horizontal direction, delta 1 For the thickness of the fixed end tubesheet, u=v/H, representing the non-uniformity coefficient of the fixed end tubesheet.
4. The method for optimizing design of a non-fully distributed tube floating head heat exchanger according to claim 1, wherein when the tube sheet is a floating end tube sheet, the formula for calculating the maximum radial bending stress of the region C is:
wherein,maximum radial bending stress, p, for zone C of the floating end tubesheet c Is the pressure, V FL H being the distance between the centre of the floating end tube plate and the furthest opening of the tube plate in the vertical direction FL Delta is the distance between the center of the floating end tube plate and the furthest opening of the tube plate in the horizontal direction 2 To the thickness of the floating end tube plate, U FL ＝V FL /H FL Representing the non-uniformity coefficient of the floating-end tubesheet.
5. An optimal design system of a non-fully-distributed floating head heat exchanger, wherein the system is applied to the method of any one of claims 1-4, the system comprising:
the zone dividing module is used for dividing the tube plate into a zone A, a zone B and a zone C; wherein the region A is a linear region comprising a tube distribution region and a non-tube distribution region between the center of the tube plate and the maximum support diameter of the tube plate along the horizontal direction, the region B is a linear region between the center of the tube plate and the furthest open hole of the tube plate along the vertical direction, and the region C is a region between the outer edge of the furthest open hole row of the tube plate and the calculated radius of the tube plate along the vertical direction; the tube plates are fixed end tube plates and/or floating end tube plates;
the maximum radial bending stress calculation module of the area A is used for calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger;
the maximum radial bending stress calculation module of the area B is used for calculating the maximum radial bending stress of the area B according to the required pipe distribution quantity when the incomplete pipe distribution floating head heat exchanger is used for completely distributing pipes;
the maximum radial bending stress calculation module of the region C is used for calculating the maximum radial bending stress of the region C based on the bending stress theory that the local equivalent circle is subjected to uniform pressure;
and adjusting the material and thickness of the tube plate according to the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C, and returning to the step of calculating the maximum radial bending stress of the area A according to the actual tube distribution number of the incomplete tube distribution floating head heat exchanger until the maximum radial bending stress of the area A, the maximum radial bending stress of the area B and the maximum radial bending stress of the area C meet preset conditions.
6. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of any one of claims 1 to 4 when executing the computer program.
7. A computer readable storage medium, characterized in that a computer program is stored thereon, which computer program, when executed, implements the method according to any of claims 1 to 4.
CN202310106100.1A 2023-01-31 2023-01-31 Optimal design method and system for incomplete pipe-distribution floating head heat exchanger Active CN116244849B (en)

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CN110619141A (en) * 2019-07-24 2019-12-27 中国特种设备检测研究院 Calculation method for tube plate and tube bundle of floating head heat exchanger
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Publication number Priority date Publication date Assignee Title
CN110619141A (en) * 2019-07-24 2019-12-27 中国特种设备检测研究院 Calculation method for tube plate and tube bundle of floating head heat exchanger
CN111177953A (en) * 2019-07-24 2020-05-19 中国特种设备检测研究院 Tube plate system strength calculation method of floating head heat exchanger with expansion joint at tail end

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