CN110864566B - Design method for balanced flow of heat exchanger with variable pipe diameter - Google Patents
Design method for balanced flow of heat exchanger with variable pipe diameter Download PDFInfo
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- CN110864566B CN110864566B CN201911138744.9A CN201911138744A CN110864566B CN 110864566 B CN110864566 B CN 110864566B CN 201911138744 A CN201911138744 A CN 201911138744A CN 110864566 B CN110864566 B CN 110864566B
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- 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
- F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
- F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
- F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
- F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/02—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by influencing fluid boundary
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- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
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- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The invention provides a design method for equalizing flow of a heat exchanger with variable pipe diameters, wherein the heat exchanger comprises an upper collecting pipe, a lower collecting pipe and a heat exchange pipe arranged between the upper collecting pipe and the lower collecting pipe; arranging a separating device in the heat exchange tube, wherein the separating device is of a sheet structure, and the sheet structure is arranged on the cross section of the heat exchange tube; the heat exchanger comprises an inlet pipe and an outlet pipe, wherein the inlet pipe is arranged in the middle of the lower header, and the outlet pipe is arranged in the middle of the upper header; the pipe diameters of different heat exchange pipes are different, and the pipe diameter of the heat exchange pipe is larger along with the farther distance from the inlet pipe. According to the invention, through the arrangement, the closer to the inlet pipe, the smaller the diameter of the heat exchange pipe, the larger the resistance of the fluid flow, so that the fluid flows into the heat exchange pipe with small flow resistance, and the fluid flows into the heat exchange pipe at the position farther away from the inlet pipe, so that the fluid is uniformly distributed.
Description
The invention is a divisional application of application number 2018108092067, application number 2018, 20/07/20/8, and name "shell-and-tube heat exchanger with unevenly arranged separators".
Technical Field
The invention relates to a heat exchanger, in particular to a shell-and-tube heat exchanger.
Background
The vapor-liquid two-phase flow heat exchange is widely applied to various heat exchange devices, and the vapor-liquid two-phase flow has low heat exchange efficiency, worsens heat exchange, is unstable in a fluid flowing process and causes water hammer in the heat exchange process due to the existence of vapor phase. When the vapor and liquid phases of the two-phase working medium are not uniformly mixed and flow discontinuously, the large-size liquid mass can occupy the air mass space at a high speed, so that the two-phase flow is unstable, equipment and a pipeline are severely impacted, strong vibration and noise are generated, and the running safety of the equipment is seriously threatened.
The inventor also devised various heat exchanger devices, such as multi-tube heat exchanger devices, which solve the above problems, but such devices have found that in operation, because the tubes are tightly combined together, the space a formed between the three tubes is relatively small, because the space a is formed by the convex arcs of the three tubes, most of the area of the space a is narrow, the fluid is difficult to enter and pass through, the fluid is short-circuited, the heat exchange of the fluid is affected, and the good flow stabilizing effect cannot be achieved. And also, since a plurality of tubes of the above-described structure are combined together, the manufacturing is difficult. For example, the 2017102671998 structure solves the fluid short circuit phenomenon, but has a problem that the flow area is greatly reduced, resulting in an increase in flow resistance. As another example, the annular partition device 2017103224953 has an annular structure, which results in uneven circumferential partition of the annular space of the partition device as a whole, and because of the annular structure, the four included angles of the annular space are acute angles smaller than 90 degrees, which may cause a problem of short circuit of fluid flow at acute angles smaller than 90 degrees.
In the normal design of the heat exchanger, the heights of the external fins of the heat exchange tube are basically the same, and the change of the fins caused by the change of specific heat exchange conditions is not considered.
Aiming at the problems, the invention is improved on the basis of the prior invention, and provides a novel heat exchanger for generating steam, thereby solving the problem of uneven steady flow heat exchange under the condition of heat exchange of a heat exchange pipe. So that the gas and the liquid are fully mixed, and the heat exchange effect is improved.
Disclosure of Invention
The present invention provides a new heat exchange tube heat exchanger to solve the foregoing technical problems.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a shell and tube heat exchanger for generating steam, the heat exchanger comprising upper and lower headers and a heat exchange tube disposed therebetween; the heat exchanger comprises an inlet pipe and an outlet pipe, the inlet pipe is arranged on the lower collecting pipe, the outlet pipe is arranged on the upper collecting pipe, the heat exchanger comprises a heat source inlet and a heat source outlet, a heat source enters from the heat source inlet, exchanges heat with fluid in the heat exchange pipe and then flows out from the heat source outlet, the fluid in the heat exchange pipe is heated into steam and flows out from the outlet pipe, fins are arranged outside the pipe wall of the heat exchange pipe and are arranged in the transverse direction, the fins are straight plates, and the height of the fins is continuously increased along the flowing direction of the fluid in the heat exchange pipe along the.
Preferably, the increase in fin height is greater and greater along the direction of flow of the fluid within the heat exchange tubes.
A shell and tube heat exchanger for generating steam, the heat exchanger comprising upper and lower headers and a heat exchange tube disposed therebetween; the heat exchanger comprises an inlet pipe and an outlet pipe, the inlet pipe is arranged on the lower collecting pipe, the outlet pipe is arranged on the upper collecting pipe, the heat exchanger comprises a heat source inlet and a heat source outlet, a heat source enters from the heat source inlet, exchanges heat with fluid in the heat exchange pipe and then flows out from the heat source outlet, the fluid in the heat exchange pipe is heated into steam and flows out from the outlet pipe, a separating device is arranged in the heat exchange pipe, the separating device is of a sheet structure, and the sheet structure is arranged on the cross section of the heat exchange pipe; the partition device is composed of square through holes and regular octagonal through holes, the side length of each square through hole is equal to that of each regular octagonal through hole, four sides of each square through hole are sides of four different regular octagonal through holes respectively, and four mutually spaced sides of each regular octagonal through hole are sides of four different square through holes respectively.
Preferably, the heat exchange tubes are square tubes.
Preferably, a plurality of separating devices are arranged in the heat exchange tube, the distance between every two adjacent separating devices is S1, the side length of each square through hole is L1, and the side length of the heat exchange tube is L2, so that the following requirements are met:
S1/L2=a*(L1/L2)2+b*( L1/L2)-c
wherein a, b, c are parameters, wherein 39.8< a <40.1,9.19< b <9.21, 0.43< c < 0.44;
9<L2<58mm；
1．9<L1<3.4mm；
15<S1<31mm。
further preferably, a =39.87, b =9.20.c =0.432
The side lengths of the square through holes in different heat exchange tubes are different, and the longer the distance from the inlet tube is, the larger the side length of the square through hole is.
Preferably, the side length of the square through hole becomes larger and larger with the distance from the inlet pipe.
Preferably, the side length of the square through hole in the heat exchange tube farthest from the inlet tube is 1.1 to 1.2 times the side length of the square through hole in the flat heat exchange tube closest to the inlet tube.
Preferably, the side length of the square through hole farthest from the inlet pipe is 1.15 times the side length of the square through hole closest to the inlet pipe.
Preferably, the spacers include at least one of a square center spacer having a square through-hole at the center of the heat exchange tube and a regular octagonal center spacer having a regular octagonal through-hole at the center of the heat exchange tube.
Preferably, the adjacently arranged spacers are of different types.
Preferably, a =42.54, b =6.383, c = 0.2438.
Compared with the prior art, the flat heat exchange tube has the following advantages:
1) the invention provides a novel shell-and-tube steam heat exchanger, because the difference between the internal temperature difference and the external temperature difference is smaller and smaller along with the flowing, the heat absorption capacity is poorer and poorer, and the heat exchange area of the fins is increased by increasing the height of the fins so as to increase the heat absorption capacity and homogenize the heat absorption capacity on the whole.
2) The invention provides a shell-and-tube heat exchanger with a novel structure of a separating device combining a novel square through hole and a novel regular octagon through hole for generating steam, wherein the included angles formed by the edges of the formed square hole and the regular octagon hole are more than or equal to 90 degrees through the square and the regular octagon, so that fluid can fully flow through each position of each hole, and the short circuit of fluid flowing is avoided or reduced. The invention separates the two-phase fluid into liquid phase and vapor phase by the separating device with a novel structure, divides the liquid phase into small liquid masses, divides the vapor phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flow of the vapor phase, plays a role in stabilizing the flow, has the effects of vibration reduction and noise reduction, and improves the heat exchange effect. Compared with the separation device in the prior art, the flow stabilizing effect is further improved, the heat transfer is enhanced, and the manufacture is simple.
3) According to the invention, the side length of the square through hole is changed along with the distance from the inlet pipe, so that the fluid flows into the heat exchange pipe with small flow resistance and far away from the inlet pipe, the fluid is uniformly distributed in the heat exchange pipe, the heat exchange efficiency is improved, and the service life is prolonged.
4) According to the invention, through reasonable layout, the square and regular octagonal through holes are uniformly distributed, so that the fluid on the whole cross street is uniformly divided, and the problem of nonuniform division of the annular structure along the circumferential direction in the prior art is avoided.
5) The invention ensures that the large holes and the small holes are uniformly distributed on the whole cross section by uniformly distributing the square holes and the regular octagonal holes at intervals, and ensures that the separation effect is better by changing the positions of the large holes and the small holes of the adjacent separation devices.
6) According to the invention, the separating device is of a sheet structure, so that the separating device is simple in structure and low in cost.
7) According to the invention, the optimal relation size of the parameters is researched by setting the regular changes of the parameters such as the distance between the adjacent separating devices, the side length of the holes of the separating devices, the pipe diameter of the heat exchange pipe, the pipe spacing and the like in the flowing direction of the fluid in the heat exchange pipe, so that the flow stabilizing effect is further achieved, the noise is reduced, and the heat exchange effect is improved.
8) According to the invention, through carrying out extensive research on the heat exchange rule caused by the change of each parameter of the annular separation device, the optimal relational expression of the vibration and noise reduction effects is realized under the condition of meeting the flow resistance.
Drawings
Fig. 1 is a schematic structural view of a heat exchanger according to the present invention.
FIG. 2 is a schematic view of the structure of the partitioning device of the present invention.
FIG. 3 is a schematic view of another embodiment of the separator of the present invention.
Figure 4 is a schematic view of the arrangement of the partitioning device of the present invention within a heat exchange tube.
FIG. 5 is a schematic cross-sectional view of the arrangement of the partitioning device of the present invention in the heat exchange tube.
Fig. 6-1 and 6-2 are schematic cross-sectional views of the arrangement of the fins of the invention outside the heat exchange tubes.
The reference numbers are as follows:
the heat exchange tube 1, the fin 2, the inlet tube 3, the outlet tube 4, the partition device 5, the square through hole 51, the regular octagonal through hole 52, the edge 53, the heat source inlet 6, the heat source outlet 7, the upper header 8 and the lower header 9.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.
A shell-and-tube heat exchanger for generating steam, as shown in FIG. 1, comprises an upper header 8 and a lower header 9, and a heat exchange tube 1 disposed between the upper and lower headers 8, 9. The heat exchanger comprises an inlet pipe 3 and an outlet pipe 4, the inlet pipe 3 is arranged on a lower collecting pipe, the outlet pipe is arranged on an upper collecting pipe, the heat exchanger comprises a heat source inlet 6 and a heat source outlet 7, a heat source enters from the heat source inlet 6, exchanges heat with fluid in the heat exchange pipe 1 and then flows out from the heat source outlet 7, and the fluid in the heat exchange pipe 1 is heated into steam and flows out from the outlet pipe 4. Preferably, fins 2 are arranged between the heat exchange tubes. This results in a two-phase vapor-liquid flow within the heat exchange tube 1 as the fluid within the heat exchange tube heats up within the heat exchange tube to produce vapor.
As shown in fig. 2-3, an annular partition 5 is provided within the heat exchange tube 1. The construction of the annular partition 5 is shown in fig. 2-3. The separating device 5 is a sheet structure which is arranged on the cross section of the heat exchange tube 6; the spacers 5 are formed in a square and regular octagonal configuration, thereby forming square through holes 51 and regular octagonal through holes 52. The side length of the square through-hole 51 is equal to the side length of the regular octagonal through-hole 52 as shown in fig. 3, the four sides 53 of the square through-hole are the sides 53 of four different regular octagonal through-holes, respectively, and the four mutually spaced sides 53 of the regular eight deformed through-hole are the sides 53 of four different square through-holes, respectively.
The invention adopts a separating device with a novel structure, and has the following advantages:
1) the invention provides a novel separation device with a novel structure combining a square through hole and a regular octagon through hole, wherein the included angles formed by the edges of the formed square hole and the regular octagon hole are larger than or equal to 90 degrees through the square and the regular octagon, so that fluid can fully flow through each position of each hole, and the short circuit of fluid flow is avoided or reduced. The invention separates the two-phase fluid into liquid phase and vapor phase by the separating device with a novel structure, divides the liquid phase into small liquid masses, divides the vapor phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flow of the vapor phase, plays a role in stabilizing the flow, has the effects of vibration reduction and noise reduction, and improves the heat exchange effect. Compared with the separation device in the prior art, the flow stabilizing effect is further improved, the heat transfer is enhanced, and the manufacture is simple.
2) According to the invention, through reasonable layout, the square and regular octagonal through holes are uniformly distributed, so that the fluid on the whole cross street is uniformly divided, and the problem of nonuniform division of the annular structure along the circumferential direction in the prior art is avoided.
3) According to the invention, the square holes and the regular octagonal through holes are uniformly distributed at intervals, so that the large holes and the small holes are uniformly distributed on the whole cross section, and the separation effect is better through the position change of the large holes and the small holes of the adjacent separation devices.
4) According to the invention, the separating device is of a sheet structure, so that the separating device is simple in structure and low in cost.
By arranging the annular separating device, the invention equivalently increases the internal heat exchange area in the heat exchange tube, strengthens the heat exchange and improves the heat exchange effect.
The invention divides the vapor phase and the liquid phase at all cross section positions of all heat exchange tubes, thereby realizing the contact area between the division of a vapor-liquid interface and a vapor phase boundary layer and a cooling wall surface on the whole heat exchange tube section and enhancing the disturbance, greatly reducing the noise and the vibration and strengthening the heat transfer.
Preferably, the spacers are of two types, as shown in figures 2 and 3, the first type being a square central spacer, the square being located in the centre of the heat exchange tubes or condenser tubes, as shown in figure 3. The second is a regular octagonal center divider, with the regular octagon being located at the center of the heat exchange tubes or the condenser tubes, as shown in fig. 2. Preferably, the two types of spacers are arranged next to each other, i.e. the type of spacers arranged next to each other is different. I.e. adjacent to the square centre spacer is a regular octagonal centre spacer and adjacent to the regular octagonal centre spacer is a square centre spacer. According to the invention, the square holes and the regular octagon holes are uniformly distributed at intervals, so that the large holes and the small holes are uniformly distributed on the whole cross section, and through the position change of the large holes and the small holes of the adjacent separation devices, the fluid passing through the large holes next passes through the small holes, and the fluid passing through the small holes next passes through the large holes to be further separated, so that the mixing of vapor and liquid is promoted, and the separation and heat exchange effects are better.
Preferably, the cross section of the heat exchange tube 1 is square.
Preferably, fins 2 are provided on the outside of the tube wall of the heat exchange tube 1. Preferably, the fins are arranged in the transverse direction. Extending in the flow direction of the heat source.
Preferably, the fins are arranged on the sides which are not facing the heat source and are opposite to the heat source. Namely, on the side wall in the flow direction of the heat source, rather than on the front and back wall in the flow direction of the heat source.
Preferably, the fin has a straight plate shape, and a transverse extending direction of the fin is along a flow direction of the heat source.
Preferably, the height of the external fin 2 is continuously increased along the flowing direction of the fluid in the heat exchange tube, and the height is increased more and more. Because the difference between the internal temperature difference and the external temperature difference is smaller and smaller along with the flowing, the heat absorption capacity is poorer and poorer, and the heat exchange area of the fins is increased by increasing the height of the fins so as to increase the heat absorption capacity and make the heat absorption capacity of the whole body uniform. Experiments show that by the arrangement, compared with the fin with the same height, the heat exchange efficiency can be improved by about 5 percent.
Preferably, the height of the fin 2 is continuously reduced along the middle to both sides of the cross section of the heat exchange tube 1. Wherein, the height of the fin is the highest at the middle position of the heat exchange tube 1.
Because through experimental discovery, the heat exchange tube dispels the heat at the middle part most, from the middle part to both sides, the heat dissipation diminishes gradually, consequently through the outside fin altitude variation who sets up the heat exchange tube, make the heat radiating area of heat exchange tube the biggest at the middle part like this, it is minimum at both sides for middle part heat-sinking capability is the biggest, accords with the thermal heat dissipation law of heat exchange tube like this, makes the heat exchange tube heat dissipation even on the whole, avoids heat exchange tube local temperature overheated, causes the radiating effect too poor, causes the shortening of heat exchange tube life-span.
Preferably, the heat exchanger comprises an inlet pipe 3 and an outlet pipe 4, the inlet pipe 3 being arranged in the middle of the lower header 9 and the outlet pipe 4 being arranged in the middle of the upper header 8. The arrangement at the middle position ensures uniform flow distribution. Mainly because the heat exchange tubes are flowing steam, the inlet tube 3 is arranged in the lower part.
Preferably, the side lengths of the square through holes in different heat exchange tubes are different, and the side lengths of the square through holes in the heat exchange tubes are larger along with the longer distance from the inlet pipe 3. By so arranging, the closer to the inlet pipe 3, the smaller the flow area caused by the small side length, the larger the resistance to fluid flow is, so that the fluid flows into the heat exchange pipe with small flow resistance, and the fluid flows into the heat exchange pipe at the position farther away from the inlet pipe 3, so that the fluid is uniformly distributed.
Preferably, the side length of the square through hole in the heat exchange tube increases more and more as the distance from the inlet tube 3 is farther, for example, in the direction of the heat exchange tube from the inlet tube 3 to the left and right in fig. 1. Experiments show that the fluid distribution can be more uniform through the increase of the side length of the square through hole in the heat exchange tube. That is, the side length of the square through hole of the tube a is less than that of the square through hole of the tube b is less than that of the square through hole of the tube c is less than that of the square through hole of the tube d is … …, and so on.
Preferably, the side length of the square through hole in the heat exchange tube farthest from the inlet tube is 1.1 to 1.2 times the side length of the square through hole in the flat heat exchange tube closest to the inlet tube.
Preferably, the side length of the square through hole farthest from the inlet pipe is 1.15 times the side length of the square through hole closest to the inlet pipe.
Preferably, the number of partitions in each heat exchange tube is the same.
Preferably, the number of partitions 5 in different heat exchange tubes varies, and decreases with increasing distance from the inlet pipe 3. By so arranging, the closer to the inlet pipe 3, the larger the distribution quantity of the separating devices, the larger the resistance of the fluid flow, the fluid flows into the heat exchange pipe with small flow resistance, and the fluid flows into the heat exchange pipe at the position farther away from the inlet pipe 3, so that the fluid is uniformly distributed.
Preferably, the distribution of the number of partitions in the heat exchanger becomes more and more numerous as the distance from the inlet pipe 3 becomes greater. Through experiments, the fluid distribution can be more uniform through the increase of the magnitude with the number being larger.
The number of the partitions distributed in the heat exchange tube farthest from the inlet tube 3 is 0.8 to 0.9 times, preferably 0.85 times, the number of the communication holes 6 distributed in the heat exchange tube closest to the inlet tube 3.
Preferably, the different heat exchange tubes have different tube diameters, the greater the tube diameter of the heat exchange tubes with increasing distance from the inlet tube 3. Through so setting up for being closer to import pipe 3, then because the heat exchange tube pipe diameter is little, then cause the resistance grow of fluid flow to make the fluid flow in to the heat exchange tube that flow resistance is little, make the fluid flow in the heat exchange tube of the position far away from the distance of import pipe 3, thereby make fluid distribution even.
Preferably, the heat exchange tubes have a greater diameter and a greater amplitude as the distance from the inlet tube 3 increases. Through experiments, the fluid distribution can be more uniform through the increase of the amplitude of the increase of the pipe diameter.
The tube diameter in the heat exchange tube furthest from the inlet tube 3 is 0.85 to 0.9 times, preferably 0.88 times, the tube diameter of the heat exchange tube closest to the inlet tube 3.
Preferably, the cross section of the heat exchange tube 1 is square.
Preferably, the diameter of the heat exchange tube 1 is continuously increased along the flowing direction of the fluid in the heat exchange tube 1. The main reasons are as follows: 1) by increasing the pipe diameter of the heat exchange pipe, the flowing resistance can be reduced, so that the evaporated steam in the heat exchange pipe continuously moves towards the direction of increasing the pipe diameter, and the circulating flow of the loop heat pipe is further promoted. 2) Because along with the continuous flow of fluid, liquid is in the continuous evaporation of heat transfer intraductal to make vapour volume bigger and bigger, the pressure also bigger and bigger, consequently satisfy the change of the vapour volume that constantly increases and pressure through increasing the pipe diameter, thereby make pressure distribution even on the whole. 3) Through the increase of the pipe diameter of the heat exchange pipe, the impact phenomenon caused by the increase of the volume of the steam outlet can be reduced.
Preferably, the tube diameter of the heat exchange tube 1 is continuously increased more and more along the flowing direction of the fluid. The amplitude change of the pipe diameter is a result obtained by a large number of experiments and numerical simulation by the applicant, and through the arrangement, the circulating flow of the loop heat pipe can be further promoted, the pressure is integrally uniform, and the impact phenomenon is reduced.
Preferably, a plurality of partitions are arranged in the heat exchange tube, and the smaller the interval between the partitions from the inlet of the heat exchange tube 1 to the outlet of the heat exchange tube 1. The distance from the inlet of the heat exchange tube is set as H, and the adjacent parts are divided intoThe spacing between the spacers is S, S = F1(H) I.e. S is a function of the height H as a variable, S' is the first derivative of S, satisfying the following requirements:
S’<0;
the main reason is that the gas in the heat exchange tube carries liquid in the rising process, the heat exchange tube is continuously heated in the rising process, so that more and more gas in the gas-liquid two-phase flow is caused, the gas phase in the gas-liquid two-phase flow is more and more, the heat exchange capacity in the heat exchange tube is relatively weakened along with the increase of the gas phase, and the vibration and the noise are also continuously increased along with the increase of the gas phase. The distance between adjacent spacers that needs to be provided is shorter and shorter.
In addition, since the space of the section from the outlet of the heat exchange tube to the upper header or the condensation header is suddenly increased, the change of the space can cause the gas to rapidly flow out and gather upwards, so that the change of the space can cause the gathered vapor phase (vapor mass) to enter the condensation header from the position of the heat exchange tube, the vapor mass can rapidly move upwards away from the position of the connecting tube due to the poor liquid tightness of the vapor (vapor), and the liquid at the original space position of the vapor mass pushed away from the wall surface by the vapor mass can also rapidly rebound and impact the wall surface, so that the impact phenomenon is formed. The more discontinuous the gas (vapor) liquid phase, the larger the gas mass accumulation and the larger the water hammer energy. The impact phenomenon can cause larger noise vibration and mechanical impact, and damage to equipment. To avoid this phenomenon, the distance between adjacent separation means is set to be shorter and shorter, thereby continuously separating the vapor phase from the liquid phase during the fluid transfer process, thereby minimizing vibration and noise.
Through the experiment discovery, through foretell setting, both can reduce vibrations and noise to the at utmost, can improve the heat transfer effect simultaneously.
It is further preferred that the distance between adjacent spacers is increasingly shorter from the inlet of the heat exchange tube 1 to the outlet of the heat exchange tube 1. I.e. S "is the second derivative of S, the following requirements are met:
S”>0;
through the experiment, the vibration and the noise of about 7% can be further reduced, and the heat exchange effect of about 8% is improved.
Preferably, a plurality of separating devices are arranged in the heat exchange tube, and the side length of the square from the inlet of the heat exchange tube 1 to the outlet of the heat exchange tube 1 is smaller and smaller. The distance from the inlet of the heat exchange tube is H, the side length of the square is C, and C = F2(H) And C' is the first derivative of C, and meets the following requirements:
C’<0;
further preferably, the side length of the square from the inlet of the heat exchange tube 1 to the outlet of the heat exchange tube 1 is gradually increased to a smaller and smaller extent. C' is the second derivative of C, and meets the following requirements:
C”>0。
see the previous spacer spacing variation for specific reasons.
Preferably, the distance between adjacent spacers remains constant.
Preferably, the inner wall of the heat exchange tube is provided with a gap, and the outer end of the separation device is arranged in the gap.
Preferably, the heat exchange tube is formed by welding a plurality of sections of structures, and a separating device is arranged at the joint of the plurality of sections of structures.
Through analysis and experiments, the spacing between the separating devices cannot be too large, the vibration and noise reduction effect is poor if the spacing is too large, meanwhile, the spacing cannot be too small, the resistance is too large if the spacing is too small, and similarly, the side length of a square cannot be too large or too small, the vibration and noise reduction effect is poor or the resistance is too large, so that the vibration and noise reduction is optimized under the condition that the normal flow resistance (the total pressure bearing is less than 2.5Mpa or the on-way resistance of a single heat exchange tube is less than or equal to 5 Pa/M) is preferentially met through a large number of experiments, and the optimal relation of each parameter is arranged.
Preferably, the distance between the adjacent separating devices is S1, the side length of the square through hole is L1, the heat exchange tube is of a square section, and the side length of the square section of the heat exchange tube is L2, so that the following requirements are met:
S1/L2=a*(L1/L2)2+b*( L1/L2)-c
wherein a, b, c are parameters, wherein 39.8< a <40.1,9.19< b <9.21, 0.43< c < 0.44;
9<L2<58mm；
1．9<L1<3.4mm；
15<S1<31mm。
further preferably, a =39.87, b =9.20.c =0.432
Further preferably, a, b are larger and c is smaller as L1/L2 is increased.
Preferably, the side length L1 of the square through hole is the average value of the inner side length and the outer side length of the square through hole, and the side length L2 of the square cross section of the heat exchange tube is the average value of the inner side length and the outer side length of the heat exchange tube.
Preferably, the length of the outer side of the square through hole is equal to the length of the inner side of the square section of the heat exchange tube.
Preferably, as L2 increases, L1 also increases. However, as L2 increases, L1 increases by a lesser and lesser magnitude. The change of the rule is obtained through a large amount of numerical simulation and experiments, and the heat exchange effect and the noise are further improved and reduced through the change of the rule.
Preferably, S1 decreases as L2 increases. But as L2 increases, S1 decreases by a lesser and lesser magnitude. The change of the rule is obtained through a large amount of numerical simulation and experiments, and the heat exchange effect and the noise are further improved and reduced through the change of the rule.
Learn through analysis and experiment, the interval of heat exchange tube also satisfies certain requirement, for example can not too big or undersize, no matter too big or undersize can lead to the heat transfer effect not good, because set up the separator in this application heat exchange tube, consequently the separator also has certain requirement to the heat exchange tube interval. Therefore, through a large number of experiments, under the condition that the normal flow resistance (the total pressure bearing is less than 2.5MPa, or the on-way resistance of a single heat exchange tube is less than or equal to 5 Pa/M) is preferentially met, the damping and noise reduction are optimized, and the optimal relation of each parameter is settled.
The distance between adjacent separating devices is S1, the side length of a square is L1, the heat exchange tube is a square section, the side length of the heat exchange tube is L2, and the distance between the centers of the adjacent heat exchange tubes is S2 so as to meet the following requirements:
S2/L2=d*(S1/L2)2+e-f*(S1/L2)3-h*(S1/L2)；
wherein d, e, f, h are parameters,
0.280<d<0.285,1.342<e<1.350,0.060<f<0.065,0.169<h<0.171；
9<L2<58mm；
1.9<L1<3.4mm；
15<S1<31mm。
16<S2<76mm。
the spacing distance between the centers of the adjacent heat exchange tubes S2 refers to the distance between the center lines of the heat exchange tubes.
Further preferably, d =0.282, e =1.347, f =0.062, h = 0.170;
preferably, d, e are larger and f, h are smaller as S1/L2 is increased.
Preferably, S2 increases with increasing L2, but S2 increases with increasing L2 to a lesser and lesser extent. The change of the rule is obtained through a large amount of numerical simulation and experiments, and the heat exchange effect can be further improved through the change of the rule.
Preferably, the length L of the heat exchange tube is 2000-2500 mm. More preferably, 2200 to 2300 mm.
By optimizing the optimal geometric dimension of the formula, the optimal effect of shock absorption and noise reduction can be achieved under the condition of meeting the normal flow resistance.
For other parameters, such as the wall thickness of the pipe and the wall thickness of the shell, the parameters are set according to normal standards.
Preferably, the fluid within the heat exchange tubes is water.
Preferably, the heat source is flue gas.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (2)
1. A design method for equalizing flow of a heat exchanger with variable pipe diameter is disclosed, wherein the heat exchanger comprises an upper header, a lower header and a heat exchange pipe arranged between the upper header and the lower header; the heat exchanger comprises an inlet pipe and an outlet pipe, wherein the inlet pipe is arranged on a lower collecting pipe, the outlet pipe is arranged on an upper collecting pipe, the heat exchanger comprises a heat source inlet and a heat source outlet, a heat source enters from the heat source inlet, exchanges heat with fluid in the heat exchange pipe and then flows out from the heat source outlet, the fluid in the heat exchange pipe is heated into steam, and the steam flows out from the outlet pipe, and the heat exchanger is characterized in that: arranging a separating device in the heat exchange tube, wherein the separating device is of a sheet structure, and the sheet structure is arranged on the cross section of the heat exchange tube; the partition device is composed of a square through hole and a regular octagonal through hole, the side length of the square through hole is equal to that of the regular octagonal through hole, four sides of the square through hole are respectively sides of four different regular octagonal through holes, and four mutually spaced sides of the regular octagonal through hole are respectively sides of four different square through holes; the inlet pipe is arranged in the middle of the lower header, and the outlet pipe is arranged in the middle of the upper header; the design method of the heat exchange tube comprises the following steps: the pipe diameters of different heat exchange pipes are different, and the pipe diameter of the heat exchange pipe is larger along with the farther distance from the inlet pipe.
2. A method according to claim 1, wherein the heat exchange tube has a greater diameter and a greater amplitude with greater distance from the inlet tube.
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| CN201911138744.9A CN110864566B (en) | 2018-07-20 | 2018-07-20 | Design method for balanced flow of heat exchanger with variable pipe diameter |
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| CN201810809206.7A CN109539635B (en) | 2018-07-20 | 2018-07-20 | Shell-and-tube heat exchanger with unevenly arranged separating device |
| CN201911138744.9A CN110864566B (en) | 2018-07-20 | 2018-07-20 | Design method for balanced flow of heat exchanger with variable pipe diameter |
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| US3683478A (en) * | 1971-01-11 | 1972-08-15 | Michael Glay | Method for producing a heat exchanger |
| NO329262B1 (en) * | 2008-10-28 | 2010-09-20 | Statoilhydro Asa | Air cooled heat exchanger |
| CN201449186U (en) * | 2009-07-14 | 2010-05-05 | 西安石油大学 | Inner/outer spiral fin type cross-flow heat exchanger of heat transferring pipe |
| CN202254946U (en) * | 2011-09-02 | 2012-05-30 | 北京光华创世科技有限责任公司 | Low flow resistance wind plate |
| JP5389227B2 (en) * | 2012-06-28 | 2014-01-15 | 三菱電機株式会社 | Refrigerant distributor and heat pump device |
| CN203132196U (en) * | 2013-01-31 | 2013-08-14 | 中国科学院上海技术物理研究所 | Hot end internal guide structure of coaxial-type pulsed tube refrigerating machine |
| CN104154778B (en) * | 2014-08-13 | 2017-02-08 | 丹佛斯微通道换热器（嘉兴）有限公司 | Heat exchanger and method for manufacturing heat exchanger |
| CN106091783B (en) * | 2015-09-01 | 2018-06-26 | 浙江昆二晶整流器有限公司 | The arc-shaped heat-dissipating pipe of cooling fin width rule variation |
| CN204923980U (en) * | 2015-09-02 | 2015-12-30 | 中国矿业大学 | Heat exchanger for flue gas condensation desulfurization |
| CN105605945B (en) * | 2015-12-30 | 2017-07-28 | 于仁麟 | A kind of different triangle through hole heat exchanger of base length |
| CN105486116B (en) * | 2015-12-30 | 2017-03-08 | 青岛酒店管理职业技术学院 | A kind of heat exchanger of isosceles triangle through hole drift angle change |
| CN107631652B (en) * | 2016-07-18 | 2019-02-19 | 青岛宝润科技有限公司 | A kind of more heat exchanger tube heat pipes of caliber change |
| CN206037785U (en) * | 2016-09-24 | 2017-03-22 | 河南神风锅炉有限公司 | Special multi -functional energy -saving appliance of boiler |
| CN108204751B (en) * | 2017-03-21 | 2019-03-26 | 山东卓奥环保科技股份有限公司 | A kind of non-condensable gas pipe heat exchanger of constant-current stabilizer spacing variation |
| CN107044789B (en) * | 2017-04-21 | 2019-02-15 | 青岛金玉大商贸有限公司 | A kind of porous constant-current stabilizer heat pipe |
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| CN110793347A (en) | 2020-02-14 |
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