CN110081745B - Loop heat pipe with evaporating part with pipe diameter larger than condensing part - Google Patents

Loop heat pipe with evaporating part with pipe diameter larger than condensing part Download PDF

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Publication number
CN110081745B
CN110081745B CN201810603156.7A CN201810603156A CN110081745B CN 110081745 B CN110081745 B CN 110081745B CN 201810603156 A CN201810603156 A CN 201810603156A CN 110081745 B CN110081745 B CN 110081745B
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pipe
heat
condensation
square
evaporation
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CN110081745A (en
Inventor
郭春生
江程
年显勃
马军
陈子昂
李言伟
谷潇潇
薛于凡
李红云
武晓阳
辛华钰
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Shandong University
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Shandong University
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28DHEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0266Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers

Abstract

A loop heat pipe comprises an evaporation part, a condensation part, and an insulation part and a reflux part which are connected with the evaporation part and the condensation part, wherein fluid absorbs heat and evaporates in the evaporation part, enters the condensation part through the insulation part, is condensed after heat exchange in the condensation part, and returns to an evaporation header through a reflux pipe; the heat-absorbing device is characterized in that the evaporation part comprises a heat-absorbing pipe, the backflow part comprises a condensing pipe, and the pipe diameter of the heat-absorbing pipe is larger than that of the condensing pipe. The invention provides a loop heat pipe with a novel structure, which mainly increases the resistance of a condenser pipe and reduces the resistance of an evaporation part, so that steam flows from the evaporation part more easily, and the loop heat pipe forms circulation better.

Description

Loop heat pipe with evaporating part with pipe diameter larger than condensing part
Technical Field
The invention belongs to the field of heat pipes, and particularly relates to a loop heat pipe.
Background
The heat pipe technology is a heat transfer element called a heat pipe invented by George Grover (George Grover) of national laboratory of Los Alamos (Los Alamos) in 1963, fully utilizes the heat conduction principle and the rapid heat transfer property of a phase change medium, quickly transfers the heat of a heating object to the outside of a heat source through the heat pipe, and the heat conduction capability of the heat transfer element exceeds the heat conduction capability of any known metal.
The heat pipe technology is widely applied to the industries of aerospace, military industry and the like, and since the heat pipe technology is introduced into the radiator manufacturing industry, the design idea of the traditional radiator is changed for people, the single heat radiation mode that a high-air-volume motor is used for obtaining a better heat radiation effect is avoided, the heat pipe technology is adopted for enabling the radiator to obtain a satisfactory heat exchange effect, and a new place in the heat radiation industry is opened up. At present, the heat pipe is widely applied to various heat exchange devices, including the field of nuclear power, such as the utilization of waste heat of nuclear power.
On the one hand, the heat pipe is in the evaporation process, inevitable can carry liquid to in the heat-absorbing pipe, simultaneously because the exothermic condensation of condensation end, thereby there is liquid in making the condensation end, liquid inevitable entering heat-absorbing pipe, thereby make the intraductal fluid of heat-absorbing be vapour-liquid mixture, the heat pipe can be because of the incondensable gas of ageing production simultaneously in the operation process, the condensable gas generally rises to the condensation end on heat pipe upper portion, the existence of incondensable gas leads to the interior pressure increase of heat pipe condensation end, pressure makes liquid flow in to the heat-absorbing pipe. Greatly influencing the heat exchange efficiency.
On the other hand, in the section from the outlet of the heat absorbing pipe to the condensing header, because the space of the section is suddenly enlarged, 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 condensing header from the position of the heat absorbing pipe, the vapor mass moves rapidly upwards from the position of the connecting pipe due to the difference of the liquid density 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 simultaneously rebounds and impacts the wall surface, so that the impact phenomenon is formed. The more discontinuous the gas (vapor) liquid phase, the larger the mass of gas is gathered and the greater the impact energy. The impact phenomenon can cause larger noise vibration and mechanical impact, and damage to equipment.
In addition, because there is the vapour-liquid problem, lead to in the heat transfer vapour liquid to separate each other for can not carry out abundant mixture between vapour and the liquid, influence the heat transfer effect, lead to the heat transfer inhomogeneous, local high temperature or low excessively.
The inventor also devised various heat pipe devices, such as a multi-pipe type, which solve the above problems, but such devices have found that in operation, because the pipes are tightly combined together, the space a formed between the three pipes is relatively small, because the space a is formed by the convex arcs of the three pipes, 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 2017102949490 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.
Aiming at the problems, the invention is improved on the basis of the prior invention, and provides a new heat pipe, thereby solving the problem of uneven steady flow heat exchange under the condition of heat exchange of the heat 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 pipe to solve the above-mentioned technical problems.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a loop heat pipe comprises an evaporation part, a condensation part, and an insulation part and a reflux part which are connected with the evaporation part and the condensation part, wherein fluid absorbs heat and evaporates in the evaporation part, enters the condensation part through the insulation part, is condensed after heat exchange in the condensation part, and returns to an evaporation header through a reflux pipe; the heat-absorbing device is characterized in that the evaporation part comprises a heat-absorbing pipe, the backflow part comprises a condensing pipe, and the pipe diameter of the heat-absorbing pipe is larger than that of the condensing pipe.
Preferably, a separating device is arranged in the heat absorbing pipe, the separating device is a sheet-shaped structure, and the sheet-shaped structure is arranged on the cross section of the heat absorbing 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 deformed through hole are sides of four different square through holes respectively.
Preferably, the heat absorbing pipe has a square cross section.
Preferably, the diameter of the heat absorbing pipe increases continuously along the direction of fluid flow.
Preferably, the pipe diameter of the heat absorption pipe is increased more and more along the flowing direction of the fluid.
Preferably, a plurality of spacers are arranged in the heat absorption tube, the distance from the inlet of the heat absorption tube is H, the distance between every two adjacent spacers is S, and S is equal to F1(H) The following requirements are met:
S’<0,S”>0。
preferably, a plurality of separating devices are arranged in the heat absorbing pipe, the distance from the inlet of the heat absorbing pipe is H, the side length of the square is C, and C is equal to F2(H) The following requirements are met:
C’<0,C”>0。
preferably, a plurality of spacers are arranged in the absorber tube, the distance from the inlet of the absorber tube is H, the diameter of the absorber tube is D, and D is F3(H) The following requirements are met:
D’>0,D”>0。
preferably, the inner wall of the heat absorbing pipe of the separating device is provided with a gap, and the outer end of the separating device is arranged in the gap.
Preferably, the heat absorbing pipe is formed by welding a multi-section structure, and the separating device is arranged at the joint of the multi-section structure.
Preferably, the distance between adjacent separators is S1, the side length of the square through hole is L1, the heat absorbing pipe is of a square section, and the side length of the square section of the heat absorbing pipe 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。
more preferably, a is 39.87, b is 9.20, and c is 0.432
Further preferably, a and b become larger and smaller as L1/L2 increases.
Preferably, as L2 increases, L1 also increases. However, as L2 increases, L1 increases by a lesser and lesser magnitude.
Preferably, S1 decreases as L2 increases. But as L2 increases, S1 decreases by a lesser and lesser magnitude.
Preferably, the evaporation part comprises a plurality of heat absorption pipes, and the plurality of heat absorption pipes are parallel structures.
Preferably, the distance between adjacent spacers is S1, the side length of the square is L1, the heat absorbing pipe is a square section, the side length of the heat absorbing pipe is L2, and the distance between the centers of the adjacent heat absorbing pipes is S2, so that the following requirements are met:
the distance between adjacent separating devices is S1, the side length of a square is L1, the heat absorbing pipe is a square section, the side length of the heat absorbing pipe is L2, and the distance between the centers of the adjacent heat absorbing pipes is S2, so that the following requirements are met:
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。
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.
Compared with the prior art, the invention has the following advantages:
1) the invention provides a loop heat pipe with a novel structure, which mainly increases the resistance of a condenser pipe and reduces the resistance of an evaporation part, so that steam flows from the evaporation part more easily, and the loop heat pipe forms circulation better.
2) 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 gas phase by the separating device with a novel structure, divides the liquid phase into small liquid groups, divides the gas phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flowing of the gas 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, 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.
4) 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.
5) 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.
6) 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 absorbing pipes, the pipe spacing and the like in the height direction of the heat absorbing pipes, so that the flow stabilizing effect is further achieved, the noise is reduced, and the heat exchange effect is improved.
7) 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 diagram of a preferred heat pipe configuration of the present invention;
FIG. 2 is a schematic cross-sectional view of a partitioning device of the present invention;
FIG. 3 is another schematic cross-sectional view of a partitioning device according to the present invention;
FIG. 4 is a schematic view of the placement of the spacers of the present invention within either the absorber or the emitter tubes;
figure 5 is a schematic cross-sectional view of the placement of the spacers of the present invention within either the absorber or the emitter tubes.
Fig. 6 is a detailed structural view of the evaporation unit or the condensation unit of fig. 1 according to the present invention.
In the figure: 1 heat pipe, 11 evaporation part, 12 condensation part, 13 heat insulation part, 14 reflux part, 15 heat absorption pipe, condensation pipe 16, 3 separation device, 31 square through hole, 32 regular octagon through hole, 33 sides
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.
As shown in fig. 1, a loop heat pipe 1 includes an evaporation portion 11, a condensation portion 12, and a heat insulation portion 13 and a return portion 14 connecting the evaporation portion and the condensation portion, wherein a fluid absorbs heat in the evaporation portion 11 and evaporates, enters the condensation portion 12 through the heat insulation portion 13, exchanges heat in the condensation portion 12 and then condenses, and the condensed fluid returns to the evaporation portion 11 through the return pipe 14. Preferably, the reflux unit is also insulated.
As a modification, the evaporation part comprises a heat absorption pipe, a separator 3 is arranged in the heat absorption pipe, and the structure of the separator 3 is shown in fig. 2 and 3. The separation means 3 is a sheet-like structure arranged over the cross section of the absorber tube 15; the spacers 3 are made of square and regular octagonal structures, thereby forming square through holes 31 and regular octagonal through holes 32. The side length of a square through hole is equal to the side length of a regular octagonal through hole as shown in fig. 1, the four sides 33 of the square through hole are the sides 33 of four different regular octagonal through holes respectively, and the four mutually spaced sides 33 of a regular eight deformed through hole are the sides 33 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 gas phase by the separating device with a novel structure, divides the liquid phase into small liquid groups, divides the gas phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flowing of the gas 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 gas 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 gas-liquid interface and a gas 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.
As a modification of the heat absorbing part or the heat radiating part of fig. 1, as shown in fig. 6, the heat absorbing part or the heat radiating part includes a plurality of heat absorbing pipes 15 or condensing pipes 16 and upper and lower headers connecting the heat absorbing pipes 15 or the condensing pipes 16.
Preferably, the separation means comprises two types, as shown in fig. 2 and 3, the first type being a square central separation means, the square being located in the centre of the heat absorption tube or the condenser tube, as shown in fig. 3; the second type is a regular octagonal central partition, which is located at the center of the heat absorbing pipe or the condensing pipe, 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 absorbing pipe 15 or the condensing pipe 16 is square.
Preferably, the diameter of the heat absorbing pipe 15 increases continuously along the direction of fluid flow. The main reasons are as follows: 1) by increasing the pipe diameter of the heat absorption pipe, the flowing resistance can be reduced, so that the vapor evaporated in the heat absorption 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 the liquid is continuously evaporated in the heat absorption pipe along with the continuous flowing of the fluid, the volume of the steam is larger and larger, and the pressure is also larger and larger, the change of the volume and the pressure of the steam which are continuously increased is met by increasing the pipe diameter, and the pressure is uniformly distributed on the whole. 3) Through the increase of the pipe diameter of the heat absorption pipe, the impact phenomenon caused by the increase of the volume of the steam outlet can be reduced.
Preferably, the diameter of the heat absorbing pipe 15 increases 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 spacers are arranged in the absorber tube, the smaller the spacing between the spacers from the inlet of the absorber tube 15 to the outlet of the absorber tube 15. Setting the distance between the heat absorbing pipe and the heat absorbing pipe inlet as H and the interval between adjacent separating devices as 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 vapor in the heat absorption pipe carries liquid in the rising process, the heat absorption pipe is continuously heated in the rising process, so that the vapor in the gas-liquid two-phase flow is more and more, the vapor phase in the vapor-liquid two-phase flow is more and more, the heat exchange capacity in the heat absorption pipe is relatively weakened along with the increase of the vapor phase, and the vibration and the noise thereof are also continuously increased along with the increase of the vapor phase. The distance between adjacent spacers that needs to be provided is shorter and shorter.
In addition, the section from the outlet of the heat absorption pipe to the upper collecting pipe or the condensing collecting pipe is provided with a suddenly enlarged space, the space change can cause the gas to rapidly flow out and collect upwards, so the space change can cause the collected vapor phase (vapor mass) to enter the condensing collecting pipe from the position of the heat absorption pipe, the vapor mass moves rapidly upwards from the position of the connecting pipe due to the liquid difference of the vapor (vapor) liquid, and the original space position of the vapor mass is pushed away from the liquid of the wall surface by the vapor mass and simultaneously rebounds and impacts the wall surface rapidly to form an impact phenomenon. 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. Therefore, in order to avoid the phenomenon, the distance between adjacent separation devices is set to be shorter and shorter, so that the gas phase and the liquid phase are continuously separated in the fluid conveying process, and vibration and noise are reduced to the maximum extent.
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 increases in decreasing magnitude from the inlet of the absorber tube 15 to the outlet of the absorber tube 15. 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 partitions are arranged in the heat absorption pipe, and the side length of the square is smaller from the inlet of the heat absorption pipe 15 to the outlet of the heat absorption pipe 15. The distance from the inlet of the heat absorption tube is H, the side length of the square is C, and C is F2(H) And C' is the first derivative of C, and meets the following requirements:
C’<0;
it is further preferred that the side length of the square increases with decreasing amplitude from the inlet of the absorber tube 15 to the outlet of the absorber tube 15. 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 absorbing pipe is provided with a gap, and the outer end of the separating device is arranged in the gap.
Preferably, the heat absorbing pipe is formed by welding a multi-section structure, and the separating device is arranged at the joint of the multi-section structure.
In the loop heat pipe shown in fig. 1, referring to fig. 6, the condenser 12 preferably includes a condenser pipe, and a partition device shown in fig. 3 is provided in the condenser pipe.
Preferably, the cross section of the condensation pipe is square.
Preferably, the diameter of the condenser tube 16 is continuously reduced in the direction of fluid flow. The main reasons are as follows: 1) because along with the continuous flow of fluid, liquid is continuous condensation in the condenser pipe to make the fluid volume littleer and littleer too, consequently satisfy the change of the fluid volume that constantly increases and pressure through reducing the pipe diameter, thereby make pressure distribution even on the whole, the heat transfer is even. 2) Through the reduction of the pipe diameter of the heat absorption pipe, materials can be saved, and the cost is reduced.
Preferably, the pipe diameter of the condensation pipe 16 is continuously reduced 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, and by means of the arrangement, the circulating flow of the loop heat pipe can be further promoted, and the pressure is integrally uniform.
Preferably, a plurality of partitions are provided in the condensation duct 16, and the distance between the partitions increases from the inlet of the condensation duct 16 to the outlet of the condensation duct 16. Setting the distance between the two adjacent separating devices as H and 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 vapor in the condensing pipe 16 is continuously condensed in the descending process, the condensing pipe continuously releases heat in the descending process, so that the vapor in the gas-liquid two-phase flow is less and less, the vapor phase in the gas-liquid two-phase flow is less and less, the heat exchange capacity in the heat absorbing pipe is relatively increased along with the increase of the vapor phase, and the vibration and the noise thereof are also continuously reduced along with the increase of the vapor phase. The distance between adjacent spacers thus needs to be set larger and larger to save costs and achieve substantially the same effect.
Through the experiment discovery, through foretell setting, both can reduce vibrations and noise to the at utmost, can reduce the flow resistance simultaneously on the basis that reaches the heat transfer effect, reduce the cost.
It is further preferred that the distance between adjacent partitions increases from the inlet of the condensation duct 16 to the outlet of the condensation duct 16 to an increasingly greater extent. I.e. S "is the second derivative of S, the following requirements are met:
S”>0;
experiments show that the cost can be further reduced by about 7% and the flow resistance can be reduced by about 5% by the arrangement.
Preferably, a plurality of partitions are arranged in the condensation pipe, and the side length of the square is larger from the inlet of the condensation pipe 16 to the outlet of the condensation pipe 16. The distance from the inlet of the heat absorption tube is H, the side length of the square is C, and C is 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 condensing pipe to the outlet of the condensing pipe is increased continuously in a larger and larger range. 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 condensation pipe is provided with a gap, and the outer end of the separation device is arranged in the gap.
Preferably, the condensation pipe is formed by welding a multi-section structure, and a separation device is arranged at the joint of the multi-section structure.
Through analysis and experiments, the spacing between the separating devices cannot be too large, the damping 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 damping and noise reduction effect is poor or the resistance is too large, so that the damping and noise reduction can be 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 absorbing pipe is less than or equal to 5Pa/M) is preferentially met through a large number of experiments, and the optimal relation of each parameter is arranged.
Preferably, the distance between adjacent separators is S1, the side length of the square through hole is L1, the heat absorption tube is a square section, and the side length of the square section of the heat absorption 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。
more preferably, a is 39.87, b is 9.20, and c is 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 of the inner side length and the outer side length of the square through hole, and the side length L2 of the square section of the heat absorbing pipe is the average of the inner side length and the outer side length of the heat absorbing pipe.
Preferably, the outer side length of the square through hole is equal to the inner side length of the square section of the heat absorbing pipe/the condensing pipe.
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.
Preferably, as shown in fig. 6, the evaporation part includes a plurality of heat absorption pipes 15, which are parallel-structured. The condensing part includes a plurality of condensing tubes 16, and the plurality of condensing tubes 16 are parallel structures connected in parallel.
Learn through analysis and experiment, the interval of heat-absorbing pipe or condenser pipe also satisfies certain requirement, for example can not be too big or the undersize, no matter too big or the undersize can lead to the heat transfer effect not good, because set up separator in this application heat-absorbing pipe moreover, consequently separator also has certain requirement to the heat-absorbing pipe 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 absorbing pipe is less than or equal to 5Pa/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 absorbing pipe is a square section, the side length of the heat absorbing pipe is L2, and the distance between the centers of the adjacent heat absorbing pipes is S2, so that the following requirements are met:
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 between the centers of adjacent absorber tubes is S2, which is the distance between the centerlines of the absorber tubes.
More preferably, d is 0.282, e is 1.347, f is 0.062, and h is 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.
The empirical formula and various changes of law after being studied in a large scale are not limited to the heat absorption pipe, but also meet the requirements of the condensation pipe 16. That is, the distance between the adjacent separators of the condensation tubes provided with the separators is S1, the side length of the square is L1, the heat absorption tube has a square section, the side length of the heat absorption tube is L2, and the distance between the centers of the adjacent heat absorption tubes is S2.
Preferably, the length L of the heat absorption pipe or the condensation pipe 16 is between 2000 and 2500 mm. More preferably, 2200-.
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 pipe is water.
Preferably, the pipe diameter of the heat absorption pipe is larger than that of the condensation pipe. The resistance of the condensing pipe is mainly increased, and the resistance of the evaporation part is reduced, so that steam flows from the evaporation part more easily, and the loop heat pipe forms circulation better.
Preferably, the condensation duct 16 and the heat absorption duct 15 are both vertically disposed.
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 loop heat pipe comprises an evaporation part, a condensation part, and an insulation part and a reflux part which are connected with the evaporation part and the condensation part, wherein fluid absorbs heat and evaporates in the evaporation part, enters the condensation part through the insulation part, is condensed after heat exchange in the condensation part, and returns to the evaporation part through the reflux part; the solar water heater is characterized in that the evaporation part comprises a heat absorption pipe, the condensation part comprises a condensation pipe, and the pipe diameter of the heat absorption pipe is larger than that of the condensation pipe;
a separating device is arranged in the heat absorbing pipe, the separating device is of a sheet structure, and the sheet structure is arranged on the cross section of the heat absorbing 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 deformed through hole are sides of four different square through holes respectively.
2. A loop heat pipe as claimed in claim 1 wherein said heat absorbing tube is square in cross-section.
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CN106091759A (en) * 2016-06-08 2016-11-09 中国航天空气动力技术研究院 A kind of type separating heat-pipe evaporator of rotating flow heating
CN107062960A (en) * 2017-04-28 2017-08-18 山东大学 A kind of loop circuit heat pipe of annular and separation device short transverse change
CN107131783A (en) * 2017-04-21 2017-09-05 青岛金玉大商贸有限公司 A kind of porous constant-current stabilizer loop circuit heat pipe
CN107167009A (en) * 2017-04-28 2017-09-15 山东大学 The annular and separation device loop circuit heat pipe of hydraulic diameter change
CN107835617A (en) * 2017-11-01 2018-03-23 深圳兴奇宏科技有限公司 Loop heat pipe structure

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SU1332140A1 (en) * 1986-04-28 1987-08-23 Киевский Политехнический Институт Им.50-Летия Великой Октябрьской Социалистической Революции Heat exchange pipe for vertical heat exchanger
CN106091759A (en) * 2016-06-08 2016-11-09 中国航天空气动力技术研究院 A kind of type separating heat-pipe evaporator of rotating flow heating
CN107131783A (en) * 2017-04-21 2017-09-05 青岛金玉大商贸有限公司 A kind of porous constant-current stabilizer loop circuit heat pipe
CN107062960A (en) * 2017-04-28 2017-08-18 山东大学 A kind of loop circuit heat pipe of annular and separation device short transverse change
CN107167009A (en) * 2017-04-28 2017-09-15 山东大学 The annular and separation device loop circuit heat pipe of hydraulic diameter change
CN107835617A (en) * 2017-11-01 2018-03-23 深圳兴奇宏科技有限公司 Loop heat pipe structure

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