JP2016191509A - Loop type heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loop type heat pipe capable of ensuring high cooling performance.SOLUTION: A loop type heat pipe 1 includes: an evaporation unit 2 configured to evaporate working fluid from a liquid-phase state to a gas-phase state with heat from outside; a condensation unit 3 configured to condense the working fluid from the gas-phase state to the liquid-phase state by radiating heat to the outside; a steam pipe 4 configured to circulate gas-phase working fluid from the evaporation unit 2 to the condensation unit 3; and a liquid pipe 5 configured to circulate liquid-phase working fluid from the condensation unit 3 to the evaporation unit 2. The evaporation unit 2 has an evaporation pipe 13 arranged below the condensation unit 3 and extending in a vertical direction, and a lower header part 30 connecting a lower end 13a of the evaporation pipe 13 and the liquid pipe 5. In the vicinity of a connection place 30 between the lower header part 30 and the liquid pipe, laid is a porous material 16 for preventing gas-phase working fluid from flowing back from the lower header part 30 to the liquid pipe 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a loop heat pipe.

  The loop type heat pipe is a gas-liquid separator by a gas pipe connected from the upper header and a liquid return pipe connected to the lower header to a heater having a plurality of vertical flow paths connecting the upper header and the lower header. Is connected. Furthermore, a radiator is provided above the heater, and the end connected to the opposite side of the radiator and the liquid return pipe of the lower header of the heater is connected by a return pipe to form a sealed circuit. An evaporative latent heat medium such as water or chlorofluorocarbon is enclosed (for example, see Patent Document 1).

  In the loop heat pipe (heat transfer device) described in Patent Document 1, the evaporative latent heat medium heated in the heater evaporates in the vertical flow path, becomes a gas-liquid two-phase state, and forms an upper header pipe and a gas. It is disclosed that the gas is introduced into the gas-liquid separator through the pipe, and the gas is led to the heat radiator through the outgoing pipe, condenses, and returned by gravity to one of the lower headers through the return pipe.

JP-A-3-213998

  In the loop heat pipe, the heat transferred to the heater (corresponding to the “evaporating part” in the present invention) is transferred to the lower header, and therefore the evaporative latent heat medium (corresponding to the “working fluid” in the present invention) in the lower header. ) May evaporate. In the loop type heat pipe in which a double pipe (corresponding to the “liquid pipe” of the present invention) is connected at a position substantially the same height as the lower header installed almost horizontally as described in Patent Document 1 above. The gas (which corresponds to the “gas phase working fluid” of the present invention) from which the evaporative latent heat medium has evaporated in the lower header is led to the radiator (corresponding to the “condensing portion” of the present invention) through the return pipe. It sometimes condensed. The fact that the evaporated gas goes to the radiator through the return pipe means that the gas must originally go from the upper header to the radiator through the outgoing pipe (corresponding to the “steam pipe” of the present invention). The gas flows backward, which hinders the circulation of the evaporative latent heat medium. As a result, the efficiency of the loop heat pipe is reduced, and high cooling capacity cannot be ensured.

  An object of this invention is to provide the loop type heat pipe which can ensure high cooling capacity.

  As a result of intensive studies to solve the above problems, the present inventors have found that the following problems can be solved by the following invention. That is, the loop heat pipe according to the present invention includes an evaporation unit that receives heat from the outside and evaporates the working fluid from the liquid phase to the gas phase, and a condensation that dissipates the heat to condense the working fluid from the gas phase to the liquid phase. A vapor pipe through which a vapor-phase working fluid flows from the evaporation section to the condensation section, and a liquid pipe through which a liquid-phase working fluid flows from the condensation section to the evaporation section, the evaporation section, The evaporating pipe is disposed below the condensing part and extends in the vertical direction, and has a lower header part connecting the lower end of the evaporating pipe and the liquid pipe, and the connection between the lower header part and the liquid pipe A porous body for preventing the working fluid in the gas phase from flowing back from the lower header portion to the liquid pipe is filled in the vicinity of the portion.

  According to the loop heat pipe according to the present invention, the porous body for preventing the working fluid in the vapor phase from flowing back from the lower header portion to the liquid pipe is filled in the vicinity of the connection portion between the lower header portion and the liquid pipe. Has been. Here, the porous body is a member that hinders the movement of liquid or gas. Both liquid and gas can pass through the porous body, but a predetermined pressure is required to pass through the porous body. That is, the porous body functions as a flow resistance of the liquid or gas, and can adjust the flow of the liquid or gas. The evaporating unit is arranged below the condensing unit, and the liquid working fluid is subjected to a predetermined vertical pressure due to gravity from the condensing unit to the evaporating unit, so the liquid working fluid is condensed. The liquid can pass through the porous body from the section to the evaporation section. However, even if the vapor-phase working fluid evaporated in the lower header part does not move toward the vapor pipe but moves toward the liquid pipe, a predetermined pressure is applied to the vapor-phase working fluid from the evaporation part to the liquid pipe. Therefore, the working fluid in the gas phase is stopped by the porous body and cannot move to the liquid pipe. As a result, it becomes possible to prevent the gas-phase working fluid from flowing back from the liquid pipe to the condensing part, and a high cooling capacity can be secured.

Further, in the loop heat pipe according to the present invention, the lower header portion includes a header connection portion connected to a lower end of the evaporation pipe and a header main body portion connected to the liquid pipe, and the header main body portion is connected to the header. It is preferable that it is arrange | positioned below the part.
Thereby, the lower header part consists of a header connecting part connected to the lower end of the evaporation pipe and a header main part connected to the liquid pipe, and the header main part is arranged below the header connecting part. It is connected to the header body below the evaporator tube. As a result, since the gas-phase working fluid is less likely to move from the evaporation pipe to the liquid pipe, a high cooling capacity can be ensured.

In the loop heat pipe according to the present invention, the porous body is preferably a sintered metal or a foam metal.
This makes it difficult for the working fluid in the gas phase to move from the evaporation pipe to the liquid pipe, and in addition to ensuring high cooling capacity, the porous body is made of metal, so the porous body is deformed even under heated high temperature conditions. There is no risk of disassembling or disassembling.

  ADVANTAGE OF THE INVENTION According to this invention, the loop type heat pipe which can ensure high cooling capability can be provided.

It is a figure which shows the basic composition of the loop type heat pipe which concerns on embodiment of this invention. It is sectional drawing along the II-II line of FIG. It is a figure which shows the evaporation part of the loop type heat pipe which concerns on other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram showing a basic configuration of a loop heat pipe according to an embodiment of the present invention. As shown in FIG. 1, a loop heat pipe 1 receives heat from the outside and evaporates the working fluid from the liquid phase to the gas phase, and radiates the outside to condense the working fluid from the gas phase to the liquid phase. A condensing unit 3, a vapor pipe 4 that sends a vapor-phase working fluid (hereinafter referred to as “vapor”) from the evaporation unit 2 to the condensing unit 3, and a liquid-phase working fluid (hereinafter “ And a liquid pipe 5 for sending a “condensate”.

  The loop heat pipe 1 is filled with a working fluid that changes between a liquid phase and a gas phase. At the time of filling, the loop heat pipe 1 is sealed in a state where non-condensable gas such as air is degassed. As this working fluid, for example, water, alcohol, ammonia, chlorofluorocarbon alternative, or the like is used. The loop heat pipe 1 that distributes the working fluid therein is made of, for example, a metal having good thermal conductivity such as copper or a copper alloy.

  The operation in the loop heat pipe 1 will be described. Heat generated in a heating element (not shown) or the like is transmitted to the evaporation unit 2 (arrow C1 in FIG. 1). And the condensate which absorbed the heat in the evaporation part 2 vaporizes, and is sent to the condensation part 3 through the vapor | steam pipe | tube 4 (arrow A1 of FIG. 1). The steam sent to the condensing unit 3 releases heat to the outside (arrow C2 in FIG. 1) and liquefies to become a condensate. The condensed liquid passes through the liquid pipe 5 (arrow B1 in FIG. 1) and is sent again to the evaporation unit 2. As described above, the working fluid (condensate and vapor) circulates in the loop heat pipe 1 in one direction, and transports heat from the evaporation section 2 to the condensation section 3.

  Moreover, in the loop type heat pipe 1 of this embodiment, the condensation part 3 is arrange | positioned in the position higher than the evaporation part 2, and the condensed condensate can be actively recirculated by gravity. The condensing unit 3 may be provided with heat exchange fins that increase heat dissipation efficiency. Furthermore, a cooling fan that blows and cools the heat exchange fins may be provided.

  In the present embodiment, a control valve 51 is provided in the liquid pipe 5 through which the condensate flows to the evaporation unit 2. The control valve 51 adjusts the amount, flow, pressure and the like of the working fluid. Note that the control valve 51 may be omitted. Further, in order to prevent the steam from radiating heat inside the steam pipe 4 and condensing and changing into a condensed liquid, the steam pipe 4 may be provided with a heat insulating material. Furthermore, the inner surface of the steam pipe 4 may be subjected to a process of repelling the condensate generated in the interior so that the condensate that has dissipated heat and condensed in the interior of the steam pipe 4 flows downward in the vertical direction. . The inner surface of the liquid pipe 5 may be subjected to a process of repelling the condensate so that the condensate can easily flow to the evaporation unit 2.

  Next, the condensation unit 3 will be described in detail. The condensing unit 3 communicates with a tubular first steam header body 6 into which steam from the evaporator 2 flows, and the first steam header body 6, and extends in parallel in the horizontal direction from the first steam header body 6. A plurality (five in the present embodiment) of first steam header connection portions 7 and the first steam header connection portions 7 communicate with each other at one end 8a side, and extend in parallel vertically downward from the first steam header connection portions 7. A plurality of (in this embodiment, 35 in total (7 per each first steam header connecting portion)) condensing pipes 8 are provided. Further, the condensing unit 3 communicates with the other end 8b side of the condensing pipe 8 so as to face each first steam header connecting unit 7, and includes a plurality of first condensate header connecting units 9 extending in parallel in the horizontal direction, A first condensate header connecting portion 9 and a tubular first condensate header main body portion 10 communicating with one end are provided. Further, the condensing unit 3 is in a state where the temperature and pressure are lower than those of the evaporating unit 2.

  In the condensing part 3 having such a configuration, the steam that has flowed into the first steam header main body part 6 is divided into a plurality of first steam header connection parts 7. Then, the divided steam is further divided into a plurality of condensing pipes 8 (in this embodiment, it is divided into a maximum of 35 condensing pipes 8), and also dissipates heat to be condensed into a condensed liquid. The condensate condensed in each condensing tube 8 flows downward, joins at each first condensate header connection portion 9, and further collects in the first condensate header main body portion 10.

  The evaporation unit 2 will be described in detail. The evaporator 2 communicates with a tubular second condensate header main body 11 (corresponding to the “header main body” of the present invention) into which the condensate from the condensing unit 3 flows, and the second condensate header main body 11. A plurality of (5 in the present embodiment) second condensate header connecting portions 12 (corresponding to the “header connecting portions” of the present invention) extending in parallel in the horizontal direction from the second condensate header main body portion 11; A plurality (35 in this embodiment (each second condensate header connection) extending in parallel with each second condensate header connecting part 12 on the lower end 13a side and extending in parallel vertically from each second condensate header connecting part 12 7)) evaporating pipes 13). Furthermore, the evaporator 2 communicates with the upper end 13b of the evaporator tube 13 so as to face each second condensate header connector 12, and a plurality of second vapor header connectors 14 extending in parallel in the horizontal direction, The second steam header connecting portion 14 and a second steam header main body portion 15 communicating with one end are provided. Further, the evaporator 2 is in a state of higher temperature and pressure than the condenser 3. In this embodiment, the second condensate header body 11 (corresponding to the “header body” of the present invention) and the second condensate header connecting part 12 (corresponding to the “header connection” of the present invention) are combined. The lower header portion 30 is referred to as the lower header portion in the present invention.

  Next, the lower header portion 30 of this embodiment will be described in detail with reference to FIGS. 1 and 2. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIG. 1, a porous body is formed in the vicinity of the connection portion 40 between the tubular second condensate header main body 11 and the liquid pipe 5 and inside the second condensate header main body 11 on the liquid pipe 5 side. 16 is arranged. Further, as shown in FIG. 2, the porous body 16 is filled in the tube of the second condensate header main body 11. In addition, the connection location 40 of the 2nd condensate header main-body part 11 and the liquid pipe 5 in this embodiment is a connection part of the 2nd condensate header main-body part 11 extended in a horizontal direction, and the liquid pipe 5 extended in a perpendicular direction. Say.

  The porous body 16 may be any member that allows a working fluid to pass through by applying a predetermined pressure. The porous body 16 generates a gas inside a sintered metal body obtained by sintering a metal powder or a molten metal, thereby forming pores therein. It is preferable that the foam metal is formed. The metal powder forming the metal sintered body can be used as appropriate depending on the type of working fluid such as copper, aluminum, iron, copper alloy and the material of the loop heat pipe 1. When the porous body 16 made of the second condensate header body 11 and the metal sintered body is joined by sintering, it is more preferable to use the same metal for the second condensate header body 11 and the metal sintered body. preferable. In this case, the step of manufacturing the porous body 16 made of a metal sintered body by sintering the metal powder and the step of joining the second condensate header main body 11 and the porous body 16 by sintering are performed simultaneously. May be. This can reduce the number of manufacturing steps and simplify the manufacturing steps. The metal forming the metal foam can be appropriately used according to the type of working fluid such as copper, aluminum, iron, copper alloy and the material of the loop heat pipe 1. When joining the 2nd condensate header main-body part 11 and the porous body 16 which consists of a metal foam by sintering, it is more preferable to use the same metal for the 2nd condensate header main-body part 11 and a metal foam. When the porous body 16 is made of a metal such as a metal sintered body or a foam metal, the porous body 16 is heated even if the heat generated in the heating element or the like is transmitted to the porous body 16 and the porous body 16 is heated. There is no possibility that 16 will be deformed or disassembled.

  In addition, the porous body 16 may be a porous body made of a metal mesh laminate in which several metal meshes are combined depending on the type of working fluid and the amount of heat received from the heating element. In addition, a porous body made of a ceramic such as a metal oxide or a metal nitride can be used, or a porous body made of a nonmetal not containing a metal such as a porous carbon material can be used. Furthermore, when the heat receiving temperature is low, a porous body made of a resin material such as sponge may be used.

  In the present embodiment, the porous body 16 can pass both liquid and gas, but functions as a fluid resistance that prevents the movement of the working fluid, and in order to pass through the porous body 16, the working fluid It is adjusted so that a predetermined pressure is required with respect to the moving direction. For example, although pressure due to gravity is applied from the liquid pipe 5 toward the second condensate header body 11, pressure as high as gravity is not applied from the second condensate header body 11 toward the liquid pipe 5. Therefore, the predetermined pressure is between the pressure at which the vapor exceeds the pressure from the second condensate header main body portion 11 toward the liquid pipe 5 and the aggregated liquid is equal to or less than the pressure at which the condensed liquid flows from the liquid pipe 5 toward the second condensate header main body 11 Is appropriately selected. Therefore, the aggregate liquid can move from the liquid pipe 5 side to the second condensate header connecting portion 12 through the porous body 16 in the second condensate header main body 11. However, since the pressure as high as the predetermined pressure is not applied from the second condensate header body 11 toward the liquid pipe 5, the vapor is supplied from the second condensate header connection part 12 side to the second condensate header body 11. It cannot pass through the inner porous body 16 and cannot move to the liquid pipe 5. That is, the porous body 16 prevents vapor from flowing back from the evaporation unit 2 through the liquid pipe 5 to the condensing unit 3.

  The flow of the working fluid in the evaporation unit 2 of the present embodiment and the operation of the loop heat pipe 1 according to the present embodiment will be described. As for the condensate, the condensate flowing into the second condensate header main body 11 from the liquid pipe 5 passes through the porous body 16 and is divided into a plurality of second condensate header connection parts 12. The separated condensate is further divided into a plurality of evaporation pipes 13 (in this embodiment, divided into a maximum of 35 evaporation pipes 13) and receives heat to evaporate to become steam. The vapor evaporated in each evaporation pipe 13 flows upward, merges at each second vapor header connection portion 14, and further collects in the second vapor header main body portion 15. At this time, the second condensate header connecting part 12 connected to the evaporation pipe 13 and the second condensate header main body 11 connected to the second condensate header connecting part 12 also receive heat received by the evaporation pipe 13. Communicate. Therefore, in the second condensate header main body 11 and the second condensate header connection part 12, the condensate may receive heat and evaporate to become steam. The vapor generated in the second condensate header main body 11 and the second condensate header connection part 12 may not flow toward the evaporation pipe 13 side and may flow back to the liquid pipe 5 side depending on circumstances.

  However, in the loop heat pipe 1 according to the present embodiment, in the vicinity of the connection portion 40 between the lower header portion 30 and the liquid pipe 5 (in the present embodiment, the inside of the second condensate header main body 11 on the liquid pipe 5 side). The porous body 16 for preventing the vapor from flowing back from the lower header portion 30 to the liquid pipe 5 is filled. As described above, the porous body 16 functions as a fluid resistance through which the working fluid passes by the pressure due to gravity.

  And in the loop type heat pipe 1 which concerns on this embodiment, the evaporation part 2 is arrange | positioned below the condensation part 3, and condensate is sent from the condensation part 3 toward the evaporation part 2 (more specifically, The condensate in the vertical direction due to gravity (from the liquid pipe 5 to the second condensate header body 11 side, and further from the second condensate header body 11 toward the plurality of second condensate header connections 12). Since the predetermined pressure is applied, the condensate can pass from the condensing unit 3 through the liquid pipe 5 to the porous body 16 and move to the evaporation unit 2. However, even if the vapor evaporated in the lower header portion 30 does not move toward the evaporation pipe 13 and moves toward the liquid pipe 5, a predetermined pressure is not applied to the vapor from the evaporation section 2 to the liquid pipe 5. The vapor is stopped by the porous body 16 and cannot move to the liquid pipe 5. As a result, it is possible to prevent the vapor from flowing back from the liquid pipe 5 to the condensing unit 3, and a high cooling capacity can be ensured.

  Subsequently, a loop heat pipe according to another embodiment will be described. FIG. 3 is a view showing an evaporation section of a loop heat pipe according to another embodiment of the invention. The loop heat pipe 21 according to the other embodiment is that the second condensate header main body 11 is disposed below the second condensate header connecting part 12. And different.

  Since the second condensate header connecting portion 12 is connected to the evaporation pipe 13, the condensate in the second condensate header connecting portion 12 is heated more than the condensate in the second condensate header main body 11. It is easy for steam to be generated. However, since the second condensate header main body 11 is disposed below the second condensate header connecting part 12, steam is transferred from the second condensate header connecting part 12 to the second condensate header main part 11. Difficult to move. Therefore, in the second condensate header main body 11 and the second condensate header connection part 12, even if the condensate receives heat and evaporates into vapor, it occurs in the second condensate header connection part 12. The steam cannot flow back to the second condensate header body 11. Therefore, the vapor | steam which the porous body 16 must prevent a backflow becomes only the vapor | steam which generate | occur | produced in the 2nd condensate header main-body part 11. FIG. That is, since the 2nd condensate header main-body part 11 is arrange | positioned below the 2nd condensate header connection part 12, the quantity of the vapor | steam which the porous body 16 must prevent a backflow reduces. Therefore, the load applied to the porous body 16 is reduced, and the porous body 16 is hardly deteriorated. In addition, a thinner porous body 16 can be used.

  As described above, in the loop heat pipe 21 according to another embodiment, the lower header part 30 is connected to the second condensate header connecting part 12 and the liquid pipe 5 connected to the lower end 13a of the evaporation pipe 13. The second condensate header main body 11 is arranged below the second condensate header connecting part 12.

  Accordingly, the lower header portion 30 includes the second condensate header connecting portion 12 connected to the lower end 13a of the evaporation pipe 13 and the second condensate header main body portion 11 connected to the liquid pipe 5, and the second condensate header main body. Since the part 11 is disposed below the second condensate header connection part 12, the liquid pipe 5 is disposed below the evaporation pipe 13. As a result, it is difficult for the vapor to move from the evaporation pipe 13 through the liquid pipe 5, so that a high cooling capacity can be ensured.

  In the present embodiment, the porous body 16 is filled only on the liquid pipe 5 side of the tubular second condensate header body 11, but the porous body 16 is filled with the second condensate header body 11. If it arrange | positions in the connection location 40 vicinity of the liquid pipe 5 and it will not be specifically limited. For example, only the inside of the liquid pipe 5 may be filled, or the liquid pipe 5 and the second condensate header main body 11 may be filled.

DESCRIPTION OF SYMBOLS 1,21 ... Loop type heat pipe 2 ... Evaporating part 3 ... Condensing part 4 ... Steam pipe 5 ... Liquid pipe 6 ... 1st steam header main-body part 7 ... 1st steam header connection part 8 ... Condensation pipe 9 ... 1st condensate Header connection part 10 ... first condensate header body part 11 ... second condensate header body part 12 ... second condensate header connection part 13 ... evaporation pipe 14 ... second steam header connection part 15 ... second steam header body part 16 ... Porous body 30 ... Lower header part 40 ... Connection location 51 ... Control valve

Claims (3)

An evaporation unit that receives heat from outside and evaporates the working fluid from the liquid phase to the gas phase, a condensing unit that radiates heat to the outside and condenses the working fluid from the gas phase to the liquid phase, and an evaporation unit from the evaporation unit to the condensing unit. A steam pipe for circulating a working fluid of a phase, and a liquid pipe for circulating a working fluid of a liquid phase from the condensing unit to the evaporation unit,
The evaporation unit is disposed below the condensing unit, and includes an evaporation pipe extending in a vertical direction, a lower header part connecting the lower end of the evaporation pipe and the liquid pipe, and the lower header part. A loop-type heat pipe, wherein a porous body for preventing a working fluid in a gas phase from flowing back from the lower header portion to the liquid pipe is filled in the vicinity of the connection portion of the liquid pipe.   The lower header part is composed of a header connection part connected to the lower end of the evaporation pipe and a header main part connected to the liquid pipe, and the header main body part is disposed below the header connection part. The loop heat pipe according to claim 1.   The loop heat pipe according to claim 1 or 2, wherein the porous body is a sintered metal or a foam metal.

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