JP2009129971A - Heat transfer apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer apparatus having a new structure which is excellent in the efficiency of heat transportation from a high temperature side heat source to a low temperature side heat source and which improves a function deterioration due to dryout. <P>SOLUTION: A heat transfer apparatus 10 has an evaporation container 15 comprising a heat conductive plate 12 for heating a liquid using a heat source, a fluid channel 13 formed on the heat conductive plate, a fluid inlet 14 for supplying the liquid to the fluid channel, and a steam recovery chamber 16 in communication with the outlet of the fluid channel. A pump function is exerted so that the liquid and the steam of the liquid are transported to the outlet of the fluid channel in one direction by using a change in volume when the liquid supplied to the fluid channel is heated to a temperature equal to or more than a boiling point by the heat conductive plate and evaporated. Dryout is prevented by forming a minute gap channel 18 in communication between the fluid channels on the heat conductive plate and securing a non boiling region in which the liquid is not evaporated. The minute gap channel is desirably formed such that the channel gives a minute gap h1 of ≤0.05 mm to the heat conductive plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat transfer device, and more particularly to a heat transfer device that can efficiently transfer heat from a high temperature side heat source to a low temperature side heat source by heating a working liquid. Although it is possible to drive the liquid with power from the outside, the heat transfer device of the present invention can be suitably implemented particularly as moving the working liquid without applying power from the outside.

  The heat transfer device as described above is used, for example, in an electronic device in which a large number of local heating elements such as a CPU and a laser diode are arranged to prevent the inside of the electronic device from being overheated. In such applications, space saving is also required.

  Conventionally adopted space-saving heat transfer devices include high-temperature heat conductors such as heat pipes, and local heat generation due to heat conduction by the metal outside the high-temperature heat conductor and heat transfer inside the working liquid. The mainstream is a method of transporting heat from a body to a heat radiating device such as a heat sink or a radiator having a large cross-sectional area and cooling the heat radiating device by forced air cooling.

  However, the above-described conventional heat transfer device can transfer heat from the high-temperature side heat source to the low-temperature side heat source without applying mechanical power, but the heat transport amount varies depending on the use posture, or the heat transfer surface When this liquid evaporates and drys out, the heat transport function may be degraded or stopped.

  Accordingly, an object of the present invention is to provide a heat transfer device having a novel configuration that has good heat transport efficiency from a high temperature side heat source to a low temperature side heat source and has a long life. More specifically, the present invention provides a heat transfer device capable of efficiently transporting heat from a high-temperature side heat source to a low-temperature side heat source, and in particular, improves both the change in the amount of heat transport depending on the use posture and the deterioration of function due to dryout It is an object of the present invention to provide a heat transfer device capable of increasing the amount of heat transport in a space-saving manner by providing a pump function for moving the liquid in one direction by evaporation of the working liquid.

  Regarding the heat transfer device that can solve the above-mentioned problems, the inventors, when placing spherical particles on the heat transfer surface in a liquid heated to a temperature higher than the boiling point, from the contact point of the heat transfer surface and the particles. A past report (Takahashi and Ishikawa, theory (B), 61-554 (1995), 1498) that foams stably from a small distance (for example, about 0.05 mm) and does not foam in the inner region including the contact point. ). Here, it is described that the heat flux flows from the heat transfer surface to the superheated liquid layer and particles, and in the vicinity of the contact, the wraparound of the heat flux to the cavity is suppressed, so that the region does not foam.

  Based on this report, the inventors have earnestly thought that a stable boiling heat transfer can be realized in a so-called horizontal boiling type microchannel heat sink by providing a fluid channel having a minute gap in addition to the microchannel. Through research and experimentation, the present invention was completed.

  That is, the heat transfer device according to the present invention includes a heat conduction plate for heating a liquid by a heat source, a fluid channel formed on the heat conduction plate, a liquid supply means for supplying the fluid to the fluid channel, and an outlet of the fluid channel. A vapor recovery chamber that communicates with the liquid channel, and the liquid supplied to the fluid channel is heated to a temperature equal to or higher than the boiling point by the heat conduction plate to evaporate the liquid and its vapor through the fluid channel. A pump function is exerted so as to move in one direction toward the outlet, and a minute gap channel communicating between the fluid channels is formed on the heat conduction plate, and the working liquid does not evaporate in the minute gap channel. It is characterized by being secured as a non-boiling region.

  According to the present invention, in a heat transfer device configured as a boiling type microchannel heat sink, a microgap channel communicating between fluid channels is formed, and the microgap channel is used as a non-boiling region where the working liquid does not evaporate. Since it is ensured, dryout can be prevented, the efficiency of heat transport from the high temperature side heat source to the low temperature side heat source can be improved, and the life can be extended.

  FIG. 1 is a schematic configuration diagram of a main part of a heat transfer device according to an embodiment of the present invention, and FIG. 2 is a partially broken exploded perspective view of a heat transfer device having a configuration according to this. The heat conduction device 10 includes a supply tank 11 to which a working liquid such as pure water is supplied, a heat conduction plate 12 for heating the working liquid (hereinafter “water”), and a fluid formed on the upper surface of the heat conduction plate 12. It has an evaporation container 15 having a channel 13 and a liquid inlet 14 for allowing water supplied to the supply tank 11 to flow into the fluid channel 13. A heating element (not shown) is attached below the heat conduction plate 12, and the water flowing through the fluid channel 13 is heated to a temperature equal to or higher than its boiling point by heat conduction to boil and evaporate. In addition, the code | symbol 19 in the heat transfer apparatus of FIG. 2 is later mentioned regarding FIG.

  A vapor recovery chamber 16 communicating with the fluid channel 13 is provided on both sides in the width direction of the evaporation container 15. When water is heated and evaporated by the heat conducting plate 12 while flowing through the fluid channel 13, water or water vapor is discharged from the inlet (liquid inlet 14) of the fluid channel 13 to the outlet (vapor recovery chamber 16) due to the volume change at that time. The pump function that moves in one direction is demonstrated. The fluid channel 13 gradually increases in width from the inlet (liquid inlet 14) to the outlet (steam recovery chamber 16) (see FIG. 1 (a) and FIG. 2), and the inlet (liquid flow The cross-sectional area of the outlet (opening leading to the steam recovery chamber 16) is designed to be larger than the cross-sectional area of the inlet 14) (see FIGS. 1B and 2).

  The upper lid 20 of the evaporation container 15 is provided so as to close the supply tank 11 and the vapor recovery chamber 16, but is provided with a liquid supply port 21 communicating with the supply tank 11 and a vapor discharge port 22 communicating with the vapor recovery chamber 16. . The steam recovered in the steam recovery chamber 16 is discharged from the steam outlet 22 to the outside of the evaporation container 15, and a circulation path is formed in which it is condensed and liquefied and then supplied from the liquid supply port 21 to the supply tank 11.

  In this heat conduction device 10, the rib 17 provided on the heat conduction plate 12 is floated from the upper surface of the heat conduction plate 12 to form the fluid channel 13, and the minute gap channel 18 is formed therebetween. In fluid communication with the fluid channel 13. The gap h1 of the minute gap channel 18 formed between the rib 17 and the heat conducting plate 12 is preferably 0.05 mm or less, for example, 0.03 mm. On the other hand, the gap h2 of the fluid channel 13 is not particularly limited as long as it is sufficiently larger than 0.05 mm, but it is, for example, about 20 mm. Therefore, as is clear from FIG. 1C, the portion where the fluid channel 13 is formed between the lower surface of the rib 17 and the heat conducting plate 12 becomes a recess, and the minute gap channel is formed between the heat conducting plate 12 and the lower surface. The portion where 18 is formed is formed in a concavo-convex shape that becomes a convex portion.

  The water supplied to the supply tank 11 is primarily heated through the heat conduction plate 12 and the rib 17 heated by the heating element, and further enters the fluid channel 13 from the liquid inlet 14 and further enters the heat conduction plate 12. Heated above. Since the fluid channel 13 communicates with the minute gap channel 18 provided below the rib 17 as described above, a part of the water flowing through the fluid channel 13 also flows into the minute gap channel 18. As will be described later, there is a characteristic that water does not evaporate in the minute gap channel 18 even when the heat conduction plate 12 is in an overheated state equal to or higher than the boiling point of water. That is, the minute gap channel 18 functions as a non-boiling region. On the other hand, in the fluid channel 13 in which a sufficient gap h2 is ensured between the heat conduction plate 12, when the heat conduction plate 12 is in an overheated state having a liquid boiling point or higher, the water becomes a boiling region.

  The above action will be described in more detail. The water in the minute gap channel 18 in which the gap h1 between the heat conducting plate 12 and the rib 17 is minute cannot allow the heat flux from the heat conducting plate 12 to wrap around the bubble core. It always exists as a liquid without evaporating, realizing a non-boiling region. This is the principle derived from the above report (Takahashi / Ishikawa, Mechanism (B), 61-554 (1995), 1498). On the other hand, in the fluid channel 13 where the gap h2 between the heat conducting plate 12 and the rib 17 is large, the heat flux from the heat conducting plate 12 wraps around the bubble nuclei, so that it becomes a boiling region where water evaporates. FIG. 3 shows a boiling / non-boiling state of water when the heat conduction device 10 of FIG. 1 is operated, and water is held as a liquid without evaporation in the shaded portion. As shown in the figure, in the minute gap channel 18, water is held as a liquid without evaporation, and it can be seen that this portion realizes a non-boiling region.

  On the other hand, liquid is always supplied near the inlet of the fluid channel 13, that is, near the liquid inlet 14. Further, as shown in FIG. 3, there is a boundary between vapor bubbles and water as a gas-liquid interface L near the liquid inlet 14, and surface tension is generated by the interface L, so that the liquid flows into the fluid channel 13. Sucked into. Therefore, as shown by shading in FIG. 3, it is ensured that liquid remains in the fluid channel 13 near the liquid inlet 14, and water enters the minute gap channel 18 from the liquid inlet 14.

  Note that when the vapor bubbles evaporated while flowing through the fluid channel 13 merge and grow large, water tends to move toward both the liquid inlet 14 and the vapor recovery chamber 16, but as described above, the liquid inlet 14 is prevented from flowing back to the liquid inlet 14 by the surface tension at the gas-liquid interface L formed near 14, and the liquid inlet 14 has a smaller cross-sectional area than the steam recovery chamber 16. The flow generated by the growth flows in one direction toward the steam recovery chamber 16 due to flow path resistance. When sufficient time has elapsed, the fluid channel 13 is substantially filled with steam, and the steam flows out of the steam recovery chamber 16.

  Needless to say, the present invention is not limited to the embodiments described above and shown in the drawings, and can take various forms within the scope of the invention described in the claims. For example, the working liquid used in the transmission device of the present invention is typically water, but any other possible liquid type can be used.

  Further, as the liquid supply mechanism for allowing the working liquid to flow into the fluid channel 13 and the minute gap channel 18, the liquid inflow port 14 is employed in the above embodiment, but a configuration as shown in FIG. 4 may be employed. In the embodiment shown in FIG. 4, a liquid inlet 14 for supplying liquid (water) from the supply tank 11 to the inlet side of the fluid channel 13 is provided as in the above embodiment, and in addition, a micro gap is provided. A plurality of liquid inflow holes 19 penetrating vertically through the ribs 17 provided above the channels 18 are formed at arbitrary intervals in the length direction of the ribs 17. According to this embodiment, the water in the supply tank 11 is supplied from the liquid inlet 14 to the inlet side of the fluid channel 13 and supplied directly from the plurality of liquid inlet holes 19 to the micro gap channel 18. As a result, the water supply to the minute gap channel 18 is more reliably ensured, and the non-boiling region can be ensured more reliably. Such a configuration is particularly effective when the diameter of the liquid inlet 14 is small.

  If the diameter of the liquid inflow hole 19 for supplying water directly to the micro gap channel 18 is too large, the liquid inflow hole 19 may boil while passing through the liquid inflow hole 19. Like the gap h1 of the gap channel 18, the diameter is preferably 0.05 mm or less.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the heat transfer apparatus by one Embodiment of this invention, (a) is longitudinal direction sectional drawing, (b) is bb arrow sectional drawing in (a), (c) is in (b). It is cc arrow sectional drawing. FIG. 2 is a partially broken exploded perspective view showing a heat transfer device configured according to FIG. 1. It is a figure which shows the boiling / non-boiling state of water when the heat conduction apparatus of FIG. 1 is operated. 3 (a) corresponds to FIG. 1 (c), and FIG. 3 (b) corresponds to FIG. 1 (b). It is a schematic block diagram of the heat transfer apparatus by other embodiment of this invention, (a) is sectional drawing, (b) is bb arrow sectional drawing in (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat transfer apparatus 11 Supply tank 12 Heat conduction plate 13 Fluid channel 14 Liquid inflow port 15 Evaporation container 16 Vapor recovery chamber 17 Rib 18 Micro gap channel 19 Liquid inflow hole 20 Evaporation container top lid 21 Liquid supply port 22 Vapor discharge port

Claims (4)

Evaporation comprising a heat conduction plate for heating a liquid by a heat source, a fluid channel formed on the heat conduction plate, a liquid supply means for supplying the fluid to the fluid channel, and a vapor recovery chamber communicating with the outlet of the fluid channel The container has a container, and the liquid and its vapor are moved in one direction toward the outlet of the fluid channel by the volume change when the liquid supplied to the fluid channel is heated to a temperature higher than the boiling point by the heat conducting plate and evaporated. A pump gap function is provided, and a minute gap channel communicating between the fluid channels is formed on the heat conducting plate, and the minute gap channel is secured as a non-boiling region where liquid does not evaporate. Heat transfer device. The heat transfer device according to claim 1, wherein the minute gap channel is formed so as to give a minute gap of 0.05 mm or less between the heat conduction plate. 3. The heat transfer device according to claim 1, wherein the liquid supply means supplies a liquid to an inlet of a fluid channel. The heat transfer device according to any one of claims 1 to 3, wherein the liquid supply means supplies a liquid to the minute gap channel.

Images