JP2018046245A - Boiling cooling device - Google Patents

Abstract

An object of the present invention is to provide a technique capable of promoting separation of air bubbles from heat radiation fins. An evaporative cooling device (2) includes an inlet (12) through which a refrigerant flows, an outlet (14) through which the refrigerant flows, and a boiler (16) through which the refrigerant flows from the inlet (12) to the outlet (14). The boiler 16 is disposed on the inner surface of the bottom surface portion 24 and has a heat radiation plate 40 thermally connected to the heating element 60 on its outer surface, a plurality of heat radiation fins 50 protruding from the inner surface of the heat radiation plate 40, and a plurality of heat radiation The fin 50 has an upper wall 22 facing the tip of the fin 50 with a space therebetween. The flow velocity of the refrigerant in the boiler 16 is faster in the region from the tips of the radiating fins 50 to the inner surface of the upper wall 22 than in the region from the inner surface of the radiating plate 40 to the tips of the radiating fins 50. Each of the plurality of radiating fins 50 is formed in a pin shape, and its tip is inclined so as to approach the upper wall 22 along the direction in which the refrigerant flows. [Selection diagram] Fig. 1

Description

  The technology disclosed in the present specification relates to a boiling cooling apparatus.

  A boiling cooling device is known that includes an inlet through which a refrigerant flows, an outlet through which the refrigerant flows out, and a boiling device through which the refrigerant flows from the inlet toward the outlet. The boiling device has a bottom wall portion whose outer surface is thermally connected to the heating element, a plurality of radiating fins protruding from the inner surface of the bottom wall portion, and an upper wall facing the tips of the plurality of radiating fins with a space therebetween Part. The flow rate of the refrigerant in the boiling device is, for example, due to the resistance of the radiation fins, rather than the region from the inner surface of the bottom wall portion to the tips of the plurality of radiation fins (that is, the region where the radiation fins are present). To the inner surface of the upper wall portion (that is, a region where there is no radiating fin). Such a flow velocity difference makes it easier for the refrigerant to boil in the radiating fin, and a large amount of heat can be recovered from the heating element. An example of such a boiling cooling device is disclosed in Patent Document 1.

JP 2013-16589 A

  In the boiling cooling device, bubbles are generated on the surface of the heat radiation fins when the refrigerant boils. At this time, if the generated bubbles continue to adhere to the radiating fins, the contact between the new refrigerant and the radiating fins is hindered, and the cooling performance may be deteriorated. In this specification, the technique which can accelerate | stimulate that a bubble detach | leaves from a thermal radiation fin is provided.

  The boiling cooling device disclosed in the present specification includes an inlet through which a refrigerant flows, an outlet through which the refrigerant flows out, and a boiling device through which the refrigerant flows from the inlet toward the outlet. The boiling device has a bottom wall portion whose outer surface is thermally connected to the heating element, a plurality of radiating fins protruding from the inner surface of the bottom wall portion, and an upper wall facing the tips of the plurality of radiating fins with a space therebetween Part. The flow rate of the refrigerant in the boiling device is faster in the region from the tips of the plurality of radiating fins to the inner surface of the upper wall portion than in the region from the inner surface of the bottom wall portion to the tips of the radiating fins. Each of the plurality of radiating fins is formed in a pin shape, and the tip thereof is inclined so as to approach the upper wall portion along the direction in which the refrigerant flows.

  Here, the terms “bottom wall” and “upper wall” do not limit the orientation of the boiling device. Therefore, for example, the boiling device may be installed in such a direction that the bottom wall portion is located above and the top wall portion is located below. The term “bottom wall portion whose outer surface is thermally connected to the heating element” is not limited to the case where the outer surface of the bottom wall portion is in direct contact with the heating element. Other objects may be interposed between the outer surface of the bottom wall portion and the heating element as long as they are thermally connected (that is, connected in a state where heat can be transferred).

  In the above boiling cooling device, the pressure is lower in the region where the radiating fins are not present than in the region where the radiating fins are present due to the flow rate difference of the refrigerant. Due to this pressure difference, a refrigerant flow is formed in a direction away from the plurality of radiating fins, and the separation of bubbles attached to the radiating fins is promoted. Furthermore, in the above-described boiling cooling device, each of the plurality of radiating fins is formed in a pin shape, and the tip thereof is inclined so as to approach the upper wall portion along the direction in which the refrigerant flows. Therefore, when the refrigerant flows along the heat radiating fins having this shape, the flow of the refrigerant in the direction away from the plurality of radiating fins is more easily formed. As a result, bubbles generated when the refrigerant boils are easily separated from the radiation fins. Therefore, according to the above-described boiling cooling device, the separation of bubbles from the heat radiating fins can be promoted.

The figure explaining the structure of the boiling cooling device of an Example. The figure which illustrates a mode that a bubble isolate | separates from a radiation fin.

(Example)
FIG. 1 shows a boiling cooling device 2 of this embodiment. The boiling cooling device 2 is a cooling device that cools the heating element 60 by boiling the refrigerant flowing in the boiling device 16 by the heat of the heating element 60. In the present embodiment, LLC (Long Life Coolant) used for cooling a vehicle engine is used as the refrigerant. In other examples, other refrigerants may be used. The heating element 60 to be cooled is, for example, a switching element.

  The boiling cooling device 2 includes an inlet 12, an outlet 14, and a boiling device 16. The inlet 12 is a refrigerant inlet. The refrigerant flows into the boiling device 16 through the inlet 12. As shown in FIG. 1, a partition plate 13 is provided at the inlet 12, and the refrigerant inflow path is divided into two. The outlet 14 is a refrigerant outlet. The refrigerant in the boiler 16 flows out through the outlet 14. Arrows F1 to F6 in FIG. 1 indicate the flow of the refrigerant. In the boiling device 16, the refrigerant mainly flows in the positive direction of the X axis of the coordinate system in FIG. Hereinafter, the positive direction side of the X axis may be referred to as “downstream side”, and the negative direction side of the X axis may be referred to as “upstream side”. In this embodiment, the diameter of the inlet 12 is larger than the diameter of the outlet 14. In another example, the diameter of the inlet 12 and the diameter of the outlet 14 may be substantially equal.

  The boiling device 16 includes a housing 20, a heat radiating plate 40, and a plurality of heat radiating fins 50. The housing 20 is a box-shaped case that constitutes the main body of the boiling device 16. The housing 20 includes an upper wall part 22, a bottom wall part 24, an upstream side wall part 26, a downstream side wall part 28, and side wall parts 30 and 32.

  The upper wall portion 22 is a wall portion that is parallel to the XY plane of the coordinate system in FIG. 1 and is located on the positive side of the Z axis among the wall portions of the boiling device 16. Hereinafter, the positive direction side of the Z axis in FIG. 1 may be referred to as “upper side” and the negative direction side of the Z axis may be referred to as “lower side”. The outlet 14 is formed on the downstream side of the upper wall portion 22. The bottom wall portion 24 is a wall portion that is parallel to the XY plane and located on the lower side. An opening 34 is formed in the bottom wall portion 24. The upstream side wall portion 26 is a wall portion that is parallel to the YZ plane and located on the upstream side. The inlet 12 is formed in the upstream side wall portion 26. The downstream side wall portion 28 is a wall portion that is parallel to the YZ plane and located on the downstream side. The side wall portions 30 and 32 are each a wall portion parallel to the XZ plane.

  The heat radiating plate 40 is a plate-like member and is disposed on the inner surface of the bottom wall portion 24. The heat radiating plate 40 is disposed so as to close the opening 34 of the bottom wall portion 24. As a result, the refrigerant flowing in the boiling device 16 is prevented from leaking out from the opening 34. When the boiling cooling device 2 is used, the heating element 60 is brought into contact with the outer surface of the heat radiating plate 40 (that is, the surface on the negative direction side of the Z axis in the drawing). Further, the heat radiating plate 40 can be removed from the inner surface of the bottom wall portion 24 while the boiling cooling device 2 is not used. The combination of the heat sink 40 and the bottom wall portion 24 in this embodiment is an example of the “bottom wall portion” in the claims.

  The plurality of radiating fins 50 are members that protrude upward from the inner surface of the radiating plate 40 (that is, the surface on the positive side of the Z axis). Hereinafter, when each of the plurality of heat radiation fins 50 is referred to without distinction, it may be simply referred to as “heat radiation fin 50”. The radiation fin 50 is formed in a pin shape. The tips of the radiating fins 50 are opposed to the upper wall portion 22 with a space therebetween. The tips of the radiating fins 50 are inclined surfaces that form an angle with respect to the direction in which the refrigerant flows (that is, the directions of arrows F3 and F4 in FIG. 1). Inclined to approach. The radiating fins 50 are arranged at a constant interval from each other. A part of the refrigerant that has flowed into the boiling device 16 flows between the radiation fins 50 (see arrow F4 in FIG. 1). Since the heat of the heat generating element 60 is transmitted to each radiation fin 50 via the heat radiation plate 40, each radiation fin 50 becomes high temperature. Therefore, when the refrigerant flowing between the radiating fins 50 touches the radiating fins 50, the refrigerant collects the heat of the radiating fins 50 (ie, absorbs heat) and boils.

  In the present embodiment, as shown in FIG. 2, the region from the inner surface of the bottom wall portion 24 to the tip of the radiating fin 50 (that is, the radiating fin 50 is disposed in the boiling device 16 due to resistance caused by the radiating fin 50 or the like. The flow velocity V2 of the refrigerant in the region from the tip of the radiating fin 50 to the inner surface of the upper wall portion 22 (that is, the region where the radiating fin 50 does not exist) is faster than the flow velocity V1 of the refrigerant in the existing region. Such a flow velocity difference makes it easier for the refrigerant to boil in the radiating fin 50, and a large amount of heat can be recovered from the heating element 60.

  When the refrigerant boils in the radiating fin 50, bubbles (that is, a gas-phase refrigerant) are generated on the surface of the radiating fin 50. At this time, if the generated bubbles continue to adhere to the radiating fins 50, the contact between the new refrigerant and the radiating fins is hindered, and the cooling performance may be deteriorated.

  In this regard, in the boiling cooling device 2 of the present embodiment, the pressure is lower in the region where the radiating fins 50 are not present than in the region where the radiating fins 50 are present due to the difference in flow rate of the refrigerant. Due to this pressure difference, as shown by an arrow F10 in FIG. 2, a refrigerant flow is formed in a direction away from each radiation fin 50. Thereby, the separation of the bubbles adhering to the heat radiating fins 50 is promoted (see symbol B in FIG. 2). The above-described flow rate difference of the refrigerant can be further increased by changing the shape of the inlet 12, the position and orientation of the partition plate 13, the cross-sectional area of the flow path through which the refrigerant flows, and the like.

  Furthermore, in the boiling cooling device 2 of the present embodiment, the radiating fins 50 are formed in a pin shape, and the tips thereof are inclined so as to approach the upper wall portion 22 along the direction in which the refrigerant flows. For this reason, when the refrigerant flows along the heat radiating fins 50 having this shape, the flow of the refrigerant in the direction away from the plurality of the heat radiating fins 50 is more easily formed. More specifically, when the refrigerant flows along the inclination of the tips of the radiating fins 50, the refrigerant can easily flow away from the plurality of radiating fins 50. Thereby, bubbles generated when the refrigerant boils easily separate from the heat radiation fin 50. According to the boiling cooling device 2 of the present embodiment, it is possible to promote the detachment of the bubbles from the radiating fins 50. As a result, a decrease in cooling performance can be suppressed.

  As mentioned above, although the specific example of the technique disclosed by this specification was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(Modification 1) In the above embodiment, the boiling device 16 is installed in such an orientation that the bottom wall portion 24 is located on the lower side and the upper wall portion 22 is located on the upper side. However, the direction in which the boiling device 16 is installed is not limited to this, and can be arranged in an arbitrary direction. For example, the boiling device 16 may be installed in such an orientation that the bottom wall portion 24 is located on the upper side and the upper wall portion 22 is located on the lower side.

(Modification 2) In the above embodiment, the outer surface of the heat sink 40 is in direct contact with the heating element 60. Not limited to this, as long as the outer surface of the heat radiating plate 40 and the heating element 60 are thermally connected (that is, connected in a state where heat can be transferred), other heat sink 40 is connected between the outer surface of the heat radiating plate 40 and the heating element 60. An object may intervene.

(Modification 3) In the above embodiment, the heat sink 40 is formed separately from the bottom wall 24. However, the heat radiating plate 40 may be formed integrally with the bottom wall 24.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Boiling cooling device 12: Inlet 13: Partition plate 14: Outlet 16: Boiler 20: Housing 22: Upper wall part 24: Bottom wall part 26: Upstream side wall part 28: Downstream side wall part 30: Side wall part 32: Side wall Portion 34: Opening 40: Radiation plate 50: Radiation fin 60: Heating element

Claims (1)

An inlet through which refrigerant flows,
An outlet through which the refrigerant flows;
A boiler through which the refrigerant flows from the inlet toward the outlet;
The boiling device has a bottom wall portion whose outer surface is thermally connected to a heating element, a plurality of radiating fins protruding from the inner surface of the bottom wall portion, and a front end of the plurality of radiating fins with a space therebetween. And an upper wall portion to be
The flow rate of the refrigerant in the boiling device is faster in the region from the front ends of the plurality of radiating fins to the inner surface of the upper wall portion than in the region from the inner surface of the bottom wall portion to the tips of the plurality of radiating fins,
Each of the plurality of radiating fins is formed in a pin shape, and the tip is inclined so as to approach the upper wall portion along a direction in which the refrigerant flows.
Boiling cooler.

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