JP7179170B2 - Self-excited oscillating heat pipe cooling device and railway vehicle equipped with the cooling device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling device using a self-oscillating heat pipe, and is suitable as a cooling device to be mounted on a railway vehicle.

Regarding the self-excited oscillating heat pipe used in the cooling device, Non-Patent Document 1 describes that one narrow flow path is reciprocated many times between the heating unit and the cooling unit, and this flow path is evacuated to a vacuum to evaporate. A liquid slug and a steam plug are formed by the surface tension effect by enclosing the liquid in about half of the volume of the channel, and as the amount of heating increases, the liquid slug vibrates spontaneously, moving from the heating section to the cooling section. It is described to transport heat.

Also, in Non-Patent Document 2, the influence of the initial gas-liquid distribution on the starting characteristics is evaluated by calculation using an internal flow model. In order for the self-excited oscillating heat pipe to start, the necessary conditions are that there is a difference in the void fraction of each turn in the initial state, or that liquid slag exists in the heating part and obtains the driving force by boiling. Says.

On the other hand, in Patent Document 1, a self-contained body having a structure in which a plurality of power semiconductor elements are arranged on one side of a heat receiving member and a heat dissipating portion composed of a self-excited oscillating heat pipe is installed on the opposite side of the other side of the heat receiving member. An excited oscillating heat pipe cooler is shown.

JP 2018-88744 A

Takao Nagasaki, "Review on heat transfer of self-oscillating heat pipes", Journal of the Heat Transfer Society of Japan, Vol. 44, No. 186 (May 2005), pp. 13-17 Takuro Daimaru, Shuhei Yoshida, Daiki Nagai, Atsushi Okamoto, Makiko Ando, Hiroyuki Sugita, "2E01 A study on self-oscillating heat pipe startup", 58th Space Science and Technology Joint Lecture Collection (2014), pp. 5-9 Daimaru, T. , Yoshida, S.; , Nagai, H.; "Study on thermal cycle in oscillating heat pipes by numerical analysis", Applied Thermal Eng. , 113 (2017), pp. 1219-1227

The knowledge shown in Non-Patent Document 2 is that, on the contrary, if the liquid slag and the steam plugs are evenly distributed in each turn, even if the heating part is heated, the steam plugs acting on both ends of the liquid slug The pressure remains the same, indicating no movement of the liquid slug and no self-oscillation.

Further, Patent Document 1 does not disclose a configuration for generating self-excited vibration when the initial distribution of liquid slag and steam plugs is uniform.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-oscillating heat pipe cooling device that generates self-oscillating vibrations and has excellent startability even when the initial distribution of liquid slag and steam plugs in the heat pipe is uniform. and

The self-excited oscillating heat pipe cooling device according to the present invention has a heat receiving part and a heat dissipating part which are formed by forming a wave-shaped pipe in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction. A heat pipe having a structure arranged alternately, a heat receiving member joined to a heat receiving part, and a heat generating element arranged on a surface of the heat receiving member opposite to a surface joined to the heat receiving part, wherein the heat generating element in the heat receiving member By making the arrangement asymmetric with respect to the central part in the longitudinal direction of the heat pipe, the temperature distribution of the heat receiving part in the longitudinal direction of the heat pipe is made asymmetric with respect to the central part in the longitudinal direction to generate self-excited vibration. It is characterized by

According to the present invention, even when the initial distribution of liquid slag and steam plugs in the heat pipe is uniform, the self-excited vibration heat pipe cooling device can generate self-excited vibration and has excellent startability. can provide.

1 is a side view showing the structure of a self-oscillating heat pipe cooling device according to Example 1 of the present invention; FIG. FIG. 2 is a diagram showing an example of a flow path structure of a self-excited oscillating heat pipe cooling device employed in an embodiment according to the present invention; FIG. 5 is a diagram showing another example of the flow path structure of the self-excited oscillating heat pipe cooling device employed in the embodiment according to the present invention; 4 is a diagram showing a cross-sectional structure of the self-excited oscillating heat pipe shown in FIG. 2 or FIG. 3; FIG. FIG. 2 is a diagram showing a schematic diagram of a self-oscillating heat pipe used for calculation and an initial gas-liquid distribution; It is a figure which shows the calculation result of the time change of gas-liquid distribution. FIG. 10 is a diagram showing the result of calculating the temperature distribution of the heat receiving portion at the start of self-excited vibration; It is a figure which shows the calculation result of the time change of the 5th and 6th liquid slug displacement from the left side of the center part of a heat pipe. FIG. 5 is a side view showing the structure of a self-oscillating heat pipe cooling device according to Embodiment 2 of the present invention; FIG. 11 is a side view showing the structure of a self-excited oscillating heat pipe cooling device according to Embodiment 3 of the present invention; FIG. 4 is a side view showing the structure of a self-oscillating heat pipe cooling device according to Embodiment 4 of the present invention; FIG. 11 is a side view showing the structure of a self-excited oscillating heat pipe cooling device according to Embodiment 5 of the present invention; FIG. 10 is a side view showing the structure of a self-excited oscillating heat pipe cooling device according to Embodiment 6 of the present invention;

Hereinafter, as modes for carrying out the present invention, Examples 1 to 6 will be described with appropriate reference to the drawings. In addition, the same code|symbol is attached|subjected to the part which is common in each figure, and the overlapping description is abbreviate|omitted.

Embodiment 1 FIG. 1 is a side view showing the structure of a self-oscillating heat pipe cooling device 100 according to Embodiment 1 of the present invention.
A self-oscillating heat pipe cooling device 100 is composed of a heat pipe 12 that self-oscillates, a heat receiving member 10 and a heating element 11 . The heating element 11 is arranged asymmetrically with respect to the central portion of the heat pipe 12 in the longitudinal direction. As the material of the heat pipe 12 and the heat receiving member 10, a metal such as an aluminum alloy or copper having good thermal conductivity is used.

The heat pipe 12 that self-oscillates has a shape in which it is bent into a U-shape a plurality of times at equal intervals along its longitudinal direction. One end of a plurality of U-shaped bent portions of the heat pipe 12 is joined to one surface of the heat receiving member 10 by brazing or the like to form a plurality of heat receiving portions 9 on the heat pipe 12 at regular intervals. In addition, a plurality of equally spaced portions of the heat pipe 12 other than the heat receiving portion 9 form a heat radiating portion 20 that exchanges heat with air 101 or 102 (winds in both directions with respect to the paper surface). Further, fins 13 are fixed by brazing or the like between the bent heat pipes 12 to form a heat radiating portion together with the heat pipes 12 .

The heating element 11 is arranged on the surface opposite to the surface of the heat receiving member 10 to which the heat receiving portion 9 of the heat pipe 12 is joined. The heat generating element 11 is disposed asymmetrically with respect to the central portion of the heat pipe 12 in the longitudinal direction, and is closer to one end portion 3 side. At that position, the heating element 11 is fixed by a screw or the like (not shown) via a member such as grease (not shown). Here, the heating element 11 is, for example, a power module provided with power semiconductor elements such as IGBTs and MOS-FETs.

2 and 3 are diagrams showing an example of the flow path structure of the self-excited oscillating heat pipe employed in the embodiments described later of the present invention. 4 is a view showing, for example, the AA cross section of FIG. 2 as the cross sectional structure of the self-oscillating heat pipe shown in FIG. 2 or FIG.

The self-oscillating heat pipe 12 shown in FIGS. 2 and 3 is composed of a multi-hole flat tube. As for the structure, for example, as shown in FIG. 2, a plurality of channels are arranged in parallel and do not communicate with each other in each row, and as shown in FIG. 3, a meandering channel is configured. may be Further, the tube constituting the self-excited oscillating heat pipe adopted by the present invention is not limited to the multi-hole flat tube described above. For example, as shown in FIG. good too.

A partition 2 is provided between adjacent channels 1, the diameter of the channel and the width of the partition (pitch between channels) are on the order of mm, and the length of the channel is sufficiently large compared to the diameter of the channel. to long.

As shown in FIG. 4, the thickness of the self-oscillating heat pipe 12 is set to about mm order from the viewpoint of thermal conductivity and ease of processing.
A working fluid (not shown) of half the volume of the channel is enclosed in the closed channel 1 .
Furthermore, in forming the self-excited vibration heat pipe into a corrugated shape, a plurality of straight multi-hole flat tubes having the same length are arranged in parallel in the thickness direction without using a bending process for the multi-hole flat tube. You may comprise by installing. That is, each end of a plurality of multi-hole flat tubes installed in parallel in the thickness direction is fixed using a member such as an end sealing member having a slit on the side of the multi-hole flat tube. By alternately communicating the ends of adjacent multi-hole flat tubes at each end of the multi-hole flat tube, movement of the hydraulic fluid is enabled. In this way, it is possible to form a self-excited oscillating heat pipe having a closed flow path in which the flow path is formed in a rectangular wave shape (alternately folded back and extended along the longitudinal direction of the multi-hole flat tube).

Next, the starting mechanism when the self-oscillating heat pipe according to the present invention starts self-oscillating will be described.
5 to 8 are diagrams showing calculation results related to startability of the self-oscillating heat pipe according to the present invention. Here, the calculation model used for the calculation is according to Non-Patent Document 3.

FIG. 5 is a schematic diagram of the self-excited oscillating heat pipe used in the calculation and a diagram showing the initial gas-liquid distribution. Here, the self-oscillating heat pipe used for the calculation is a copper pipe with an inner diameter of 1.0 mm and an outer diameter of 1.6 mm, and has a length of one turn (the length of the heat pipe between adjacent U-shaped bent portions of the heat pipe). direction distance) is 240 mm, and the number of turns is 10.

Each turn has a heat-receiving portion of 8 mm, a heat-radiating portion of 204 mm, and the rest of the heat-insulating portion. Moreover, a portion extended by 50 mm is provided at both ends of the heat pipe to form a steam chamber portion. Calculations were performed both without and with one-sided insulation. As the one-side heat insulation, the cooling portion on the right end of the heat pipe is heat-insulated by 13 mm (hatched portion in FIG. 5).

As the working fluid enclosed in the heat pipe, R1336mzz (Z) was used, and the enclosure rate was set to 0.5. Here, R1336mzz(Z) corresponds to a refrigerant number indicating a refrigerant based on standards, and is one of the new refrigerants.

The above calculation assumes that there is one liquid slug per turn, and the length of the liquid slug is 120 mm, which is half the length of one turn. A uniform distribution was assumed as the distribution of the initial liquid slag, and one liquid slug was distributed symmetrically on the heat radiation part side of each turn.

As the heat flux of the heat-receiving portion, a value corresponding to 3W of heater heating amount per turn was given. The cooling temperature of the heat radiating part was 20° C., and the heat transfer coefficient was a value corresponding to the heat transfer coefficient outside the tube at a wind speed of 4 m/sec. It was also assumed that the initial steam plug had a 5 μm thick liquid film all around it. The initial temperature of the heat pipe was the same as the cooling temperature, and heating was started at 0 sec.

FIG. 6 is a graph showing temporal changes in gas-liquid distribution without one-side heat insulation shown in (a) and with one-side heat insulation shown in (b). The vertical axis of the figure is the distance from the origin of the heat pipe (the left end excluding the steam chamber section), and the horizontal axis of the figure is the time after the start of heating. The black part in the figure represents the liquid slag and the white part represents the steam plug. After the start of heating, no vibration occurs in the case of one-side heat insulation shown in (a), and vibration occurs at around 16 seconds in the case of one-side heat insulation shown in (b).

FIG. 7 is a diagram showing the results of calculating the temperature distribution of the heat receiving part at the start of self-excited vibration (around 16 sec) without one-side heat insulation shown in (a) and with one-side heat insulation shown in (b). The temperature distribution of the heat-receiving part is uniform without the one-sided insulation shown in (a), but with the one-sided insulation shown in (b), the temperature of the heat-receiving part at the right end is higher than the temperature of the other heat-receiving parts. It's becoming

FIG. 8 is a diagram showing the calculation results of the time change up to 20 sec for the fifth and sixth liquid slug displacements from the left side of the central portion of the heat pipe.

Without thermal insulation on one side as shown in (a), the displacements of the 5th and 6th liquid slugs showed almost symmetrical −1 mm and +1 mm at around time 9.6 sec, after which minute vibrations with an amplitude of about 2 mm were observed. However, it does not cause large vibrations.

Here, it will be explained that the displacement of the fifth liquid slug is −1 mm and the displacement of the sixth liquid slug is +1 mm. There are steam chambers at both ends of the heat pipe, and the 1st and 11th steam plugs on the left end and the 11th steam plug on the right end are similar to the other steam plugs. Larger than other steam plugs. Therefore, the pressure rise is small, and the liquid slug moves from the center of the heat pipe toward both ends due to the pressure difference acting on both ends of the liquid slug.

On the other hand, with one-side insulation shown in (b), the displacement of both liquid slugs is -3 mm at around 10.0 sec. This is because the local insulation of the right end causes the pressure of the 11th steam plug to be higher than the others, and the pressure difference acting on both ends of the liquid slug causes all the liquid slugs to move from the right end to the left end of the heat pipe. It's for.

After a time of 10.0 sec, the liquid slug repeats positive and negative displacements of about 3 mm twice, and then vibrates with a negative displacement from a time of 12.7 sec while gradually increasing the amplitude. After that, after a time of 15.7 seconds, it vibrates with a large amplitude of 5 mm or more.

In this way, the steam plug moves along with the displacement of the liquid slug, and evaporation and condensation occur in the liquid film at the steam plug due to the temperature difference from the wall temperature. This causes the mass of the steam plug to increase or decrease, causing the steam plug pressure to rise and fall accordingly. Vibration of the liquid slug after time 15.7 sec begins due to an increase in the fluctuation of the pressure difference acting on both ends of the liquid slug.

From the above, the mechanism of starting self-excited vibration by one-sided insulation is summarized.
By insulating one end of the heat pipe, the liquid slug moves in the same direction after heating, and the displacement of the liquid slug is aligned in one direction. Due to the movement of this liquid slag, evaporation and condensation occur in the liquid film in the steam plug due to the temperature difference with the pipe wall. This causes the mass of the steam plug to increase or decrease and the pressure to rise and fall accordingly. Therefore, the pressure difference acting on both ends of the liquid slug fluctuates, generating minute vibrations.

At this time, with one-sided insulation, the displacement of the liquid slugs is aligned in one direction, so that the motions of the liquid slugs do not cancel each other out and develop into large vibrations. On the other hand, without insulation on one side, the displacement of the liquid slug is small at the central part of the heat pipe, which tends to vibrate, and the direction is also reversed, so the generated minute vibrations cancel each other out and do not develop into large vibrations.

The present invention applies the above calculation results. That is, in the self-oscillating heat pipe cooling device according to the present invention, as shown in FIG. 7B, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is higher at one end than at the other. That is, by having asymmetrical characteristics with respect to the central portion in the longitudinal direction of the heat pipe, excellent startability is exhibited.

In the first embodiment, the heating element 11 is arranged in the longitudinal direction of the heat pipe 12 so that the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction of the heat pipe 12 . are arranged asymmetrically with respect to the center of the

As shown in FIGS. 5 to 8, in the calculation, one channel of a single circular tube was used as the heat pipe, but the same effect can be obtained with a plurality of channels of the multi-hole flat tube shown in FIG. .

On the other hand, in the meandering flow path shown in FIG. 3, the flow resistance at the turn portion at the end of the flat tube is large, and the working fluid is difficult to move at the end of the flat tube. Occurs mainly in parts other than the part.

Therefore, in the first embodiment, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is asymmetrical with respect to the central portion in the longitudinal direction of the heat pipe, as in the case of circular pipes and multiple flow paths. As a result, after the start of heating, the liquid slugs move in one direction, and the displacement of the liquid slugs aligns in one direction at the central part of the pipe, which is prone to vibration. It develops into vibration and generates self-excited vibration.

Next, the configurations and effects of Examples 2 to 5 of the present invention will be described. At that time, in Examples 2 to 5, the portions different from Example 1 will be explained, and the explanation of the portions overlapping with Example 1 will be omitted.

FIG. 9 is a side view showing the structure of a self-oscillating heat pipe cooling device 100a according to Embodiment 2 of the present invention.
A self-excited oscillating heat pipe cooling device 100a according to the second embodiment has a plurality of heating elements 11a arranged asymmetrically with respect to the central portion of the heat pipe 12 in the longitudinal direction. FIG. 9 shows a case where two heating elements 11a are arranged.

As described above, in the second embodiment, as in the first embodiment, the temperature distribution of the heat receiving part 9 in the longitudinal direction of the heat pipe is high at one end and Since it has asymmetrical characteristics, self-excited vibration is generated and excellent startability is obtained.

FIG. 10 is a side view showing the structure of a self-oscillating heat pipe cooling device 100b according to Embodiment 3 of the present invention.
In the self-oscillating heat pipe cooling device 100b according to the third embodiment, the number of fins 13a closest to one longitudinal end 3 of the heat pipe 12 is reduced. As a result, heat dissipation at one end is suppressed and the temperature at the one end increases.

As described above, in Example 3 as well, the temperature distribution of the heat receiving portion 9 in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction of the heat pipe 12, so that self-excited vibration occurs. Excellent startability.

FIG. 11 is a side view showing the structure of a self-oscillating heat pipe cooling device 100c according to Embodiment 4 of the present invention.
A self-oscillating heat pipe cooling device 100c according to the fourth embodiment has a heat insulating member 14 provided in a portion of the heat radiating portion 20 of the heat pipe 12 closest to one end 3 of the heat pipe 12 in the longitudinal direction. As a result, heat dissipation at one end is suppressed and the temperature at the one end increases.

Here, the method for providing the heat insulating member 14 in a part of the heat radiating section 20 is not limited. For example, in FIG. 11, a method of attaching the heat insulating member 14 to a part of the heat radiating portion 20 is used.
As described above, in the fourth embodiment as well, the temperature distribution of the heat receiving portion 9 in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction of the heat pipe 12, so that self-excited vibration occurs. Excellent startability.

FIG. 12 is a side view showing the structure of a self-oscillating heat pipe cooling device 100d according to Embodiment 5 of the present invention.
In the self-oscillating heat pipe cooling device 100d according to the fifth embodiment, the length of the end portion of the heat receiving member 10a on the side of one end portion 3 of the heat pipe 12 is shortened, and both ends of the heat pipe 12 in the longitudinal direction are individually cooled. The lengths of both end portions of the heat receiving member 10a corresponding to are different. As a result, the thermal resistance at the one end increases and the temperature at the one end rises.

As described above, in Example 5 as well, the temperature distribution of the heat receiving portion 9 in the longitudinal direction of the heat pipe is asymmetrical with respect to the central portion in the longitudinal direction of the heat pipe 12, so that self-excited vibration occurs. Excellent startability.

FIG. 13 is a side view showing the structure of a self-oscillating heat pipe cooling device 100e according to Embodiment 6 of the present invention.
In the self-excited oscillating heat pipe cooling device 100e according to the sixth embodiment, the area of the heat receiving portion located at one end portion 3 of the heat pipe 12 in the longitudinal direction is made wider than the other heat receiving portions. As a result, the amount of heat received at one end increases and the temperature rises.

Here, the method for increasing the area of the heat receiving portion described above is not limited. For example, in FIG. 13, the heat receiving portion 9b of one end portion 3 in the longitudinal direction of the heat pipe 12 is joined to the heat receiving portion 9b provided on the heat receiving member 10 by brazing or the like. increasing the area.

As described above, in Example 5 as well, the temperature distribution of the heat receiving portion 9 in the longitudinal direction of the heat pipe is asymmetrical with respect to the central portion in the longitudinal direction of the heat pipe 12, so that self-excited vibration occurs. Excellent startability.

Furthermore, the self-excited oscillating heat pipe cooling devices 100, 100a, 100b, 100c, 100d and 100e described as the first to sixth embodiments are power modules (power semiconductors such as IGBTs and MOS-FETs) for driving mounted on railway vehicles. It is suitable for cooling a power module provided with an element.

For example, the self-excited vibration heat pipe cooling devices 100, 100a to 100e in which the power module is mounted on the heat receiving member 10 as the heating element 11 are mounted under the floor of the railway vehicle. As a result, it is possible to compactly install the cooling device for the power module even under the floor of a railway vehicle in which various types of equipment are mounted.

1 closed flow path, 2 partition, 3 one end of heat pipe,
9, 9b heat receiving portion, 10 heat receiving member, 10b projection,
11, 11a heating element, 12 self-oscillating heat pipe,
13, 13a fins, 14 heat insulating member, 20 heat radiating part,
100, 100a-100e Self-oscillating heat pipe cooling device

Claims (11)

a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, which is formed by forming a wavy shape by connecting a tube in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction;
a heat receiving member joined to the heat receiving part;
a heating element arranged on the surface of the heat receiving member opposite to the surface to which the heat receiving part is bonded,
By arranging the heat generating element in the heat receiving member asymmetrically with respect to the central portion in the longitudinal direction of the heat pipe, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is changed with respect to the central portion in the longitudinal direction. to generate self-excited oscillation
A self-oscillating heat pipe cooling device characterized by: The self-oscillating heat pipe cooling device of claim 1, comprising:
said arrangement of a plurality of said heating elements is said asymmetrical
A self-oscillating heat pipe cooling device characterized by: a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, which is formed by forming a wavy shape by connecting a tube in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction;
a heat receiving member joined to the heat receiving part;
a heating element arranged on the surface of the heat receiving member opposite to the surface to which the heat receiving part is bonded;
with
all the heat radiating parts have fins installed between the adjacent heat radiating parts,
By making the number of the fins installed at a position closest to one end in the longitudinal direction of the heat pipe smaller than the number of the fins installed at other positions, the heat reception in the longitudinal direction of the heat pipe A self-excited oscillating heat pipe cooling device, characterized in that self-excited oscillation is generated by making the temperature distribution of a portion asymmetric with respect to the central portion in the longitudinal direction . a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, which is formed by forming a wavy shape by connecting a tube in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction;
a heat receiving member joined to the heat receiving part;
a heating element arranged on the surface of the heat receiving member opposite to the surface to which the heat receiving part is bonded;
with
By providing a heat insulating member in the heat radiating portion closest to one end in the longitudinal direction of the heat pipe, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is made asymmetric with respect to the central portion in the longitudinal direction. A self-excited oscillating heat pipe cooling device, characterized in that self-excited oscillation is generated by a heat pipe. a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, which is formed by forming a wavy shape by connecting a tube in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction;
a heat receiving member joined to the heat receiving part;
a heating element arranged on the surface of the heat receiving member opposite to the surface to which the heat receiving part is bonded;
with
By varying the lengths of both ends of the heat receiving member corresponding to both ends of the heat pipe in the longitudinal direction, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is centered in the longitudinal direction. A self-excited oscillating heat pipe cooling device characterized by generating self-excited oscillation in an asymmetrical manner . a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, which is formed by forming a wavy shape by connecting a tube in which a working fluid is enclosed and sealed in a rectangular wave shape in the thickness direction;
a heat receiving member joined to the heat receiving part;
a heating element arranged on the surface of the heat receiving member opposite to the surface to which the heat receiving part is bonded;
with
By making the area of the heat receiving portion closest to one end of the heat pipe in the longitudinal direction larger than the area of the other heat receiving portions, the temperature distribution of the heat receiving portion in the longitudinal direction of the heat pipe is changed. A self-excited oscillating heat pipe cooling device, wherein self -excited oscillation is generated asymmetrically with respect to the center of the heat pipe. The self-excited oscillating heat pipe cooling device according to any one of claims 1 to 6 ,
The wavy shape of the heat pipe is formed by bending the tube in its own longitudinal direction into the rectangular wavy shape a plurality of times.
A self-oscillating heat pipe cooling device characterized by: In the self-excited oscillating heat pipe cooling device according to any one of claims 1 to 6 ,
The wavy shape of the heat pipe is formed by arranging a plurality of the pipes in parallel in the thickness direction and alternately communicating adjacent ends of the pipes in the rectangular wave shape.
A self-oscillating heat pipe cooling device characterized by: The self-excited oscillating heat pipe cooling device according to any one of claims 1 to 8 ,
Said tube is a multi-hole flat tube
A self-oscillating heat pipe cooling device characterized by: The self-excited oscillating heat pipe cooling device according to any one of claims 1 to 9,
The heating element is a power module having a power semiconductor element
A self-oscillating heat pipe cooling device characterized by: A railway vehicle equipped with the self-oscillating heat pipe cooling device according to claim 10.

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