CN113710982B

CN113710982B - Self-oscillation heat pipe cooling device and railway vehicle equipped with same

Info

Publication number: CN113710982B
Application number: CN202080029866.9A
Authority: CN
Inventors: 远藤和广; 安田阳介; 锅岛史花
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2019-05-08
Filing date: 2020-03-17
Publication date: 2023-05-30
Anticipated expiration: 2040-03-17
Also published as: JP7179170B2; CN113710982A; WO2020225981A1; JPWO2020225981A1

Abstract

In order to provide a self-oscillation heat pipe cooling device excellent in starting performance by generating self-oscillation even in the case where initial distribution of liquid slugs and vapor slugs in a heat pipe is uniform, the self-oscillation heat pipe cooling device comprises: a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, wherein the heat pipe is configured by connecting a sealed pipe, in which a working fluid is enclosed, in a rectangular wave shape in a thickness direction, and forming the sealed pipe into a wave shape; a heat receiving member joined to the heat receiving member; and a heating element disposed on a surface of the heat receiving member opposite to the surface to which the heat receiving member is joined, wherein at least one of the arrangement of the heating element, the structure of the heat radiation portion, the structure of the heat receiving member, and the structure of the heat receiving member is changed such that the temperature distribution of the heat receiving member in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction, thereby generating self-oscillation.

Description

Self-oscillation heat pipe cooling device and railway vehicle equipped with same

Technical Field

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

Background

Regarding a self-oscillating heat pipe for a cooling device, non-patent document 1 describes the following: a thin flow path is reciprocated between a heating part and a cooling part for a plurality of times, the flow path is vacuumized, and the evaporating liquid is sealed in the half volume of the flow path, so that a liquid slug and a vapor slug are formed by the surface tension effect, and vibration of the liquid slug is generated by self-excitation along with the increase of heating quantity, and heat is transferred from the heating part to the cooling part.

In addition, non-patent document 2 evaluates the influence of initial gas-liquid distribution on start-up characteristics by calculation using an internal flow model. In order to start the self-oscillating heat pipe, it is described that there is a difference in void ratio of each turn in the initial state or that a liquid slug exists in the heating portion to obtain a driving force generated by boiling.

On the other hand, patent document 1 discloses a self-oscillating heat pipe cooler having a structure in which a plurality of power semiconductor elements are arranged on one surface of a heat receiving member, and a heat radiating portion constituted by a self-oscillating heat pipe is provided on the opposite surface of the other surface of the heat receiving member.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2018-88744

Non-patent literature

Non-patent document 1: nagasaki 'evaluation of heat transfer on self-oscillating heat pipe', journal of the Heat Transfer Society of Japan, vol.44, no.186 (month 5 2005), pp.13-17

Non-patent document 2: pill Tuolang, ji Tianzhou Ping, yongjing big tree, okadam Va, an Tengma Ji Zi, fir Tian Bozhi, "2E 01" a investigation about the start of self-oscillating heat pipe, "58 th Universal science and technology joint lecture set (2014), pp.5-9

Non-patent document 3: 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

Disclosure of Invention

Problems to be solved by the invention

The findings shown in non-patent document 2 indicate that, in contrast, for example, when the liquid slugs and the vapor slugs are uniformly distributed in each turn, even if the heating portion is heated, the vapor slugs acting on both ends of the liquid slug have the same pressure, and thus the liquid slug is not moved, and self-oscillation is not generated.

Further, patent document 1 does not disclose a structure for generating self-oscillation in the case where initial distribution of liquid slugs and vapor lock is uniform.

The invention aims to provide a self-oscillation heat pipe cooling device which can generate self-oscillation and has excellent starting performance even under the condition that initial distribution of liquid slugs and vapor slugs in a heat pipe is uniform.

Technical scheme for solving problems

The self-oscillation heat pipe cooling device of the invention is basically characterized by comprising: a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, wherein the heat pipe is configured by connecting a sealed pipe, in which a working fluid is enclosed, in a rectangular wave shape in a thickness direction, and forming the sealed pipe into a wave shape; a heat receiving member joined to the heat receiving member; and a heating element disposed on a surface of the heat receiving member opposite to the surface to which the heat receiving member is joined, wherein at least one of the arrangement of the heating element, the structure of the heat radiating portion, the structure of the heat receiving member, and the structure of the heat receiving member is changed such that the temperature distribution of the heat receiving member in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction, thereby generating self-oscillation.

Effects of the invention

According to the present invention, a self-oscillation heat pipe cooling device capable of generating self-oscillation and having excellent starting performance can be provided even when initial distribution of liquid slugs and vapor slugs in a heat pipe is uniform.

Drawings

Fig. 1 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 1 of the present invention.

Fig. 2 is a diagram showing an example of a flow path structure of a self-oscillating heat pipe cooling device used in the embodiment of the present invention.

Fig. 3 is a diagram showing another example of the flow path structure of the self-oscillating heat pipe cooling device employed in the embodiment of the present invention.

Fig. 4 is a view showing a cross-sectional structure of the self-oscillating heat pipe shown in fig. 2 or 3.

Fig. 5 is a schematic diagram showing a self-oscillation heat pipe used for calculation and an initial gas-liquid distribution.

Fig. 6 is a graph showing the calculation result of the time change of the gas-liquid distribution.

Fig. 7 is a graph showing the result of calculating the temperature distribution of the heat receiving unit at the start of self-oscillation.

Fig. 8 is a graph showing the calculation results of the time change of the fifth and sixth slug displacements from the left side of the center portion of the heat pipe.

Fig. 9 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 2 of the present invention.

Fig. 10 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 3 of the present invention.

Fig. 11 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 4 of the present invention.

Fig. 12 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 5 of the present invention.

Fig. 13 is a side view showing the structure of a self-oscillating heat pipe cooling device according to embodiment 6 of the present invention.

Detailed Description

Examples 1 to 6 will be described below as modes for carrying out the present invention with reference to the drawings. In addition, common parts in the drawings are denoted by the same reference numerals, and repetitive description thereof will be omitted.

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.

The self-oscillation heat pipe cooling device 100 is constituted by a heat pipe 12 that performs self-oscillation, a heat receiving member 10, and a heat generating body 11. The heating element 11 is disposed asymmetrically with respect to the central portion of the heat pipe 12 in the longitudinal direction. As a material of the heat pipe 12 and the heat receiving member 10, a metal such as aluminum alloy or copper having good heat conductivity is used.

The heat pipe 12 that performs self-oscillation is bent in a U-shape at equal intervals in the longitudinal direction thereof a plurality of times. One end of each of the 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, and a plurality of heat receiving members 9 are formed at equal intervals on the heat pipe 12. Further, a plurality of equally spaced portions of the heat pipe 12 other than the heat receiving portion 9 form heat radiating portions 20 that exchange heat with air 101 or 102 (the wind in the two directions with respect to the drawing sheet). Further, the heat radiation fins 13 are fixed between the heat pipes 12 that are bent, and form a heat radiation portion together with the heat pipes 12 by brazing or the like.

The heat generating element 11 is disposed on a surface opposite to a surface of the heat receiving member 10 to which the heat receiving member 9 of the heat pipe 12 is joined. The heating element 11 is disposed at an asymmetric position with respect to the central portion of the heat pipe 12 in the longitudinal direction, and is disposed on the side of the one end portion 3. In this position, the heating element 11 is fixed by a bolt or the like (not shown) through a member (not shown) such as a grease portion. Here, the heating element 11 is a power module including a power semiconductor element such as an IGBT or a MOS-FET.

Fig. 2 and 3 are diagrams showing an example of a flow path structure of a self-oscillating heat pipe used in an embodiment of the present invention. Fig. 4 is a view showing a cross section A-A of fig. 2, for example, as a cross section structure of the self-oscillating heat pipe shown in fig. 2 or 3.

The self-oscillating heat pipe 12 shown in fig. 2 and 3 is constituted by a porous flat pipe. As a configuration, for example, there are a case where a plurality of flow paths which are arranged in parallel and side by side and do not communicate with each other in each row as shown in fig. 2, and a case where a plurality of flow paths are formed by bending as shown in fig. 3. The tube constituting the self-oscillating heat pipe used in the present invention is not limited to the porous flat tube described above, and may be constituted by a single round tube, for example, as shown in fig. 5.

A partition 2 is provided between adjacent channels 1, and the width (inter-channel pitch) of each of the channels and the partition is in the order of mm, and the channel length is very long compared to the channel length.

As shown in fig. 4, the thickness of the self-oscillating heat pipe 12 is set to be in the order of mm in view of heat conductivity and ease of processing.

A working fluid (not shown) is enclosed in the sealed flow path 1 in a half flow path volume.

Further, when the self-oscillating heat pipe is formed into a wave form, the porous flat pipe may be formed by arranging a plurality of linear porous flat pipes having the same length in the thickness direction without using a bending step. That is, the ends of the porous flat tubes, which are arranged side by side in the thickness direction, are fixed to each other by using a member such as an end seal member having slits on the porous flat tube side, and the ends of the porous flat tubes, which are adjacent to each other at the ends of the porous flat tubes, are alternately communicated with each other through the slits, whereby the movement of the working fluid can be achieved. In this way, a self-oscillating heat pipe having a closed flow path in which the flow path is formed in a rectangular wave shape (alternately folded back along the longitudinal direction of the porous flat tube) can be formed.

Next, a mechanism of starting when the self-oscillation heat pipe of the present invention starts self-oscillation will be described.

Fig. 5 to 8 are graphs showing calculation results related to the starting performance of the self-oscillating heat pipe of the present invention. Here, the calculation model used for the calculation is based on non-patent document 3.

Fig. 5 is a schematic diagram showing a self-oscillation heat pipe used for calculation and an initial gas-liquid distribution. The self-oscillation heat pipe used for calculation was a copper pipe having an inner diameter of 1.0mm and an outer diameter of 1.6mm, and a length of 1 turn (distance in the longitudinal direction of the heat pipe between adjacent U-shaped bent portions of the heat pipe) was 240mm, and the number of turns was 10.

For every 1 turn, the heated portion was 8mm, the heat sink portion was 204mm, and the other was a heat shield portion. In addition, portions extending 50mm are provided at both ends of the heat pipe as vapor chamber portions. The calculation was performed without and with both single-sided insulation. As one-side heat insulation, the cooling portion at the right end of the heat pipe was insulated by 13mm (hatched portion in fig. 5).

R1336mzz (Z) was used as the working fluid enclosed in the heat pipe, and the sealing rate was set to 0.5. Here, R1336mzz (Z) is one of new coolants, corresponding to the coolant number indicating the coolant, based on the standard.

In the above calculation, assuming that 1 slug exists per 1 turn, the length of the slug is set to 120mm which is half of the length of 1 turn. As the initial liquid slug distribution, 1 liquid slug is symmetrically distributed on the heat radiating portion side of each turn assuming equal distribution.

As the heat flux of the heat receiving portion, a value corresponding to 3W of the heating amount of the heater per 1 turn was given. The cooling temperature of the heat sink was 20℃and the thermal conductivity was set to a value corresponding to the thermal conductivity outside the tube at a wind speed of 4 m/sec. Further, on the initial vapor plug, it is assumed that a liquid film having a thickness of 5 μm exists around the entire periphery thereof. The initial temperature of the heat pipe was set to be the same as the cooling temperature, and heating was started at time 0 sec.

Fig. 6 is a graph showing a temporal change in gas-liquid distribution without the single-side heat insulation shown in (a) and with the single-side heat insulation shown in (b). The vertical axis of the graph indicates the distance between the heat pipe and the origin (the left end excluding the vapor chamber), and the horizontal axis of the graph indicates the time after the start of heating. The black part of the diagram represents the liquid slug and the white part represents the vapor slug. After the start of heating, vibration was not generated when the one-side heat insulation shown in (a) was not performed, and vibration was generated around 16sec when the one-side heat insulation shown in (b) was performed.

Fig. 7 is a graph showing the results of calculating the temperature distribution of the heat receiving unit at the start of self-oscillation (around 16 sec) without the single-side heat insulation shown in (a) and with the single-side heat insulation shown in (b). The temperature distribution of the heat receiving unit is uniform when the single-side heat insulation shown in (a) is not provided, but the temperature of the heat receiving unit at the right end portion is higher than the temperature of the heat receiving unit at the other portion when the single-side heat insulation shown in (b) is provided.

Fig. 8 is a graph showing the calculation results of time variation up to 20sec as the fifth and sixth slug displacements from the left side of the central portion of the heat pipe.

In the absence of the single-sided insulation shown in (a), the displacement of the fifth and sixth slugs almost symmetrically represents-1 mm and +1mm around time 9.6sec, and then a minute vibration of about 2mm in amplitude was seen, but a large vibration was not achieved.

Here, the displacement of the fifth slug means-1 mm, and the displacement of the sixth slug means +1 mm. The vapor chamber parts are arranged at the two ends of the heat pipe, and the eleventh vapor plug at the first and the right ends of the left end is the same as the other vapor plugs, and even if the mass of the vapor plug is increased due to the evaporation of the liquid film, the original volume is larger than that of the other vapor plugs. Therefore, the pressure rise is small, and the liquid slug moves from the center of the heat pipe to the both ends due to the pressure difference acting on the both ends of the liquid slug.

On the other hand, when the single-side heat insulation is provided as shown in (b), the displacement of both slugs is-3 mm at a time of about 10.0 sec. This is because the eleventh vapor lock is higher than the other due to the partial insulation at the right end, and all the liquid slugs move from the right end to the left end of the heat pipe due to the pressure difference acting on both ends of the liquid slugs.

After the time of 10.0sec, the slug was repeatedly displaced about 3mm twice, and then vibrated with a slight increase in amplitude by a negative displacement from the time of 12.7 sec. After 15.7sec, the vibration was performed at a large amplitude of 5mm or more.

In this way, the vapor lock also moves with displacement of the slug, in which the evaporation and condensation takes place on the liquid film by a temperature difference from the wall temperature. Thus, the mass of the vapor lock increases and decreases, and the pressure of the vapor lock increases and decreases. Vibration of the slug for 15.7sec or later starts by increasing the fluctuation of the pressure difference acting on both ends of the slug.

As above, the mechanism of starting self-oscillation caused by the single-sided insulation is summarized.

By insulating the one-side end portion of the heat pipe, the liquid slug moves in the same direction after heating, and the displacement of the liquid slug is in a state of being uniform in one direction. By this movement of the slug, in the vapour plug, evaporation and condensation takes place on the liquid film by a temperature difference with the pipe wall. Thus, the mass of the vapor lock increases and decreases, and the pressure increases and decreases accordingly. Therefore, the pressure difference acting on both ends of the slug fluctuates, and minute vibrations are generated.

In this case, when the single-side heat insulation is provided, the displacement of the liquid slugs is uniform in one direction, and thus, the movement of each liquid slug is not canceled out, but large vibration is developed. On the other hand, when there is no one-sided heat insulation, the displacement of the slug is small in the central portion of the heat pipe which is liable to vibrate, and the direction is also the opposite direction, so that the generated minute vibrations cancel each other out, and large vibrations do not develop.

The present invention is an invention to which the above calculation results are applied. That is, in the self-oscillating heat pipe cooling device of the present invention, as shown in fig. 7 (b), the temperature distribution of the heat receiving unit in the longitudinal direction of the heat pipe is higher at one end than the other. That is, the heat pipe has a characteristic of being asymmetric with respect to the central portion in the longitudinal direction of the heat pipe, and thus exhibits excellent starting performance.

In example 1, the heating element 11 was disposed asymmetrically with respect to the longitudinal center of the heat pipe 12 so that the temperature distribution of the heat receiving element with respect to the longitudinal direction of the heat pipe had a characteristic of being asymmetric with respect to the longitudinal center of the heat pipe 12.

As shown in fig. 5 to 8, in the calculation, one flow path of a single round tube is used as the heat pipe, but the same effect can be obtained even with a plurality of flow paths of the porous flat tube shown in fig. 2.

On the other hand, in the tortuous flow path shown in fig. 3, the flow resistance of the turns at the ends of the flat tubes is high, and the working fluid is difficult to operate at the ends of the flat tubes, so that vibration of the liquid slugs mainly occurs at the portions of the ends of the flat tubes other than the turns.

Therefore, in embodiment 1, the temperature distribution of the heat receiving unit with respect to the longitudinal direction of the heat pipe has a characteristic of being asymmetric with respect to the central portion of the heat pipe in the longitudinal direction, as in the case of the round pipe or the plurality of flow paths. Thus, after the start of heating, the liquid slugs move in one direction, and the displacement of the liquid slugs is uniform in one direction at the center of the tube which is easy to vibrate, so that the movement of each liquid slug is not counteracted, and the generated small vibration is developed into large vibration to generate self-oscillation.

Next, the structure, effects, and the like of examples 2 to 5 of the present invention are shown. In this case, in examples 2 to 5, the portions different from example 1 will be described, and the description of the portions overlapping with example 1 will be omitted.

Example 2

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.

The self-oscillation heat pipe cooling device 100a of example 2 is a device in which a plurality of heating elements 11a are arranged asymmetrically with respect to the central portion in the longitudinal direction of the heat pipe 12. Fig. 9 shows a case where two heating elements 11a are arranged.

As described above, in example 2, as in example 1, the temperature distribution of the heat receiving unit 9 in the longitudinal direction of the heat pipe is high at one end, and the heat receiving unit has a characteristic of being asymmetric with respect to the central portion in the longitudinal direction of the heat pipe 12, and therefore self-oscillation occurs and the starting performance is excellent.

Example 3

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.

The self-oscillation heat pipe cooling device 100b of example 3 is a device in which the number of fins 13a closest to one end 3 in the longitudinal direction of the heat pipe 12 is smaller than the other fins. This suppresses heat dissipation at the one-side end, and increases the temperature at the one-side end.

In this way, in example 3, the temperature distribution of the heat receiving unit 9 with respect to the longitudinal direction of the heat pipe has a characteristic of being asymmetric with respect to the central portion of the longitudinal direction of the heat pipe 12, and therefore self-oscillation occurs, and the startability is excellent.

Example 4

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.

The self-oscillation heat pipe cooling device 100c of embodiment 4 is a device in which a heat insulating member 14 is provided in a part of the heat radiation portion 20 of the heat pipe 12 closest to the one end 3 in the longitudinal direction of the heat pipe 12. This suppresses heat dissipation at the one-side end, and increases the temperature at the one-side end.

Here, the method for providing the heat insulating member 14 to a part of the heat radiating portion 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.

In this way, in example 4, the temperature distribution of the heat receiving unit 9 with respect to the longitudinal direction of the heat pipe has a characteristic of being asymmetric with respect to the central portion of the longitudinal direction of the heat pipe 12, and therefore self-oscillation occurs, and the startability is excellent.

Example 5

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.

The self-oscillating heat pipe cooling device 100d of example 5 is a device that shortens the length of the end portion of the heat receiving member 10a on the side of the one end portion 3 of the heat pipe 12, and makes the lengths of the two end portions of the heat receiving member 10a respectively corresponding to the two end portions in the longitudinal direction of the heat pipe 12 different. This increases the thermal resistance of the one-side end, and increases the temperature of the one-side end.

In this way, in example 5, the temperature distribution of the heat receiving unit 9 with respect to the longitudinal direction of the heat pipe has a characteristic of being asymmetric with respect to the central portion of the longitudinal direction of the heat pipe 12, and therefore self-oscillation occurs, and the startability is excellent.

Example 6

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.

The self-oscillating heat pipe cooling device 100e of example 6 is a device in which the area of the heat receiving unit located at one end 3 in the longitudinal direction of the heat pipe 12 is made larger than the other heat receiving units. This increases the amount of heat received by the one-side end portion, and increases the temperature.

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

Further, the self-oscillating heat

pipe cooling devices

100, 100a, 100b, 100c, 100d, and 100e described in examples 1 to 6 are preferably used for cooling power modules for driving (power modules including power semiconductor elements such as IGBTs and MOS-FETs) mounted on railway vehicles.

For example, self-oscillating heat

pipe cooling devices

100, 100a to 100e in which the power module is mounted as a heating element 11 on a heat receiving member 10 are mounted under the floor of a railway vehicle. Thus, even under the floor of a railway vehicle on which various kinds of equipment are mounted, the cooling device for the power module can be compactly equipped.

Description of the reference numerals

1a closed flow path, 2 a partition part, 3 one end part of a heat pipe,

9. 9b heat receiving unit, 10b protrusion,

11. 11a heating element, 12 self-oscillation heat pipe,

13. 13a heat sink, 14 heat insulating member, 20 heat dissipating portion,

100. 100 a-100 e self-oscillating heat pipe cooling device.

Claims

1. A self-oscillating heat pipe cooling device, comprising:

a heat pipe having a structure in which a heat receiving portion and a heat radiating portion are alternately arranged, wherein the heat pipe is configured by connecting a sealed pipe, in which a working fluid is enclosed, in a rectangular wave shape in a thickness direction, and forming the sealed pipe into a wave shape;

a heat receiving member joined to the heat receiving member; and

a heating element disposed on a surface of the heat receiving member opposite to a surface to which the heat receiving member is joined,

the arrangement of the heating element in the heat receiving member is made asymmetric with respect to the central portion in the longitudinal direction of the heat pipe, and the temperature distribution of the heat receiving member in the longitudinal direction of the heat pipe is made asymmetric with respect to the central portion in the longitudinal direction, thereby generating self-oscillation.

2. A self-oscillating heat pipe cooling device according to claim 1, wherein:

the arrangement of the plurality of heating elements is the asymmetry.

3. A self-oscillating heat pipe cooling device, comprising:

a heat receiving member joined to the heat receiving member; and

all the heat dissipation parts have heat dissipation fins arranged between the adjacent heat dissipation parts,

the number of the heat radiating fins provided at a position closest to one end portion in the longitudinal direction of the heat pipe is made smaller than the number of the heat radiating fins provided at other positions, so that the temperature distribution of the heat receiving unit in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction, thereby generating self-oscillation.

4. A self-oscillating heat pipe cooling device, comprising:

a heat receiving member joined to the heat receiving member; and

a heat insulating member is provided on the heat radiating portion closest to one end portion of the heat pipe in the longitudinal direction such 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, thereby generating self-oscillation.

5. A self-oscillating heat pipe cooling device, comprising:

a heat receiving member joined to the heat receiving member; and

the lengths of the two end portions of the heat receiving member corresponding to the two end portions of the heat pipe in the longitudinal direction are different from each other, so that the temperature distribution of the heat receiving member in the longitudinal direction of the heat pipe is asymmetric with respect to the central portion in the longitudinal direction, and self-oscillation is generated.

6. A self-oscillating heat pipe cooling device, comprising:

a heat receiving member joined to the heat receiving member; and

the area of the heat receiving unit closest to one end of the heat pipe in the longitudinal direction is made larger than the areas of the other heat receiving units, so that the temperature distribution of the heat receiving unit in the longitudinal direction of the heat pipe is asymmetric with respect to the central part in the longitudinal direction, thereby generating self-oscillation.

7. A self-oscillating heat pipe cooling device according to any one of claims 1 to 6, wherein:

the corrugated shape of the heat pipe is formed by bending the pipe into the rectangular wave shape a plurality of times in the longitudinal direction of the pipe itself.

8. A self-oscillating heat pipe cooling device according to any one of claims 1 to 6, wherein:

the corrugated shape of the heat pipe is formed by arranging a plurality of heat pipes side by side in the thickness direction and alternately connecting adjacent ends of the heat pipes to each other in the rectangular wave shape.

9. A self-oscillating heat pipe cooling device according to any one of claims 1 to 6, wherein:

the tube is a porous flat tube.

10. A self-oscillating heat pipe cooling device according to any one of claims 1 to 6, wherein:

the heating element is a power component with a power semiconductor element.

11. A railway vehicle characterized in that:

a self-oscillating heat pipe cooling device according to claim 10.