JP3554820B2 - Heat pipe heating device for high temperature - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat pipe that transports heat input from the outside as latent heat of a working fluid.
[0002]
[Prior art]
A conventional heat pipe is one in which a condensable fluid such as water or alcohol is sealed as a working fluid in a container (in this specification, referred to as a “container”) such as a sealed metal tube that has been degassed under vacuum. In this case, the operation is performed by generating a temperature difference, and the working fluid evaporated in the high temperature portion flows to the low temperature portion to radiate and condense, thereby performing heat transport as latent heat of the working fluid. When transferring high-temperature heat, a liquid metal such as sodium, potassium, cesium, and lithium is used as a working fluid. As an example of a means for uniformly supplying a liquid-phase working fluid over a wide range in the circumferential direction or longitudinal direction in the container, a wick made of a metal mesh material, a groove, a sintered metal, or the like is laid on the inner wall surface of the container. I have. Usually, as the wick material, a material having joints as fine as possible is employed in order to obtain a higher capillary pressure.
[0003]
[Problems to be solved by the invention]
However, when a conventional high-temperature heat pipe equipped with this type of wick is operated, the wettability of the working fluid with the container and the wick to the working fluid is not uniform over several tens to several hundred hours after startup. As a result, the working fluid does not work uniformly in the wick, and partial evaporation also occurs, causing local high temperatures and local low temperatures in areas where the liquid thickness is large, causing thermal stress in the container. However, there has been a problem that the flow of the working steam is disturbed and the heat transport performance cannot be sufficiently obtained.
[0004]
The present invention has been proposed in order to solve such problems of the related art, and improves heat transport performance in a period from the start of use of a high-temperature heat pipe to a stable period, and at the time of a stable period. The purpose is to shorten the time required to reach the temperature and reduce thermal stress.
[0005]
[Means for Solving the Problems]
A heating device for a high-temperature heat pipe according to the present invention is a high-temperature heat pipe in which a wick is laid on an inner wall surface of a container, wherein a temperature sensor for observing a temperature of a high-temperature portion of the high-temperature heat pipe inserted into the heater and the temperature sensor. A control device for controlling the high temperature section to a constant temperature is provided and a vibrating body for vibrating the container in a radial direction is mounted on one side of the container, and a power meter for measuring the input of power from the power supply to the heater is provided. The vibrating body is operated during a period from the start of use of the high-temperature heat pipe to a stable period . Further, the heating device for a heat pipe for high temperature according to the present invention is characterized in that a vibrating body is attached to an end of a container on a high temperature portion side of the heat pipe for high temperature.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall configuration of an embodiment according to the present invention, and a high-temperature heat pipe 1 includes a cylindrical container 7 whose both ends in a longitudinal direction are sealed. Examples of the material forming the container 7 include copper, aluminum, steel, stainless steel, nickel, titanium, and Inconel. When the high-temperature heat pipe 1 is divided in the operation region in the longitudinal direction, it is divided into a high-temperature portion a that absorbs heat, a heat-insulating portion b where heat does not enter and exit, and a low-temperature portion c that releases heat. The high temperature part a is inserted into the heater 2 such as a tubular electric furnace, and is supported by heat insulating materials 5 provided on both sides of the heater 2 to prevent heat radiation from the heater 2. Further, a heat insulating material 6 is provided on an outer peripheral portion of the heat insulating portion b of the heat pipe 1 for high temperature.
FIG. 2 shows a cross section of the heat pipe 1 for high temperature. A wick 8 made of a metal mesh material, a groove, a sintered metal or the like is laid on the inner wall surface of the container 7 over the entire length in the longitudinal direction.
[0007]
In FIG. 1, a temperature sensor 9 such as a thermocouple is inserted into the heater 2, the temperature of the high-temperature portion a of the high-temperature heat pipe 1 is observed, and the controller 11 controls the temperature to be equal to or higher than the operating temperature of the high-temperature heat pipe 1. Control and maintain at temperature. Input of power from the power supply 12 to the heater 2 is measured by the power meter 10.
In the high-temperature section a of the high-temperature heat pipe 1, the container 7 has an extension 13 extending through the heater 2. One end of the connection member 3 is provided on the outer periphery of the extension portion 13 so as to fit, and the vibrating body 4 is fixed to the other end of the connection member 3.
[0008]
The vibrating body 4 is composed of, for example, an ultrasonic vibrator, and transmits vibration to the working fluid in the container 7 via the connecting member 3. In the present invention, the vibrating body 4 promotes the contact between the working fluid in the high-temperature portion a and the inner surface of the container 7 and the wick 8 (hereinafter, the “inner surface and wick” are collectively referred to as “inner surface”). Since it is provided, the direction of vibration is not the longitudinal direction of the container 7 as in the conventional case, but the radial direction of the container 7.
Further, since the connecting member 3 connects the high-temperature heat pipe 1 and the vibrating body 4 to be heated to a high temperature, it is preferable that the connecting member 3 be made of ceramic or the like having a low thermal conductivity.
[0009]
Next, the operation of the present invention configured as described above will be described. At the start of use, when the high temperature portion a of the high temperature heat pipe 1 is heated by the heater 2, the working fluid evaporates, and the evaporated working fluid flows to the low temperature portion c to radiate and condense, thereby generating heat as latent heat of the working fluid. Transport takes place. At the same time, when the vibrating body 4 is operated, the vibration in the radial direction of the vibrating body 4 is transmitted to the working fluid in the high-temperature heat pipe 1 via the connecting member 3, and the contact between the working fluid and the inner surface is promoted. You. Further, the vibration by the vibrating body 4 also has an effect of averaging the flow of the working fluid.
[0010]
Normally, the inside of the high-temperature heat pipe 1 is washed before the working fluid is sealed therein. However, it is difficult to obtain a completely clean inner surface or the like, and the wettability between the working fluid and the inner surface or the like (ease of conformity). Above the temperature at which evaporation occurs, there is a difference in the surface temperature of the high-temperature portion. When the operation is continued, the working fluid gradually contacts the inner surface and the like by the flow of the working fluid, and the wettability is also improved. Along with this, the temperature difference in the high temperature section a also decreases, and the internal steam flow is also stabilized, so that the heat transport amount increases, and the change can be known from the increase in the reading of the power meter 10. The start of the stationary phase is determined based on the state in which the change has decreased.
[0011]
The time until the stationary period depends on the type of the working fluid, the materials of the container 7 and the wick 8, the structure of the wick 8, the operating temperature, and the like. For example, when the surface temperature of the high temperature part a was 900 ° C., the working fluid was sodium, the material of the container 7 was Inconel 600, and the two-layer mesh wick was used, it took about 500 hours.
By applying minute vibrations in the radial direction to the heat pipe 1 for high temperature by the vibrator 4, it is possible to reduce the temperature difference in the high temperature section a, and the contact between the working fluid and the inner surface is promoted, and the wettability is improved. Can be promoted, and the time until a steady state can be shortened.
[0012]
It is desirable to observe the heat radiation from the heater 2 by the heat flow sensor 14, but since the internal temperature of the heater 2 is kept constant, it is considered that the change in the heat radiation amount is small. Since the liquid metal such as sodium as a working fluid is solid at normal temperature, the temperature gradually rises at the time of startup, and if the liquid metal is not started to evaporate from a state in which a sufficient liquid liquid metal stays in the high-temperature portion a, a partial However, applying vibrations has the effect of promoting the dissolution of liquid metal remaining in a solid state because the liquid moves inside by applying vibration.
[0013]
【The invention's effect】
As described above, according to the present invention, the contact between the working fluid, the container, and the wick is promoted by the radial vibration of the vibrator, so that the heat transport performance is improved during the period from the start of use to the stable period. And shortening the period until the stable period is reached. Further, since the flow of the working fluid is also averaged, an effect of reducing thermal stress can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an entire configuration of a starting device for a high-temperature heat pipe according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the high-temperature heat pipe according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High temperature heat pipe 2 Heater 3 Connecting member 4 Oscillator 5 Insulating material 6 Insulating material 7 Container 8 Wick 9 Temperature sensor 10 Wattmeter 11 Control device 12 Power supply 13 Extension part 14 Heat flow sensor a High temperature part b Thermal insulation part c Low temperature part

Claims (2)

In a high-temperature heat pipe in which a wick is laid on an inner wall surface of a container, a temperature sensor for monitoring a temperature of a high-temperature portion of the high-temperature heat pipe inserted into the heater and a control device for controlling the high-temperature portion to a constant temperature are provided. At the same time, a vibrating body for radially vibrating the container is mounted on one side of the container, and a power meter for measuring the input of power from the power supply to the heater is provided. A heating device for a heat pipe for high temperature , wherein the vibrator is operated in a period up to a period . The heating device for a high-temperature heat pipe according to claim 1, wherein a vibrating body is attached to an end of the container on the high-temperature portion side of the high-temperature heat pipe.

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