JPH0560477A - Heat pipe - Google Patents

Abstract

PURPOSE:To permit the excess of limit in the heat transporting characteristics of a heat pipe by improving the heat transfer rate of boiling as well as condensing of operating liquid in the heat pipe remarkably. CONSTITUTION:An electric insulating body 4, having air-tight property, is attached to one end of a metallic tube 1 and an electrode, which penetrates the insulating body 4, is inserted into the insulating body while non-conductive operating liquid is sealed thereinto, and a high voltage is impressed between the metallic tube and the electrode. A multitude of fine grooves or projections, continuous lengthwisely, are formed in or on the surface of the electrode while groove wicks 6 are provided on the inner wall surface of the metallic tube 1 integrally with the wall surface.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat pipe.

[0002]

2. Description of the Related Art A commonly used heat pipe is shown in FIG.
As shown in FIG. 3, the working fluid 2 is sealed inside the metal tube 1 whose both ends are closed after removing the non-condensable gas component, and the inner space thereof is substantially filled with only the working fluid and its vapor. It is a thing. A wick 3 is attached to the inner wall surface of the metal tube 1 as needed. The wick 3 is usually composed of a groove, a metal mesh, a wire bundle, etc. integrally formed with the inner wall surface of the pipe.

[0003]

However, in the above-mentioned conventional heat pipe, regarding the heat transport characteristics such as the maximum heat transport amount and the heat resistance, the heat flux, the outer diameter, and the length at the heat input / output portion are described. There are limits inherent to heat pipes that are determined by factors such as operating mode (top heat / bottom heat, tilt angle with respect to the horizontal, etc.), hydraulic fluid characteristics, and operating temperature. In particular, the maximum heat transport rate may be limited due to boiling and condensation performance limitations of the working fluid.

Therefore, an object of the present invention is to solve the above problems and to greatly improve the boiling and condensation heat transfer coefficients of the working fluid in the heat pipe, thereby limiting the heat transfer characteristics of the conventional heat pipe. To improve.

[0005]

According to the present invention, in a heat pipe having a metal tube whose both ends are closed and a working liquid sealed therein, an electric insulator having airtightness is provided at one end of the metal tube. The electrode is attached, the electrode penetrating the electrical insulator is inserted inside, and the non-conductive hydraulic fluid is sealed. It is preferable to form a large number of thin grooves or protrusions continuous in the longitudinal direction on the surface of the electrode.

[0006]

When a high voltage is applied between the metal pipe and the electrode and one end (lower side) of the heat pipe is operated as a heating part and the other end (upper side) is operated as a cooling part, boiling of the working liquid is caused in the heating part. Also, in the cooling section, the condensation of the working fluid vapor is promoted by the effect of the high voltage applied between the container and the electrode,
The heat transport properties of the heat pipe are improved. Further, forming a large number of thin grooves or protrusions on the surface of the electrode contributes to the promotion of boiling.

The technique itself, in which an electrode is provided in the vicinity of a boiling or condensing heat transfer surface and a high voltage is applied between them to improve the heat transfer coefficient, is generally a heat exchanger using an electrically insulating heat transfer medium. Are known in the art (Japanese Patent Laid-Open No. 56-42096, Japanese Patent Laid-Open No. 61-225590, etc.). The reason why the heat transfer performance is improved is that in the case of boiling, bubbles of a heat medium such as CFCs generated on the heat transfer surface are attracted to the electrodes and quickly leave due to the effect of the electric field, and boiling is activated, and condensation is also caused. In the case of (2), it is considered that the heat transfer medium condensed on the heat transfer surface is attracted to the electrode side, and the liquid film thickness on the condensation surface is kept thin by removing it by an appropriate means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below with reference to the accompanying drawings in FIG.

In FIG. 1, reference numeral 1 denotes a metal pipe which serves as a heat pipe container, and is composed of a metal pipe whose one end is closed and the other end is opened. A ceramic insulator 4, which is an electric insulator having airtightness, is attached to one end (opening end) of the metal tube 1, whereby the open end of the metal tube 1 is hermetically sealed. A rod-shaped electrode 5 is inserted through the ceramic insulator 4 to the inside of the metal tube 1 and coaxially extends inside the metal tube 1 so as not to come into contact with the metal tube 1. The ceramic insulator 4 at the open end of the metal tube electrically insulates and supports the electrode 5, and also maintains the airtightness between the electrode 5 and the ceramic insulator 4. After all, the metal tube 1, the electrode 5 and the ceramic insulator 4 are hermetically bonded to each other, and as a result, the metal tube 1 having both ends closed is formed.

Inside the metal tube 1 whose both ends are closed, a non-conducting hydraulic fluid 2 is sealed after the non-condensable gas component is removed. Further, a groove wick 6 is provided on the inner wall surface of the metal tube 1 integrally with the wall surface over almost the entire surface, and a large number of thin continuous grooves 7 are formed over the entire surface of the electrode 5.

A high voltage is applied between the metal tube 1 and the electrode 5 by an external high voltage power supply 8. Here, if one end (lower side) of the heat pipe is used as a heating unit and the other end (upper side) is used as a cooling unit, boiling of the working liquid is promoted in the heating unit, and condensation of the working liquid vapor is performed in the cooling unit. The heat transfer characteristics of the heat pump are greatly enhanced by being promoted by the high voltage applied between the electrode and the electrode. Therefore, it can be applied to, for example, a thyristor cooling device mounted on a train, a snow melting branch line, and the like to obtain a good cooling or heating effect.

The present invention is not limited to the above-mentioned embodiment, and a large number of thin grooves or projections continuous in the longitudinal direction are formed on the inner wall surface of the metal tube 1 and / or the surface of the electrode 5 to reduce the area thereof. It is also possible to increase the amount and increase the similar boiling promoting action.

[0013]

In summary, according to the present invention, an electrode insulated from the container is provided inside, a high voltage is applied between the container and the electrode, and one end (lower side) of the heat pipe is connected to the heating section and the other end (lower side). When the upper side) is operated as a cooling unit, boiling of the working liquid in the heating unit and condensation of the working liquid vapor in the cooling unit are promoted by the effect of the high voltage applied between the container and the electrode, and the heat pipe The heat transport properties of are improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a heat pipe of the present invention.

FIG. 2 is a cross-sectional view of a conventional heat pipe.

[Explanation of symbols]

 1 Metal Tube 2 Hydraulic Fluid 3 Wick 4 Ceramic Insulator 5 Electrode 6 Group Wick 7 Continuous Groove 8 External High Voltage Power Supply

Claims (2)

[Claims] 1. A heat pipe comprising a metal tube whose both ends are closed, and a working liquid sealed inside the container. An electric insulator having airtightness is attached to one end of the metal tube, and the electric insulator is penetrated. The heat pipe is characterized in that the non-conductive hydraulic fluid is enclosed while the electrode is inserted inside. 2. The heat pipe according to claim 1, wherein
A heat pipe, characterized in that a large number of thin grooves or protrusions continuous in the longitudinal direction are formed on the surface of the electrode.