SU609946A1 - Coaxial heat pipe - Google Patents

Description

(54) COAXIAL HEAT PIPE

one

The invention relates to heat transfer devices, namely to heat pipes.

Coaxial heat pipes are known, comprising a body partially filled with g working fluid and consisting of coaxially arranged hermetic cylinders with a capillary-porous filler on the walls, the cylindrical joints being connected by radial porous ribs of a dielectric Yu, for example, oriented glass fibers spaced one from the other at an angle of 30 -45. Along the axis of the hull a heat-generating source is located for transferring the heat flux in the radial direction from the center to the periphery 13 of the ri. The ribs can also be made in the form of a pack of plates installed with a gap of 0 mm, and mesh tubular elements are placed in the cavity between the cylinders, for example, from a metal or dielectric 20 1.

However, such heat pipes have insufficient heat transfer efficiency, significant hydraulic resistance and pressure inside the sealed chamber. 25

The purpose of the invention is the intensification of heat transfer.

The goal is achieved by having an annular chamber between the heat source and the surface of the body with radial and end gaps, connected to the supply and extraction lines of the refrigerant and forming a circulating circuit for the working fluid in the gaps with the heat source and the surface of the body. The heat source is connected to the walls of the chamber by means of radial ribs. The surface of the heat-slitting source and the inner walls of the chamber can be made of shaped, for example corrugated.

FIG. Figure 1 shows schematically the described coaxial heat pipe, in longitudinal section; in fig. 2 - section A-A of FIG. 1 in FIG. 3 - heat pipe when performing the surface of a heat-fissile source of corrugated, transverse section; in fig. 4th heat pipe when making the inner walls of the chamber corrugated, cross-section.

The coaxial heat pipe comprises a housing 1, partially filled with a working fluid, and a heat snapping source 2, placed along the axis of the housing 1. Between the heat sink and another. A source 2 and a housing surface 1 with radial 3 and 4 and front .5 gaps are fitted with an annular chamber 6.

The annular chamber 6 is connected to lines 7 and 8 of supply (inlet) and refrigerant recovery (outlet) and forms inside the housing 1

in gaps 3-5 a circulation circuit for the working fluid.

The heat-snapping source 2, which forms the heating zone, is connected to the walls of the annular chamber 6 by means of radial ribs 9.

Depending on the problem to be solved for the heat transfer of the surface of the heat shed source 2 or the inner walls of the chamber 6, it can be made profiled, for example corrugated.

The coaxial heat pipe operates as follows jo6pa30M.

Under the action of heat flux from a heat-shedding source 2 located along the axis of body 1, part of the working fluid in the annular radial gap 3 changes its state of aggregation. The resulting vapor under the action of Archimedean forces rushes upward and pushes the working fluid, washing and heating the height of the chamber walls. The working fluid under its own weight through the upper end gap 3 enters the annular gap 4, where it partially cools. The vapor condenses on the walls of chamber 6,

attached to lines 7 and 8 of the supply and extraction of the refrigerant, over the entire surface accessible to it and in the form of condensate is mixed with the working fluid.

In the annular radial gap 3, the two-phase vapor-liquid system has a total density lower than the density of the working medium in the annular radial gap 4, and is also relatively cooled when it contacts the walls of the chamber 6. as with the cooler. This circumstance contributes to the creation of a directional circulation of the working fluid along a closed circuit, which ensures reliable cooling of the heat-shedding source 2.

The normal mode of operation of the heat pipe should be considered as the continuous washing of the entire heated surface of chamber 6 by the working fluid. It is provided with a selection: the width of the annular radial gap 3 (usually 3-5 mm, but with large thermal hoTo and significant length of the heat pipe can be increased to 10 mm ) required (at least 1/3). the height of the heat pipe filling the working fluid, flow

cooling agent. These parameters for optimal thermal coaxial tube operation are determined experimentally.

It should be noted that the coaxial heat pipe can work if its axis deviates from the vertical to 55. If the heat source is a moving medium, such as high-temperature gas, then the coaxial heat pipe can also be used as a transport channel, which has high reliability and low service life, and a cooling flow device. Cooling agent and working fluid can be water.

The reliability and durability of the coaxial pipe operation determine the following factors.

The surface of the annular chamber 6 connected to the supply lines 7 and 8 and the removal of the refrigerant is 1.8-2.2 times larger than the area of the heating zone, which ensures that there is no overpressure inside the heat pipe.

An emergency exit from the line of a coaxial heat pipe (burnout) will result in a release into the working space of the unit, of which it is part, of a limited and, as a rule, small amount of working fluid, and not the entire flow chla. agent (most likely industrial water). At the same time, the annular chamber located inside will play the role of an obtrusive caisson.

The proposed coaxial heat pipe makes it possible to significantly intensify heat transfer, i.e. to increase the efficiency of its use as caisson gas ducts, for example, in pyrometallurgical units.

Claims (3)

one.; A coaxial heat pipe containing a body partially filled with working fluid and a heat source placed along the axis of the body differ from the fact that, in order to intensify heat transfer, between the heat source and the body surface with radial and end gaps relative to them are installed an annular chamber, connected to the supply and extraction lines of the refrigerant and forming a circulating circuit FOR the working fluid in the gaps with the heat source and the surface of the body. 2. A pipe according to claim 1, wherein the heat-generating source is connected to the walls of the chamber by means of radial ribs. 3. A pipe according to Claim 1, clause 1 and so on. The surface of the heat-snapping source is profiled, for example, corrugated. 4, The pipe according to claim 1, characterized in 1; that is, the inner walls of the chamber are 6 Figz AT Ф // г4 are filled with profiled, for example corrugated. Sources of information taken into account in the examination; 1. Author's certificate N 436964, class, G 25 V 19/04. 1970.