JPS63183388A - Heat transfer body - Google Patents

Abstract

PURPOSE:To obtain good discharging performance of liquid, to increase reflux speed, and to prevent condensation promoting effect from lowering, by providing channels continuously extending to the flowing direction of liquid that is a heating medium, on porous layers having a number of tubular recesses with bottom on them, provided on the surface of the base body of a metallic pipe. CONSTITUTION:Porous plated layers 11 formed on the whole inside surface of a pipe body 10 which is made of metal such as copper have a number of tubular recesses 12 with bottom, of which openings are narrowed relatively. A plurality of channels 13 having cross sectional shapes of U, extending spirally to the axial direction of a pipe body 10, are continuously provided on the plated layer 11 and also on the inside wall of a pipe body 10. The structures is such that liquid can flow into the channels 13 when it condenses on the surfaces of porous plated layers 11 in a radiating part, and it is transmitted to a heating part by the capillary effect of the channels 13.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is applicable to, for example, evaporation tubes and condensation tubes of heat exchangers for air conditioning;
Alternatively, the present invention relates to a heat transfer body such as a heat vibrator used as a heat transfer body in a road snow melting device or the like.

"Prior Art" The above-mentioned evaporation tube, condensation tube, or heat vibrator causes a phase transformation (gas-to-liquid) of a heat medium sealed inside the tube due to the temperature difference between the inside and outside of the tube. heat transfer in the longitudinal direction of the tube.

For example, a heat pipe is a metal tube with a reduced pressure and a liquid such as water or alcohol sealed inside it. When one end of the pipe is heated, the liquid boils and the vapor flows to the other end (heat dissipation part) due to the vapor pressure difference. There, it condenses into a liquid, which is then returned to the heating section. To perform this function, a structure called a wick is formed on the inner surface of the tube. Therefore, in order to improve heat transfer performance in a heat pipe, (a) heat transfer performance inside and outside the tube, (b) ability to promote boiling or condensation on the inner surface of the tube, and (c) medium ( There is a need to form a wick with improved performance, especially for transporting liquids.

As an improvement to this type of heat transfer body, the present applicant previously proposed the one shown in FIG. 5 in Japanese Patent Application No. 60-252358.

This heat transfer body has a large number of bottomed cylindrical recesses 2 with relatively narrow openings on the inner surface of a metal tube body (Jl (body) 1).
It is characterized by forming a porous plating layer 3 having ..., and the recesses 2 increase the heat transfer area of the inner surface of the tube l to improve the performance of (a) above. At the same time, the above performance (b) is improved by promoting nucleation for generating bubbles and promoting nucleate boiling, thereby improving the heat transport ability.

``Problems to be Solved by the Invention'' However, in the above heat transfer body, since the adjacent recesses 2 are often independent, this heat transfer body is When used as a part, there was a problem that the condensed liquid remained in the recesses 2 and was not discharged, and the reflux rate of the liquid was low. Furthermore, since the porous plating layer 3 is covered with the condensed liquid, there is a drawback that the condensation promoting effect of the porous plating layer 3 is difficult to be sufficiently exhibited.

"Means for Solving the Problems" The present invention aims to solve the above problems, and therefore, a large number of bottomed cylindrical recesses with relatively narrow openings are formed on the surface of a metal base. The present invention is characterized in that a porous layer is formed, and grooves are formed in this porous layer that are continuous in the direction in which a liquid serving as a heat medium should flow.

"Function" In the heat transfer body of the present invention, when vapor condenses on the surface of the porous layer and becomes liquid, this liquid flows into the grooves and is carried in the direction in which the liquid should flow by the capillary action of the grooves. Therefore, the liquid discharge property is good, the reflux rate can be improved, and the porous layer can be prevented from being submerged in the liquid and the condensation promoting effect is prevented from decreasing.

"Embodiments" Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figures 1 and 2 show an example in which the present invention is implemented as a heat vibrator (heat transfer body). Figure 1 is an enlarged view of the cross-sectional properties of the heat vibe, and Figure 2 is an enlarged view of the inner surface properties. .

In these figures, reference numeral 10 indicates a tube (substrate) made of metal such as copper, and 11 indicates a porous plating layer (porous layer) formed on the entire inner surface of the tube 10.

This porous plating layer 11 has a large number of bottomed cylindrical recesses 12 whose openings are relatively sandwiched, and the surface area ratio of these recesses I2 is 10 to 50%. This ratio is 1
If it is less than 0%, the effect will be small, and if it is more than 50%, it will be difficult to manufacture, and the heat transfer ability will not improve enough to justify the increase in cost.

Further, a plurality of grooves 13 having a U-shaped cross section are formed in the plating layer 11 and the inner wall of the tubular body 10, and extend continuously and spirally in the axial direction of the tubular body 10. These M+3
It is desirable that the width and depth of the groove 13 be determined so as to obtain the best liquid transport ability, taking into account the capillary phenomenon of the groove 13.

Then, an appropriate amount of liquid such as water or alcohol is put into the tube IO, and the inside is reduced in pressure and both ends are closed.

Next, a method for manufacturing such a heat pipe will be explained.

First, a diluted hydrophobic substance such as silicone oil with a volatile solvent such as ethanol is applied to the inner surface of the tubular body 10, and then the solvent is evaporated to form a hydrophobic thin film.

The thickness of this hydrophobic thin film is preferably 0.1 to 5 μm. If it is less than 0.1 μm, the formation of the recess 12 will be reduced, while if it exceeds 5 μm, the insulation will become too high. A uniform porous plating layer 11 cannot be obtained.

Next, using a plating apparatus as shown in FIG. 3, a porous plating layer 11 is electroplated on the inner surface of the tubular body 1O. In this device, an insoluble anode wire 14 made of Ti-P or the like is stretched under tension along the axis of a tube 10, and insulating spacers 15 are provided around the wire 14 at appropriate intervals. , storage hff for storing copper sulfate plating solution 16
and a chemical pump 17 for flowing the plating solution into the pipe body lO, the storage tank 16 is configured to supplement the loss of copper ions due to plating by adding basic copper carbonate and to circulate the solution. There is.

Then, a pulse current such as an intermittent current 1, a normal pulse current, or a PR current is applied between the anode wire 14 and the tubular body 10, as appropriate. Then, the water in the plating solution is electrolyzed and oxygen gas is generated from the anode wire 14. A part of this oxygen gas adheres to the hydrophobic thin film coated on the inner surface of the tube body 10, which is the cathode, and the air bubbles are generated. The nearby metal grows in such a way as to envelop it, forming a porous plating layer IT. Note that the anode current density needs to be 20 A/dm" or more; if it is less than that, oxygen gas will not be sufficiently generated.

Eventually, when the porous plating layer 11 reaches a predetermined thickness, the tubular body 10 is removed, and this tubular body 10 is applied to a rolling device.
Spiral grooves on the plating layer 11 and the inner wall of the tube IO! 3...
・Form.

In the heat pipe having such a configuration, when liquid condenses on the surface of the porous plating layer 11 in the heat dissipation section, this liquid flows into the groove 13 and is carried to the heating section by the capillary phenomenon of 'tM I 3. This improves the liquid discharge performance and improves the reflux rate. In addition, it is possible to prevent the porous plating layer II from being submerged in the liquid and reducing the condensation promotion effect, thereby increasing the heat transport capacity of the heat pipe. -It is possible to do this.

Note that in the above heat pipe, the grooves 13 are rolled after forming the plating layer It on the inner surface of the tube body 10, or instead, the grooves 13 are formed in the tube body 10 in advance, this! Mask the inside of f + T l a with insulating paint, etc.
It is preferable to adopt a method of forming the plating layer 11 by electrodeposition. In that case, there is a fl1 point that the adhesive strength of the plating layer 10 is not affected by rolling.

Moreover, instead of forming 'tii I 3 by rolling, a masking 20 in the shape of a tome band is formed on the inner surface of the tube 10 as shown by the dashed line in FIG. 4, and in this state, the porous plating layer 11 After the masking 20 is electrodeposited, the masking 20 can be removed and its traces can be left in line with the grooves 21, making it easier to form the grooves than in the method described above.

The shape of the tube and iM is not limited to a spiral shape, but may be a straight shape along the axial direction of the tube body 10. In this case, set the number of latents to 1
The heat pipe may be made of wood, and when the heat pipe is used, the second groove is located on the lower inner surface of the heat pipe, so that the liquid flowing downward by gravity can be transported.

In the above embodiment, the recess 12 of the plating layer 11 was formed perpendicularly to the inner surface of the tube body 10.
When applying 1 to 711, set the flow rate of the plating solution to high speed,
By forming the recess 12 so as to be inclined in the direction in which the liquid in the heat pipe flows, the heat transfer characteristics can be further improved.

Furthermore, the present invention is not limited to heat pipes, and can be implemented as condensation tubes, evaporation tubes, plate-shaped heat transfer bodies, and heat transfer bodies in which a porous layer is formed on the outer surface of a tube body.

"Effects of the Invention" In the heat transfer body of the present invention, when liquid condenses on the surface of the porous plating layer, this liquid flows into dI\ and is carried in the direction in which the liquid should flow by the capillary action of the grooves.

Therefore, the liquid can be drained well on the porous layer, and its reflux rate can be improved. At the same time, it is possible to prevent the porous layer from being submerged in the liquid and reducing the condensation promoting effect, thereby improving the heat transport ability.

[Brief explanation of the drawing]

Fig. 1 is an enlarged view showing the cross-sectional properties of a heat pipe (heat transfer body) according to an embodiment of the present invention, Fig. 2 is an enlarged view showing the properties of the inner surface of the heat pipe, and Fig. 3 is an enlarged view showing the properties of the inner surface of the heat pipe. Figure 1 is an enlarged view showing the cross-sectional properties of an embodiment of the plating device of the present invention. It is an enlarged view showing the cross-sectional properties of the heating body. 1O... tube body (weir body), It/porous plating layer, 12
... recess, 13.21 ... groove.

Claims (1)

[Claims] A porous layer having a large number of bottomed cylindrical recesses with relatively narrow openings is formed on the surface of the metal base, and a direction in which a liquid serving as a heat medium should flow in this porous layer is formed. A heat transfer body characterized by having continuous grooves formed therein.