JPH01266492A - Heat pipe for rotor and manufacture thereof - Google Patents

Abstract

PURPOSE:To expand the evaporating area of operating liquid in an evaporating section to the whole periphery of a pipe to permit efficient heat transfer, by a method wherein the evaporating section is provided with a wick of porous body and a condensing section is provided with a spiral coil respectively while the coil side and of the wick is contacted or proximated to the end of the coil. CONSTITUTION:A heat pipe 11 is divided into an evaporating section H absorbing heat and a condensing section L dissipating the heat while the evaporating section H is provided with a wick 12 of porous body axially on the surface of the inner wall thereof and the condensing section L is provided with a spiral coil 13 contacted closely to the surface of the inner wall of the pipe. When the heat pipe 11 is rotated, operating liquid filled in the pipe is transferred by the propelling force thereof and is fed back to the evaporating section H from the condensing section L. In this case, the coil side end of the wick 12 is brought in contact or proximated to the end of the coil to facilitate the transfer of the operating liquid sent from the condensing section L into the evaporating section H. A thin circular tube 14 inscribed to the coil 13 is preferably provided so as to be neighbored to the evaporating section H and a heat insulating section S is provided between the coil 13 and the evaporating section H to separate vapor passing through the side of the part of the axis of the pipe from returning liquid passing through the outside of the thin circular tube 14 at the side of the coil 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat pipe for a rotating body, and more particularly to a heat pipe with a built-in coil in which a coil is brought into close contact with the inner wall surface of the pipe, and a method for manufacturing the same.

Prior Art> This type of heat pipe, which is used to cool rotating objects such as hot coils, has a coil inserted tightly into the inner wall of the tube, and the thrust of the coil caused by the rotation of the tube causes the working fluid at the bottom of the condensing section to cool. is transferred to the evaporation section along the spiral of the coil.

Problems to be Solved by the Invention However, the working fluid to be transferred can only be transferred if it stagnates between the inner wall surface of the tube and the coil, and as the rotation speed increases, the stagnant liquid is centrifuged. Due to the force, it spreads in the circumferential direction of the inner wall of the tube, and in extreme cases, it adheres to the inner wall of the tube with the same thickness, rotates with the tube due to frictional force or viscous force, and becomes impossible to transport. On the other hand, in the case of low-speed rotation, if the heat flux in the evaporation section is large, heat input from the entire circumference is generated by the amount of retained liquid that adheres to the tube wall, so the heat pipe evaporates before it completes one revolution. It is completely useless as a heat pipe in areas where the liquid has run out. This will be explained with reference to FIG. 4. Reference numeral 1 denotes a heat nob that rotates in the direction of arrow a, and a coil 2 is inserted into the inner wall surface in close contact with it. Reference numeral 3 denotes a staying liquid, and as the heat pipe 1 rotates, an adhering liquid 4 adheres due to the wettability of the tube wall. If the rotation speed is slow, the attached liquid 4 becomes an extremely thin film that covers area B, but it evaporates midway due to the input heat and the attached liquid 4
This results in a C area with no .

° The thermal conductivity of the retained liquid 3 (area A) is very poor, and high thermal conductivity of the heat pipe cannot be expected, so the heat transfer effect of the heat pipe is ultimately limited to area B. Therefore,
The smaller the C area of the heat pipe, the larger the effective area.

As mentioned above, there is an upper limit and a lower limit to the usable rotational speed, and the range of use is narrow.

The purpose of the present invention is to widen the range of use as much as possible, and to explain in more detail, among the upper and lower limit rotation speeds,
The former is caused by the centrifugal force due to the heat pipe diameter, the viscosity of the working fluid,
Alternatively, since it is difficult to change it due to physical characteristics such as friction, the latter is an improvement to widen the adhering liquid (area B) in the evaporation section.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention divides a heat pipe into an evaporation section that absorbs heat and a condensation section that releases heat, and a porous wick is provided in the axial direction of the inner wall surface of the evaporation section. In addition to establishing
The heat pipe for a rotating body is characterized in that a helical coil is provided in close contact with the inner wall surface of the pipe of the condensing part, and the coil side end of the wick and the coil end are in contact with or close to each other. Claim 1) further characterized in that a thin-walled cylinder inscribed in the spiral coil adjacent to the evaporator section is provided to serve as a heat insulating section.
The heat pipe for a rotating body was prepared as described above.

The method for manufacturing a heat pipe for a rotary body according to claim 1), further comprising the step of manufacturing the evaporation section and the condensation section separately, and after filling them with a working fluid, the outer periphery of the tube is hermetically joined. A condensing section consisting of a helical coil tightly attached to the inner wall of the tube, which has an outer diameter slightly smaller than the inner diameter of the tube, is inserted into an evaporator section in which a porous wick is provided in the axial direction on the inner wall of the tube. After touching or coming close to the end,
Claim 3) characterized in that the outer periphery is closely joined.
The heat pipe for a rotating body was prepared as described above.

With the above structure, the return of the working fluid from the condensing part to the evaporating part is carried out by the spiral coil in the condensing part, and the porous wick is moved by the surface tension in the capillary element. Even if evaporation progresses due to heat input to the evaporation section, a thin layer of adhered liquid can be constantly spread around the entire circumference of the tube.

Embodiment> Next, one embodiment of the present invention will be explained with reference to FIG. 1.
is a heat pipe and is divided into an evaporation section H that absorbs heat and a condensation section L that releases heat, and a porous wick 12 is provided on the inner wall surface of the evaporation section H in the axial direction. Further, a spiral coil 13 is provided in close contact with the inner wall surface of the pipe of the condensing part L, and when the heat pipe 11 rotates, the working fluid (not shown) filled inside the pipe is transferred by the driving force from the condensing part L. It returns to the evaporation section H. The coil side end of the wick 12 and the coil end are in contact with or are close to each other, so that the working fluid sent from the condensing section L can easily move to the evaporating section H.

Further, the vapor of the working fluid evaporated in the evaporation section is condensed in the condensation section, returns to liquid, and is transferred to the evaporation section by the propulsive force of the spiral coil, but the transferred liquid is blown away by the vapor from the evaporation section. In such a case, as shown in FIG. 2, the thin cylinder 1 in which the coil 13 is inscribed
4 is provided adjacent to the evaporation part H, and a heat insulation part S is provided between them,
It is also good to separate the steam passing through the shaft center side from the return liquid passing outside the thin-walled cylinder 14 on the coil 13 side.

Furthermore, when manufacturing the above-mentioned tubular heat pipe, it is extremely difficult to provide a porous wick in the evaporator section or to incorporate a spiral coil in the condensing section with good adhesion, and dust may form in the evaporator section with the wick installed. It is best to manufacture the condensing section incorporating the coil and the coil separately, and then join the two parts after injecting the working fluid.Also, to make joining easier, the tube 15 of the evaporating section H is installed as shown in Fig. 3. A porous wick 16 is provided on the inner wall surface of the evaporator section H, and the tube 17 of the condensation section has an outer diameter slightly smaller than the inner diameter of the tube 15 of the evaporation section H. When assembling the evaporation section H and the condensation section, The tube 17 of the condensing section is inserted into the inner diameter of the tube 15 of the evaporation section H, and the ends of the wick 16 and the coil 18 are brought into contact or close to each other, and then the connection section 19 is closely joined.

<Effects of the Invention> Since the above-mentioned configuration and operation are performed, the evaporation area of the working fluid in the evaporator section spreads over the entire circumference of the tube, allowing efficient heat transfer, and is extremely convenient for manufacturing heat pipes. It is effective for

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing another embodiment according to the present invention. FIG. 3 is a diagram illustrating a method for manufacturing a heat pipe according to the present invention. FIG. 4 is a cross-sectional view illustrating the state of the working fluid inside the heat pipe. 11.15.17...Pipe, 12, 16...Porous wick, 13, 18...Spiral coil, 19...
・Joint part, H...evaporation part, L...condensation part

Claims (1)

[Claims] 1) A heat pipe is divided into an evaporation section that absorbs heat and a condensation section that releases heat, and a porous wick is provided in the axial direction of the inner wall surface of the tube in the evaporation section, and it is tightly attached to the inner wall surface of the condensation section. A heat pipe for a rotating body, characterized in that a spiral coil is provided, and a coil side end of the wick and the coil end are in contact with or close to each other. 2) Claim 1) characterized in that a thin-walled cylinder inscribed in the spiral coil adjacent to the evaporator section is provided to serve as a heat insulating section.
Heat pipe for rotating bodies as described. 3) The method of manufacturing a heat pipe for a rotating body according to claim 1, wherein the evaporating section and the condensing section are separately manufactured, and after being filled with a working fluid, the outer periphery of the tube is hermetically joined. 4) Inserting into an evaporator section in which a porous wick is provided in the axial direction on the inner wall surface of the tube, a condensing section consisting of a helical coil tightly attached to the inner wall surface of the tube, which has an outer diameter slightly smaller than the inner diameter of the tube of the evaporator section;
4. The heat pipe for a rotating body according to claim 3, wherein the wick and the coil end are brought into contact with each other or brought close to each other, and then their outer peripheries are closely joined.