JPS58120086A - Heat transmitting tube - Google Patents

Abstract

PURPOSE:To permit active grow and separation of vapor bubbles by a method wherein an annular thin thickness member having a multitude of fine holes is inserted into the heat transmitting tube to form continuous tunnels having proper configurations between both parts and communicate a fluid through the fine holes. CONSTITUTION:An outer tube 1 is formed with a multitude of rectangular fine grooves 2 on the inner wall thereof, the thin thickness inner tube 3 provided with a multitude of fine holes 4 is inserted into the outer tube 3, and is adhered closely thereto by forcing a tube expander 6 thereinto to form triangular continuous tunnels 5 between the inner and outer tubes 3, 1 while the tunnels 5 and the inner tube 3 are communicated by the fine holes 4. Thus, liquid 7, flowing in the tunnels 5 is heated through the gas flowing through the outside of the outer tube 1, therefore, vapor bubbles 8 are generated. When the vapor bubbles 8 are generated once, the vapor bubbles 8 are held in the tunnels at all times so as to be a nuclear 9 for the bubble and whereby the grow and the separation of the bubble becomes active and a heat transmitting rate upon boiling or vaporizing of the liquid flowing in the inner tube may be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat transfer tube that exchanges heat by flowing a phase-changing fluid inside the tube and at the same time flowing a separate fluid outside the tube.

As shown in the fs1 diagram, as a conventional heat exchanger tube for a heat exchanger, a heat exchanger tube 1 having a smooth surface without any processing on the inner surface of the tube is generally used, but recently the heat transfer coefficient of the heat exchanger tube In order to improve this, inner tubes with protrusions inserted inside the tube have been developed.

According to the above-mentioned inner tube, although the heat transfer coefficient can be improved, the disadvantage is that the pressure loss increases significantly. In addition, a spiral groove is provided on the inner surface of the tube for better heat transfer (not shown).
However, this heat exchanger tube is widely used because it has a good heat transfer coefficient. However, in order to achieve further energy savings, it is required to further improve the heat transfer coefficient of heat exchanger tubes.

An object of the present invention is to provide a heat exchanger tube that satisfies the above-mentioned requirements.An annular thin-walled member having an arbitrary number of pores is inserted into the heat exchanger tube, and between this thin-walled member and the tube. The present invention is characterized in that a continuous tunnel having an appropriately shaped cross section is formed, and the tunnel and the interior of the thin member are communicated with each other via the pores.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 2 to 6, 1 indicates the outer diameter Do.

The outer tube 2, which has an inner diameter, is formed in an arbitrary number on the inner wall of the outer tube 1, and the narrow grooves 2 have regular and continuous triangular cross sections. 3 is the outer diameter k
It is a thin inner tube having an inner diameter of d and an arbitrary number of pores 4 on its circumferential surface, and its outer diameter d0 is smaller than the inner diameter D1 of the outer tube 1.

In this embodiment, a triangular narrow groove 2 is provided on the inner circumferential surface of the outer tube 1, but as shown in FIGS. 7 and 8, a trapezoidal groove 2A and a rectangular narrow groove 2B1゜ or irregularly shaped narrow grooves (not shown) may be provided.On the other hand, the pores 4 provided in the inner tube 3 are not limited to the rectangular shape as shown in FIG. , triangular, circular or other complex shapes.

To describe one means for integrally connecting the inner tube 3 and the outer tube l, first, as shown in FIG.
- Insert the inner and outer tubes 3 and 1 as shown in Figure 10.
A tube expansion tool 6 shown in FIG. 11 is press-fitted into the inner tube 3 from one side (the left (Ml) in the figure).

Next, when the tube expansion tool 6 is rotated and moved forward in the direction of the arrow, the inner tube 3 is expanded and successively closely adhered to the inner wall of the outer tube 1 and joined together as one body. At the same time, a continuous tunnel 5 having a triangular cross section as shown in FIG.

Since the performance changes depending on the pitch and depth of the narrow grooves 2 of the outer tube 1 and the pitch and diameter of the pores 4 of the inner tube 3, it is necessary to determine the dimensions according to the specifications of the heat exchanger tube. In addition, in this embodiment, the outer tube 1 and the inner tube 3 are brought into close contact with each other from the standpoint of heat transfer. It goes without saying that simply inserting it inside the body can be effective.

The present embodiment has the above-mentioned configuration, and since the liquid 7 flowing inside the tunnel 5 is heated via the gas flowing outside the outer tube 1, the liquid 7 generates vapor m5ft.

When the steam bubbles 8 are generated in this way, the steam bubbles are always retained in the tunnel 7 and become bubble nuclei 9, and the bubbles actively grow and separate.

Next, another embodiment will be described with reference to FIGS. 12 to 19.

In FIGS. 12 and 13, 11 is an outer tube, and 12 is a thin inner tube having an annular circumferential surface consisting of a concavo-convex portion with a continuous cross section. This inner tube 12 is inscribed in and continuous with the outer tube 11. A tunnel 14 is formed. 13 are pores provided at the bottom of the concave portion and the top of the convex portion of the inner tube 12, respectively;
The tunnel 14 communicates with the interior of the inner tube 12 through this pore 13 .

The inner tube 12 is manufactured as follows. That is,
First, as shown in FIG. 14, the pores 13 are formed in a rectangular shape.
A continuous corrugated thin plate 12A is formed by bending the nine thin plates 12A in the direction of the arrow ED at a predetermined interval P an arbitrary number of times as shown in FIG. Then,
The inner tube 12 shown in FIG. 12 can be manufactured by curving such a corrugated thin plate 12A in the direction of the arrow FG with a curvature commensurate with the inner diameter of the outer tube 11.

In this case, the waveform of the thin plate 12A shown in FIG. 15 in the direction of the arrow ED is similarly formed in the direction of the arrow CD shown in FIG. In addition, in the thin plate 12A shown in FIG. 15, the pores 13 are provided in the middle part of the corrugations, but instead, as shown in FIG.
may be provided.

The embodiments shown in FIGS. 17 and 18 show modified examples of the waveform of the thin plate 12A, that is, rectangular and sawtooth waveforms. Such shapes can be formed in the same manner as in FIG. 15. I can do it. Said sawtooth waveform (Figure 18)
A perspective view of the is shown in FIG. Such a corrugated thin plate 1
2A is annularly curved in the direction of arrow FG with a curvature commensurate with the outer tube to form the inner tube 12.
Insert it into the outer tube 11 as shown in the figure. The outer tube 11 and the inner tube 12 are brought into contact with each other as shown, and then soldered, brazed, or otherwise bonded. If the thin plate 12A has a strong elastic force in the direction of arrows F-G in FIG. 19, it is not necessary to fix it to the contacting means as described above.

In the heat exchanger tube shown in FIG. 12 and FIG. It is provided. Therefore, among the liquid 15 flowing near the inner surface of the outer tube 1, the liquid 15a inside the tunnel 14 is heated by the gas 16 flowing outside the outer tube 1, so that the liquid 15a generates vapor bubbles 171. .

When the steam bubbles 17 are generated in this way, the tunnel 1
Steam bubbles are always retained in the chamber 4 and become bubble nuclei 18, and the bubbles actively grow and separate.

The same effect can be obtained even if the device is arranged so as to be tilted at an arbitrary angle.

As explained above, according to the present invention, steam bubbles are always retained in the tunnels formed in the inner and outer tubes and become bubble nuclei, and the growth and separation of the steam bubbles are actively carried out. ,
Since the heat transfer coefficient increases significantly when the liquid flowing through the inner tube boils or evaporates, heat transfer performance can be significantly improved.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional heat exchanger tube, Figure 2 is a sectional view showing an embodiment of the heat exchanger tube of the present invention, Figure m3 is a partially exploded view of the inside of the same embodiment, and Figure 4 is a The A-A sectional view in the figure, Figures 5 and 6 are respective perspective views of the outer tube and inner tube in Figure 2, and Figures 7 and 8 are deformation of the thin groove provided in the outer tube. FIGS. 9 and 110 are explanatory diagrams showing means for manufacturing heat exchanger tubes, FIG. 11 is a perspective view of a tube expansion tool, and FIG. 12 is a cross-sectional view showing another embodiment of the present invention. Figure 13 is the first
An enlarged detailed view of part B in FIG. 2 and FIGS. 14 to 19 are explanatory views for manufacturing the inner tube. 1.11... Outer tube, 2... Thin groove, 3.12... Thin wall member (inner tube), 4,13... Pore, 4.14...
tunnel. Agent Patent Attorney Toshiyuki Usuda No. 1 No. 3 No. 1 No. 4 No. 4 No. 7 En 4' Figure 1s Figure 16 ¥5 / Figure 7 Figure 78 % tQ diagram

Claims (1)

[Claims] 1. In a heat transfer tube in which heat exchange is performed between the two fluids by flowing different fluids inside and outside the tube, an arbitrary number of pores are provided in the tube. A continuous tunnel having an appropriately shaped cross section is formed between the thin walled member and the tube, and this tunnel and the interior of the thin walled member are interconnected through the pores. A heat exchanger tube characterized by being made to communicate. 2. In the heat exchanger tube according to claim 11, an arbitrary number of narrow grooves are provided on the inner wall of the tube, and the thin-walled member is a thin-walled tube having a diameter smaller than the inner diameter of the tube and having an arbitrary number of pores. A heat exchanger tube characterized in that it is used. 3. In the heat exchanger tube according to claim 1, an annular tube formed by curving a corrugated thin plate having an arbitrary number of pores with a curvature smaller than the inner diameter of the tube is used as the thin wall member. A heat exchanger tube characterized by: