JP3350104B2 - Heat transfer tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer tube having a structure in which a fin having an angled cross section is attached to a side wall facing a fluid passage through which a heating fluid flows, in a longitudinal direction of the tube.

[0002]

2. Description of the Related Art There is known a heat transfer tube provided facing a fluid passage through which a heating fluid flows, and having a structure in which a fin having an angled cross section is attached to a side wall facing the fluid passage in a longitudinal direction of the tube. Have been. FIG. 3 is a diagram showing a cross section of a conventional heat transfer tube of this type. As shown in the figure, a fin 1 having an angled cross section is attached to a side wall of a heat transfer tube 2 facing a fluid passage 4 through which a heating fluid flows.

[0003]

In the heat transfer tube having the above-mentioned conventional structure, the fin 1 having an angled cross section is attached to the side wall facing the fluid passage 4, so that the heating fluid flowing through the fluid passage 4 is heated by the heat transfer tube 2. The direction of the flow is changed while colliding with the side surface of the fin 1 having an angled cross section, and the heat flows along the side surface of the heat transfer tube 2 or the surface of the fin 1 having an angled cross section. However, if the conventional fin 1 having an angled cross section is simply attached to the side wall of the heat transfer tube 2, a vortex is generated at a mounting portion of the fin 1 having an angled cross section, and this eddy current becomes a flow that inhibits heat transfer. was there.

[0004] The present invention has been made in view of the above points, and an object of the present invention is to eliminate the above-mentioned conventional problems and to provide a heat transfer tube excellent in heat transfer.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a fin having an angled cross section on a side wall facing a fluid passage formed by an inner water pipe wall and an outer water pipe wall, through which a heating fluid flows. Constructs the water pipe wall with a structure attached in the longitudinal direction of the pipe
A fin having a cross section at an angle, the surface of which is substantially parallel to the tangential surface of the surface of the fin mounting portion,
And the heat transfer tube is attached so that the surface of the fin is smooth from the surface of the fin to the surface of the fin, and the top of the fin is attached to the fin.
The heating fluid protruding into the fluid passage and flowing from a direction orthogonal to the heat transfer tube is arranged so as to change the direction of the flow while colliding with the heat transfer tube side surface or the fin surface.

Further, the angle between the two surfaces of the fin having an angled cross section is substantially 90 °.

[0007]

With the above construction, the heating fluid flowing from the direction perpendicular to the heat transfer tube flows smoothly and continuously from the surface of the heat transfer tube to the surface of the fin, and the fin having an angled cross section is formed. Since there is no stagnant area for the heating fluid on the surface of the heat transfer tube of the mounting portion, heat transfer is improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a heat transfer tube according to one embodiment of the present invention. As shown in the figure, a heat transfer tube 2 is provided facing a fluid passage 4 through which a heating fluid flows.
Fin 1 having an angled cross section on the side wall facing the fluid passage 4 of FIG.
Are attached in the longitudinal direction of the tube. The tangential surfaces of the surfaces 1a and 1b of the fin 1 having an angled cross section and the surfaces 2a and 2b of the heat transfer tube 2 at the mounting portion of the fin 1 are substantially parallel (in the drawing, they substantially coincide with each other).

In the heat transfer tube 2 having the above-described structure, the heating fluid flowing from the direction perpendicular to the heat transfer tube 2 as shown by the arrow 3 collides with the surface of the heat transfer tube 2 and changes the direction of the flow. It becomes the flow along. At this time, since the surfaces 2a and 2b of the heat transfer tubes 2 at the attachment portions of the fins 1 having an angled cross section and the surfaces 1a and 1b of the fins 1 are substantially parallel, the heating fluid flows from the heat transfer surfaces of the heat transfer tubes 2 to the fins. The fins 1 continuously flow to the surfaces 1a and 1b of the heat transfer tube 1, and there is no stagnation area on the surfaces 2a and 2b of the heat transfer tube 2 at the mounting portion of the fin 1 having an angled cross section.

Therefore, a vortex is generated as a stagnation area in the past, and the heat transfer between the main flow of the heating fluid and the heat transfer surface is hindered. The main flow of the heating fluid flows in the heat transfer region, and the heat transfer surface is effectively used, so that heat transfer can be improved.

FIG. 2 is a sectional view showing the structure of a heat transfer tube according to another embodiment of the present invention. As shown in the figure, a fin 1 having an angled cross section is attached to the side wall of the heat transfer tube 2 facing the fluid passage 4 in the longitudinal direction of the tube. The angle between the surface 1a and the surface 1b of the fin 1 having an angled cross section is substantially 90 °. By making the angle between the surface 1a and the surface 1b of the fin 1 approximately 90 °, the heating fluid flows more smoothly and continuously from the heat transfer surface of the heat transfer tube 2 to the surfaces 1a and 1b of the fin 1. Will be.

FIGS. 4 and 5 are views showing the structure of a water tube boiler using the heat transfer tubes having the above structure. FIG. 4 is a longitudinal sectional view, and FIG. 5 is a transverse sectional view. The upper header or upper shell 5 and the lower header or lower shell 6 are both formed in a ring shape, and the upper header or upper shell 5 and the lower header or lower shell 6 are as many as the inner water pipes 2-1. Outside water pipe 2-2.

A large number of inner water pipes 2-1 are arranged in close contact with each other and are configured as annular water pipe walls. The outer water pipes 2-2 are connected to each other by fins 7 and are configured as annular water pipe walls. The combustion gas passage 8 is provided between the water pipe wall of the inner water pipe 2-1 and the water pipe wall of the outer water pipe 2-2.
Is formed, a casing 9 is provided outside the water pipe wall of the outer water pipe 2-2, and a heat insulating material 10 is provided outside the casing 9.

A combustion chamber 11 is formed in the water pipe wall of the inner water pipe 2-1 formed in an annular shape. A combustion device 15 is provided inside the upper header or upper body 5. An opening 12 is provided at a predetermined position of the inner water pipe 2-1 row over the entire length of the water pipe, and a combustion chamber 11 and a combustion gas passage 8 are provided.
Is communicated. Further, an opening 13 is provided at a predetermined position of the outer water pipe 2-2 row over the entire length of the water pipe, and the combustion gas passage 8 and the flue 14 are connected.

The inner water pipe 2-1 and the outer water pipe 2-2 are arranged so as to be shifted from each other by a substantially half pitch in the circumferential direction, and are provided on the side walls of the inner water pipe 2-1 and the outer water pipe 2-2 facing the combustion gas passage 8. Is provided with a fin 1 having an angled cross section over the entire length of the water pipe. The tangential surface between the surface of the fin 1 and the surface of the heat transfer tube at the mounting portion of the fin 1 is substantially parallel as described above. Accordingly, the inner water pipe 2-2 for the combustion gas flowing through the combustion gas passage 8 is formed.
1, the outer water pipes 2-2 and the fins 1 having an angled cross-section attached thereto are the same as described above, and the efficiency of heat transfer to the water pipes is improved.

[0016]

As described above, according to the present invention, the surface of the fin having a cross section at an angle is substantially parallel to the tangent surface of the surface of the fin mounting portion , and the surface of the heat transfer tube of the heat transfer tube.
From the fin to the surface of the fin for a smooth surface
The heat transfer tube faces the fluid passage and is directly connected to the heat transfer tube.
Heated fluid flowing from the intersecting direction is
It is arranged to change the direction of the flow while colliding with the surface
Since, the heating fluid flowing from a direction perpendicular to the heat transfer tube is smoothly flows continuously into fin surface from <br/> heat transfer tube surface,
Since there is no stagnant area of the heating fluid on the surface of the heat transfer tube at the fin attachment portion, an excellent effect of improving heat transfer can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a heat transfer tube according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a structure of a heat transfer tube according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a structure of a conventional heat transfer tube.

FIG. 4 is a longitudinal sectional view showing a structure of a water tube boiler using the heat transfer tube of the present invention.

FIG. 5 is a cross-sectional view showing a structure of a water tube boiler using the heat transfer tube of the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 Cross-section of fin having an angled shape 2 Heat transfer tube 3 Arrow indicating flow of heating fluid 4 Fluid passage 5 Upper header or upper body 6 Lower header or lower body 7 Fin 8 Combustion gas passage 9 Casing 10 Heat insulator 11 Combustion chamber 12 Opening 13 Opening 14 Flue 15 Combustion device

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F28F 1/00-1/44 F28F 9/00-9/26

Claims (2)

(57) [Claims] 1. A structure in which a fin having an angled cross section is attached in a longitudinal direction of a pipe on a side wall facing a fluid passage formed by an inner water pipe wall and an outer water pipe wall, through which a heating fluid flows . The water pipe wall
A heat transfer tube comprising: a fin having a cross section at an angle, wherein a surface of the fin is substantially parallel to a tangent surface of a surface of the heat transfer tube of the fin attachment portion, and the surface of the fin has a smooth surface from the surface of the fin to the surface of the fin. The heat transfer tube is mounted so that the top of the fin projects into the fluid passage.
A heat transfer tube, wherein the heat transfer tube is arranged so that a heating fluid flowing out from the direction perpendicular to the heat transfer tube collides with a heat transfer tube side surface or a fin surface and changes a flow direction. 2. An angle between two surfaces of a fin having an angled cross section is substantially 90 °.
Heat transfer tube as described.