JP2726018B2 - Multi-tube heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-tube heat exchanger in which a large number of heat transfer tubes constituting a tube nest are arranged at equal intervals in a fluid flow direction and in parallel at an equal pitch in a direction perpendicular to the fluid flow. About.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are cross-sectional views showing the arrangement of heat transfer tubes in a conventional multi-tube heat exchanger.
FIG. 4 shows a multi-tubular heat exchanger having a grid arrangement in which a number of heat transfer tubes 1 are arranged in a grid pattern with respect to the flow direction of the fluid, and FIG. 2 shows a staggered multi-tube heat exchanger arranged in a staggered pattern.

[0003]

In the conventional multi-tube heat exchanger having a grid pattern shown in FIG. 3, the pressure loss of the fluid flow is low, but the heat transfer tubes 1 of each row are arranged in the fluid flow direction a. Because of the overlapping structure, the tubes enter each other's dead water area, and the fluid blows straight through between the heat transfer tubes 1, so that the heat transfer coefficient around the tubes decreases, and the performance as a heat exchanger There was a problem that was bad.

Further, in the staggered multi-tube heat exchanger shown in FIG. 4, the odd-numbered rows of heat transfer tubes 1 and the even-numbered rows of heat transfer tubes 1 located in the fluid flow direction a overlap each other in the fluid flow direction. Due to the structure, the performance as a heat exchanger also deteriorates, and the streamlines of the fluid flow are finely bent for each row, so that the pressure loss increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a tube array capable of improving a heat transfer coefficient while suppressing an increase in pressure loss of a fluid flowing through a tube nest. It is to provide a multi-tube heat exchanger.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a heat exchanger in which a plurality of heat transfer tubes constituting a tube nest are arranged at regular intervals in a fluid flow direction and in a direction orthogonal to the fluid flow. In a multi-tube heat exchanger arranged in parallel with a pitch P,
Multiple rows of pipes 1a, 1b, 1 located in the fluid flow direction a
.. of the adjacent odd-numbered pipe rows and even-numbered pipe rows in the staggered arrangement in which the pitch P is shifted by half in the direction perpendicular to the fluid flow. For the first staggered tube group X constituted by the tube lines 1b of the second line, the second staggered tube group constituted by the tube lines of the third line 1c and the fourth line 1d. Y is shifted rightward or leftward in the direction perpendicular to the fluid flow by a displacement distance S1 corresponding to 1/8 to 3/8 pitch (preferably 2/8 pitch), and the fifth and sixth tube rows 1e are arranged. , 1f return to the same staggered array position as the first and second tube rows 1a, 1b, and are configured to have an array that repeats the same pattern.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. In the first embodiment, a large number of heat transfer tubes 1 constituting a tube nest have an equal interval (for example, an interval of 16 mm) in the direction of fluid flow and an equal pitch P (for example, a pitch of 32 mm) in the direction perpendicular to the fluid flow. In a multi-tube heat exchanger arranged in parallel with the same arrangement pitch at intervals), a large number of tube rows 1a, 1b, 1c located in the fluid flow direction a
.. Among the adjacent odd-numbered tube rows and even-numbered tube lines (the first tube line 1a and the second tube line 1b, the third tube line 1
..) in the direction perpendicular to the fluid flow.

The first staggered tube group X composed of the first tube line 1a and the second tube line 1b is:
The second staggered tube group Y composed of the third tube line 1c and the fourth line 1d is moved to the right in the direction perpendicular to the fluid flow by 1 /
The tube rows 1e and 1f of the fifth and sixth rows are shifted by a displacement distance S1 corresponding to 8 to 3/8 pitch (2/8 pitch in the embodiment). Tube row 1a,
Returning to the same staggered arrangement position as in 1b, the tube nest is constituted by an arrangement in which the same pattern is repeated thereafter.

FIG. 2 shows a second embodiment of the present invention. In the second embodiment, the second zigzag array tube group Y composed of the third tube row 1c and the fourth row 1d is arranged in the first row 1a and the second row. With respect to the first staggered tube group X constituted by the eye tube row 1b, 1/8 to 3
This embodiment differs from the first embodiment in that it is shifted by a displacement distance S1 corresponding to / 8 pitch (2/8 pitch in the embodiment). The other configuration is the same as that of the first embodiment, and the same parts are denoted by the same reference numerals and detailed description will be omitted.

Note that the displacement distance S1 of the second staggered array tube group Y with respect to the first staggered array tube group X in the direction orthogonal to the fluid flow is 1 /.
The reason that the pitch is limited to the range of 8 to 3/8 pitch is based on a staggered arrangement in which the pitch difference between the odd-numbered row of rows and the even-numbered row of rows in the direction perpendicular to the fluid flow is 1/2 (4/8). Therefore, if the displacement distance S1 is less than or equal to 1/8 pitch or greater than or equal to 3/8 pitch, the heat transfer tubes 1 in each row are displaced in a direction overlapping with the fluid flow direction a, and the performance such as the heat transfer coefficient is reduced. Because.

FIG. 5 shows a comparison diagram of the prior art and the present invention due to a change in the tube arrangement pattern. The comparison diagram of FIG. 5 is made based on numerical values obtained by performing a performance test on the conventional multitubular heat exchanger and the multitubular heat exchanger of the present invention, and is based on the tube displacement arrangement of the present invention. The multi-tubular heat exchanger has a better heat transfer coefficient than the conventional multi-tubular heat exchanger with a grid and staggered arrangement,
In addition, the result is that the pressure loss is larger than that of the conventional multi-tube heat exchanger of the grid pattern, but lower than that of the conventional multi-tube heat exchanger of the staggered arrangement.

[0012]

According to the multi-tube heat exchanger of the present invention, the back side of the front heat transfer tubes (the first row heat transfer tubes) up to the fourth row where the influence of the dead water area downstream of each heat transfer pipe is reduced. No downstream pipes (heat transfer pipes from the second row to the fourth row) enter the pipe, so that the heat transfer coefficient around the pipes is kept high as in the first row.

The important items in the heat exchanger are to improve the heat transfer coefficient by making the temperature distribution on each heat transfer tube closer to an equal distribution, and to keep the pressure loss of the fluid flow generated by the tube arrangement low. Is a point.

In the multi-tube heat exchanger of the present invention, since the arrangement distribution of the tubes is kept appropriate, the tubes do not enter each other's dead water area, and the temperature distribution on the heat transfer tubes is relatively small. Even distribution is maintained, a high level of heat transfer coefficient is secured as shown in FIG. 5, and high performance can be obtained even in a heat exchanger having a tube nest composed of many heat transfer tubes. Further, since the fluid flow passing through the heat exchanger becomes a large wavy flow and the linear flow is not bent finely, the pressure loss of the fluid flow is kept lower than that of the staggered heat exchanger as shown in FIG. There is a merit that it is.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an arrangement of heat transfer tubes in a multi-tube heat exchanger according to a first embodiment of the present invention.

FIG. 2 is an essential part cross-sectional view showing an arrangement configuration of heat transfer tubes in a multi-tube heat exchanger according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part showing a configuration of a heat transfer tube in a conventional multi-tube heat exchanger in a grid pattern.

FIG. 4 is a cross-sectional view of a main part showing a configuration in a staggered arrangement of heat transfer tubes in a conventional multi-tube heat exchanger.

FIG. 5 is a diagram showing a comparison between the conventional and the present invention due to a change in the tube arrangement pattern.

[Explanation of symbols]

Reference numeral 1 denotes a heat transfer tube, a denotes a fluid flow direction, P denotes an arrangement pitch of the heat transfer tubes in a direction perpendicular to the fluid flow, 1a denotes a first tube row,
1b: second row of rows, X: first staggered pipe group, 1c
... Third row of rows, 1d Fourth row of rows, Y. Second staggered pipe group, 1e fifth row of rows, 1f sixth row of rows, S1 ... Displacement distance.

Claims (2)

(57) [Claims] 1. A multi-tube heat exchanger in which a plurality of heat transfer tubes constituting a tube nest are arranged at equal intervals in a fluid flow direction and in parallel at an equal pitch in a direction orthogonal to the fluid flow. Of the odd rows and the even rows of adjacent rows of pipes in a staggered arrangement in which the pitch shift in the direction perpendicular to the fluid flow is halved. For a first staggered tube group consisting of a tube line and a second tube line, a second staggered tube line composed of a third line line and a fourth line line The groups are shifted to the right or to the left, which is in the direction perpendicular to the fluid flow, with a displacement distance corresponding to 1/8 to 3/8 pitch, and the fifth and sixth rows of tube rows are the first and second rows. A multi-tubular heat exchanger comprising an array that returns to the same staggered array position as the row of tubes and repeats the same pattern below . 2. The displacement distance of the second staggered array tube group in the direction perpendicular to the fluid flow with respect to the first staggered array tube group is 2/8 (1/1).
(4) The pitch is set.
A multi-tube heat exchanger according to item 1.