JPS6138396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger having a structure that improves the flow pattern of a primary fluid.

A heat exchanger, for example, a steam generator, which is a device for generating steam, which is a driving source for a turbine, from the heat generated in a nuclear reactor in a nuclear reactor heat transport system, supports a heat transfer tube through which a secondary fluid flows. A heat exchanger tube support plate is used that has both the function of forming a flow path for the primary side fluid, which is the shell side fluid. This heat exchanger tube support plate has a disk shape and has a large circular hole in the center thereof for forming a flow path for the primary fluid. Usually, in addition to this donut-shaped heat exchanger tube support plate, a disk-type heat exchanger tube support plate is used together with a gap for forming a bypass flow path for the primary fluid between the outer periphery of the heat exchanger tube bundle and the body. , the support plates are arranged alternately in the flow direction of the primary fluid. This results in 1
A part of the next fluid flows perpendicularly to the heat exchanger tube, and the amount of heat exchanged can be increased. By the way, since conventional donut-shaped support plates only have circular holes that are concentric with the body axis, the primary fluid passing through the circular holes only travels straight, but only in the circumferential direction. No flow occurs and stagnant regions are likely to exist within the heat exchanger. Therefore, there are parts of the heat exchanger tube where the temperature locally increases, which may cause damage to the heat exchanger tube. Furthermore, since the primary fluid flows in a laminar manner along the heat transfer tube, there is a drawback that heat transfer efficiency deteriorates.

The present invention was made in view of these points, and by flowing the primary fluid in a helical shape in the direction of the cylinder axis, the present invention prevents a local temperature rise in the heat transfer tube and improves heat transfer efficiency. The purpose is to provide an exchanger.

An embodiment 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 exchanger according to the present invention. As shown in the figure, the shell of the heat exchanger 10 consists of an upper shell 11, an intermediate shell 12, and a lower shell 13. A primary fluid inlet nozzle 14 is connected to the side surface of the upper shell 11, and the side surface of the lower shell 13 A primary side fluid outlet nozzle 15 is connected to the upper shell 11 and the lower shell 13, which are connected to the intermediate shell 12 so as to sandwich the hollow cylindrical intermediate shell 12 from both sides. Moreover, inner cylinders 11a and 13a are provided inside the upper shell 11 and the lower shell 13, respectively, so that the primary fluid flows uniformly into the bundle of heat exchanger tubes. Reference numeral 16 denotes a bellows, which can alleviate expansion and contraction due to a difference in thermal expansion between the upper shell, the lower shell, and the intermediate shell. Further, each of the upper body 11 and the lower body 13 has an upper tube plate 1 that supports the end of the heat exchanger tube.
7. The upper water chamber 19 and the lower water chamber 20 through which the secondary fluid flows are connected via the lower tube plate 18. Both open ends of the heat transfer tube are open to the upper water chamber 19 and the lower water chamber 20, and the upper water chamber 19
A secondary fluid outlet nozzle 21 and a secondary fluid inlet nozzle 22 are connected to the lower water chamber 20, respectively. A bypass flow of the primary fluid is established between the donut-shaped heat exchanger tube support plate 23 having a circular hole through which the primary fluid passes in the shell of the heat exchanger 10 having such a configuration, the outer periphery of the heat exchanger tube bundle portion, and the shell. Disc-type heat exchanger tube support plate 2 having a gap for forming a flow path
4 are arranged alternately at right angles to the barrel axis direction. Reference numeral 25 is a line indicating the outer periphery of the heat exchanger tube bundle portion.

FIG. 2 is a diagram for explaining a method of arranging the donut-shaped heat exchanger tube support plate 23. As shown in FIG. In the donut-shaped heat exchanger tube support plate 23, a hole 26 through which the primary fluid passes is bored eccentrically with respect to the body axis 27. The support plates 23 are arranged so as to be shifted from each other by a certain angle. For example, in the example shown in FIG. 2, the hole 26a of the support plate 23a is offset by 90 degrees with respect to the eccentric position of the hole 26 of the support plate 23, and the hole 26d of the support plate 23b is offset by 90 degrees with respect to the eccentric position of the hole 26 of the support plate 23a. It's off by ゜.

FIG. 3 is a sectional view taken along the line A-A in FIG. 1, and shows the disk-type heat exchanger tube support plate 24. The diameter of the disk type heat exchanger tube support plate 24 is smaller than the inner diameter of the intermediate shell 12 and the inner tubes 11a, 13a, and the diameter of the disk type heat exchanger tube support plate 24 is smaller than the inner diameter of the intermediate shell 12 and the inner tubes 11a, 13a.
A bypass flow region 28 for primary fluid is formed between the two. FIG. 4 is a partially enlarged view of the disk-type heat exchanger tube support plate 24 shown in FIG.
A minute circular hole 31 is bored between the holes 30 that pass through the hole 9, and a certain amount of the primary fluid can pass through the circular hole 31 as well.

To explain the function and effect of the heat exchanger 10 having such a configuration, first, the low temperature secondary fluid flows into the heat exchanger from the secondary fluid inlet nozzle 22 of the lower water chamber 20 as shown by the arrow 32. The fluid enters the heat exchanger tube and exits from the secondary fluid outlet nozzle 21 of the upper water chamber 19. The high temperature primary fluid flows into the upper body 11 from the inlet nozzle 14 as indicated by an arrow 33, rises along the inner cylinder 11a, and uniformly enters the heat exchanger tube bundle. And the primary fluid is
In the donut-shaped heat exchanger tube support plate 23 section, the flow passes through eccentric perforations 26 as shown by arrow 33a, and in the disc-shaped heat exchanger tube support plate 24 section, the flow flows through small circular holes drilled in the support plate 24 as shown by arrow 33b. 31 and bypass flow region 28 to the lower shell 13, transferring heat to the secondary fluid and exiting from the outlet nozzle 15. In this case, the primary fluid passing through the perforations 26 of the donut-shaped heat exchanger tube support plate 23 is
6 are arranged at eccentric positions between the support plates 23, so that the flow helically flows in the direction of the cylinder axis as shown by the arrow 33a. For this reason, a circumferential flow component is generated in the primary fluid, the formation of a laminar temperature distribution in the primary fluid is disturbed, and the heat transfer efficiency of the heat transfer tube is improved. Further, a stagnant portion is less likely to be formed between the donut-shaped heat exchanger tube support plate and the disc-shaped heat exchanger tube support plate, and local temperature increases in the heat exchanger tubes are prevented. Furthermore, the disk-type heat exchanger tube support plate is provided with minute circular holes, and the primary fluid flows through these minute holes. is less likely to form. Therefore, good heat transfer efficiency can be maintained without causing damage to the heat transfer tubes. Furthermore, compared to the case where no circumferential flow component occurs in the primary fluid,
The flow of the primary fluid 33 becomes smooth, and the pressure loss of the primary fluid 33 is alleviated.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the heat exchanger according to the present invention, FIG. 2 is a view showing a method of arranging donut-shaped heat exchanger tube support plates, and FIG. 3 is a cross-sectional view taken along line A-A in FIG. 1. , FIG. 4 is a partially enlarged view of FIG. 3. 23...Doughnut-shaped heat exchanger tube support plate, 24...Disc-type heat exchanger tube support plate, 26, 26a, 26b...
...Primary side fluid passage hole.

Claims (1)

[Claims] 1. In a straight tube heat exchanger in which a large number of donut-shaped heat exchanger tube support plates and disk-type heat exchanger tube support plates having primary side fluid passage holes are alternately arranged in the shell at right angles to the axial direction, the above-mentioned The primary side fluid passage holes are arranged in sequence in the circumferential direction of the donut-shaped heat exchanger tube support plate.
1. A heat exchanger that is arranged to be rotated by an angle of less than 180 degrees, and wherein the disk-type heat exchanger tube support plate is provided with minute circular holes.