JP2003121091A - Plate fin type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate fin type heat exchanger preventing crack due to thermal stress inside the heat exchanger. SOLUTION: The plate fin type heat exchanger is provided with a first channel 1 for passing through first fluid, a second channel 3 formed into such a state as approximately orthogonally crossing the first channel flow direction with a second fluid flow direction, and fins 2a and 4a installed in the first and second channels. This heat exchanger is formed with the first channel and the second channel into a layer and exchange the heat between the first fluid and the second fluid. An outlet 3b of the second channel is installed toward the upstream side of the first fluid flow direction of its inlet 3a. This exchanger is provided with a cut-off wall 9 spacing the inlet from the outlet in the direction approximately orthogonally to the first fluid direction in the second channel and controlling the second fluid flow direction. The cut-off wall is provided with a stress buffer part deformable in the first fluid flow direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in heat exchangers, particularly plate fin type heat exchangers.

[0002]

2. Description of the Related Art Conventional heat exchangers, especially flat plates
A so-called plate fin type heat exchanger, which is configured by alternately bonding and corrugated plates (fins) in a laminated form, is a fluid (for example, a high temperature fluid) that performs heat exchange between the fluid passages between the plates. And low temperature fluid) are alternately flowed, whereby heat exchange is performed between the high temperature fluid and the low temperature fluid.

[0003]

However, in such a heat exchanger, thermal stress is generated due to the temperature difference between the high temperature fluid and the low temperature fluid and the temperature difference between the inlet and the outlet of the high temperature fluid, and the fins, plates or There is a problem that cracks occur at the joint between the fin and the plate.

Therefore, an object of the present invention is to provide a plate fin type heat exchanger which prevents cracks caused by thermal stress.

[0005]

According to a first aspect of the present invention, a first flow passage through which a first fluid flows and a second flow passage through which a flow direction of the first flow passage and a flow direction of the second fluid are substantially A first flow path and a second flow path formed so as to be orthogonal to each other, and fins installed in the first and second flow paths. In a plate fin type heat exchanger for exchanging heat between a fluid and a second fluid, an outlet of the second flow path is installed upstream of an inlet of the second fluid in a flow direction of the first fluid,
A shielding wall that controls the flow direction of the second fluid is provided in the second flow path by separating the inlet and the outlet in a direction substantially orthogonal to the flow of the first fluid. It has a stress buffer that is deformable in the flow direction.

In a second aspect based on the first aspect, the stress buffer portion of the shielding wall has a bellows shape.

In a third aspect based on the first aspect, the stress buffer portion of the shielding wall is a slit extending in a direction orthogonal to the flow of the first fluid.

In a fourth aspect based on any one of the first to third aspects, the shielding wall is formed integrally with the plate of the heat exchanger.

In a fifth aspect based on the fourth aspect, the slits are two slits arranged in a straight line so as to open at both end surfaces of the plate.

In a sixth aspect based on the fourth aspect, one slit is installed in the central portion of the plate.

In a seventh aspect based on the first aspect, the fin comprises a projection that repeats unevenness at a predetermined cycle with respect to a reference plane.

In an eighth aspect based on the seventh aspect, the contour of the sectional shape connecting the tops of the protrusions shows a sine curve.

In a ninth aspect based on the seventh aspect, the sectional shape connecting the tops of the protrusions is trapezoidal.

A tenth aspect of the invention is the fuel cell system according to any one of the seventh to ninth aspects, wherein the fin is installed at the inlet of at least one of the first flow path and the second flow path.

[0015]

According to the first invention, in the plate fin type heat exchanger, an inlet for the second fluid and an outlet are provided upstream of the inlet in the flow direction of the first fluid, and the inlet and the outlet are separated from each other. A partition for controlling the flow direction of the second fluid is provided,
Since the thermal stress generated by the temperature difference between the second fluid on the inlet side and the temperature on the outlet side can be relieved by the stress buffering portion provided on the partition wall, it is possible to prevent cracks generated on the plate or the like.

In the second aspect of the present invention, since the stress buffer portion of the shield wall is formed in a bellows shape, the deformation caused by the temperature difference due to the portion of the second fluid is absorbed, the thermal stress is reduced, and the processing is easy. The cost is low.

In the third to sixth inventions, since the stress buffer portion of the shielding wall is a slit extending in the direction orthogonal to the flow of the first fluid, the temperature distribution changes depending on the shape of the heat exchanger, Although the temperature difference increases depending on the region and thermal stress is generated, the thermal stress can be relaxed by setting the slits according to the temperature distribution.

In the seventh to tenth aspects of the invention, the fin is composed of projections that repeat irregularities with respect to the reference surface at a predetermined cycle, so the fin has a shape with a high degree of freedom in the deformation direction and absorbs deformation due to temperature differences. The thermal stress can be relieved.

[0019]

1 to 3 show the construction of a plate fin type heat exchanger to which the present invention is applied.

According to FIG. 1 showing the whole structure of the plate fin type heat exchanger, FIG. 2 showing the section AA of FIG. 1 and FIG. 3 showing the section BB of FIG. The first flow path 1 through which the high temperature fluid passes is formed by stacking the first flow path 1 through which the fluid flows and the second flow path 3 through which the low temperature fluid (the second fluid) flows. So that it flows from right to left,
On the other hand, the low temperature fluid passing through the second flow path 3 is formed with the first and second flow paths 1 and 3 so as to be orthogonal to the flow direction of the high temperature fluid.

As shown in FIG. 2, the inlet 1a and the outlet 1b of the high temperature fluid are formed by opening to the outer surface, while the inlet 3a and the outlet 3b of the low temperature fluid shown in FIG. 1 are respectively formed on the upper surface of the heat exchanger. It is provided. Here, the cryogenic fluid inlet 3a and outlet 3b
As will be described later, when the inlet 3a is arranged on the same side along the flow direction of the high temperature fluid, that is, on the left side when viewed from the upstream side of the high temperature fluid, the outlet 3b is also arranged on the left side.

The first flow path 1 and the second flow path 3 will be described with reference to FIGS.
In the first flow passage 1 and the second flow passage 3, bellows-shaped fins 2a and 4a are installed, and these fins 2a and 4a are provided in upper and lower plates 2 to be described later.
It is formed by being sandwiched between b and 4b. As described above, the heat of the high temperature fluid is efficiently transferred to the second flow path 3 through which the low temperature fluid flows through the fins and the plate of the first flow path 1 to raise the temperature of the low temperature fluid.

The structure in the second flow path 3 and the flow of the low temperature fluid will be described. The second flow path 3 is partitioned by the barrier wall 9 into the upstream flow path 10 and the downstream flow path 11, and the low temperature fluid flows in from the inlet 3 a and flows along the barrier wall 9.
The downstream side flow passage 11 communicates with the upstream side flow passage 10 through a collecting portion 12 provided on the downstream side in the flow direction. Upstream channel 1
The low temperature fluid that has flowed into 0 flows out through the outlet 3b.

FIGS. 4 and 5 are views for explaining the flow of the low temperature fluid from the inlet 3a to the second flow path 3, and the inlet 3a
Is the main body 3 of the heat exchanger in which the first and second flow paths 1 and 3 are stacked.
It is configured as an upper opening end of the inlet constituting member 5 that vertically penetrates 0, and the other end of the lower portion is closed. The inlet component 5 is provided with a flow hole 6 at a position facing the second flow path 3,
By providing this circulation hole 6, the low temperature fluid flowing from the inlet 3a can be introduced into each second flow path 3.

On the other hand, the low temperature fluid, which has been heated by the heat from the high temperature fluid and is heated, is discharged from the outlet 3b.
Shown in. The outlet component 7 that vertically penetrates the main body 30 of the heat exchanger in which the first and second flow paths 1 and 3 are stacked closes the lower end face and closes the upper open end similarly to the inlet component 5. Exit 3
b. A circulation hole 8 is formed at a position of the outlet component 7 facing the second flow path 3, and the low temperature fluid whose temperature has been raised is guided into the outlet component 7 from the second flow path 3 and discharged from the outlet 3b. To be done.

With such a configuration, the cryogenic fluid first passes through the inlet 3a and the inlet constituting member 5 and is introduced into the downstream side passage 11 of the second passage 3, where heat is exchanged with the high temperature fluid. Exchange. The temperature of the high temperature fluid in this region has already exchanged heat with the low temperature fluid on the upstream side in the flow direction of the high temperature fluid (that is, after heat exchange in the upstream side flow passage 10 of the second flow passage 3).
Therefore, the temperature is lower than the temperature of the high temperature fluid immediately after being supplied to the heat exchanger.

The low temperature fluid whose temperature has been raised in the downstream flow passage 11 flows into the upstream flow passage 10 via the collecting portion 12 and exchanges heat with the high temperature fluid immediately after being supplied to the heat exchanger. The temperature of the high temperature fluid in this region is high, but the temperature of the low temperature fluid has already risen, so the temperature difference between the two is smaller than the difference in the temperature immediately after each fluid is supplied to the heat exchanger. .

As described above, the low temperature fluid efficiently exchanges heat with the high temperature fluid by performing heat exchange (that is, heat exchange in the downstream side flow passage 11 and the upstream side flow passage 10) in two stages. The heat exchanger can be miniaturized by increasing the temperature and making the flow of the low temperature fluid into a U-shaped flow by using the shielding wall 9.

However, due to the temperature difference between the low temperature fluid in the upstream side flow passage 10 and the low temperature fluid in the downstream side flow passage 11, a shield for separating the downstream side flow passage 11 and the upstream side flow passage 10 is formed. The wall 9 may be cracked by thermal stress. The present invention is characterized in that the shielding wall 9 is provided with a configuration for alleviating this thermal stress.

Next, the structure of the shielding wall 9 of the present invention will be described. First, a conventional configuration will be described with reference to FIG.
FIG. 7 is an enlarged view of the X portion of FIG. Of the upper and lower plates 4b forming the second flow path 3, part of the lower plate 4b is projected to form the convex portion 13 as the shielding wall 9, and the upper surface of the convex portion 13 is welded to the upper plate 4b. And the like, so that the low temperature fluid does not leak to the upstream flow path 10. In this configuration, the rigidity of the convex portion 13, especially the rigidity in the flow direction of the high temperature fluid is high, so that the thermal stress due to the thermal expansion difference caused by the temperature difference between the upstream side flow path 10 and the downstream side flow path 11 causes the connecting portion to be connected to the joint part. A crack occurs.

On the other hand, FIG. 8 is an enlarged view of the X portion of FIG. 4, showing the structure of the present invention. In the present invention, the shielding wall 9 is processed into a bellows-like shape that is easy to process on each of the upper and lower plates 4b, and these are overlapped to form a stress buffer portion. Therefore, by forming the shield wall 9 in a bellows shape, the bellows-shaped shield wall 9 absorbs the deformation due to the difference in thermal expansion between the upstream flow passage 10 and the downstream flow passage 11, and thus buffers the thermal stress. , Suppress the occurrence of cracks. Further, the processing is easy, and the cost can be suppressed.

In this embodiment, the shield wall 9 is formed integrally with the plate, but the present invention is not limited to this, and the shield wall may be a separate member.

FIG. 9 shows a second embodiment for stress relief, which is the plate 4 facing the upper surface of the barrier 9.
Two slits 14 and 15 are provided in b in a direction orthogonal to the flow direction of the high temperature fluid, and these slits 14 and 15 are
Each plate 4b is configured to open at another end surface. With this configuration, especially when the shape of the heat exchanger is long in the direction orthogonal to the flow direction of the high temperature fluid, the temperature difference in the orthogonal direction becomes large, but the slits 14 and 15 are provided. Can reduce the thermal stress of the heat exchanger.

FIG. 10 shows a third embodiment for stress relaxation, in which the plate 4b facing the upper surface of the shielding wall 9 is placed in a direction orthogonal to the flow direction of the hot fluid.
The slit 16 is provided at a substantially central portion of b. With this configuration, especially the shape of the heat exchanger,
When the temperature of the high temperature fluid is long in the flow direction, the temperature difference in the flow direction becomes large. However, the provision of the slit 16 can reduce the thermal stress of the heat exchanger.

As described above, the slits shown in FIGS. 9 and 10 are deformed due to a temperature difference by setting the shape of the slits according to the temperature distribution in the upstream flow passage 10 and the downstream flow passage 11. Is absorbed and the thermal stress is relaxed.

Although the shape of the fins 2a, 4a has been described as a bellows shape, the present invention is not limited to this. For example, in the structure shown in FIG. 10, the fins 2a and 4a are configured to have a large number of small semicircular protrusions 17 formed in a plane. With this configuration, it is possible to reduce the rigidity of the flow direction of the high-temperature fluid and the rigidity in the direction orthogonal to the flow direction, and absorb the deformation in both directions due to the difference in thermal expansion caused by the temperature difference between the flow paths 10 and 11. As a result, the generation of thermal stress can be reduced and the generation of cracks can be suppressed. The shape of the protrusion 17 is, for example, a three-dimensional shape conforming to a sine curve.

The shape of the protrusion 17 is not limited to the shape conforming to the sine curve, but may be a trapezoidal shape as shown in FIG. 11, for example. Even with such a shape, the displacement of the high temperature fluid in the flow direction and the orthogonal direction can be absorbed, and the occurrence of cracks can be suppressed.

The present invention is not limited to the above-mentioned embodiments, and it is obvious that various modifications can be made within the scope of the technical idea of the present invention.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a plate fin type heat exchanger.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 and is a view for explaining the details of the first flow path.

FIG. 3 is also a BB cross-sectional view of FIG. 1, illustrating the details of the second flow path.

FIG. 4 is a sectional view taken along line C-C of FIG. 3, illustrating the inlet and outlet of the cryogenic fluid.

FIG. 5 is a sectional view taken along the line D-D of FIG. 3, which illustrates the flow of the cryogenic fluid.

6 is a sectional view taken along the line EE of FIG. 3 and illustrating the flow of the cryogenic fluid.

FIG. 7 is a diagram illustrating a configuration of a conventional barrier wall.

FIG. 8 is a diagram illustrating a configuration of a barrier wall of the present invention.

FIG. 9 is a diagram showing a configuration of a shielding wall according to a second embodiment.

FIG. 10 is a diagram showing a configuration of a shielding wall according to a third embodiment.

FIG. 11 is a diagram illustrating another shape of the fin.

FIG. 12 is a diagram illustrating another shape of the fin.

[Explanation of symbols]

1st flow path 1a entrance 1b exit 2a fin 2b plate 3 Second channel 3a entrance 3b exit 4a fin 4b plate 5 entrance components 6 distribution holes 7 outlet components 8 distribution holes 9 Barrier 10 upstream side flow path 11 Downstream flow path 12 Assembly Department 30 body

Claims (10)

[Claims] 1. A first flow passage through which a first fluid flows, a second flow passage through which a second fluid flows, and a second flow formed so that a flow direction of the first flow passage and a flow direction of the second fluid are substantially orthogonal to each other. A flow path and fins installed in the first and second flow paths, the first flow path and the second flow path are stacked, and heat is generated between the first fluid and the second fluid. In a plate fin type heat exchanger for exchanging, the outlet of the second flow path is installed upstream of the inlet in the flow direction of the first fluid, and is substantially orthogonal to the flow of the first fluid in the second flow path. A shielding wall that controls the flow direction of the second fluid by separating the inlet and the outlet in a direction, and the shielding wall has a stress buffering portion that is deformable in the flow direction of the first fluid. Plate fin type heat exchanger. 2. The plate fin type heat exchanger according to claim 1, wherein the stress buffering portion of the shielding wall has a bellows shape. 3. The plate fin type heat exchanger according to claim 1, wherein the stress buffering portion of the shielding wall is a slit extending in a direction orthogonal to the flow of the first fluid. 4. The plate fin type heat exchanger according to claim 1, wherein the shield wall is formed integrally with a plate of the heat exchanger. 5. The plate fin type heat exchanger according to claim 4, wherein the slits are two slits which are installed in a straight line so as to open at both end surfaces of the plate. 6. The plate fin type heat exchanger according to claim 4, wherein one of the slits is installed in a central portion of the plate. 7. The fin comprises a projection that repeats unevenness at a predetermined cycle with respect to a reference plane.
The plate fin type heat exchanger described in. 8. The profile of the cross-sectional shape connecting the tops of the protrusions is
The plate fin type heat exchanger according to claim 7, which exhibits a sinusoidal curve. 9. The plate fin type heat exchanger according to claim 7, wherein the cross-sectional shape connecting the tops of the protrusions is a trapezoidal shape. 10. The plate fin type heat exchange according to claim 7, wherein the fins are installed at an inlet of at least one of the first flow path and the second flow path. vessel.