U.S. patent application number 14/413689 was filed with the patent office on 2015-05-21 for heat exchanger.
The applicant listed for this patent is SUMITOMO PRECISION PRODUCTS CO., LTD.. Invention is credited to Yasuhiro Fujita, Kenichiro Fukui, Hiroyuki Takahashi, Akihiro Tanabe.
Application Number | 20150136366 14/413689 |
Document ID | / |
Family ID | 49915665 |
Filed Date | 2015-05-21 |
United States Patent
Application |
20150136366 |
Kind Code |
A1 |
Fukui; Kenichiro ; et
al. |
May 21, 2015 |
HEAT EXCHANGER
Abstract
First passages of a heat exchanger each include a plurality of
channels that each connect an inlet formed in an inflow surface of
a core and an outlet formed in an outflow surface of the core
together. The channels have different channel resistances. The heat
exchanger includes a flow-directing member of a first type disposed
to a side of the core where the inflow surface is located to
provide a uniform distribution of a dynamic pressure of the first
fluid flowing into the core to the inflow surface; and a
flow-directing member of a second type reducing a difference
between flow rates of the first fluid through the channels arising
from a difference in channel resistance between the channels
forming each first passage of the core.
Inventors: |
Fukui; Kenichiro;
(Amagasaki-shi, JP) ; Takahashi; Hiroyuki;
(Amagasaki-shi, JP) ; Tanabe; Akihiro;
(Amagasaki-shi, JP) ; Fujita; Yasuhiro;
(Amagasaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUMITOMO PRECISION PRODUCTS CO., LTD. |
Amagasaki-shi, Hyogo |
|
JP |
|
|
Family ID: |
49915665 |
Appl. No.: |
14/413689 |
Filed: |
June 21, 2013 |
PCT Filed: |
June 21, 2013 |
PCT NO: |
PCT/JP2013/003907 |
371 Date: |
January 8, 2015 |
Current U.S.
Class: |
165/148 |
Current CPC
Class: |
F28D 7/005 20130101;
F28D 9/0068 20130101; F28F 13/06 20130101; F28F 9/028 20130101;
F28F 9/0265 20130101; F28F 2009/222 20130101; F28D 9/0006
20130101 |
Class at
Publication: |
165/148 |
International
Class: |
F28D 7/00 20060101
F28D007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2012 |
JP |
2012-153240 |
Claims
1. A heat exchanger comprising: a core having at least a plurality
of first passages through which a first fluid flows and a plurality
of second passages through which a second fluid flows, and at least
exchanging heat between the first fluid and the second fluid,
wherein the core has an inflow surface through which the first
fluid flows into the core and an outflow surface through which the
first fluid flows out of the core, at least the first passages each
include a plurality of channels that each connect an inlet formed
in the inflow surface and an outlet formed in the outflow surface
together, the channels having different channel resistances, and
the heat exchanger further includes: a flow-directing member of a
first type disposed to a side of the core where the inflow surface
is located to provide a uniform distribution of a dynamic pressure
of the first fluid flowing into the core to the inflow surface; and
a flow-directing member of a second type reducing a difference
between flow rates of the first fluid through the channels arising
from a difference in channel resistance between the channels
forming each first passage of the core.
2. The heat exchanger of claim 1, wherein the flow-directing member
of the second type is disposed to a side of the core where the
outflow surface is located.
3. The heat exchanger of claim 2, wherein while the outlets of the
channels are uniformly spaced from each other in the outflow
surface of the core, a flow rate distribution of the first fluid
through the outflow surface of the core is equivalent to a
predetermined channel resistance distribution corresponding to
channel resistances of the channels, the flow-directing member of
the second type is a plate-like member facing at least a portion of
the outflow surface, and has a plurality of holes passing through
the flow-directing member of the second type along a thickness of
the flow-directing member of the second type, and an aperture ratio
of the flow-directing member of the second type defined by the
holes is determined such that a distribution of the aperture ratio
corresponds to the channel resistance distribution equivalent to
the flow rate distribution of the first fluid through the outflow
surface of the core.
4. The heat exchanger of claim 1, wherein the core is a plate fin
core including the first and second passages that are alternately
stacked, and at least the first passages each include a distributor
fin configured to change a direction of flow of fluid through the
first passage.
Description
TECHNICAL FIELD
[0001] The technique disclosed herein relates to heat exchangers,
and more particularly relates to the structure of a heat exchanger
that includes a core as a heat transfer part and can reduce uneven
flow of fluid passing through the core.
BACKGROUND ART
[0002] An uneven flow phenomenon has been conventionally known. In
the uneven flow phenomenon, for example, the shapes and layout of
header tanks, nozzles, and other elements of a heat exchanger cause
the flow rate distribution of fluid passing through a core of the
heat exchanger to be uneven. For example, Patent Document 1
describes a plate fin heat exchanger including a core and a long
and thin header tank extending from an opening of an inflow nozzle
in a direction of flow of fluid through the inflow nozzle. This
header tank shape causes the flow rate of fluid passing through a
back part of the core remote from the opening of the nozzle to be
higher than that of fluid passing through a front part of the core
near the opening of the nozzle. Patent Document 1 shows that a
baffle plate (a flow director) is placed in the header tank of the
plate fin heat exchanger. Fluid flowing through the nozzle into the
header tank interferes with the baffle plate to reduce the flow of
fluid toward the back of the header tank, thereby reducing uneven
flow of fluid passing through the core.
[0003] Likewise, Patent Document 2 describes a plate fin heat
exchanger including a header tank. The header tank extends
vertically downward from the upper end of the header tank having an
opening of an inflow nozzle. Patent Document 2 describes a
technique in which the plate fin heat exchanger includes a
cylindrical flow director protruding upwardly from the bottom of
the header tank. The provision of the cylindrical flow director
reduces the cross-sectional area of a portion of a channel near the
inside bottom of the header tank to reduce the downward flow of
fluid through an inlet into the header tank toward the bottom of
the header tank. This reduces uneven flow of fluid passing through
the core.
[0004] By contrast, Patent Documents 3 and 4 each describe a
multitubular heat exchanger. The multitubular heat exchanger
includes a core and a header tank, and the header tank has a
central part having an opening of an inflow nozzle. The width of
the header tank gradually increases from the opening of the inflow
nozzle to the core. These Patent Documents each describe a
technique in which the multitubular heat exchanger includes a flow
director disposed near the opening of the nozzle to allow the flow
of fluid through the nozzle into the heat exchanger to collide with
the flow director. This collision allows the flow of the fluid to
be spread outwardly, thereby reducing uneven flow of fluid passing
through the core.
CITATION LIST
Patent Document
[0005] PATENT DOCUMENT 1: Japanese Unexamined Patent Publication
No. 2002-310593
[0006] PATENT DOCUMENT 2: Japanese Unexamined Patent Publication
No. 2007-71434
[0007] PATENT DOCUMENT 3: Japanese Unexamined Patent Publication
No. S50-139454
[0008] PATENT DOCUMENT 4: Japanese Unexamined Patent Publication
No. 2001-248980
SUMMARY OF THE INVENTION
Technical Problem
[0009] Reducing such uneven flow of fluid passing through a core as
described above increases the heat exchange efficiency of the core,
and helps, for example, downsize heat exchangers. Here, a possible
uneven flow of fluid in the heat exchanger described in each of
Patent Documents 1-4 described above results from an uneven
distribution of dynamic pressure of fluid that has yet to flow into
the core to an inflow surface of the core through which the fluid
flows into the core and which has many inlets. The flow director
described in each Patent Document reduces high dynamic pressures to
allow the distribution of dynamic pressure of the fluid to the
inflow surface of the core to be as even as possible.
[0010] Studies of the inventors of this application show that
different channel resistances of many channels forming a core also
cause uneven flow of fluid passing through the core. For example,
in a core of a plate fin heat exchanger, channels are defined by a
corrugated fin placed in a passage, and a distributor fin is placed
in the passage to change the direction of flow of fluid, thereby
causing the channels from their inlets to their outlets to have
different lengths. Such differences in length among the channels
cause the channels to have different channel resistances. A core of
a multitubular heat exchanger includes pipes corresponding to
channels. The pipes are bent in a U shape to cause the pipes to
have different channel lengths. Such differences in channel length
among the pipes cause the channels to have different channel
resistances. In the core of the plate fin heat exchanger or the
core of the multitubular heat exchanger, the differences in channel
resistance among the channels cause the flow rates of fluid passing
through some of the channels having relatively low channel
resistances to be relatively high while causing the flow rates of
fluid passing through the other channels having relatively high
channel resistances to be relatively low. This results in uneven
flow of fluid passing through the core. The direction of deviation
of the fluid flow arising from the differences in channel
resistance among the channels forming the core may be different
from that of deviation of the fluid flow arising from the
above-described distribution of dynamic pressure of fluid to the
inflow surface. The provision of such a flow director as described
in any one of Patent Documents 1-4 could not eliminate uneven flow
of the fluid.
[0011] It is therefore an object of the technique disclosed herein
to reduce uneven flow of fluid passing through a core of a heat
exchanger.
Solution to the Problem
[0012] The inventors of this application decided to reduce uneven
flow of fluid passing through a core by providing two types of
flow-directing members having different configurations to address
the two causes of the uneven flow, i.e., the distribution of the
dynamic pressure of fluid to the inflow surface and the differences
in channel resistance among the channels forming the core.
[0013] Specifically, the technique disclosed herein relates to a
heat exchanger comprising: a core having at least a plurality of
first passages through which a first fluid flows and a plurality of
second passages through which a second fluid flows and at least
exchanging heat between the first fluid and the second fluid.
[0014] The core has an inflow surface through which the first fluid
flows into the core and an outflow surface through which the first
fluid flows out of the core. At least the first passages each
include a plurality of channels that each connect an inlet formed
in the inflow surface and an outlet formed in the outflow surface
together. The channels have different channel resistances.
[0015] The heat exchanger further includes: a flow-directing member
of a first type disposed to a side of the core where the inflow
surface is located to provide a uniform distribution of a dynamic
pressure of the first fluid flowing into the core to the inflow
surface; and a flow-directing member of a second type reducing a
difference between flow rates of the first fluid through the
channels arising from a difference in channel resistance between
the channels forming each first passage of the core.
[0016] Here, the "channels" include, in addition to channels
separated from each other, channels substantially along which fluid
flows without completely separating the channels from each
other.
[0017] With such a configuration, in the heat exchanger in which
the distribution of dynamic pressure of the first fluid to the
inflow surface of the core is not uniform due to, for example, the
configuration of an inflow header tank connected to the core or an
inflow nozzle placed on the header tank, the flow-directing member
of the first type is disposed to the side of the core where the
inflow surface is located to provide a uniform distribution of
dynamic pressure of the first fluid. The flow-directing member of
the first type can be, for example, such a baffle that interferes
with the flow of the first fluid flowing through the inflow nozzle
into the header tank to reduce the dynamic pressure.
[0018] On the other hand, in a heat exchanger which includes a core
having first passages and in which a plurality of channels forming
the first passages have different channel resistances due to, for
example, different channel lengths and different channel diameters,
the flow-directing member of the second type is provided
independently of the flow-directing member of the first type. The
flow-directing member of the second type reduces the differences
among the flow rates of fluid through the channels arising from the
differences in channel resistance among the channels. Specifically,
the flow-directing member of the second type restricts the flow
rates of the first fluid flowing into at least some of the channels
having relatively low channel resistances or restricts the flow
rates of the first fluid flowing out of at least the some of the
channels having relatively low channel resistances to reduce the
differences among the flow rates of the first fluid through the
channels independently of the differences in channel resistance
among the channels.
[0019] As such, the provision of the flow-directing members of two
types, i.e., the flow-directing member of the first type and the
flow-directing member of the second type, can effectively reduce
both uneven flow of fluid arising from the distribution of dynamic
pressure of fluid to the inflow surface of the core and uneven flow
of fluid arising from the differences in channel resistance among
the channels of the core. This can enhance the heat exchange
efficiency of the heat exchanger. This helps, for example, downsize
heat exchangers.
[0020] The core does not always need to exchange heat between two
types of fluid, i.e., the first fluid and the second fluid, and may
exchange heat among three or more types of fluid.
[0021] The flow-directing member of the second type may be disposed
to a side of the core where the outflow surface is located. As
described above, the flow-directing member of the second type can
adjust the flow rates of the first fluid flowing into the channels
toward inlets of the first passages or adjust the flow rates of the
first fluid flowing out of the channels toward outlets of the first
passages to reduce the differences among the flow rates of the
first fluid through the channels. The flow-directing member of the
second type can be disposed to the side of the core where either
the inflow surface or outflow surface is located.
[0022] However, the flow-directing member of the first type is
disposed to the side of the core where the inflow surface is
located, and for this reason, when an attempt is made to dispose
the flow-directing member of the second type to the side of the
core where the inflow surface is located, it may be difficult to
dispose the flow-directing members of the two types to the side of
the core where the inflow surface is located due to, for example,
limitations of placement space.
[0023] Here, the flow-directing member of the second type can be a
plate-like member having many holes passing therethrough and
arranged in a predetermined pattern as described below. The
diameter of each hole passing through the flow-directing member of
the second type, the number of the holes, and/or the spacing
between each adjacent pair of the holes are appropriately varied to
allow the distribution of the aperture ratio of the flow-directing
member of the second type (the total area of holes per unit area)
to be uneven. On the other hand, the channel resistance
distribution across the inflow surface of the core in which the
inlets of the channels are uniformly spaced or the outflow surface
of the core in which the outlets of the channels are uniformly
spaced is determined to correspond to the channel resistances of
the channels. Thus, the flow-directing member of the second type
faces the inflow surface or the outflow surface such that the
distribution of the aperture ratio of the flow-directing member of
the second type corresponds to the channel resistance distribution
across the inflow surface or the outflow surface. In other words,
if a portion of the flow-directing member of the second type having
low aperture ratios faces a portion of the inflow surface or the
outflow surface corresponding to the corresponding ones of the
inlets and the outlets of some of the channels having low channel
resistances, the flow rates of the first fluid flowing into or out
of at least some of the channels having relatively low channel
resistances are restricted.
[0024] If the flow-directing member of the second type configured
as above is disposed to the side of the core where the inflow
surface is located, and is apart from the inflow surface, the
differences among the flow rates of the first fluid caused by the
passage of the first fluid through the flow-directing member of the
second type and corresponding to the distribution of the aperture
ratio of the flow-directing member of the second type are less
effective before the first fluid reaches the inflow surface. This
prevents the flow-directing member of the second type from
functioning. Thus, the flow-directing member of the second type is
preferably close to the inflow surface.
[0025] By contrast, the steep velocity gradient of fluid between
portions of the flow-directing member of the second type
corresponding to the through holes (i.e., openings) and the other
portion thereof (i.e., a portion thereof except the openings)
occurs downstream of the flow-directing member of the second type.
Thus, if the flow-directing member of the second type is
excessively close to the inflow surface, the velocity gradient
affects the flow of the first fluid through the inlets of the
channels formed in the inflow surface of the core into the
channels. Specifically, while the flow rates of the first fluid
into some of the channels having the inlets facing the through
holes increase, the first fluid hardly flows into the other ones of
the channels having the inlets that do not face the through holes.
This not only prevents the flow-directing member of the second type
from functioning, but also may increase the differences among the
flow rates of the first fluid through the channels. For this
reason, if the flow-directing member of the second type is disposed
to the side of the core where the inflow surface is located, the
flow-directing member of the second type is often difficult to
position.
[0026] On the other hand, when the flow-directing member of the
second type is disposed to the side of the core where the outflow
surface is located, the flow-directing member of the first type and
the flow-directing member of the second type are respectively
disposed to the side of the core where the inflow surface is
located and the side of the core where the outflow surface is
located. This facilitates ensuring space for placing each of the
flow-directing members of the first and second types. When the
flow-directing member of the second type having the many through
holes faces the outflow surface, the flow-directing member of the
second type closer to the outflow surface more easily functions,
whereas unlike when the flow-directing member of the second type is
disposed to the side of the core where the inflow surface is
located, the velocity gradient downstream of the flow-directing
member of the second type does not need to be considered. Thus, the
flexibility in positioning the flow-directing member of the second
type is relatively high.
[0027] In view of the foregoing, the flow-directing member of the
second type is advantageously disposed to the side of the core
where the outflow surface is located. This allows the
flow-directing member of the second type to be relatively flexibly
positioned while reliably ensuring the function of the
flow-directing member of the second type.
[0028] While the outlets of the channels may be uniformly spaced
from each other in the outflow surface of the core, a flow rate
distribution of the first fluid through the outflow surface of the
core may be equivalent to a predetermined channel resistance
distribution corresponding to channel resistances of the channels.
The flow-directing member of the second type may be a plate-like
member facing at least a portion of the outflow surface, and may
have a plurality of holes passing through the flow-directing member
of the second type along a thickness of the flow-directing member
of the second type. An aperture ratio of the flow-directing member
of the second type defined by the holes may be determined such that
a distribution of the aperture ratio corresponds to the channel
resistance distribution equivalent to the flow rate distribution of
the first fluid through the outflow surface of the core.
[0029] Here, the distribution of the aperture ratio of the
flow-directing member of the second type is equivalent to the
channel resistance distribution corresponding to the distribution
of the flow rate of fluid flowing through the outflow surface. The
aperture ratio of a portion of the flow-directing member of the
second type facing some of the channels having high channel
resistances is increased to allow the fluid to easily pass through
the some of the channels, whereas the aperture ratio of the other
portion of the flow-directing member of the second type facing the
other ones of the channels having low channel resistances is
decreased to make it difficult for the fluid to pass through the
other ones of the channels. This allows the flow-directing member
of the second type to adjust the flow rates of the first fluid
through the channels even with differences in channel resistance
among the channels, thereby reducing the differences among the flow
rates of the first fluid through the channels. In other words,
uneven flow of fluid arising from the differences in channel
resistance among the channels is reduced.
[0030] The core may be a plate fin core including the first and
second passages that are alternately stacked, and at least the
first passages may each include a distributor fin configured to
change a direction of flow of fluid through the first passage.
[0031] In other words, placing the distributor fin in each first
passage of the plate fin core causes the channels to have different
lengths, resulting in different channel resistances. However, the
above-described flow-directing member of the second type reduces
the differences among the flow rates of the fluid through the
channels arising from the differences in channel resistance among
the channels. This reduces uneven flow of the fluid through the
core.
Advantages of the Invention
[0032] As described above, according to the heat exchanger, the
flow-directing member of the first type and the flow-directing
member of the second type are individually provided. The
flow-directing member of the first type reduces uneven flow of
fluid arising from the distribution of dynamic pressure of fluid to
the inflow surface of the core. The flow-directing member of the
second type reduces uneven flow of fluid arising from the
differences in channel resistance among the channels of the core.
The individual provision of the flow-directing members of the first
and second types can effectively reduce uneven flow of fluid
through the heat exchanger. This helps enhance the heat exchange
efficiency and downsize heat exchangers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1A is a partially fragmented, schematic front view of
the configuration of a heat exchanger, and FIG. 1B is a partially
fragmented, schematic side view of the configuration of the heat
exchanger.
[0034] FIG. 2 is a front view of a flow-directing member of a first
type.
[0035] FIG. 3 is a front view of a flow-directing member of a
second type.
[0036] FIG. 4 is a front view of another flow-directing member of
the second type having a shape different from the shape of the
flow-directing member of the second type in FIG. 3.
[0037] FIGS. 5A and 5B illustrate a heat exchanger having a
configuration different from that of the heat exchanger in FIG. 1
and including still another flow-directing member of the second
type, and correspond to FIGS. 1A and 1B, respectively.
[0038] FIGS. 6A and 6B illustrate a heat exchanger including yet
another flow-directing member of the second type placed upstream of
first passages, and correspond to FIGS. 1A and 1B,
respectively.
[0039] FIGS. 7A and 7B illustrate a heat exchanger omitting the
flow-directing member of the first type, and correspond to FIGS. 1A
and 1B, respectively.
DESCRIPTION OF EMBODIMENTS
[0040] An embodiment of a heat exchanger will now be described with
reference to the drawings. The following preferred embodiment will
be described merely as an example. FIGS. 1A and 1B schematically
illustrate the configuration of a heat exchanger 1 according to an
embodiment. FIG. 1A is a front view of the heat exchanger 1, and
FIG. 1B is a side view of the heat exchanger 1. For convenience of
explanation, the upward and downward directions of the drawing
sheet of FIG. 1A are referred to as X directions, the rightward and
leftward directions of the drawing sheet of FIG. 1A are referred to
as Y directions, and the rightward and leftward directions of the
drawing sheet of FIG. 1B are referred to as Z directions.
[0041] The heat exchanger 1 includes a plate fin core 2 exchanging
heat between a first fluid and a second fluid. As illustrated in
FIG. 1A, the core 2 includes first passages 21 through which the
first fluid flows, and second passages 22 through which the second
fluid flows. The first passages 21 and the second passages 22 are
alternately stacked along the Y directions with a tube plate 23
interposed between each adjacent pair of the first and second
passages 21 and 22. In the illustrated example, the core 2 has a
box-like shape. The length of the box-like shape in the Z direction
illustrated in FIG. 1B is shorter than that of the box-like shape
in each of the X direction and the Y direction illustrated in FIG.
1A. The shape of the core 2 should not be limited to the box-like
shape, and can be selected from among various shapes.
[0042] As indicated by solid arrows in FIGS. 1A and 1B, the first
fluid flows through an upper end surface of the core 2 into the
first passages 21, flows through the core 2 downwardly, and then
flows out of the core 2 through a side surface of a lower end
portion of the core 2 in one of the Z directions. As indicated by
hollow arrows in FIGS. 1A and 1B, the second fluid flows through a
lower end surface of the core 2 into the second passages 22, flows
through the core 2 upwardly, and then flows out of the core 2
through a side surface of an upper end portion of the core 2 in the
other one of the Z directions. As such, the core 2 is a so-called
counter-flow core through which the first fluid and the second
fluid flow in opposite directions. Note that the core 2 should not
be limited to the counter-flow core, and may be a parallel-flow
core designed such that the first fluid and the second fluid flow
through the core in the same direction, or a cross-flow core
through which the first fluid and the second fluid flow in
directions orthogonal to each other.
[0043] As schematically illustrated in FIG. 1B, the first passages
21 of the core 2 each include a corrugated fin 211. The corrugated
fin 211 partitions the corresponding one of the first passages 21
into a plurality of channels arranged in the Z direction. Any one
of various types of corrugated fins 211, such as plain fins or
perforated fins, can be used as the corrugated fin 211. Although
not shown, the second passages 22 each include a corrugated fin,
and the corrugated fin also partitions the corresponding one of the
second passages into a plurality of channels arranged in the Z
direction. Furthermore, although not shown, the first and/or second
passages 21, 22 may each include, for example, a serrated fin. In
this case, while the channels are not completely separated from one
another, fluid flows along the fin principally in the X directions.
The provision of the serrated fin is, therefore, substantially
equivalent to the partitioning of the corresponding one of the
first and second passages 21 and 22 into a plurality of
channels.
[0044] A portion of each first passage 21 near an outlet thereof
corresponds to a lower end portion of the core 2, and includes a
distributor fin 212, which changes the direction of flow of fluid
through the corresponding first passage 21 from one of the X
directions, i.e., the downward direction, to one of the Z
directions, i.e., a horizontal direction (the leftward direction of
the drawing sheet of FIG. 1B). A portion of each second passage 22
near an outlet thereof corresponds to an upper end portion of the
core 2, and also includes a distributor fin 222, which changes the
direction of flow of fluid through the corresponding second passage
22 from one of the X directions, i.e., the upward direction, to one
of the Z directions, i.e., a horizontal direction (the rightward
direction of the drawing sheet of FIG. 1B).
[0045] As such, the upper end surface of the box-like core 2 forms
an inflow surface 31 thereof through which the first fluid flows
into the core 2, and the side surface of the lower end portion of
the core 2 forms an outflow surface 32 thereof through which the
first fluid flows out of the core 2. The lower end surface of the
core 2 forms an inflow surface 33 thereof through which the second
fluid flows into the core 2, and the side surface of the upper end
portion of the core 2 forms an outflow surface 34 thereof through
which the second fluid flows out of the core 2.
[0046] The core 2 configured as above has the inflow surface 31
through which the first fluid flows into the core 2 and on which an
inflow header tank 41 is placed to distribute the first fluid into
the channels of each first passage 21. The inflow header tank 41
has a shape corresponding to that of the inflow surface 31 through
which the first fluid flows, is long and thin, and extends along
the Y direction. An inflow nozzle 411 through which the first fluid
flows into the inflow header tank 41 is placed on a central portion
of the inflow header tank 41 in the Y direction. By contrast, the
core 2 has the outflow surface 32 through which the first fluid
flows out of the core 2 and on which an outflow header tank 42 is
placed to collect the first fluid that has passed through the
channels of each first passage and to allow the collected first
fluid to flow out of the outflow header tank 42. The outflow header
tank 42 is also long and thin, and also extends along the Y
direction. An outflow nozzle 421 through which the first fluid
flows out of the outflow header tank 42 is placed on a central
portion of the outflow header tank 42 in the Y direction. An inflow
header tank 43 is placed on the inflow surface 33 through which the
second fluid flows, and an outflow header tank 44 is placed on the
outflow surface 34 through which the second fluid flows. The
configurations of the inflow header tank 43 and the outflow header
tank 44 both for the second fluid are respectively identical to
those of the inflow header tank 41 and the outflow header tank 42
both for the first fluid. An inflow nozzle 431 and an outflow
nozzle 441 are respectively placed on central portions of the
inflow header tank 43 and the outflow header tank 44 in the Y
direction.
[0047] The heat exchanger 1 includes two types of flow-directing
members, i.e., a flow-directing member 51 of a first type and a
flow-directing member 52 of a second type, for the first passages
21 through which the first fluid flows, and two types of
flow-directing members, i.e., another flow-directing member 51 of
the first type and another flow-directing member 52 of the second
type, for the second passages 22 through which the second fluid
flows. The flow-directing members 51 of the first type are each
placed in one of the inflow header tanks 41 and 43. The
flow-directing members 51 of the first type each enable a uniform
distribution of dynamic pressure of fluid to the corresponding one
of the inflow surface 31 through which the first fluid flows and
the inflow surface 33 through which the second fluid flows. In
other words, while the core 2 and the inflow header tanks 41 and 43
are all long and thin, and all extend along the Y direction, the
inflow nozzles 411 and 431 are each placed on the central portion
of the corresponding one of the inflow header tanks 41 and 43 in
the Y direction. Furthermore, the inflow header tanks 41 and 43
each have a relatively short length in the X direction. As a
result, fluid that has flowed into the inflow header tanks 41 and
43 is difficult to spread in the Y and Z directions. This tendency
is accelerated, in particular, when the velocity of flow of fluid
through each inflow nozzle 411, 431 is high. This causes the
distribution of dynamic pressure of fluid to each inflow surface
31, 33 to be uneven. For example, in the uneven distribution, while
the dynamic pressure of fluid to a region of each inflow surface
31, 33 onto which an opening of the corresponding one of the inflow
nozzles 411 and 431 is projected and its surrounding region is
extremely high, the dynamic pressure of fluid to a region of each
inflow surface 31, 33 outside the region of each inflow surface 31,
33 onto which the opening of the corresponding one of the inflow
nozzles 411 and 431 is projected and its surrounding region is
relatively low, and the dynamic pressure of fluid to a peripheral
portion of each inflow surface 31, 33 is lower. Such an uneven
distribution of dynamic pressure causes uneven flow of fluid. The
uneven flow of fluid corresponds to a situation where while the
flow rates of fluid through central ones of the passages in the Y
direction are high, the flow rates of fluid through the other ones
of the passages located outwardly along the Y directions are low.
In the illustrated core 2, uneven flow of fluid arising from an
uneven distribution of dynamic pressure of the fluid corresponds to
variations in the flow rate of fluid among different portions of
the core 2 aligned in a direction in which the first and second
passages 21 and 22 are stacked.
[0048] The flow-directing members 51 of the first type each enable
a uniform distribution of dynamic pressure of fluid to the
corresponding one of the inflow surfaces 31 and 33. Specifically,
the illustrated flow-directing members 51 of the first type are
plate-like baffles. The plate-like baffles are each disposed in the
vicinity of the opening of the corresponding one of the inflow
nozzles 411 and 431 placed on the central portion of the
corresponding one of the inflow header tanks 41 and 43. As
illustrated in the enlarged view in FIG. 2, each flow-directing
member 51 of the first type has a plurality of through holes 511
penetrating the flow-directing member 51 along the thickness
thereof. The through holes 511 have the same diameter, and are
spaced substantially uniformly.
[0049] The length of each flow-directing member 51 of the first
type in the Y direction is slightly greater than the diameter of
the corresponding one of the inflow nozzles 411 and 431. Each
flow-directing member 51 of the first type crosses the flow of
fluid through the corresponding one of the inflow nozzles 411 and
431 into the corresponding one of the inflow header tanks 41 and
43, and is fixed to the inner wall of the corresponding one of the
inflow header tanks 41 and 43 by, for example, welding as
illustrated in FIG. 1B.
[0050] Each flow-directing member 51 of the first type configured
as above interferes with the flow of fluid having flowed through
the corresponding one of the inflow nozzles 411 and 431 into the
corresponding one of the inflow header tanks 41 and 43. Part of the
fluid flows through the through holes 511 of the flow-directing
members 51 of the first type in the X directions without changing
the directions of flow of the fluid, whereas the direction of flow
of the remaining fluid is changed as indicated by the solid arrows
in FIG. 1A such that the remaining fluid bypasses the
flow-directing members 51 of the first type, thereby allowing the
remaining fluid to flow while spreading in the Y directions. This
enables a uniform distribution of dynamic pressure of fluid to each
inflow surface 31, 33, and reduces variations in the flow rate of
fluid into the core 2 among different portions of the core 2
aligned in the direction in which the first and second passages 21
and 22 are stacked. In other words, the flow rates of fluid into
the first passages 21 are equalized, and the flow rates of fluid
into the second passages 22 are equalized. This helps enhance the
heat exchange efficiency of the heat exchanger 1.
[0051] Here, each flow-directing member 51 of the first type that
is closer to the opening of the corresponding one of the inflow
nozzles 411 and 431 than to the corresponding one of the inflow
surfaces 31 and 33 of the core 2 enhances the dispersibility of
fluid flowing through the corresponding one of the inflow nozzles
411 and 431 into the corresponding one of the inflow header tanks
41 and 43, and helps prevent variations in the flow rate of fluid
through the core 2 among different portions of the core 2 aligned
in the direction in which the first and second passages 21 and 22
are stacked. Note that the distribution of dynamic pressure of
fluid to each inflow surface 31, 33 varies depending on, for
example, the size of each inflow surface 31, 33, the shape of the
corresponding one of the inflow header tanks 41 and 43, the shape
and placement of the corresponding one of the inflow nozzles 411
and 431, and the velocity of flow of fluid. The size of each
flow-directing member 51 of the first type, the sizes, number, and
placement of the through holes 511, and the placement of each
flow-directing member 51 of the first type merely need to be
appropriately determined depending on the distribution of dynamic
pressure of fluid to the corresponding one of the inflow surfaces
31 and 33. If necessary, the through holes may be omitted. A
plurality of baffles may be placed in each header tank 41, 43.
[0052] By contrast, unlike the flow-directing members 51 of the
first type, the flow-directing members 52 of the second type each
reduce the differences among the flow rates of fluid through the
channels of the corresponding ones of the first passages 21 and the
second passages 22 due to different channel resistances of the
channels. In other words, the first passages 21 and the second
passages 22 of the core 2 each include the corresponding one of the
distributor fins 212 and 222 as described above, and the channels
defined by the corrugated fin 211 and the distributor fin 212 in
each first passage 21 and the channels defined by the corrugated
fin 211 and the distributor fin 222 in each second passage 22 have
different lengths from their inlets to their outlets. In the
example illustrated in FIG. 1B, in each first passage 21, some of
the channels each having the outlet formed in a relatively upper
portion of the outflow surface 32 have relatively short lengths,
and the other ones of the channels each having the outlet formed in
a relatively lower portion of the outflow surface 32 have
relatively long lengths. The differences in length among the
channels cause the differences in channel resistance among the
channels, and the differences in channel resistance among the
channels cause the differences among the flow rates of fluid
through the channels. In other words, in the illustrated example,
in each first passage 21, the flow rates of fluid through the some
of the channels each having the outlet formed in the relatively
upper portion of the outflow surface 32 are relatively high, and
the flow rates of fluid through the other ones of the channels each
having the outlet formed in the relatively lower portion of the
outflow surface 32 are relatively low. Although not shown, in each
second passage 22, some of the channels each having the outlet
formed in a relatively upper portion of the outflow surface 34 have
relatively long lengths, and the flow rates of fluid through the
some of the channels are, therefore, relatively low, whereas the
other ones of the channels each having the outlet formed in a
relatively lower portion of the outflow surface 34 have relatively
short lengths, and the flow rates of fluid through the other ones
of the channels are, therefore, relatively high. The flow rate
distribution of fluid flowing through each outflow surface 32, 34
is equivalent to the channel resistance distribution corresponding
to the resistances of the channels. The uneven flow of fluid
through the illustrated core 2 due to the differences in channel
resistance among the channels corresponds to variations in the flow
rate of fluid among different portions of the core 2 aligned in the
Z direction (along the width of the core 2).
[0053] The flow-directing members 52 of the second type, which
reduce the uneven flow of fluid arising from the differences in
channel resistance among the channels, are each placed in the
corresponding one of the outflow header tanks 42 and 44 unlike the
flow-directing members 51 of the first type. Specifically, the
flow-directing members 52 of the second type are plate-like
members, and are each placed in a portion of the interior of the
corresponding one of the outflow header tanks 42 and 44 near the
corresponding one of the outflow surface 32 and 34 to face the
corresponding one of the outflow surfaces 32 and 34. The
flow-directing members 52 of the second type are also each fixed to
the inner wall of the corresponding one of the outflow header tanks
42 and 44 by, for example, welding.
[0054] As illustrated in FIG. 3, the flow-directing members 52 of
the second type also each have a plurality of same-diameter through
holes 521 similar to those of the flow-directing members 51 of the
first type. The through holes 521 penetrate the corresponding one
of the flow-directing members 52 of the second type along the
thickness thereof. In contrast to the flow-directing members 51 of
the first type, the through holes 521 of each flow-directing member
52 of the second type are not spaced uniformly. Upper ones of the
through holes 521 in the drawing sheet of FIG. 3 are spaced
relatively widely, and lower ones of the through holes 521 in the
drawing sheet of FIG. 3 are spaced relatively narrowly. Thus, the
aperture ratio (the total area of holes per unit area) of an upper
portion of each flow-directing member 52 of the second type is
relatively low, and the aperture ratio of a lower portion thereof
is relatively high. Such flow-directing members 52 of the second
type are each positioned in response to the above-described channel
resistance distribution corresponding to the flow rate distribution
of fluid flowing through the corresponding one of the outflow
surfaces 32 and 34. Specifically, a portion of each flow-directing
member 52 of the second type having low aperture ratios faces the
outlets of some of the channels having relatively low channel
resistances in the corresponding one of the outflow surfaces 32 and
34, and a portion of each flow-directing member 52 of the second
type having high aperture ratios faces the outlets of the other
ones of the channels having relatively high channel resistances in
the corresponding one of the outflow surfaces 32 and 34.
Specifically, as illustrated in FIG. 3, one of the flow-directing
members 52 of the second type faces the outflow surface 32 through
which the first fluid flows such that the portion of the one of the
flow-directing members 52 of the second type having low aperture
ratios is above the portion of the one of the flow-directing
members 52 of the second type having high aperture ratios. By
contrast, the other one of the flow-directing members 52 of the
second type faces the outflow surface 34 through which the second
fluid flows such that the flow-directing member 52 illustrated in
FIG. 3 is turned upside down, i.e., such that the portion of the
other one of the flow-directing members 52 of the second type
having high aperture ratios is above the portion of the other one
of the flow-directing members 52 of the second type having low
aperture ratios. Thus, since the portion of each flow-directing
member 52 of the second type having low aperture ratios faces the
outlets of the some of the channels having relatively low channel
resistances, fluid is less likely to flow out of the some of the
channels, whereas since the portion of each flow-directing member
52 of the second type having high aperture ratios faces the outlets
of the other ones of the channels having relatively high channel
resistances, fluid easily flows out of the other ones of the
channels. This reduces the differences among the flow rates of
fluid through the channels independently of the differences in
channel resistance among the channels. In other words, the
flow-directing members 52 of the second type reduce the uneven flow
of fluid arising from the differences in channel resistance among
the channels. This helps enhance the heat exchange efficiency of
the heat exchanger 1.
[0055] If the flow-directing members 52 of the second type are
relatively close to the corresponding outflow surfaces 32 and 34,
the differences among the flow rates of fluid through the channels
due to the differences in channel resistance among the channels are
highly effectively reduced. If the flow-directing members 52 of the
second type are away from the corresponding outflow surfaces 32 and
34, the portion of each flow-directing member 52 of the second type
having low aperture ratios less effectively restricts the flow
rates of fluid through the corresponding channels.
[0056] As such, the provision of the flow-directing members of two
types, i.e., the flow-directing members 51 of the first type and
the flow-directing members 52 of the second type, can reduce both
the uneven flow of fluid arising from the dynamic pressure
distribution of fluid to each inflow surface 31, 33 of the core 2
(in the illustrated example, variations in the flow rate of fluid
among different portions of the core 2 aligned in the direction in
which the first and second passages 21 and 22 are stacked) and the
uneven flow of fluid arising from the differences in channel
resistance among the channels of the core 2 (in the illustrated
example, variations in the flow rate of fluid among different
portions of the core 2 aligned along the width of the core 2). In
other words, two types of uneven flows of fluid with different
mechanisms for flow generation are each reduced by the
corresponding ones of the two types of the flow-directing members,
i.e., the flow-directing members 51 of the first type and the
flow-directing members 52 of the second type, to accurately reduce
the two types of even flows, thereby enhancing the heat exchange
efficiency of the heat exchanger 1.
[0057] Here, the spacing between each adjacent pair of the
same-diameter through holes 521 of the flow-directing member 52 of
the second type illustrated in FIG. 3 is varied to vary the
aperture ratio. In contrast to this, the diameter of through holes
spaced uniformly may be varied to vary the aperture ratio.
Alternatively, both the diameter of through holes and the spacing
between each adjacent pair of the through holes may be varied to
vary the aperture ratio of the flow-directing member 52 of the
second type.
[0058] The through holes of the flow-directing members 52 of the
second type should not be limited to such circular holes as
illustrated in FIG. 3, and may be, for example, such elongated
through holes 531 as illustrated in FIG. 4. In the example
illustrated in FIG. 4, the size of each elongated through hole 531
and the spacing between each adjacent pair of the elongated through
holes 531 are both varied. Only either the size of each elongated
through hole 531 or the spacing between each adjacent pair of the
elongated through holes 531 may be varied to vary the aperture
ratio.
[0059] The aperture ratio of each flow-directing member 52 of the
second type may be successively varied along the X direction as
illustrated in FIG. 3, or may be varied in stages along the X
direction as illustrated in FIG. 4.
[0060] One of the flow-directing members 52 of the second type may
be positioned to face at least a portion of the outflow surface 32
as illustrated in, for example, FIG. 5 instead of positioning the
flow-directing members 52 of the second type to face the
corresponding entire outflow surfaces 32 and 34. FIGS. 5A and 5B
illustrate an example in which one of the flow-directing members 52
of the second type for the first passages 21 faces a portion of the
outflow surface 32 that is about half the size of the outflow
surface 32. A portion of the outflow surface 32 that does not face
the one of the flow-directing members 52 of the second type is
equivalent to a portion of the outflow surface 32 facing a portion
of a flow-directing member 52 of the second type having higher
aperture ratios.
[0061] Furthermore, one of the flow-directing members 52 of the
second type may be placed in the inflow header tank 41 instead of
in the outflow header tank 42. FIGS. 6A and 6B illustrate an
example in which one of the flow-directing members 52 of the second
type for the first passages 21 is placed in the inflow header tank
41. The one of the flow-directing members 52 of the second type is
also a plate-like member having different aperture ratios as
illustrated in FIGS. 3 and 4. The one of the flow-directing members
52 of the second type is positioned to face the inflow surface 31
such that the aperture ratio distribution of the one of the
flow-directing members 52 of the second type corresponds to the
channel resistance distribution across the inflow surface 31. This
allows the flow rates of fluid into the channels to be adjusted in
response to the channel resistances, thereby reducing the
differences among the flow rates of fluid passing through the
channels.
[0062] Here, also in the case where the one of the flow-directing
members 52 of the second type is positioned to face the inflow
surface 31, the one of the flow-directing members 52 of the second
type is preferably close to the inflow surface 31 to adequately
reduce the uneven flow of fluid. Specifically, the one of the
flow-directing members 52 of the second type placed in the inflow
header tank 41 has different aperture ratios, which cause the flow
rates of fluid through the one of the flow-directing members 52 of
the second type and thus the flow rates of fluid through the inflow
surface 31 into the core 2 to be different. This reduces the
differences among the flow rates of fluid through the channels. For
this reason, if the one of the flow-directing members 52 of the
second type is away from the inflow surface 31, the differences
among the flow rates of fluid through the channels, which are
provided by passing fluid through the one of the flow-directing
members 52 of the second type, are less effective before the fluid
reaches the inflow surface 31. By contrast, if the one of the
flow-directing members 52 of the second type is excessively close
to the inflow surface 31, the velocity gradient of fluid between
portions of the one of the flow-directing members 52 of the second
type corresponding to the through holes 521 (i.e., openings) and
the other portion thereof (i.e., a portion thereof except the
openings) affects the flow of fluid through the inflow surface 31
into the channels. Specifically, while the flow rate of fluid into
some of the inlets facing the openings increases, fluid hardly
flows into the other ones of the inlets facing the portion of the
one of the flow-directing members 52 of the second type except the
openings. This not only prevents the one of the flow-directing
members 52 of the second type from functioning to reduce the
differences among the flow rates of fluid through the channels, but
also may increase the differences. When, as such, the one of the
flow-directing members 52 of the second type is placed in the
inflow header tank 41, the one of the flow-directing members 52 of
the second type may be difficult to position. By contrast, when the
one of the flow-directing members 52 of the second type is placed
in the outflow header tank 42 as illustrated in, for example, FIG.
1, the velocity gradient of fluid that has passed through the one
of the flow-directing members 52 of the second type does not need
to be considered. This increases the flexibility in positioning the
flow-directing member 52 of the second type, and can effectively
reduce the uneven flow of fluid arising from the differences in
channel resistance among the channels.
[0063] One of the flow-directing members 51 of the first type is
placed in the inflow header tank 41. Thus, when the one of the
flow-directing members 52 of the second type is placed in the
inflow header tank 41, the two types of flow-directing members,
i.e., the one of the flow-directing members 51 and the one of the
flow-directing members 52, are placed in the inflow header tank 41.
For this reason, the configuration of the inflow header tank 41 and
the configuration of the inflow nozzle 411 may make it difficult
for the two types of flow-directing members, i.e., the one of the
flow-directing members 51 and the one of the flow-directing members
52, to be each positioned to adequately function. Placing one of
the flow-directing members 52 of the second type in the outflow
header tank 42 means that the one of the flow-directing members 51
of the first type and the one of the flow-directing members 52 of
the second type are respectively placed to sides of the core 2
where the inflow surface 31 and the outflow surface 32 are located.
This helps suitably position the flow-directing members 51 and 52
of the first and second types.
[0064] A heat exchanger 10 providing a substantially uniform
distribution of dynamic pressure of fluid to an inflow surface 31
of a core 2 as illustrated in, for example, FIGS. 7A and 7B may
fail to include a flow-directing member of the first type facing
the inflow surface 31. In other words, in FIGS. 7A and 7B, ducts 44
and 45 form a passage of a first fluid. This allows the
distribution of dynamic pressure of the first fluid to the inflow
surface 31 of the core 2 to be substantially uniform. This
eliminates the need for one of the flow-directing members of the
first type. By contrast, first passages 21 of the core 2 each
include at least a distributor fin 212 as described above,
resulting in differences in channel resistance among the channels.
To address this problem, in the heat exchanger 10 illustrated in
FIGS. 7A and 7B, a flow-directing member 52 of the second type is
positioned to face an outflow surface 32 of the core 2. This can
prevent variations in the flow rate of the first fluid among
different portions of the core 2 aligned along the width of the
core 2. The variations may be caused by the differences in channel
resistance among the channels. In the example illustrated in FIGS.
7A and 7B, a flow-directing member 52 of the second type may be
placed to the side of the core 2 where the inflow surface 31 is
located.
[0065] Depending on the configuration of a heat exchanger, only
either channels for the first fluid or channels for the second
fluid may be provided with the flow-directing members of the first
and second types or the flow-directing member of the first or
second type.
[0066] The flow-directing members of the first type reducing uneven
flow of fluid caused by the distribution of dynamic pressure should
not be limited to baffles, and the configuration of the
flow-directing members of the first type may be selected from
various known configurations, depending on the configurations of
the corresponding inflow header tanks and the configurations and
placement of the corresponding inflow nozzles.
[0067] Here, the heat exchanger 1, 10 including the plate fin core
2 is used as an example to describe the flow-directing members of
the first and second types. Flow-directing members of the first and
second types can be used for a multitubular heat exchanger. A
multitubular heat exchanger including, for example, pipes bent in a
U shape causes channels to have different channel resistances. This
may cause uneven flow of fluid. The flow-directing members of the
second type help reduce the uneven flow of fluid also in such a
multitubular heat exchanger.
[0068] In either the plate fin heat exchanger or the multitubular
heat exchanger, the differences in channel resistance among the
channels may be caused not only by the differences in length among
the channels but also by the differences in cross-sectional area
among the channels or both the differences in length among the
channels and the differences in cross-sectional area among the
channels. In either of the cases, the flow-directing members of the
second type can reduce the differences among the flow rates of
fluid through the channels arising from the differences in channel
resistance among the channels.
INDUSTRIAL APPLICABILITY
[0069] As described above, the heat exchanger disclosed herein
includes the flow-directing members of the first type and the
flow-directing members of the second type. The flow-directing
members of the first type each provide a uniform distribution of
dynamic pressure of fluid to the corresponding one of the inflow
surfaces. The flow-directing members of the second type reduce the
differences among the flow rates of fluid through the corresponding
channels arising from the differences in channel resistance among
the corresponding channels. The flow-directing members of the first
and second types can reduce the uneven flow of fluid. This helps
enhance the heat exchange efficiencies of various heat exchangers.
The flow rates of fluid through the channels are equalized, thereby
helping improve the reaction efficiency and thus performance of a
heat exchanger (i.e., a catalytic reactor) that has channels each
including a catalyst support and is used, for example, to cause the
fluid passing through the channels to react.
DESCRIPTION OF REFERENCE CHARACTERS
[0070] 1 Heat Exchanger [0071] 10 Heat Exchanger [0072] 2 Core
[0073] 21 First Passage [0074] 22 Second Passage [0075] 211
Corrugated Fin [0076] 212, 222 Distributor Fin [0077] 31, 33 Inflow
Surface [0078] 32, 34 Outflow Surface [0079] 51 Flow-Directing
Member Of First Type [0080] 52 Flow-Directing Member Of Second Type
[0081] 521, 531 Through Hole
* * * * *