U.S. patent application number 15/366968 was filed with the patent office on 2017-07-27 for heat exchanger and heat exchange method.
This patent application is currently assigned to Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). The applicant listed for this patent is Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). Invention is credited to Koji NOISHIKI.
Application Number | 20170211893 15/366968 |
Document ID | / |
Family ID | 57389321 |
Filed Date | 2017-07-27 |
United States Patent
Application |
20170211893 |
Kind Code |
A1 |
NOISHIKI; Koji |
July 27, 2017 |
HEAT EXCHANGER AND HEAT EXCHANGE METHOD
Abstract
A heat exchanger includes a channel structure including a first
substrate in which a first channel is arrayed, and a second
substrate stacked on the first substrate, in which a second channel
is arrayed. The first channel has an effective area overlapping a
range where the second channel is provided, when viewed in a
lamination direction of the first and second substrates. The
effective area includes a standard heat transfer channel part
including a high temperature end, and a high heat transfer channel
part including a low temperature end, which is a part of the
effective area other than the standard heat transfer channel part.
The high heat transfer channel part has a bent shape so that a
channel length thereof per unit distance of an end-to-end distance
thereof is greater than a channel length of the standard heat
transfer channel part per unit distance of an end-to-end distance
thereof.
Inventors: |
NOISHIKI; Koji;
(Takasago-shi, Hyogo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) |
Hyogo |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Kobe Seiko Sho
(Kobe Steel, Ltd.)
Hyogo
JP
|
Family ID: |
57389321 |
Appl. No.: |
15/366968 |
Filed: |
December 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 3/08 20130101; F28F
3/048 20130101; F28F 2210/10 20130101; F28F 13/12 20130101; F28F
2255/00 20130101; F28F 2260/02 20130101; F28D 9/0037 20130101 |
International
Class: |
F28F 3/04 20060101
F28F003/04; F28F 3/08 20060101 F28F003/08; F28D 9/00 20060101
F28D009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2016 |
JP |
2016-010670 |
Claims
1. A heat exchanger that causes a plurality of fluids to flow
therethrough so as to cause heat exchange to occur between the
fluids, the heat exchanger comprising a channel structure that
includes: a first layer in which a first channel that is a
microchannel through which one fluid is caused to flow is arrayed;
and a second layer stacked on the first layer, in which a second
channel that is a microchannel through which another fluid is
caused to flow is arrayed, the other fluid being a fluid different
from the one fluid, wherein the first channel has an effective area
that overlaps a range where the second channel in the second layer
is provided, when viewed in a direction in which the first layer
and the second layer are stacked, wherein the effective area
includes: a standard heat transfer channel part that includes a
high temperature end that is one of ends of the effective area; and
a high heat transfer channel part that is equivalent to a part of
the effective area other than the standard heat transfer channel
part, the high heat transfer channel part including a low
temperature end that is an end of the effective area on a side
opposite to the high temperature end and through which the one
fluid having a temperature lower than a temperature of the one
fluid flowing at the high temperature end, and wherein the high
heat transfer channel part has a channel shape bent in such a
manner that a channel length thereof per unit distance of an
end-to-end distance thereof is greater than a channel length of the
standard heat transfer channel part per unit distance of an
end-to-end distance thereof.
2. The heat exchanger according to claim 1, wherein the standard
heat transfer channel part is a straight channel, and wherein the
high heat transfer channel part is a wavy type channel.
3. The heat exchanger according to claim 2, wherein the high heat
transfer channel part meanders in such a manner as being deflected
to both sides with respect to a center line that is a straight
line, and wherein the end-to-end distance of the high heat transfer
channel part in a direction along the center line is 60% or less of
an end-to-end distance of the effective area.
4. The heat exchanger according to claim 3, wherein the end-to-end
distance of the high heat transfer channel part in a direction
along the center line is 10% or more of the end-to-end distance of
the effective area.
5. The heat exchanger according to claim 2, wherein the high heat
transfer channel part meanders in such a manner as being deflected
to both sides with respect to a center line that is a straight
line, and wherein the end-to-end distance of the high heat transfer
channel part in a direction along the center line is smaller than
the end-to-end distance of the standard heat transfer channel
part.
6. A heat exchange method comprising: causing one fluid to flow
through the first channel in the heat exchanger according to claim
1 from the standard heat transfer channel part toward the high heat
transfer channel part, and at the same time, causing a refrigerant
as another fluid to flow through the second channel in the heat
exchanger, so as to cause heat exchange to occur between the one
fluid and the refrigerant.
7. A heat exchange method comprising: causing one fluid to flow
through the first channel in the heat exchanger according to claim
1 from the high heat transfer channel part toward the standard heat
transfer channel part, and at the same time, causing a hot medium
as another fluid to flow through the second channel in the heat
exchanger, so as to cause heat exchange to occur between the one
fluid and the hot medium.
Description
BACKGROUND OF THE INVENTION
[0001] Field of the Invention
[0002] The present invention relates to a heat exchanger and a heat
exchange method.
[0003] Description of the Related Art
[0004] Conventionally, a stacked-type heat exchanger has been known
as one kind of a heat exchanger having excellent heat exchanger
performance. This stacked-type heat exchanger includes a stacked
body obtained by stacking a plurality of substrates in each of
which a plurality of microchannels are arrayed. This heat exchanger
is configured so that heat exchange is performed between fluid
flowing through microchannels arrayed in one substrate and fluid
flowing through microchannels arrayed in another substrate adjacent
to the foregoing substrate. JP 2010-286229 A discloses one example
of such a stacked-type heat exchanger.
[0005] The stacked-type heat exchanger disclosed in JP 2010-286229
A includes a stacked body in which a high temperature part layer
and a low temperature part layer are stacked with a partition wall
being interposed therebetween. In the high temperature part layer,
a plurality of microchannels through which high temperature fluid
is caused to flow are arrayed, and in the low temperature part
layer, a plurality of microchannels through which low temperature
fluid is caused to flow are arrayed. This heat exchanger has a
configuration in which a straight channel is provided in a fluid
distributing part, whereas a corrugated channel having higher heat
transmission and causing greater pressure drop is provided in a
heat transfer part, so that the heat exchanger is made compact.
[0006] In the heat exchanger of JP-2010-286229-A, priority is given
to heat transfer performance in order to make the heat exchanger
compact, but this leads to a risk that an excessive pressure drop
is caused by the corrugated channel of the microchannel, that is,
an excessive pressure loss occurs.
[0007] An object of the present invention is to improve heat
transfer performance of a heat exchanger, and prevent excessive
pressure loss from occurring, while preventing the increase in the
size of the heat exchanger.
[0008] A heat exchanger according to the present invention is a
heat exchanger that causes a plurality of fluids to flow
therethrough so as to cause heat exchange to occur between the
fluids. The heat exchanger includes a channel structure that
includes: a first layer in which a first channel that is a
microchannel through which one fluid is caused to flow is arrayed;
and a second layer stacked on the first layer, in which a second
channel that is a microchannel through which another fluid is
caused to flow is arrayed, the other fluid being a fluid different
from the one fluid. The first channel has an effective area that
overlaps a range where the second channel in the second layer is
provided, when viewed in a direction in which the first layer and
the second layer are stacked. The effective area includes: a
standard heat transfer channel part that includes a high
temperature end that is one of ends of the effective area; and a
high heat transfer channel part that is equivalent to a part of the
effective area other than the standard heat transfer channel part,
the high heat transfer channel part including a low temperature end
that is an end of the effective area on a side opposite to the high
temperature end and through which the one fluid having a
temperature lower than a temperature of the one fluid flowing at
the high temperature end. The high heat transfer channel part has a
channel shape bent in such a manner that a channel length thereof
per unit distance of an end-to-end distance thereof is greater than
a channel length of the standard heat transfer channel part per
unit distance of an end-to-end distance thereof.
[0009] In this heat exchanger, the effective area of the first
channel includes the high heat transfer channel part, and this high
heat transfer channel part has a channel shape bent in such a
manner that the channel length thereof per unit distance of the
end-to-end distance thereof is greater than the channel length of
the standard heat transfer channel part of the effective area per
unit distance of the end-to-end distance thereof. In other words,
the high heat transfer channel part has a greater number of bent
portions than the standard heat transfer channel part, or
alternatively, has a bent portion having a greater degree of
bending than the standard heat transfer channel part. This makes it
possible to improve heat transfer performance owing to the fluid
turbulence at the bent portions of the high heat transfer channel
part. Further, with the high heat transfer channel part formed in
the bent channel shape, which suppresses the increase in the
end-to-end distance thereof, the increase in the size of the heat
exchanger can be prevented. Accordingly, the increase in the size
of this heat exchanger can be prevented, and the heat transfer
performance thereof can be improved.
[0010] Moreover, in this heat exchanger, the standard heat transfer
channel part is a part that includes the high temperature end of
the effective area, and the high heat transfer channel part is
equivalent to a part of the effective area other than the standard
heat transfer channel part, which includes the low temperature end
of the effective area. The amplitude of the increase in the
pressure loss in the effective area of the first channel,
therefore, can be reduced. More specifically, since a pressure loss
in a channel is proportional to a flow rate of a fluid flowing
through the channel, the configuration in which a part of the
effective area through which the first fluid having a low
temperature and hence having a relatively higher density flows and
that includes the low temperature end at which the first fluid
comes to have a smaller flow rate is the high heat transfer channel
part, and the other part of the effective area that includes the
high temperature end is the standard heat transfer channel part,
enables to reduce the amplitude of the increase in the pressure
loss, even if the pressure loss is increased by the high heat
transfer channel part thus bent. It is therefore possible to
prevent excessive pressure loss from occurring in the first
channels. Still further, since the first fluid has a higher density
and hence has a smaller flow rate at and near the low temperature
end of the effective area as described above, the heat transfer
performance is relatively low in this part. In this heat exchanger,
however, since the high heat transfer channel part includes the low
temperature end, the relatively low heat transfer performance at
and near the low temperature end can be improved by the high heat
transfer channel part. This makes it possible to achieve the high
heat transfer performance with a good balance in the entirety of
the effective area of the first channel.
[0011] In the above-described heat exchanger, preferably, the
standard heat transfer channel part is a straight channel, and the
high heat transfer channel part is a wavy type channel.
[0012] With this configuration in which the standard heat transfer
channel part is a straight channel, the pressure loss in the
standard heat transfer channel part can be reduced, as compared
with a case where the standard heat transfer channel part has a
curved channel shape or a bent channel shape. To this extent, the
increase in the pressure loss in the effective area can be
suppressed.
[0013] In this case, preferably, the high heat transfer channel
part meanders in such a manner as being deflected to both sides
with respect to a center line that is a straight line, and the
end-to-end distance of the high heat transfer channel part in a
direction along the center line is 60% or less of an end-to-end
distance of the effective area.
[0014] With this configuration, the pressure loss in the effective
area can be suppressed to less than twice the pressure loss in the
effective area in a case where the entirety of the effective area
is a straight channel. In view of practical application of the heat
exchanger, if the pressure loss in the effective area of the first
channel increases to twice or more the value of pressure loss in an
effective area in a case where the entire effective area is a
straight channel, it is difficult to use a first channel having
such an effective area. With the present configuration, the
increase in the pressure loss can be suppressed to less than twice
as described above, and hence, a first channel that is sufficiently
able to be adopted for practical application in view of pressure
loss can be obtained.
[0015] Further, in this case, the end-to-end distance of the high
heat transfer channel part in a direction along the center line is
preferably 10% or more of the end-to-end distance of the effective
area.
[0016] With this configuration, a heat transfer area that can
sufficiently compensate the reductions in the heat transfer
performance that are generally expected due to dirt and/or fluid
conditions in the effective area can be ensured in the effective
area.
[0017] Still further, in the configuration in which the standard
heat transfer channel part is a straight channel and the high heat
transfer channel part is a wavy type channel, preferably, the high
heat transfer channel part meanders in such a manner as being
deflected to both sides with respect to a center line that is a
straight line, and the end-to-end distance of the high heat
transfer channel part in a direction along the center line is
smaller than the end-to-end distance of the standard heat transfer
channel part.
[0018] With this configuration, the improvement of the heat
transfer performance and the prevention of excessive increase in
the pressure loss can be achieved with a good balance, while the
increase in the size of the heat exchanger can be prevented.
[0019] A heat exchange method according to the present invention
includes causing one fluid to flow through the first channel in the
above-described heat exchanger from the standard heat transfer
channel part toward the high heat transfer channel part, and at the
same time, causing a refrigerant as another fluid to flow through
the second channel in the heat exchanger, so as to cause heat
exchange to occur between the one fluid and the refrigerant.
[0020] Further, a heat exchange method according to the present
invention includes causing one fluid to flow through the first
channel in the above-described heat exchanger from the high heat
transfer channel part toward the standard heat transfer channel
part, and at the same time, causing a hot medium as another fluid
to flow through the second channel of the heat exchanger, so as to
cause heat exchange to occur between the one fluid and the hot
medium.
[0021] As described above, according to the present invention, it
is possible to improve heat transfer performance of a heat
exchanger, and prevent excessive pressure loss from occurring,
while preventing the increase in the size of the heat exchanger
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic perspective view of a heat exchanger
according to one embodiment of the present invention.
[0023] FIG. 2 is a plan view of a first substrate that composes a
channel structure of the heat exchanger illustrated in FIG. 1.
[0024] FIG. 3 is a plan view of a second substrate that composes
the channel structure heat exchanger illustrated in FIG. 1.
[0025] FIG. 4 is an enlarged view of high heat transfer channel
parts of first channels.
[0026] FIG. 5 is a partial sectional view of the first substrate in
which the first channels are formed and its surrounding area, in
the channel structure.
[0027] FIG. 6 illustrates correlation between a ratio of an
end-to-end distance of a high heat transfer channel part of a first
channel to an end-to-end distance of an effective area of the same
and a pressure loss calculated by simulation.
[0028] FIG. 7 illustrates correlation between a ratio of an
end-to-end distance of a high heat transfer channel part of a first
channel to an end-to-end distance of an effective area of the same
and a heat transfer coefficient calculated by simulation.
[0029] FIG. 8 illustrates correlation between a ratio of an
end-to-end distance of a high heat transfer channel part of a first
channel to an end-to-end distance of an effective area of the same
and a ratio of pressure loss to a heat transfer coefficient
calculated by simulation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] The following description describes an embodiment of the
present invention, while referring to the drawings.
[0031] FIG. 1 illustrates an overall configuration of a heat
exchanger 1 according to one embodiment of the present invention.
The heat exchanger 1 has such a configuration that a first fluid
and a second fluid are caused to exchange heat while flowing
through the heat exchanger. The heat exchanger 1 includes a channel
structure 2, a first supply header 3, a second supply header 4, a
first discharge header 5, and a second discharge header 6.
[0032] The channel structure 2 is a rectangular parallelepiped
structure that includes, in the inside thereof, a multiplicity of
first channels 21 (see FIG. 2) that are microchannels through which
the first fluid is caused to flow, and a multiplicity of second
channels 22 (see FIG. 3) that are microchannels through which the
second fluid is caused to flow. The channel structure 2 includes a
plurality of first substrates 11 in each of which a plurality of
the first channels 21 are arrayed, and a plurality of second
substrates 12 in each of which a plurality of the second channels
22 are arrayed. The first substrate 11 is one example of the first
layer in the present invention, and the second substrate 12 is one
example of the second layer in the present invention.
[0033] Each of the first substrates 11 and the second substrates 12
is a flat plate in a rectangular shape when viewed from one side in
the thickness direction thereof, and is formed with, for example, a
stainless steel plate. In the channel structure 2, the first
substrates 11 and the second substrates 12 are alternately stacked
and bonded to one another. This results in that, in the channel
structure 2, the first channels 21 arrayed in the first substrate
11, and the second channels 22 arrayed in the second substrate 12
are arrayed alternately in a lamination direction where the
substrate 11 and the substrate 12 are stacked. The channel
structure 2 has four lateral faces that are formed with end faces
that correspond to four sides of each of the substrates 11, 12.
[0034] On one of plate surfaces of each first substrate 11, as
illustrated in FIG. 2, a plurality of first grooves 23 that form a
plurality of the first channels 21 are formed. Each of the first
grooves 23 is formed by etching, and has an arc-shaped cross
section, as illustrated in FIG. 5. The openings of the first
grooves 23 on one of plate surfaces of the first substrate 11 are
sealed by the second substrate 12 stacked on the plate surface of
the first substrate 11, whereby a plurality of the first channels
21 arrayed on the one plate surface are formed.
[0035] Each first channel 21 extends approximately in the
longitudinal direction of the first substrate 11. In the present
embodiment, the channel structure 2 is arranged in such a posture
that a standard heat transfer channel part 25 to be described below
of each first channel 21 extends in an up-to-down direction. In
other words, the channel structure 2 is arranged in such a posture
that the longitudinal direction of each of the substrates 11, 12
coincides with the vertical direction.
[0036] Each first channel 21 has, at one end thereof, an
introduction port 21a (see FIG. 2) through which the first fluid is
introduced, and at an end on a side opposite to the introduction
port 21a, an outflow port 21b through which the first fluid having
flown through the first channel 21 is allowed to flow out. The
introduction ports 21a are open on a lateral face of the channel
structure 2, which is formed with end faces on one side in the
longitudinal direction of the substrates 11, 12, and the outflow
ports 21b are open on a lateral face on a side opposite to the side
of the lateral face where the introduction ports 21a are open. In
other words, the introduction ports 21a are open on a lateral face
of the channel structure 2 that faces downward, and the outflow
ports 21b are open on a lateral face of the channel structure 2
that faces upward.
[0037] In the present embodiment, to the first channels 21, a first
fluid having a low temperature is introduced from the introduction
ports 21a, respectively, and the first fluid thus introduced
thereto, as flowing toward the outflow port 21b, exchanges heat
with the high temperature second fluid flowing through the second
channels 22, whereby the temperature of the first fluid rises. In
the present embodiment, therefore, in a part closer to the
introduction port 21a in each first channel 21, the first fluid
flowing there has a lower temperature, and in a part closer to the
outflow port 21b in each first channel 21, the first fluid flowing
there has a relatively higher temperature.
[0038] The first channel 21 has an effective area 24 (see FIG. 2)
that contributes to heat exchange between the first fluid flowing
through the first channel 21 and the second fluid flowing through
the second channel 22. The effective area 24 is an area of the
first channel 21 that overlaps a range where the second channels 22
are provided in the second substrate 12 when viewed in the
lamination direction of the substrates 11, 12. More specifically,
when viewed in the lamination direction of the substrates 11, 12, a
small area at and near the introduction ports 21a and a small area
at and near the outflow ports 21b in the first channels 21 do not
overlap the range where the second channels 22 are provided in the
second substrate 12, and hence, the effective area 24 is equivalent
to an area of the first channel 21 from which these small areas are
excluded.
[0039] The effective area 24 is composed of the standard heat
transfer channel part 25 and the high heat transfer channel part
26, as illustrated in FIG. 2.
[0040] The standard heat transfer channel parts 25, in the present
embodiment, are straightly extending channels, that is, straight
channels, and extend in the longitudinal direction of the first
substrate 11. The standard heat transfer channel part 25 includes a
high temperature end 24a, which is one end of the effective area
24. The high temperature end 24a is a part through which the first
fluid flows that has a higher temperature as compared with the
first fluid flowing through a low temperature end 24b to be
described below. More specifically, the high temperature end 24a is
a part through which the first fluid flows that has the highest
temperature in the effective area 24. The standard heat transfer
channel part 25 is equivalent to a part of the effective area 24
having a predetermined length from the high temperature end 24a
toward the introduction port 21a.
[0041] The high heat transfer channel part 26 is equivalent to a
part of the effective area 24 other than the standard heat transfer
channel part 25. The high heat transfer channel part 26 includes a
low temperature end 24b that is an end of the effective area 24 on
a side opposite to the high temperature end 24a. The low
temperature end 24b is a part through which the first fluid flows
that has a lower temperature as compared with the first fluid
flowing through the high temperature end 24a. More specifically,
the low temperature end 24b is a part through which the first fluid
flows that has the lowest temperature in the effective area 24. The
high heat transfer channel part 26 is equivalent to a part of the
effective area 24 having a predetermined length from the low
temperature end 24b toward the high temperature end 24a.
[0042] Each high heat transfer channel part 26 has a channel shape
bent in such a manner that a channel length thereof per unit
distance of the end-to-end distance thereof is greater than a
channel length of the standard heat transfer channel part 25 per
unit distance of the end-to-end distance thereof. More
specifically, each high heat transfer channel part 26 is a wavy
type channel that meanders in such a manner as being deflected to
both sides with respect to, as the center, a meander center line 27
that is a straight line. The meander center line 27 is a line
extending in the same direction as the direction of the center line
of the channel width of the standard heat transfer channel part 25.
Further, the "end-to-end distance of the high heat transfer channel
part 26" refers to an end-to-end distance of the high heat transfer
channel part 26 in the direction along the meander center line 27.
Still further, the channel length of the high heat transfer channel
part 26 per unit distance of the end-to-end distance thereof is
equivalent to a value obtained by diving the entire channel length
of the high heat transfer channel part 26 by the end-to-end
distance of the high heat transfer channel part 26. Sill further,
the end-to-end distance of the standard heat transfer channel part
25 is equivalent to the end-to-end straight distance of the
standard heat transfer channel part 25. Still further, the channel
length of the standard heat transfer channel part 25 per unit
distance of the end-to-end distance thereof is equivalent to a
value obtained by dividing the entire channel length of the
standard heat transfer channel part 25 by the end-to-end distance
of the standard heat transfer channel part 25.
[0043] The high heat transfer channel part 26, as illustrated in
FIG. 4, includes a plurality of first straight parts 26a, a
plurality of second straight parts 26b, and a plurality of corner
parts 26C.
[0044] The first straight part 26a is a part that straightly
extends from a side of one end of the high heat transfer channel
part 26 toward a side of the other end thereof, intersecting with
the meander center line 27 obliquely from one side thereto to the
other side thereto. The second straight part 26b is a part that
straightly extends from a side of one end of the high heat transfer
channel part 26 toward a side of the other end thereof,
intersecting with the meander center line 27 obliquely from the
above-described other side to the above-described one side. The
first straight parts 26a and the second straight parts 26b are
alternately repeatedly arranged from a side of one end of the high
heat transfer channel part 26 toward a side of the other end
thereof.
[0045] The channel width center line of each of the first straight
parts 26a is tilted by an angle D with respect to the meander
center line 27. The channel width center line of each of the second
straight parts 26b is tilted with respect to the meander center
line 27, in an orientation opposite to the orientation where the
center line of the first straight part 26a is tilted, by the same
angle as the tilt angle of the center line of the first straight
part 26a, that is, the angle D. Each corner part 26C is formed in a
rounded shape, and connects an end of the first straight part 26a
and an end of the second straight part 26b that are opposite each
other.
[0046] By forming each of the first straight parts 26a, each of the
second straight parts 26b, and each of the corner parts 26C as is
described above, the high heat transfer channel part 26 is formed
in a zig-zag shape with respect to the meander center line 27, and
in an overall configuration, extends along the meander center line
27.
[0047] The end-to-end distance of the high heat transfer channel
part 26 in the direction along the meander center line 27 is given
as "L.sub.x", a pressure loss of the effective area 24 is given as
"f.sub.x", and a film coefficient of heat transfer of the first
fluid in the effective area 24 (hereinafter referred to simply as
the "heat transfer coefficient for the effective area 24) is given
as "j.sub.x". Then, the end-to-end distance L.sub.x of the high
heat transfer channel part 26, the pressure loss f.sub.x of the
effective area 24, and the heat transfer coefficient j.sub.x
satisfy the following relational expression (1):
(.alpha..times.f.sub.x/j.sub.x)<A.times.L.sub.x (1)
[0048] In the relational expression (1), a is a correction
coefficient defined by the following relational expression (2):
.alpha..times.f.sub.0/j.sub.0=1 (2)
[0049] In this relational expression (2), "f.sub.0" represents a
pressure loss of an effective area in a case where the entirety of
the effective area 24 is composed of a straight channel such as the
standard heat transfer channel part 25, and "j.sub.0" represents a
heat transfer coefficient for an effective area in a case where the
entirety of the effective area 24 is composed of a straight channel
such as the standard heat transfer channel part 25.
[0050] Further, in the above-described relational expression (1),
"A" represents a value defined by the following relational
expression (3):
A=(.alpha..times.f.sub.all/j.sub.all)/L.sub.all (3)
[0051] In this relational expression (3), "f.sub.all" represents a
pressure loss of an effective area in a case where the entirety of
the effective area 24 is formed in a bent channel shape like the
high heat transfer channel part 26, and "j.sub.all" represents a
heat transfer coefficient of an effective area in a case where the
entirety of the effective area 24 is formed in a bent channel shape
like the high heat transfer channel part 26. Further, "L.sub.all"
represents an end-to-end distance of the effective area 24, and is
equivalent to the distance between the low temperature end 24b and
the high temperature end 24a. The end-to-end distance of the
effective area 24, more specifically, refers to the end-to-end
distance of the effective area 24 in a direction along the channel
width center line of the standard heat transfer channel part 25 and
the meander center line 27 of the high heat transfer channel part
26.
[0052] In the present embodiment, the end-to-end distance of the
high heat transfer channel part 26 in the direction along the
meander center line 27 is set to 10% or more of the end-to-end
distance of the effective area 24 and 60% or less of the end-to-end
distance of the effective area 24. In addition, preferably, the
end-to-end distance of the high heat transfer channel parts 26 in
the direction along the meander center lines 27 is set to be a
distance smaller than the end-to-end distance of the standard heat
transfer channel parts 25, in other words, a distance smaller than
50% of the end-to-end distance of the effective area 24.
[0053] Further, each first channel 21 includes an introduction
channel part 29 and an outflow channel part 30, as illustrated in
FIG. 2.
[0054] The introduction channel part 29 is a small part at and near
the introduction port 21a of the first channel 21, and is
equivalent to a part of the first channel 21 that does not overlap
a range where the second channels 22 are provided on the second
substrate 12. In other words, the introduction channel part 29 is
equivalent to a part of the first channel 21 positioned on the
introduction port 21a side with respect to the effective area 24.
The introduction channel part 29 straightly extends from the
introduction port 21a, and is connected to the high heat transfer
channel part 26. The first fluid supplied to the introduction port
21a passes through the introduction channel part 29, and flows to
the high heat transfer channel part 26.
[0055] The outflow channel part 30 is a small part at and near the
outflow port 21b of the first channel 21, and is equivalent to a
part that does not overlap a range where the second channels 22 are
provided on the second substrate 12. In other words, the outflow
channel part 30 is equivalent to a part of the first channel 21
positioned on the outflow port 21b side with respect to the
effective area 24. The outflow channel part 30 straightly extends
in the same direction as the standard heat transfer channel part 25
on a line of extension of the standard heat transfer channel part
25, and is connected to the outflow port 21b. The first fluid that
has flown through the standard heat transfer channel part 25 passes
through the outflow channel part 30, and flows out of the outflow
port 21b.
[0056] On one of the plate surfaces of each second substrate 12
(see FIG. 3), a plurality of second grooves 32 that form the second
channels 22 are formed by etching. FIG. 3 principally illustrates
an outer shape of a collective configuration of the second grooves
32 formed on the second substrate 12, and the illustration of each
second groove 32 and each second channel 22 is omitted, except for
parts thereof at and near the upstream ends thereof and parts
thereof at and near the downstream ends thereof. The opening of
each second groove 32 on one of plate surfaces of the second
substrate 12 is sealed by the first substrate 11 stacked on the
plate surface, whereby a plurality of the second channels 22
arrayed on the one of the plate surfaces are formed.
[0057] In the present embodiment, in each second channel 22, a part
that straightly extends from one side to the other side in the
transverse direction of the second substrate 12, and a part that is
turned back therefrom and straightly extends from the
above-described other side to the above-described one side, are
repeatedly provided, so that the second channel 22 as a whole is in
a largely wavy type shape.
[0058] Each second channel 22 has, at one end thereof, an
introduction port 22a through which the second fluid is introduced,
and at an end on a side opposite to the introduction port 22a, an
outflow port 22b through which the second fluid having passed
through the second channel 22 is allowed to flow out.
[0059] The introduction ports 22a are open on a lateral face of the
channel structure 2, which is formed with end faces on one side in
the transverse direction of the substrates 11, 12. In the present
embodiment, the introduction ports 22a are open on a lateral face
of the channel structure 2 that faces to one side in the horizontal
direction, and are arranged at and near an upper end art of the
lateral face. In other words, the introduction ports 22a are
arranged closer to the outflow ports 21b of the first channels
21.
[0060] The outflow ports 22b are open on a lateral face of the
channel structure 2 on a side opposite to the lateral face of the
channel structure 2 where the introduction ports 22a are open. In
the present embodiment, the outflow ports 22b are arranged at and
near a lower end part of the lateral face of the channel structure
2 where the outflow ports 22b are open. In other words, the outflow
ports 22b are arranged closer to the introduction ports 21a of the
first channel 21.
[0061] In the present embodiment, to the second channels 22, the
second fluid having a temperature higher than the first fluid is
introduced from the introduction ports 22a, and the second fluid
thus introduced thereto, as flowing to the outflow port 22b,
exchanges heat with the first fluid having a low temperature
flowing through the first channels 21, whereby the temperature of
the second fluid drops.
[0062] The first supply header 3 (see FIGS. 1 and 2) distributes
and supplies the first fluid to all of the respective introduction
ports 21a of the first channels 21 provided in the channel
structure 2. The first supply header 3 is attached to one of the
lateral faces of the channel structure 2 where the introduction
ports 21a of the first channels 21 are open. The first supply
header 3 collectively covers all of the introduction ports 21a that
are open on the lateral face of the channel structure 2 to which
the first supply header 3 is attached. This allows the space in the
first supply header 3 to communicate with each introduction port
21a. To the first supply header 3, a supply pipe (not illustrated)
is connected, so that the first fluid supplied through the supply
pipe to the first supply header 3 is distributed from the space in
the first supply header 3 to the introduction ports 21a.
[0063] The first discharge header 5 (see FIGS. 1 and 2) receives
the first fluid flowing out of all of the outflow ports 21b of the
first channels 21 provided in the channel structure 2. The first
discharge header 5 is attached to one of the lateral faces of the
channel structure 2 where the outflow ports 21b of the first
channels 21 are open. The first discharge header 5 collectively
covers all of the outflow ports 21b that are open on the lateral
face of the channel structure 2 to which the first discharge header
5 is attached. This allows the space in the first discharge header
5 to communicate with each outflow port 21b. To the first discharge
header 5, a discharge pipe (not illustrated) is connected, so that
the first fluid having flown out of each outflow port 21b to the
space in the first discharge header 5 is discharged through this
discharge pipe.
[0064] The second supply header 4 (see FIGS. 1 and 3) distributes
and supplies the second fluid to all of the introduction ports 22a
of the second channels 22 provided in the channel structure 2. The
second supply header 4 is attached to the one of the lateral faces
of the channel structure 2 where the introduction ports 22a of the
second channels 22 are open, and collectively covers all of the
introduction ports 22a that are open on the lateral face. This
allows the space in the second supply header 4 to communicate with
each introduction port 22a. To the second supply header 4, a supply
pipe (not illustrated) is connected, so that the second fluid
having been supplied through the supply pipe to the second supply
header 4 is distributed from the space in the second supply header
4 to the introduction ports 22a.
[0065] The second discharge header 6 (see FIGS. 1 and 3) receives
the second fluid flowing out of all of the outflow ports 22b of the
second channels 22 provided in the channel structure 2. The second
discharge header 6 is attached to one of the lateral faces of the
channel structure 2 where the outflow ports 22b of the second
channels 22 are open, and collectively covers all of the outflow
ports 22b that are open on the lateral face to which the second
discharge header 6 is attached. This allows the space in the second
discharge header 6 to communicate with each outflow port 22b. To
the second discharge header 6, a discharge pipe (not illustrated)
is connected, so that the second fluid having flown out of the each
outflow port 22b to the space in the second discharge header 6 is
discharged through this discharge pipe.
[0066] In the present embodiment, a heat exchange method for heat
exchange between the first fluid and the second fluid is performed
by using the heat exchanger 1 having a configuration as described
above. For example, in order to raise the temperature of the first
fluid, a heat exchange method for heat exchange between the first
fluid and a hot medium (heat medium) as the second fluid having a
temperature higher than that of the first fluid is performed.
[0067] More specifically, the first fluid is supplied through the
supply pipe to the first supply header 3 so that the first fluid is
supplied from the first supply header 3 to each first channel 21,
whereby the first fluid is caused to flow through each first
channel 21 from the high heat transfer channel part 26 toward the
standard heat transfer channel part 25. On the other hand, the hot
medium as the second fluid is supplied through the supply pipe to
the second supply header 4 so that the hot medium is supplied from
the second supply header 4 to each second channel 22, whereby the
hot medium is caused to flow through each second channel 22. By
doing so, heat exchange is caused to occur between the first fluid
flowing through the first channels 21 and the hot medium flowing
through the second channels 22, whereby the temperature of the
first fluid is raised.
[0068] In the heat exchanger 1 according to the present embodiment,
the effective area 24 of the first channel 21 includes the high
heat transfer channel part 26, and this high heat transfer channel
part 26 is a wavy type channel that is bent in such a manner that
the channel length of the high heat transfer channel part 26 per
unit distance of the end-to-end distance thereof is greater than
the channel length of the standard heat transfer channel part 25
per unit distance of the end-to-end distance thereof. This causes
fluid turbulence at bent portions of the high heat transfer channel
part 26, which improves heat transfer performance.
[0069] Further, since the bent channel shape of the high heat
transfer channel part 26 makes it possible to suppress the increase
in the end-to-end distance thereof, in the present embodiment, it
is possible to prevent the increase in the size of the heat
exchanger 1. In the present embodiment, therefore, it is possible
to improve the heat transfer performance while preventing the
increase in the size of the heat exchanger 1.
[0070] Still further, in the heat exchanger 1 according to the
present embodiment, the standard heat transfer channel part 25 is a
part that includes the high temperature end 24a of the effective
area 24, and the high heat transfer channel part 26 is a part that
is equivalent to a part of the effective area 24 other than the
standard heat transfer channel part 25 and includes the low
temperature end 24b of the effective area 24. This makes it
possible to reduce the amplitude of the increase in the pressure
loss in the effective area 24 of the first channel 21. In other
words, since a pressure loss of a channel is proportional to a flow
rate of a fluid flowing through the channel, the configuration in
which a part of the effective area 24 through which the first fluid
having a low temperature and hence having a relatively higher
density flows and that includes the low temperature end 24b at
which the first fluid comes to have a smaller flow rate is formed
with the high heat transfer channel part 26, and the other part of
the effective area 24 that includes the high temperature end 24a is
the standard heat transfer channel part 25, enables to reduce the
amplitude of the increase in the pressure loss, even if the
pressure loss is increased by the high heat transfer channel part
26 thus bent. It is therefore possible to prevent excessive
pressure loss from occurring in the first channels 21.
[0071] Still further, since the first fluid has a higher density
and hence has a smaller flow rate at and near the low temperature
end of the effective area as described above, the heat transfer
performance is relatively low in this part. In the present
embodiment, however, since the high heat transfer channel part 26
includes the low temperature end 24b, the relatively low heat
transfer performance at and near the low temperature end 24b can be
improved by the high heat transfer channel part 26. This makes it
possible to achieve the high heat transfer performance with a good
balance in the entirety of the effective areas 24 of the first
channels 21.
[0072] Still further, in the present embodiment, since the high
heat transfer channel part 26 is a wavy type channel, it is
possible to increase the channel length of the high heat transfer
channel part 26 so as to increase the heat transfer area, while
suppressing the increase in the end-to-end distance of the high
heat transfer channel part 26, as compared with a configuration in
which a high heat transfer channel part is simply curved. In other
words, it is possible to improve the heat transfer performance more
effectively, while suppressing the increase in the end-to-end
distance of the high heat transfer channel part 26. Still further,
since the standard heat transfer channel part 25 is a straight
channel, the pressure loss in the standard heat transfer channel
part 25 can be reduced, as compared with a case where the standard
heat transfer channel part has a curved channel shape or a bent
channel shape. To this extent, the increase in the pressure loss in
the effective area 24 can be suppressed.
[0073] Still further, in the present embodiment, since the
end-to-end distance of the high heat transfer channel part 26 in
the direction along the meander center line 27 is set to 60% or
less of the end-to-end distance of the effective area 24, the
pressure loss in the effective area 24 can be suppressed to less
than twice the pressure loss in an effective area in a case where
the entirety of the effective area is a straight channel, which
sufficiently satisfies the requirements regarding the pressure loss
of the heat exchanger for practical application.
[0074] Still further, in the present embodiment, the end-to-end
distance of the high heat transfer channel part 26 in the direction
along the meander center line 27 is set to 10% or more of the
end-to-end distance of the effective area 24.
[0075] In a heat exchanger, generally, a heat transfer area is set
with a margin with respect to the theoretical value of a heat
transfer area determined by computation, with consideration given
to a possibility that the heat transfer performance decreases due
to dirt (deposit) in channels and/or fluid conditions such as
temperature and pressure of fluid. In this case, generally, a heat
transfer area about 5% to 10% larger than the theoretical value of
the heat transfer area is set. In contrast, with such a setting
that the end-to-end distance of the high heat transfer channel part
26 in the direction along the meander center line 27 is set to 10%
or more of the end-to-end distance of the effective area 24, as is
the case with the present embodiment, a heat transfer area that can
sufficiently compensate the reductions in the heat transfer
performance that are generally expected due to dirt and/or fluid
conditions in the effective area 24 can be ensured in the effective
area 24.
[0076] Still further, in a more preferable configuration of the
present embodiment, the end-to-end distance of the high heat
transfer channel part 26 in the direction along the meander center
line 27 is set to be smaller than the end-to-end distance of the
standard heat transfer channel part 25. In this case, the
improvement of the heat transfer performance and the prevention of
excessive increase in the pressure loss can be achieved with a good
balance, while the increase in the size of the heat exchanger 1 can
be prevented.
[0077] More specifically, if it is assumed that the end-to-end
distance of the high heat transfer channel part 26 is greater than
the end-to-end distance of the standard heat transfer channel part
25, the effect of improvement of the heat transfer performance
owing to the high heat transfer channel parts 26 would increase,
but on the other hand, the amplitude of the increase in the
pressure loss would be expanded. To suppress the increase in the
pressure loss, for example, the number of the first channels 21
provided in the channel structure 2 may be increased, but this
necessarily increases the size of the channel structure 2. In other
words, this necessarily increases the size of the heat exchanger 1.
In contrast, with the configuration in which the end-to-end
distance of the high heat transfer channel part 26 is smaller than
the end-to-end distance of the standard heat transfer channel part
25, the improvement of the heat transfer performance and the
prevention of excessive increase in the pressure loss can be
achieved with a good balance, which results in that the increase in
the size of the heat exchanger 1 can be prevented.
[0078] The following description describes results of simulation
performed in order to examine the effects achieved by the heat
exchanger 1 of the present embodiment, that is, the effects
achieved by the configuration in which parts of the effective areas
24 that are other than the standard heat transfer channel parts 25
and that include the low temperature ends 24b of the effective
areas 24 are the high heat transfer channel parts 26.
[0079] First of all, as examples corresponding to the present
embodiment, Examples 1 to 4 were set in which only an end-to-end
distance of the high heat transfer channel part 26 as a wavy type
channel, that is, an end-to-end distance of the high heat transfer
channel part 26 in the direction along the meander center line 27,
was varied, as follows.
Example 1
[0080] The end-to-end distance of each high heat transfer channel
part 26 was set to a distance equivalent to 20% of the end-to-end
distance of the effective area 24, and a part of each effective
area 24 other than the high heat transfer channel part 26 was the
standard heat transfer channel part 25, which was a straight
channel.
Example 2
[0081] The end-to-end distance of each high heat transfer channel
part 26 was set to a distance equivalent to 40% of the end-to-end
distance of the effective area 24, and a part of each effective
area 24 other than the high heat transfer channel part 26 was the
standard heat transfer channel part 25, which was a straight
channel.
Example 3
[0082] The end-to-end distance of each high heat transfer channel
part 26 was set to a distance equivalent to 60% of the end-to-end
distance of the effective area 24, and a part of each effective
area 24 other than the high heat transfer channel part 26 was the
standard heat transfer channel part 25, which was a straight
channel.
Example 4
[0083] The end-to-end distance of each high heat transfer channel
part 26 was set to a distance equivalent to 80% of the end-to-end
distance of the effective area 24, and a part of each effective
area 24 other than the high heat transfer channel part 26 was the
standard heat transfer channel part 25, which was a straight
channel.
[0084] In addition, as comparative examples for comparison of
effects with the examples, Comparative Examples 1 to 6 described
below were set.
Comparative Example 1
[0085] The entirety of each effective area 24 was a straight
channel.
Comparative Example 2
[0086] A part of each effective area 24 ranging from the high
temperature end 24a toward the low temperature end 24b which was
equivalent to 20% of the end-to-end distance of the effective area
24, was a wavy type channel corresponding to the high heat transfer
channel part 26, and the other part of each effective area 24 was a
straight channel.
Comparative Example 3
[0087] A part of each effective area 24 ranging from the high
temperature end 24a toward the low temperature end 24b, which was
equivalent to 40% of the end-to-end distance of the effective area
24, was a wavy type channel corresponding to the high heat transfer
channel part 26, and the other part of each effective area 24 was a
straight channel.
Comparative Example 4
[0088] A part of each effective area 24 ranging from the high
temperature end 24a toward the low temperature end 24b, which was
equivalent to 60% of the end-to-end distance of the effective area
24, was a wavy type channel corresponding to the high heat transfer
channel part 26, and the other part of each effective area 24 was a
straight channel.
Comparative Example 5
[0089] A part of each effective area 24 ranging from the high
temperature end 24a toward the low temperature end 24b, which was
equivalent to 80% of the end-to-end distance of the effective area
24, was a wavy type channel corresponding to the high heat transfer
channel part 26, and the other part of each effective area 24 was a
straight channel.
Comparative Example 6
[0090] The entirety of each effective area 24 was a wavy type
channel corresponding to the high heat transfer channel part
26.
[0091] As to each of Examples 1 to 4 and Comparative Examples 1 to
6 described above, a pressure loss and a heat transfer coefficient
in the effective areas 24 as a whole were calculated by simulation.
Here, the pressure loss and the heat transfer coefficient were
calculated, with physical properties and flow rates of the fluid
flowing through the channels, and other conditions being set to be
equal in all of the examples and the comparative examples.
[0092] Table 1 shown below indicates, regarding each of Examples 1
to 4, calculation results of the pressure loss f and the heat
transfer coefficient j, and a ratio f/j of a pressure loss f to the
heat transfer coefficient j. Further, Table 2 shown below
indicates, regarding each of Comparative Examples 1 to 6,
calculation results of the pressure loss f and the heat transfer
coefficient j, and the ratio f/j of the pressure loss f to the heat
transfer coefficient j. In each table shown below, the value of the
pressure loss calculated regarding Comparative Example 1 is assumed
to be 100, and values of the pressure loss calculated regarding
Examples 1 to 4 and Comparative Examples 2 to 6 are expressed as
values with respect to the value of the pressure loss of
Comparative Example 1. Besides, in each table shown below, the
value of the heat transfer coefficient calculated regarding
Comparative Example 1 is assumed to be 100, and values of the heat
transfer coefficient calculated regarding Examples 1 to 4 and
Comparative Examples 2 to 6 are expressed as values with respect to
the value of the heat transfer coefficient of Comparative Example
1.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 f
128 160 195 234 j 123 147 170 191 f/j 104% 109% 115% 123%
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative
Comparative Comparative Comparative example 1 example 2 example 3
example 4 example 5 example 6 f 100 142 181 216 248 276 j 100 120
142 165 188 211 f/j 100% 118% 127% 131% 131% 131%
[0093] Further, FIG. 6 illustrates, regarding each of Examples 1 to
4 denoted by "E1" to "E4", and Comparative Examples 1 to 6 denoted
by "R1" to "R6", correlation between the ratio of the end-to-end
distance of the high heat transfer channel part to the end-to-end
distance of the effective area and the calculated pressure loss f.
FIG. 7 illustrates, regarding each of Examples 1 to 4 denoted by
"E1" to "E4", and Comparative Examples 1 to 6 denoted by "R1" to
"R6", correlation between the ratio of the end-to-end distance of
the high heat transfer channel part to the end-to-end distance of
the effective area and the calculated heat transfer coefficient j.
Still further, FIG. 8 illustrates, regarding each of Examples 1 to
4 denoted by "E1" to "E4", and Comparative Examples 1 to 6 denoted
by "R1" to "R6", correlation between the ratio of the end-to-end
distance of the high heat transfer channel part to the end-to-end
distance of the effective area and the calculated ratio f/j of the
pressure loss f to the heat transfer coefficient j.
[0094] With reference to Tables 1 and 2 as well as FIG. 7, the heat
transfer coefficients j are compared between examples having the
same end-to-end distance of the high heat transfer channel part,
among E1 to E4 of Examples 1 to 4 and R2 to R5 of Comparative
Examples 2 to 5. Then, it is clear that Examples had slightly
greater heat transfer coefficients j as compared with Comparative
Examples. On the other hand, with reference to Tables 1 and 2 as
well as FIG. 6, the pressure losses f are compared between examples
having the same end-to-end distance of the high heat transfer
channel part among E1 to E4 of Examples 1 to 4 and R2 to R5 of
Comparative Examples 2 to 5. Then, it is clear that Examples had
significantly smaller pressure losses f as compared with
Comparative Examples.
[0095] Further, with reference to Tables 1 and 2 as well as FIG. 8,
the ratios f/j of the pressure loss f to the heat transfer
coefficient j are compared between examples having the same
end-to-end distance of the high heat transfer channel part among E1
to E4 of Examples 1 to 4 and R2 to R5 of Comparative Examples 2 to
5. Then, it is clear that Examples had significantly smaller ratios
f/j as compared with Comparative Examples.
[0096] What is described above clarifies the following: in a case
where the parts including the low temperature ends of the effective
areas are high heat transfer channel parts (wavy type channels) as
is the case with Examples, the pressure loss increases as compared
with a case where no high heat transfer channel part is provided in
the effective areas; but excellent heat transfer performance can be
achieved, while the amplitude of the increase in the pressure loss
can be reduced, as compared with a case where a part of the
effective area having a distance equal to the end-to-end distance
of the high heat transfer channel part from the high temperature
end of the effective area is the high heat transfer channel part
(wavy type channel), as is the case with each Comparative
Example.
[0097] Further, a reference line S illustrated in FIG. 8 is a
straight line extended between the point of R1 of Comparative
Example 1 and the point of R6 of Comparative Example 6, and this
line can be used as a reference for determining whether or not the
disadvantage of the increase in the pressure loss in the effective
area 24 exceeds the advantage of the increase in the heat transfer
coefficient for the effective area 24, which is achieved by the
increase in the end-to-end distance of the high heat transfer
channel part 26. More specifically, in a case where the point
specified by the relationship between the end-to-end distance of
the high heat transfer channel part 26 and the above-described
ratio f/j is positioned in a range below the reference line S, this
indicates that the disadvantage of the increase in the pressure
loss in the effective area 24 does not exceed the advantage of the
increase in the heat transfer coefficient for the effective area
24. Since a comprehensive heat transfer coefficient, which is a
factor for determining the size of the heat exchanger 1, is
determined according to the film coefficient of heat transfer in
the first channel 21 of the first fluid flowing through the first
channel 21 and the film coefficient of heat transfer in the second
channel 22 of the second fluid flowing through the second channel
22, the comprehensive heat transfer coefficient of the heat
exchanger 1 can be improved by the increase in the film coefficient
of heat transfer of the first fluid in the effective area 24, and
to this extent, the heat exchanger 1 can be made compact.
[0098] In a case where the point specified by the relationship
between the end-to-end distance of the high heat transfer channel
part 26 and the above-described ratio f/j is positioned in a range
above the reference line S, this indicates that the disadvantage of
the increase in the pressure loss in the effective area 24 exceeds
the advantage of the increase in the heat transfer coefficient for
the effective area 24. The range below the reference line S
corresponds to the range defined by the relational expression (1),
and the tilt of this reference line S corresponds to the value of A
in the relational expression (1).
[0099] According to FIG. 8, E1 to E4 of Examples 1 to 4 are
positioned in the range below the reference line S, and it is
therefore clear that in the cases of E1 to E4 of Examples 1 to 4,
the disadvantage of the increase in the pressure loss in the
effective area 24 does not exceed the advantage of the increase in
the heat transfer coefficient for the effective area 24, which
indicates that the relationship satisfies the above-described
expression (1). On the other hand, R2 to R5 of Comparative Examples
2 to 5 are positioned in the range above the reference line S, and
it is therefore clear that in the cases of R2 to R5 of Comparative
Examples 2 to 5, the disadvantage of the increase in the pressure
loss in the effective area 24 exceeds the advantage of the increase
in the heat transfer coefficient for the effective area 24, which
indicates that the relationship does not satisfy the
above-described relational expression (1).
[0100] Further, in a heat exchanger, a pressure loss in a channel
is a very important factor in view of practical application. For
example, a compressor for compressing fluid is included in a supply
device for supplying fluid to a channel of a heat exchanger in some
cases, and when in such a case the pressure loss in the channels of
the heat exchanger increases, it becomes necessary to boost the
pressure of the fluid supplied to the channels, which causes the
power of the compressor necessary for boosting the pressure of the
fluid to increase, which results in an increase in the energy
consumption. Even if providing high heat transfer channel parts in
channels inevitably results in an increase in pressure loss,
therefore, it is important to reduce the amplitude of the increase.
In a case where providing high heat transfer channel parts in the
effective areas of the first channels causes the pressure loss in
the effective areas to increase to twice or more the value of
pressure loss in a case where the entire effective areas are
straight channels, such first channels cannot be used in view of
practical application of the heat exchanger.
[0101] As is clear from Table 1, in Examples 1 to 3 among Examples
1 to 4, the pressure loss f can be suppressed to less than 200,
which is a value twice the pressure loss f of Comparative Example
1. It is therefore clear that, in a case where the end-to-end
distance of the high heat transfer channel parts including the low
temperature ends of the effective area is 60% or less of the
end-to-end distance of the effective areas, the first channels are
sufficiently able to be adopted for practical application, in view
of pressure loss.
[0102] The heat exchanger according to the present invention is not
necessarily limited to a heat exchanger according to the
above-described embodiment. As a configuration of the heat
exchanger according to the present invention, the following
configuration, for example, can be adopted.
[0103] As a bent channel shape of the high heat transfer channel
part, for example, a corrugated shape formed with continuous
curves, such as a sine curve, may be used. Further, corners of a
zig-zag shape of the high heat transfer channel part do not have to
be rounded, but may be angular.
[0104] Further, the lengths of the first straight part and the
second straight part of the high heat transfer channel part in the
above-described embodiment, and the tilt angle D formed between the
first straight part or the second straight part and the wavy type
center line, can be set appropriately. More specifically, the
lengths and/or the tilt angle D of the first and second straight
parts may be by appropriately increased/decreased, and thereby the
amplitude of the zig-zag of the high heat transfer channel part or
the repetition period of zig-zag thereof may be appropriately
changed. Further, the curvature of the rounded corner parts may be
appropriately changed.
[0105] Still further, the channel shape of the standard heat
transfer channel part is not limited to the straight shape, and may
be any one as long as the channel shape is such that the channel
length of the standard heat transfer channel part per unit distance
of the end-to-end distance (straight distance) thereof is smaller
than the channel length of the high heat transfer channel part per
unit distance of the end-to-end distance thereof. For example, the
channel shape of the standard heat transfer channel part may be a
gradually curved shape or the like.
[0106] Still further, the second channel does not necessarily have
a meander shape, and the overall shape thereof may be a straight
channel shape or another channel shape, for example.
[0107] Still further, the fluids flowing through the channels in
the heat exchanger are necessarily limited to two types of fluids,
i.e., the first fluid and the second fluid. More specifically,
three or more types of the fluids may be caused to flow through
respective channels in the heat exchanger, so that heat exchange
occurs among the fluids.
[0108] Still further, the configuration of the fluid is not
necessarily limited to a configuration in which the first fluid
flowing through the first channels is a low temperature fluid and
the second fluid flowing through the second channels is a high
temperature fluid. More specifically, a first fluid having a high
temperature may be caused to flow through the first channels, and a
second fluid having a low temperature may be caused to flow through
the second channels. For example, such a heat exchange method may
be performed that in order to lower the temperature of the first
fluid, heat exchange is performed between the first fluid and a
refrigerant as a second fluid having a temperature lower than that
of the first fluid.
[0109] In this case, the first discharge header 5 is used as a
first supply header to which a supply pipe for supplying the first
fluid is connected, and the first supply header 3 is used as a
first discharge header that receives the first fluid flowing out of
the first channels 21. Further, the second discharge header 6 is
used as a second supply header to which a supply pipe for supplying
the refrigerant is connected, and the second supply header 4 is
used as a second discharge header for receiving the refrigerant
flowing out of the second channels 22. Still further, in this case,
the introduction ports 21a of the first channels 21 serve as
outflow ports through which the first fluid is allowed to flow out,
and the outflow ports 21b of the first channels 21 serve as
introduction ports through which the first fluid is introduced.
Still further, the introduction ports 22a of the second channels 22
serve as outflow ports through which the second fluid is allowed to
flow out, and the outflow ports 22b of the second channels 22 serve
as introduction ports through which the second fluid is
introduced.
[0110] Then, the first fluid is supplied through the supply pipe to
the first supply header and then the first fluid is supplied from
the first supply header to each first channel 21, whereby, to each
first channel 21, the first fluid is caused to flow from the
standard heat transfer channel part 25 toward the high heat
transfer channel part 26. In other words, the first fluid is caused
to flow through each first channel 21 in an orientation opposite to
the orientation in the case of the above-described embodiment. On
the other hand, the refrigerant as the second fluid is supplied
through the supply pipe to the second supply header, and then is
supplied from the second supply header to each second channel 22,
whereby the refrigerant is caused to flow through each second
channel 22 in an orientation opposite to the orientation in which
the second fluid is caused to flow in the above-described
embodiment. This causes heat exchange to occur between the first
fluid flowing through the first channels 21 and the refrigerant
flowing through the second channels 22, thereby to lower the
temperature of the first fluid. [0111] 1 Heat exchanger [0112] 2
Channel structure [0113] 11 First substrate (first layer) [0114] 12
Second substrate (second layer) [0115] 21 First channel [0116] 22
Second channel [0117] 24 Effective area [0118] 24a High temperature
end [0119] 24b Low temperature end [0120] 25 Standard heat transfer
channel part [0121] 26 High heat transfer channel part [0122] 27
Meander center line
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