U.S. patent application number 13/706985 was filed with the patent office on 2013-06-20 for heat exchanger.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is Mitsubishi Heavy Industries, Ltd.. Invention is credited to Satoshi Hiraoka, Kenji Kirihara, Masahiko Nagai.
Application Number | 20130152585 13/706985 |
Document ID | / |
Family ID | 48522154 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130152585 |
Kind Code |
A1 |
Hiraoka; Satoshi ; et
al. |
June 20, 2013 |
HEAT EXCHANGER
Abstract
Thermal expansion of U-shaped tubes is permitted to prevent
damage to it. A heat exchanger includes a casing having a first
fluid inlet provided at one end thereof and a first fluid outlet
provided at the other end thereof, the first fluid inlet and the
first fluid outlet being connected to each other via a first flow
path extending in a straight line from the first fluid inlet to the
first fluid outlet; and multiple tube sets accommodated inside the
casing so that a fluid that flows through the interiors thereof
undergoes heat exchange with a fluid that flows via the first flow
path. The multiple tube sets are arrayed along the first flow path,
and multiple U-shaped tubes constituting the tube sets are fixed
only to a tube plate disposed parallel to the first flow path and
located at both ends of the U-shaped tubes.
Inventors: |
Hiraoka; Satoshi; (Tokyo,
JP) ; Kirihara; Kenji; (Tokyo, JP) ; Nagai;
Masahiko; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Heavy Industries, Ltd.; |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
48522154 |
Appl. No.: |
13/706985 |
Filed: |
December 6, 2012 |
Current U.S.
Class: |
60/641.8 ;
165/172; 165/173 |
Current CPC
Class: |
Y02E 10/46 20130101;
F28D 7/06 20130101; F28D 21/001 20130101; F28F 2265/26 20130101;
F03G 6/064 20130101; F28F 1/00 20130101; F28F 9/005 20130101 |
Class at
Publication: |
60/641.8 ;
165/172; 165/173 |
International
Class: |
F28F 1/00 20060101
F28F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2011 |
JP |
2011-274785 |
Claims
1. A heat exchanger comprising: a casing having a first fluid inlet
provided at one end thereof and a first fluid outlet provided at
the other end thereof opposite the one end, the first fluid inlet
and the first fluid outlet being connected to each other via a
first flow path extending in a straight line from the first fluid
inlet to the first fluid outlet; and multiple tube sets
accommodated inside the casing so that a fluid that flows through
the interiors thereof undergoes heat exchange with a fluid that
flows via the first flow path, wherein the multiple tube sets are
arrayed along the first flow path, and multiple U-shaped tubes
constituting the tube sets are fixed only to a tube plate disposed
parallel to the first flow path and located at both ends of the
U-shaped tubes.
2. A heat exchanger according to claim 1, wherein a partition plate
separating straight portions and turning portions of the U-shaped
tubes is disposed parallel to the first flow path, and gaps are
provided between the inner circumferential surfaces of tube holes
that are provided in the partition plate and through which the
straight portions of the U-shaped tubes are inserted and the outer
circumferential surfaces of the U-shaped tubes.
3. A heat exchanger according to claim 1, wherein a header that
communicates between the outlet end of a tube set located on the
upstream side and the inlet end of a tube set located on the
downstream side thereof is provided.
4. A heat exchanger according to claim 1, wherein the U-shaped
tubes are fixed to the tube plate by expanding the ends of the
U-shaped tubes inserted through the tube holes.
5. A solar-heat gas-turbine power generating system comprising a
heat exchanger according to claim 1 as a repeater that preheats a
high-pressure compressible working fluid ejected from a compressor
through heat exchange with a high-temperature compressible working
fluid discharged from a turbine.
Description
TECHNICAL FIELD
[0001] This application is based on Japanese Patent Application No.
2011-274785, the contents of which are incorporated herein by
reference.
[0002] The present invention relates to heat exchangers. More
specifically, the present invention relates to a heat exchanger
that is suitable as a repeater of a solar-heat gas turbine driven
with a compressible working fluid, such as air, heated by using
sunlight.
BACKGROUND ART
[0003] Recently, in order to solve environmental problems, such as
global warming, there is interest in natural energy, such as
sunlight and wind power.
[0004] Accordingly, there have been proposals for solar-heat gas
turbines that are driven by generating a high-temperature,
high-pressure compressible working fluid by means of solar heat by
using sunlight, which is a type of natural energy, and solar-heat
gas-turbine power generating units that generate power by driving a
generator by means of such a solar-heat gas turbine.
[0005] Known examples of such a solar-heat gas turbine and a
solar-heat gas-turbine power generating unit are disclosed in
Patent Document 1.
CITATION LIST
Patent Literature
[0006] {PTL 1}
[0007] Japanese Unexamined Patent Application, Publication No.
2010-281272
SUMMARY OF INVENTION
Technical Problem
[0008] In a solar-heat gas turbine, the temperature of the interior
of a reheater that preheats a high-pressure compressible working
fluid ejected from a compressor through heat exchange with a
high-temperature compressible working fluid discharged from a
turbine becomes very high since the high-temperature compressible
working fluid discharged from the turbine passes through the
interior. Thus, for example, when the heat exchanger disclosed in
Japanese Unexamined Patent Application, Publication No. 2001-147093
is adopted as a reheater of a solar-heat gas turbine, thermal
expansion of the U-shaped tubes 18a in the lengthwise direction is
restrained by the U-shaped-tube fixing plate 19, possibly damaging
the U-shaped tubes 18a.
[0009] The present invention has been made in view of the problem
described above, and it is an object thereof to provide a heat
exchanger that permits thermal expansion of U-shaped tubes in the
lengthwise direction, thus serving to prevent damage to the
U-shaped tubes, that causes less heat dissipation, thus serving to
improve the heat efficiency, that is easy to inspect and repair,
and that can produce compressed air with less pulsation of
temperature.
Solution to Problem
[0010] In order to solve the problem described above, the present
invention employs the following solutions.
[0011] A heat exchanger according to a first aspect of the present
invention is a heat exchanger including a casing having a first
fluid inlet provided at one end thereof and a first fluid outlet
provided at the other end thereof opposite the one end, the first
fluid inlet and the first fluid outlet being connected to each
other via a first flow path extending in a straight line from the
first fluid inlet to the first fluid outlet; and multiple tube sets
accommodated inside the casing so that a fluid that flows through
the interiors thereof undergoes heat exchange with a fluid that
flows via the first flow path, wherein the multiple tube sets are
arrayed along the first flow path, and multiple U-shaped tubes
constituting the tube sets are fixed only to a tube plate disposed
parallel to the first flow path and located at both ends of the
U-shaped tubes.
[0012] In the heat exchanger according to the first aspect of the
present invention, the U-shaped tubes are fixed only at a single
side thereof to tube holes that are provided in the tube plate and
through which both ends of the U-shaped tubes are inserted.
[0013] Thus, thermal expansion of the U-shaped tubes in the
lengthwise direction is permitted, which serves to prevent damage
to the U-shaped tubes.
[0014] Furthermore, in the heat exchanger according to the present
invention, the first fluid inlet and the first fluid outlet are
connected to each other via a single path, namely, the first flow
path extending in a straight line from the first fluid inlet to the
first fluid outlet.
[0015] Thus, pressure loss in the first flow path can be reduced.
Furthermore, it is possible to make a large amount of fluid flow
via the first flow path, which serves to improve the heat exchange
efficiency.
[0016] In the above heat exchanger, more preferably, a partition
plate separating straight portions and turning portions of the
U-shaped tubes is disposed parallel to the first flow path, and
gaps are provided between the inner circumferential surfaces of
tube holes that are provided in the partition plate and through
which the straight portions of the U-shaped tubes are inserted and
the outer circumferential surfaces of the U-shaped tubes.
[0017] In the heat exchanger constructed as described above, a
space is formed outside the first flow path by the partition plate
and the casing, causing a portion of the fluid passing via the
first flow path to stagnate in that space.
[0018] Thus, the fluid present in the space acts as a heat
insulating layer. This serves to maintain the temperature of the
fluid passing via the first flow path, which serves to improve the
heat exchange efficiency even further.
[0019] In the above heat exchanger, more preferably, a header that
communicates between the outlet end of a tube set located on the
upstream side and the inlet end of a tube set located on the
downstream side thereof is provided.
[0020] In the heat exchanger constructed as described above, the
fluid that has undergone heat exchange with the fluid passing via
the first flow path while passing through a tube set located on the
upstream side is guided to the tube set located on the downstream
side thereof so that the fluid then undergoes heat exchange with
the fluid passing via the first flow path. This serves to improve
the heat exchange efficiency even further.
[0021] In the above heat exchanger, more preferably, the U-shaped
tubes are fixed to the tube plate by expanding the ends of the
U-shaped tubes inserted through the tube holes.
[0022] In the heat exchanger constructed as described above, the
ends of the U-shaped tubes are fixed to the tube plate just by tube
expansion, without employing welding.
[0023] Thus, the combination of the material of the tube plate and
the material of the U-shaped tubes, which must be taken into
account when welding, need not be considered here, allowing free
choice of the material of the tube plate and the material of the
U-shaped tubes.
[0024] A solar-heat gas-turbine power generating system according
to a second aspect of the present invention includes any one of the
above heat exchangers as a repeater.
[0025] In the solar-heat gas-turbine power generating system
according to the second aspect of the present invention, since the
heat exchanger that permits thermal expansion of the U-shaped tubes
in the lengthwise direction, which serves to prevent damage to the
U-shaped tubes, is included as the reheater, the reliability of the
solar-heat gas-turbine power generating system can be improved.
[0026] Furthermore, in the solar-heat gas-turbine power generating
system according to the present invention, since the heat exchanger
having a high heat exchange efficiency is included as the reheater,
it is possible to further boost the temperature of the compressible
working fluid introduced into the turbine. This serves to improve
the cycle efficiency of the heat cycle.
Advantageous Effects of Invention
[0027] According to the present invention, because the partition
plates and the tubes are not joined together, thermal expansion of
the U-shaped tubes in the lengthwise direction is permitted. Thus,
an advantage is afforded in that damage to the U-shaped tubes can
be prevented.
[0028] Furthermore, the space between the first partition plate and
the casing serves as a stagnation region that is separated from the
fluid path. Thus, an advantage is afforded in that the stagnation
region exhibits a heat insulating effect, serving to reduce heat
dissipation.
[0029] Furthermore, the header itself is designed to have a size
large enough for a person to enter, a hatch for inspection work of
the diameter-expanded joints with the tubes is provided at the
header, and a ladder is provided inside the header. This structure
facilitates inspection, making it easy to seal off a tube with a
plug even if the tube is damaged, forming a perforation.
[0030] Furthermore, since multiple headers are provided in the
middle of the tube path, the air whose temperature has been boosted
by compression and the air that has been further heated by the heat
exchanger are mixed in the headers, so that the temperature becomes
uniform before it is fed to the heat receiver. Thus, the air
discharged from the heat receiver becomes free of pulsation of
temperature, so that the rotation rate of the turbine directly
connected to the generator becomes free of minute fluctuations.
Accordingly, an advantage is afforded in that power of good quality
with extremely small frequency fluctuations can be obtained.
[0031] Furthermore, it is possible to pull out the headers and tube
sets without removing the casing, which facilitates replacement of
tubes when the tubes become degraded.
[0032] Furthermore, since a gap is provided between tube sets,
where the first fluid becomes uniform, the temperature efficiency
can be improved.
BRIEF DESCRIPTION OF DRAWINGS
[0033] FIG. 1 is a construction diagram (system diagram) showing a
specific example of a case where a heat exchanger according to an
embodiment of the present invention is used as a reheater for a
solar-heat gas turbine and a solar-heat gas-turbine power
generating unit.
[0034] FIG. 2 is a perspective view of the heat exchanger according
to the embodiment of the present invention.
[0035] FIG. 3 is a sectional view of the heat exchanger according
to the embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0036] Now, a heat exchanger according to an embodiment of the
present invention, in particular, a heat exchanger that can be
suitably used as a reheater of a solar-heat gas turbine that is
driven by using a compressible working fluid, such as air, heated
by using sunlight, will be described with reference to FIGS. 1 to
3.
[0037] FIG. 1 is a construction diagram (system diagram) showing a
specific example of a case where the heat exchanger according to
this embodiment is used as a reheater for a solar-heat gas turbine
and a solar-heat gas-turbine power generating unit. FIG. 2 is a
perspective view of the heat exchanger according to the embodiment.
FIG. 3 is a sectional view of the heat exchanger according to the
embodiment.
[0038] As shown in FIG. 1, a solar-heat gas turbine GT includes, as
its main components, a compressor 1 that compresses a compressible
working fluid to boost its pressure, a heat receiver 2 that heats
the compressible working fluid with heat obtained by converting
sunlight to boost its temperature, and a turbine 3 that converts
thermal energy possessed by the high-temperature, high-pressure
compressible working fluid into mechanical energy. That is, the
solar-heat gas turbine GT includes the heat receiver 2 that heats
the high-pressure compressible working fluid by using the thermal
energy of sunlight to boost its temperature instead of a combustor
that combusts a fuel such as natural gas to generate
high-temperature, high-pressure combustion gas.
[0039] The heat receiver 2 in this case is a device for converting
sunlight into thermal energy. With the heat receiver 2, it is
possible to heat a high-pressure compressible working fluid to
boost its temperature by using the heat of light collected by a
light concentrator (heliostat), which is not shown.
[0040] Furthermore, a solar-heat gas-turbine power generating unit
that generates electric power by using sunlight can be constructed
by connecting a generator 4 coaxially to the solar-heat gas turbine
GT so that the generator 4 is driven by the solar-heat gas turbine
GT.
[0041] Furthermore, a reheater 5 preheats the high-pressure
compressible working fluid whose pressure has been boosted by the
compressor 1, by using exhaust heat of the compressible working
fluid that is discharged from a chimney 6 into the air after
performing work in the turbine 3.
[0042] The heat exchanger 10 according to this embodiment is a heat
exchanger that can be suitably used as the reheater 5 of the
solar-heat gas turbine GT in particular. As shown in FIG. 2 or FIG.
3, the heat exchanger 10 includes a casing 11 and multiple (four in
this embodiment) tube sets 12.
[0043] The casing 11 has a substantially rectangular parallelepiped
or cubic external shape and accommodates the tube sets 12 inside.
On the front face of the casing 11, a first fluid inlet 21 is
provided, which is an opening having a rectangular shape when
viewed from the front and through which a high-temperature fluid
(the high-temperature compressible working fluid discharged from
the turbine 3) flows in. On the back face, a first fluid outlet 22
is provided, which is an opening having a rectangular shape when
viewed from the back and through which the fluid that has undergone
heat exchange inside the casing flows out. On a first face, a tube
plate 23 is provided. Furthermore, the three faces of the casing
other than the front face, the back face, and the first face are
closed off with a second face, a third face, and a fourth face
surrounding the front and back faces together with the first
face.
[0044] In the tube plate 23, multiple (672 in this embodiment) tube
holes (not shown) are provided, through which both ends of multiple
(336 in this embodiment) U-shaped tubes 24 constituting the tube
sets 12 are inserted.
[0045] The ends of the U-shaped tubes 24 inserted through the tube
holes are expanded by using a tool such as a mandrel, so that the
U-shaped tubes 24 are fixed to the tube plate 23 only on that
single side.
[0046] The first fluid inlet 21 and the first fluid outlet 22 are
connected to each other via a first flow path 25 extending in a
straight line from the first fluid inlet 21 to the first fluid
outlet 22. A fluid that flows in from the first fluid inlet 21
undergoes heat exchange with a fluid that passes through the
U-shaped tubes 24 (the high-pressure compressible working fluid
ejected from the compressor) and then flows out from the first
fluid outlet 22. The first flow path 25 is formed by four faces,
namely, the tube plate 23, the second face, a first partition plate
(support plate) 26 disposed at the inner side of the third face and
parallel to the third face, and the fourth face. Furthermore,
between the tube plate 23 and the first partition plate 26, a
second partition plate (support plate) 27 and a third partition
plate (support plate) 28 are disposed parallel to the tube plate 23
and the first partition plate 26, which separate the first flow
path 25 into three flow paths along the flow direction. In each of
the first partition plate 26, the second partition plate 27, and
the third partition plate 28, multiple (672 in this embodiment)
tube holes (not shown) are provided, through which the multiple
U-shaped tubes 24 constituting the tube sets 12 are inserted. The
tube holes provided in the first partition plate 26 and the second
partition plate 27 have an inner diameter greater than the outer
diameter of the U-shaped tubes 24 so that thermal expansion of the
U-shaped tubes 24 in the lengthwise direction (lateral direction in
FIG. 3) will not be restrained. The tube holes provided in the
third partition plate 28 disposed so as to separate the straight
portions and turning portions of the U-shaped tubes 24 have an
inner diameter greater than the inner diameter of the tube holes
provided in the first partition plate 26 and the second partition
plate 27 so that thermal expansion of the U-shaped tubes 24 in the
lengthwise direction will not be restrained and so that a slight
amount of the fluid that flows via the first flow path 25 flows
into a space S formed between the third partition plate 28 and the
third face.
[0047] The space S is formed by the third partition plate 28, the
second face, the third face, the fourth face, the front face except
the area where the first fluid inlet 21 is formed, and the back
face except the area where the first fluid outlet 22 is formed.
[0048] On the outer side of the tube plate 23, multiple headers,
namely, three headers 31, 32, and 33 in this embodiment, are
provided.
[0049] The first header 31 is a housing substantially having an
external shape of a cylinder cut into half with both ends closed.
The first header 31 guides the fluid that undergoes heat exchange
with the fluid passing via the first flow path 25 to the inlet end
of the tube set 12 located on the most upstream side via a second
fluid inlet 34 and guides the fluid that flows out from the outlet
end of the same tube set 12 to the inlet end of the tube set 12
located on the downstream side thereof. In the first header 31, a
barrier wall 35 is provided to prevent mixing between the fluid
guided from the second fluid inlet 34 to the inlet end of the tube
set 12 located on the most upstream side and the fluid that flows
out from the outlet end of the same tube set 12.
[0050] The second header 32 is a housing substantially having an
external shape of a cylinder cut into half with both ends closed.
The second header 32 guides the fluid that flows out from the
outlet end of the tube set 12 located second from the upstream side
to the inlet end of the tube set 12 located on the downstream side
thereof.
[0051] The third header 33 is a housing substantially having an
external shape of a cylinder cut into half with both ends closed.
The third header 33 guides the fluid that flows out from the outlet
end of the tube set 12 located third from the upstream side to the
inlet end of the tube set 12 located on the downstream side thereof
and guides the fluid that flows out from the outlet end of the same
tube set 12 to the outside via a second fluid outlet 36. In the
third header 33, a barrier wall 37 is provided to prevent mixing
between the fluid guided to the inlet end of the tube set 12
located fourth from the upstream side and the fluid that flows out
from the outlet end of the same tube set 12.
[0052] In each of the tube sets 12, multiple (four in this
embodiment) U-shaped tubes 24 having straight portions of the same
length and turning portions with different radii are laid out
within the same plane such that the U-shaped tubes 24 having
smaller radii are disposed at the inner side and the U-shaped tubes
24 having greater radii are disposed at the outer side, and
multiple (21 in this embodiment) sets of this arrangement are
arrayed so as to be stacked in the direction perpendicular to this
plane.
[0053] A certain gap is provided between the U-shaped tubes 24 laid
out within the same plane and between the U-shaped tubes 24 stacked
in the direction perpendicular to the plane, so that the fluid that
flows from the first fluid inlet 21 toward the first fluid outlet
22 passes through these gaps.
[0054] Furthermore, reference sign 38 in FIG. 3 denotes a hatch for
inspection work.
[0055] In the heat exchanger 10 according to this embodiment, the
U-shaped tubes 24 are fixed only at a single side thereof to the
tube holes provided in the tube plate 23, through which both ends
of the U-shaped tubes 24 are inserted.
[0056] This permits thermal expansion of the U-shaped tubes 24 in
the lengthwise direction, which serves to prevent damage to the
U-shaped tubes 24.
[0057] Furthermore, in the heat exchanger 10 according to this
embodiment, the first fluid inlet 21 and the first fluid outlet 22
are connected to each other via a single path, namely, the first
flow path 25 extending in a straight line from the first fluid
inlet 21 to the first fluid outlet 22.
[0058] Thus, pressure loss in the first flow path 25 can be
reduced. Furthermore, it is possible to make a large amount of
fluid flow via the first flow path 25. This serves to improve the
heat exchange efficiency.
[0059] Furthermore, in the heat exchanger 10 according to this
embodiment, the space S is formed by the first partition plate 26
and the casing 11 outside the first flow path 25. The fluid passing
via the first flow path 25 flows into this space S via the gaps
provided between the inner circumferential surfaces of the tube
holes and the outer circumferential surfaces of the U-shaped tubes
24, causing a portion of the fluid that passes via the first flow
path 25 to stagnate in the space S.
[0060] Thus, the fluid present in the space S acts as a heat
insulating layer. This serves to maintain the temperature of the
fluid passing via the first flow path 25, which serves to improve
the heat exchange efficiency even further.
[0061] Furthermore, in the heat exchanger 10 according to this
embodiment, the fluid that has undergone heat exchange with the
fluid passing via the first flow path 25 while passing through a
tube set 12 located on the upstream side is guided to the tube set
12 located on the downstream side thereof so that the fluid then
undergoes heat exchange with the fluid passing via the first flow
path 25. This serves to improve the heat exchange efficiency even
further.
[0062] Furthermore, in the heat exchanger 10 according to this
embodiment, the ends of the U-shaped tubes 24 are fixed to the tube
plate 23 just by tube expansion, without employing welding.
[0063] Thus, the combination of the material of the tube plate 23
and the material of the U-shaped tubes 24, which must be taken into
account when welding, need not be considered here, allowing free
choice of the material of the tube plate 23 and the material of the
U-shaped tubes 24.
[0064] Since the solar-heat gas turbine GT according to this
embodiment includes, as the reheater 5, the heat exchanger 10 that
permits thermal expansion of the U-shaped tubes 24 in the
lengthwise direction, which serves to prevent damage to the
U-shaped tubes 24, the reliability of the solar-heat gas turbine GT
can be improved.
[0065] Furthermore, since the solar-heat gas turbine GT according
to this embodiment includes, as the reheater 5, the heat exchanger
10 having a high heat exchange efficiency, it is possible to
further boost the temperature of the compressible working fluid
introduced into the turbine 3. This serves to improve the cycle
efficiency of the heat cycle.
[0066] The present invention is not limited to the embodiment
described above, and suitable modifications and alternatives may be
introduced as needed.
[0067] For example, although the above-described embodiment
includes the four tube sets 12 as a specific example, the present
invention is not limited to this embodiment, and the number of tube
sets included may be two, three, or five or more.
[0068] Furthermore, although the second fluid outlet 36 is provided
at the first fluid inlet 21 side, and the second fluid inlet 34 is
provided at the first fluid outlet 22 side in the above-described
embodiment, the present invention is not limited to this
embodiment, and the second fluid inlet 34 may be provided at the
first fluid inlet 21 side, and the second fluid outlet 36 may be
provided at the first fluid outlet 22 side.
REFERENCE SIGNS LIST
[0069] 1 Compressor [0070] 3 Turbine [0071] 5 Reheater [0072] 10
Heat exchanger [0073] 11 Casing [0074] 12 Tube sets [0075] 21 First
fluid inlet [0076] 22 First fluid outlet [0077] 23 Tube plate
[0078] 24 U-shaped tubes [0079] 25 First flow path [0080] 26 First
partition plate (partition plate) [0081] 31 First header (header)
[0082] 32 Second header (header) [0083] 33 Third header (header)
[0084] GT Solar-heat gas turbine
* * * * *