U.S. patent application number 16/749459 was filed with the patent office on 2020-10-01 for rotating machinery.
The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Masamichi IINO, Yoshihiro KUWAMURA, Martino RECLARI, Takeshi SANO, Shuichi YAMASHITA.
Application Number | 20200309149 16/749459 |
Document ID | / |
Family ID | 1000004655259 |
Filed Date | 2020-10-01 |
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United States Patent
Application |
20200309149 |
Kind Code |
A1 |
IINO; Masamichi ; et
al. |
October 1, 2020 |
ROTATING MACHINERY
Abstract
There is provided a rotating machinery including: a rotating
body R which is rotatable around an axis O and has a first facing
surface P1 that widens in a plane intersecting the axis O; a
stationary body S which faces the first facing surface P1 from the
axial direction O, and has a second facing surface P2 forming a
flow path F1 through which a fluid flows from a radially inner side
toward the radially outer side between the first facing surface P1
and the second facing surface P2; and a rotation side projection
portion 80 which projects from the first facing surface P1 toward
the second facing surface P2, has an annular shape around the axis
O, and faces the second facing surface P2 via a clearance C.
Inventors: |
IINO; Masamichi; (Tokyo,
JP) ; RECLARI; Martino; (Tokyo, JP) ; SANO;
Takeshi; (Tokyo, JP) ; YAMASHITA; Shuichi;
(Tokyo, JP) ; KUWAMURA; Yoshihiro; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000004655259 |
Appl. No.: |
16/749459 |
Filed: |
January 22, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/4206 20130101;
F04D 17/08 20130101 |
International
Class: |
F04D 29/42 20060101
F04D029/42; F04D 17/08 20060101 F04D017/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2019 |
JP |
2019-069112 |
Claims
1. A rotating machinery comprising: a rotating body which is
rotatable around an axis and has a first facing surface that widens
in a plane intersecting the axis; a stationary body has a second
facing surface which faces the first facing surface in an axial
direction and forms a flow path through which a fluid flows from a
radially inner side toward a radially outer side between the first
facing surface and the second facing surface; and at least one
rotation side projection portion which projects from the first
facing surface toward the second facing surface, has an annular
shape around the axis, and faces the second facing surface via a
clearance.
2. The rotating machinery according to claim 1, wherein positions
of a first inner region which is a region on the radially inner
side with respect to the at least one rotation side projection
portion and a first outer region which is a region on the radially
outer side with respect to the at least one rotation side
projection portion on the first facing surface, are the same in the
axial direction.
3. The rotating machinery according to claim 1, wherein a first
outer region which is a region on the radially outer side with
respect to the at least one rotation side projection portion on the
first facing surface widens to a position further away from the
second facing surface in the axial direction than a first inner
region which is a region on the radially inner side with respect to
the at least one rotation side projection portion on the first
facing surface.
4. The rotating machinery according to claim 3, wherein the first
outer region extends in a direction gradually spaced apart from the
second facing surface as going from the radially inner side toward
the radially outer side in a sectional view including the axis.
5. The rotating machinery according to claim 1, wherein a second
outer region which is a region on the radially outer side with
respect to the at least one rotation side projection portion on the
second facing surface extends in a direction gradually spaced apart
from the first facing surface as going from the radially inner side
toward the radially outer side in a sectional view including the
axis.
6. The rotating machinery according to claim 1, further comprising:
at least one stationary side projection portion which is provided
at a position facing the at least one rotation side projection
portion on the second facing surface and projects toward the at
least one rotation side projection portion.
7. The rotating machinery according to claim 6, wherein an end
surface facing the first facing surface in the at least one
stationary side projection portion is formed in a planar shape that
widens in a plane intersecting the axis.
8. The rotating machinery according to claim 6, wherein the at
least one stationary side projection portion includes a plurality
of stationary side projection portions; and the plurality of
stationary side projection portions are arranged at intervals in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going from the
radially inner side toward the radially outer side.
9. The rotating machinery according to claim 6, wherein a second
outer region which is a region on the radially outer side with
respect to the at least one rotation side projection portion
extends in a direction gradually spaced apart from the first facing
surface starting from an end edge of the at least one stationary
side projection portion on a first facing surface side as going
from the radially inner side toward the radially outer side in a
sectional view including the axis.
10. The rotating machinery according to claim 1, wherein the at
least one rotation side projection portion includes a plurality of
rotation side projection portions; and the plurality of rotation
side projection portions are provided at intervals in a radial
direction on the first facing surface.
11. The rotating machinery according to claim 1, wherein the at
least one rotation side projection portion has a radial dimension
that decreases going from the first facing surface side toward the
second facing surface side.
12. A rotating machinery comprising: a rotating body which is
rotatable around an axis and has a first facing surface that widens
in a plane intersecting the axis; a stationary body which has a
second facing surface which faces the first facing surface in an
axial direction and forms a flow path through which a fluid flows
from a radially outer side toward a radially inner side between the
first facing surface and the second facing surface; and at least
one rotation side projection portion which is provided in an end
portion on the radially outer side on the first facing surface,
projects toward the second facing surface, has an annular shape
around the axis, and faces the second facing surface via a
clearance.
13. The rotating machinery according to claim 12, further
comprising: a recess portion provided adjacent to the radially
inner side with respect to the at least one rotation side
projection portion on the first facing surface and recessed in a
direction spaced apart from the second facing surface.
14. The rotating machinery according to claim 13, wherein a bottom
surface of the recess portion extends in a direction gradually
spaced apart from the second facing surface as going from a
radially inner side toward the radially outer side in a sectional
view including the axis.
15. The rotating machinery according to claim 13, further
comprising: a stationary side recess portion provided in a region
facing the recess portion on the second facing surface, and
recessed in a direction spaced apart from the first facing surface,
wherein a bottom surface of the stationary side recess portion
extends in a direction gradually spaced apart from the first facing
surface as going from the radially outer side to the radially inner
side in a sectional view including the axis.
16. The rotating machinery according to claim 12, further
comprising: at least one stationary side projection portion which
is provided at a position facing the at least one rotation side
projection portion on the second facing surface and projects toward
the at least one rotation side projection portion.
17. The rotating machinery according to claim 16, wherein an end
surface facing the first facing surface in the at least one
stationary side projection portion is formed in a planar shape that
widens in a radial direction.
18. The rotating machinery according to claim 16, wherein the at
least one stationary side projection portion includes a plurality
of stationary side projection portions; and the plurality of
stationary side projection portions are arranged at intervals in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going from the
radially outer side toward the radially inner side.
19. The rotating machinery according to claim 13, wherein a region
facing the recess portion on the second facing surface extends in a
direction gradually spaced apart from the first facing surface as
going from the radially outer side to the radially inner side in a
sectional view including the axis.
20. The rotating machinery according to claim 12, wherein the at
least one rotation side projection portion includes a plurality of
rotation side projection portions; and the plurality of rotation
side projection portions are provided at intervals in a radial
direction on the first facing surface.
21. The rotating machinery according to claim 12, wherein the at
least one rotation side projection portion has a radial dimension
that decreases going from the first facing surface side toward the
second facing surface side.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a rotating machinery.
[0002] Priority is claimed on Japanese Patent Application No.
2019-069112, filed on Mar. 29, 2019, the content of which is
incorporated herein by reference.
Description of Related Art
[0003] For example, a rotating machinery, such as a centrifugal
compressor, a centrifugal pump, a generator, or a turbine, includes
a rotor as a rotating body that rotates around an axis, and a
casing as a stationary body that covers the rotor from the outside.
Between the rotating rotor and the stationary casing, a frictional
resistance (disk friction loss) is generated via a working fluid.
In particular, in a case of the centrifugal compressor, it is known
that the disk friction loss increases because an outer diameter of
an impeller increases in order to obtain a high lifting height with
respect to a discharge flow rate.
[0004] As a technique for reducing such a disk friction loss, a
technique described in Japanese Unexamined Patent Application,
First Publication No. H3-11198 is known. In Japanese Unexamined
Patent Application, First Publication No. H3-11198, a space on a
back surface side is divided into a plurality of spaces by
providing a plurality of fences at intervals in a radial direction
on an impeller back surface side of the centrifugal compressor.
Accordingly, the velocity distribution in each space is controlled,
and the disk friction loss can be reduced.
SUMMARY OF THE INVENTION
[0005] However, in an apparatus described in Japanese Unexamined
Patent Application, First Publication No. H3-11198, a fluid that
flows in the divided space is in contact with an inner surface of
the casing which is a stationary body. Therefore, a friction loss
exists between the impeller back surface and the casing. In other
words, there is still room for improvement in the apparatus
described in Japanese Unexamined Patent Application, First
Publication No. H3-11198.
[0006] The present invention provides a rotating machinery with
improved efficiency by further reducing a friction loss.
[0007] According to an aspect of the present invention, there is
provided a rotating machinery including: a rotating body which is
rotatable around an axis and has a first facing surface that widens
in a plane intersecting the axis; a stationary body has a second
facing surface which faces the first facing surface in an axial
direction and forms a flow path through which a fluid flows from a
radially inner side toward a radially outer side between the first
facing surface and the second facing surface; and at least one
rotation side projection portion which projects from the first
facing surface toward the second facing surface, has an annular
shape around the axis, and faces the second facing surface via a
clearance.
[0008] According to the configuration, the fluid that flows toward
the radially outer side in the flow path flows toward the second
facing surface side along the rotation side projection portion
provided on the first facing surface. In other words, the flow of
the fluid is peeled off from the first facing surface and flows to
the stationary body side. Thereafter, the fluid passes through the
clearance between the rotation side projection portion and the
second facing surface. At this time, a flow velocity of the fluid
increases. From the flow of the fluid having a high flow velocity,
some components are peeled toward the rotating body side (that is,
the first facing surface side). The peeled flow forms a vortex
(stagnation) in a region close to the first facing surface and on
the radially outer side of the rotation side projection portion.
More specifically, the vortex flows toward the radially outer side,
and then flows from the radially outer side toward the rotation
side projection portion along the first facing surface. By forming
such a vortex constantly, the remaining flow components except for
the vortex are inhibited by the vortex and flow toward the radially
outer side at a position close to the stationary body side (second
facing surface side). As a result, a friction loss between the
first facing surface and the second facing surface can be
reduced.
[0009] In the rotating machinery, positions of a first inner region
which is a region on the radially inner side with respect to the at
least one rotation side projection portion and a first outer region
which is a region on the radially outer side with respect to the at
least one rotation side projection portion on the first facing
surface, may be the same in the axial direction.
[0010] According to the configuration, the first inner region and
the first outer region are provided at the same position in the
axial direction. In other words, the first inner region and the
first outer region can be formed only by providing the rotation
side projection portion on the first facing surface formed in
advance in a planar shape. Accordingly, the cost and time required
for manufacturing the rotating machinery can be reduced.
[0011] In the rotating machinery, a first outer region which is a
region on the radially outer side with respect to the at least one
the rotation side projection portion on the first facing surface
may widen to a position further away from the second facing surface
in the axial direction than a first inner region which is a region
on the radially inner side with respect to the at least one
rotation side projection portion on the first facing surface.
[0012] According to the configuration, the first outer region
positioned on the radially outer side nipping the rotation side
projection portion widens to the position further away from the
second facing surface than the first inner region positioned on the
radially inner side. Therefore, the region where the vortex is
formed on the first outer region side can be enlarged. Accordingly,
as the remaining flow components except for the vortex are
inhibited by the vortex, the remaining flow components flow toward
the radially outer side at a position close to the stationary body
side (second facing surface side). As a result, friction loss
between the first facing surface and the second facing surface can
further be reduced.
[0013] In the rotating machinery, the first outer region may extend
in a direction gradually spaced apart from the second facing
surface as going from the radially inner side toward the radially
outer side in a sectional view including the axis.
[0014] According to the configuration, the first outer region may
extend in the direction gradually spaced apart from the second
facing surface as going toward the radially outer side in a
sectional view including the axis. Therefore, the region where the
vortex is formed on the first outer region side can further be
enlarged. Accordingly, as the remaining flow components except for
the vortex are inhibited by the vortex, the remaining flow
components flow toward the radially outer side at a position close
to the stationary body side (second facing surface side). As a
result, a friction loss between the first facing surface and the
second facing surface can further be reduced.
[0015] In the rotating machinery, a second outer region which is a
region on the radially outer side with respect to the at least one
the rotation side projection portion on the second facing surface
may extend in a direction gradually spaced apart from the first
facing surface as going from the radially inner side toward the
radially outer side in a sectional view including the axis.
[0016] According to the configuration, the second outer region on
the second facing surface extends in the direction gradually spaced
apart from the first facing surface as going toward the radially
outer side in a sectional view including the axis. Accordingly, as
the flow path sectional area between the second outer region and
the first facing surface is gradually enlarged as going toward the
radially outer side, an effect as a diffuser can be achieved. As a
result, the flow velocity of the fluid that flows through the
second outer region decreases, and the formation of the vortex on
the first outer region side can be promoted.
[0017] In the rotating machinery, at least one stationary side
projection portion which is provided at a position facing the at
least one rotation side projection portion on the second facing
surface and projects toward the at least one projection portion,
may be provided.
[0018] According to the configuration, the stationary side
projection portion which projects toward the rotation side
projection portion is provided at the position facing the rotation
side projection portion on the second facing surface. By providing
the stationary side projection portion, the position of the
clearance formed between the rotation side projection portion and
the stationary side projection portion in the axial direction can
be adjusted. Accordingly, the position of the region where the
vortex is formed can be adjusted appropriately.
[0019] In the rotating machinery, an end surface facing the first
facing surface in the at least one stationary side projection
portion may be formed in a planar shape that widens in a plane
intersecting the axis.
[0020] According to the configuration, the end surface of the
stationary side projection portion is formed in a planar shape that
widens in a plane intersecting the axis. Therefore, for example,
even in a case where the rotation side projection portion is
relatively displaced in the radial direction with respect to the
stationary side projection portion, it is possible to reduce a
possibility that the size or the opening direction of the clearance
between the rotation side projection portion and the stationary
side projection portion changes.
[0021] In the rotating machinery, the at least one stationary side
projection portion includes a plurality of stationary side
projection portions; and the plurality of stationary side
projection portions may be arranged at intervals in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going from the
radially inner side toward the radially outer side.
[0022] According to the configuration, a plurality of the
stationary side projection portions are arranged in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going toward the
radially outer side. Accordingly, when the fluid passes between the
plurality of stationary side projection portions, it is possible to
add a swirl flow component toward the front side in a rotational
direction of the rotating body with respect to the fluid. As a
result, the peeling of the flow from the second facing surface is
promoted, and an increase in the circumferential velocity component
of the vortex on the first facing surface side can be promoted.
[0023] In the rotating machinery, a second outer region which is a
region on the radially outer side with respect to the at least one
the rotation side projection portion may extend in a direction
gradually spaced apart from the first facing surface starting from
an end edge of the at least one stationary side projection portion
on a first facing surface side as going from the radially inner
side toward the radially outer side in a sectional view including
the axis.
[0024] According to the configuration, the second outer region on
the second facing surface extends in the direction gradually spaced
apart from the first facing surface starting from the end edge of
the stationary side projection portion as going toward the radially
outer side in a sectional view including the axis. Accordingly, as
the flow path sectional area between the second outer region and
the first facing surface is gradually enlarged as going toward the
radially outer side, an effect as a diffuser can be achieved. As a
result, the flow velocity of the fluid that flows through the
second outer region decreases, and the formation of the vortex on
the first outer region side can be promoted.
[0025] In the rotating machinery, the at least one rotation side
projection portion includes a plurality of rotation side projection
portions; and the plurality of rotation side projection portions
may be provided at intervals in a radial direction on the first
facing surface.
[0026] According to the configuration, since the plurality of
rotation side projection portions are provided at intervals in the
radial direction on the first facing surface, in a wider region on
the first facing surface, the friction loss between the rotating
body side and the stationary body side can be reduced
uniformly.
[0027] In the rotating machinery, the at least one rotation side
projection portion may have a radial dimension that decreases going
from the first facing surface side toward the second facing surface
side.
[0028] According to the configuration, the rotation side projection
portion is formed in a tapered shape as the dimension in radial
direction decreases going toward the second facing surface side.
Accordingly, the fluid that passes through the clearance can be
further accelerated.
[0029] According to another aspect of the present invention, there
is provided a rotating machinery including: a rotating body which
is rotatable around an axis and has a first facing surface that
widens in a plane intersecting the axis; a stationary body has a
second facing surface which faces the first facing surface in an
axial direction and forms a flow path through which a fluid flows
from a radially outer side toward a radially inner side between the
first facing surface and the second facing surface; and at least
one rotation side projection portion which is provided at a
position on the most radially outer side on the first facing
surface, projects toward the second facing surface, has an annular
shape around the axis, and faces the second facing surface via a
clearance.
[0030] According to the configuration, the fluid that flows toward
the radially inner side in the flow path flows toward the second
facing surface side along the projection portion provided on the
first facing surface. In other words, the flow of the fluid is
peeled off from the first facing surface and flows to the
stationary body side. Thereafter, the fluid passes through the
clearance between the rotation side projection portion and the
second facing surface. At this time, a flow velocity of the fluid
increases. From the flow of the fluid having a high flow velocity,
some components are peeled toward the rotating body side (that is,
the first facing surface side). The peeled flow forms the vortex
(stagnation) in the region close to the first facing surface and on
the radially inner side of the rotation side projection portion.
More specifically, the vortex flows toward the radially inner side,
and then flows from the radially outer side toward the projection
portion along the first facing surface. By forming such a vortex
constantly, the remaining flow components except for the vortex are
inhibited by the vortex and flow toward the radially inner side at
a position close to the stationary body side (second facing surface
side). As a result, a friction loss between the first facing
surface and the second facing surface can be reduced.
[0031] In the rotating machinery, a recess portion provided
adjacent to the radially inner side with respect to the at least
one rotation side projection portion on the first facing surface
and recessed in a direction spaced apart from the second facing
surface, may further be provided.
[0032] According to the configuration, the recess portion is formed
adjacent to the radially inner side of the rotation side projection
portion. By providing the recess portion, the region where the
vortex is formed can be enlarged. Accordingly, as the remaining
flow components except for the vortex are inhibited by the vortex,
the remaining flow components flow toward the radially inner side
at a position close to the stationary body side (second facing
surface side). As a result, a friction loss between the first
facing surface and the second facing surface can further be
reduced.
[0033] In the rotating machinery, the bottom surface of the recess
portion may extend in a direction gradually spaced apart from the
second facing surface as going from a radially inner side toward
the radially outer side in a sectional view including the axis.
[0034] According to the configuration, the bottom surface of the
recess portion may extend in the direction gradually spaced apart
from the second facing surface as going toward the radially inner
side in a sectional view including the axis. Therefore, the region
where the vortex is formed can be further enlarged. Accordingly, as
the remaining flow components except for the vortex are inhibited
by the vortex, the remaining flow components flow toward the
radially inner side at a position close to the stationary body side
(second facing surface side). As a result, a friction loss between
the first facing surface and the second facing surface can further
be reduced.
[0035] In the rotating machinery, a stationary side recess portion
may be provided in a region facing the recess portion on the second
facing surface, and recessed in a direction spaced apart from the
first facing surface, in which a bottom surface of the stationary
side recess portion may extend in a direction gradually spaced
apart from the first facing surface as going from the radially
outer side toward the radially inner side in a sectional view
including the axis.
[0036] According to the configuration, the stationary side recess
portion is formed in the region facing the recess portion on the
second facing surface. Furthermore, the bottom surface of the
stationary side recess portion extends in the direction gradually
spaced apart from the first facing surface as going toward the
radially inner side in a sectional view including the axis.
Accordingly, as the flow path sectional area between the recess
portion and the stationary side recess portion is gradually
enlarged as going toward the radially inner side, an effect as a
diffuser can be achieved. As a result, the flow velocity of the
fluid that flows into the recess portion decreases, and the
formation of the vortex in the recess portion can be promoted.
[0037] In the rotating machinery, at least one stationary side
projection portion which is provided at a position facing the at
least one rotation side projection portion on the second facing
surface and projects toward the at least one projection portion,
may further be provided.
[0038] According to the configuration, the stationary side
projection portion which projects toward the rotation side
projection portion is provided at the position facing the rotation
side projection portion on the second facing surface. By providing
the stationary side projection portion, the position of the
clearance formed between the projection portion and the stationary
side projection portion in the axial direction can be adjusted.
Accordingly, the position of the region where the vortex is formed
can be adjusted appropriately.
[0039] In the rotating machinery, an end surface facing the first
facing surface in the at least one stationary side projection
portion may be formed in a planar shape that widens in the radial
direction.
[0040] According to the configuration, the end surface of the
stationary side projection portion is formed in a planar shape that
widens in a plane intersecting the axis. Therefore, for example,
even in a case where the rotation side projection portion is
relatively displaced in the radial direction with respect to the
stationary side projection portion, it is possible to reduce a
possibility that the size or the opening direction of the clearance
between the rotation side projection portion and the stationary
side projection portion changes.
[0041] In the rotating machinery, the at least one stationary side
projection portion includes a plurality of stationary side
projection portions; and the plurality of stationary side
projection portions may be arranged at intervals in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going from the
radially outer side toward the radially inner side.
[0042] According to the configuration, a plurality of the
stationary side projection portions are arranged in a
circumferential direction and extend to a front side in a
rotational direction of the rotating body as going toward the
radially inner side. Accordingly, when the fluid passes between the
plurality of stationary side projection portions, it is possible to
add a swirl flow component toward the front side in a rotational
direction of the rotating body with respect to the fluid. As a
result, the peeling of the flow from the second facing surface is
promoted, and an increase in the circumferential velocity component
of the vortex on the first facing surface side can further be
promoted.
[0043] In the rotating machinery, a region facing the recess
portion on the second facing surface may extend in a direction
gradually spaced apart from the first facing surface as going from
the radially outer side toward the radially inner side in a
sectional view including the axis.
[0044] According to the configuration, the region facing the recess
portion on the second facing surface extends in the direction
gradually spaced apart from the first facing surface as going
toward the radially inner side in a sectional view including the
axis. Accordingly, as the flow path sectional area between the
second facing surface and the recess portion is gradually enlarged
as going toward the radially inner side, an effect as a diffuser
can be achieved. As a result, the flow velocity of the fluid that
flows between the second facing surface and the recess portion
decreases, and the formation of the vortex in the recess portion
can be promoted.
[0045] In the rotating machinery, the at least one rotation side
projection portion includes a plurality of rotation side projection
portions; and the plurality of rotation side projection portions
may be provided at intervals in the radial direction on the first
facing surface.
[0046] According to the configuration, since the plurality of
rotation side projection portions are provided at intervals in the
radial direction on the first facing surface, in a wider region on
the first facing surface, the friction loss between the rotating
body side and the stationary body side can be reduced
uniformly.
[0047] In the rotating machinery, the at least one rotation side
projection portion may have a radial dimension that decreases going
from the first facing surface side toward the second facing surface
side.
[0048] According to the configuration, the rotation side projection
portion is formed in a tapered shape as the dimension in radial
direction decreases going toward the second facing surface side.
Accordingly, the fluid that passes through the clearance can be
further accelerated.
[0049] According to the present invention, it is possible to
provide a rotating machinery with improved efficiency by further
reducing a friction loss.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a sectional view showing a configuration of a
centrifugal compressor as a rotating machinery according to a first
embodiment of the present invention.
[0051] FIG. 2 is an enlarged view showing a configuration around an
impeller of the centrifugal compressor according to the first
embodiment of the present invention.
[0052] FIG. 3 is an enlarged sectional view of a main part of the
centrifugal compressor according to the first embodiment of the
present invention.
[0053] FIG. 4 is an enlarged sectional view of a main part of a
centrifugal compressor according to a second embodiment of the
present invention.
[0054] FIG. 5 is an enlarged sectional view of a main part showing
a modification example of the centrifugal compressor according to
the second embodiment of the present invention.
[0055] FIG. 6 is an enlarged sectional view of a main part of a
centrifugal compressor according to a third embodiment of the
present invention.
[0056] FIG. 7 is an enlarged sectional view of a main part showing
a modification example of the centrifugal compressor according to
the third embodiment of the present invention.
[0057] FIG. 8 is a view when a stationary side projection portion
in FIG. 7 is viewed from an axial direction.
[0058] FIG. 9 is an enlarged sectional view of a main part of a
centrifugal compressor according to a fourth embodiment of the
present invention.
[0059] FIG. 10 is an enlarged sectional view of a main part of a
centrifugal compressor according to a fifth embodiment of the
present invention.
[0060] FIG. 11 is an enlarged sectional view of a main part of a
centrifugal compressor according to a sixth embodiment of the
present invention.
[0061] FIG. 12 is an enlarged sectional view of a main part of a
centrifugal compressor according to a seventh embodiment of the
present invention.
[0062] FIG. 13 is an enlarged sectional view of a main part of a
centrifugal compressor according to an eighth embodiment of the
present invention.
[0063] FIG. 14 is an enlarged sectional view of a main part of a
centrifugal compressor according to a ninth embodiment of the
present invention.
[0064] FIG. 15 is an enlarged sectional view of a main part of a
centrifugal compressor according to a tenth embodiment of the
present invention.
[0065] FIG. 16 is an enlarged sectional view of a main part of a
centrifugal compressor according to an eleventh embodiment of the
present invention.
[0066] FIG. 17 is an enlarged sectional view of a main part of a
centrifugal compressor according to a twelfth embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0067] A first embodiment of the present invention will be
described with reference to FIGS. 1 to 3. In the present
embodiment, a multistage centrifugal compressor as a rotating
machinery will be described as an example. In addition, it is also
possible to apply the configuration of the present embodiment to a
single-stage centrifugal compressor, a centrifugal pump, a
generator, or a turbine, as a rotating machinery.
[0068] A centrifugal compressor 100 includes a rotating shaft 1
that rotates around an axis, a casing 3 as a stationary body S that
forms a fluid flow path 2 by covering the periphery of the rotating
shaft 1, and a plurality of impellers 4 as rotating bodies R
provided on the rotating shaft 1.
[0069] The casing 3 is formed in a cylindrical shape that extends
along an axis O. The rotating shaft 1 extends so as to penetrate
the inside of the casing 3 along the axis O. Journal bearings 5 and
thrust bearings 6 are provided in both end portions of the casing 3
in the direction of the axis O, respectively. The rotating shaft 1
is supported by the journal bearings 5 and the thrust bearings 6 so
as to be rotatable around the axis O.
[0070] An intake port 7 for taking in air as a working fluid G from
the outside is provided on one side of the casing 3 in the
direction of the axis O. Furthermore, an exhaust port 8 through
which the working fluid G compressed inside the casing 3 is
exhausted is provided on the other side of the casing 3 in the
direction of the axis O.
[0071] Inside the casing 3, an internal space in which the intake
port 7 and the exhaust port 8 communicate with each other and which
repeats the diameter reduction and the diameter expansion is
formed. The internal space accommodates the plurality of impellers
4 and forms a part of the fluid flow path 2. In the following
description, a side on which the intake port 7 is positioned on the
fluid flow path 2 is referred to as an upstream side. Further, the
side on which the exhaust port 8 is positioned on the fluid flow
path 2 is referred to as a downstream side.
[0072] The rotating shaft 1 is provided with a plurality (six) of
impellers 4 at intervals on the outer circumferential surface in
the direction of the axis O. As shown in FIG. 2, each impeller 4
includes a disk 41 having a substantially circular section when
viewed from the direction of the axis O, a plurality of blades 42
provided on a surface on the upstream side of the disk 41, and a
cover 43 that covers the plurality of blades 42 from the upstream
side.
[0073] The disk 41 is formed such that the radial dimension is
gradually enlarged as going from one side toward the other side in
the direction of the axis O when viewed from the direction
intersecting the axis O. Accordingly, the disk 41 has a generally
conical shape.
[0074] A plurality of blades 42 are radially arranged toward the
radially outer side around the axis O, on the conical surface
facing the upstream side of both surfaces of the disk 41 in the
direction of the axis O. More specifically, the blades are formed
by thin plates that are erected from the surface on the upstream
side of the disk 41 toward the upstream side. The plurality of
blades 42 are curved from one side toward the other side in the
circumferential direction in a case of being viewed from the
direction of the axis O.
[0075] The cover 43 is provided at an end edge on the upstream side
of the blade 42. In other words, the plurality of blades 42 are
sandwiched by the cover 43 and the disk 41 from the direction of
the axis O. Accordingly, a space is formed between the cover 43,
the disk 41, and a pair of blades 42 adjacent to each other. The
space forms a part (compression flow path 22) of a fluid flow path
2 which will be described later.
[0076] The fluid flow path 2 is a space in which the impeller 4
configured as described above and the internal space of the casing
3 communicate with each other. In the present embodiment,
description will be made assuming that one fluid flow path 2 is
formed for each impeller 4 (for each compression stage). In other
words, in the centrifugal compressor 100, five fluid flow paths 2
from the upstream side toward the downstream side are continuously
formed corresponding to the five impellers 4 excluding the impeller
4 on the last stage.
[0077] Each fluid flow path 2 has a suction flow path 21, a
compression flow path 22, a diffuser flow path 23, a return bend
portion 24, and a guide flow path 25. FIG. 2 shows only the
impeller 4 on the first stage among the fluid flow path 2 and the
impeller 4.
[0078] In the impeller 4 on the first stage, the suction flow path
21 is directly connected to the above-described intake port 7. By
the suction flow path 21, the external air is taken into each flow
path on the fluid flow path 2 as a working fluid G. More
specifically, the suction flow path 21 is gradually curved from the
direction of the axis O toward the radially outer side as going
from the upstream side toward the downstream side.
[0079] The suction flow path 21 in the impellers 4 on the second
and subsequent stages communicates with a downstream end of a guide
flow path 25 (will be described later) in the fluid flow path 2 of
the previous stage (first stage). In other words, similar to the
description above, the flow direction of the working fluid G that
has passed through the guide flow path 25 is changed so as to face
the downstream side along the axis O.
[0080] The compression flow path 22 is a flow path surrounded by
the surface on the upstream side of the disk 41, the surface on the
downstream side of the cover 43, and a pair of blades 42 adjacent
to each other in the circumferential direction. More specifically,
the sectional area of the compression flow path 22 gradually
decreases going from the radially inner side toward the radially
outer side. Accordingly, the working fluid G which flows in the
compression flow path 22 in a state where the impeller 4 is
rotating is gradually compressed to become a high-pressure
fluid.
[0081] The diffuser flow path 23 is a flow path that extends from
the radially inner side of the axis O toward the radially outer
side. The end portion on the radially inner side in the diffuser
flow path 23 communicates with the end portion on the radially
outer side of the compression flow path 22.
[0082] The return bend portion 24 reverses the flow direction of
the working fluid G flowing from the radially inner side toward the
radially outer side through the diffuser flow path 23, toward the
radially inner side. One end side (upstream side) of the return
bend portion 24 communicates with the diffuser flow path 23, and
the other end side (downstream side) communicates with the guide
flow path 25. In the middle of the return bend portion 24, a part
positioned on the most radially outer side is a top portion.
[0083] The guide flow path 25 extends toward the radially inner
side from the end portion on the downstream side of the return bend
portion 24. The end portion on the radially outer side of the guide
flow path 25 communicates with the above-described return bend
portion 24. The end portion on the radially inner side of the guide
flow path 25 communicates with the suction flow path 21 in the
fluid flow path 2 on the subsequent stage as described above.
[0084] In the centrifugal compressor 100 configured as described
above, a gap is formed between the casing 3 and the impeller 4 in
order to realize smooth rotation of the impeller 4. More
specifically, the gap is formed between a disk back surface 41A
facing the downstream side of the disk 41 and a casing back surface
3A facing the disk back surface 41A. The gap is a flow path F1
which will be described later. In the flow path F1, as indicated by
an arrow A in FIG. 2, a high-pressure fluid leaking from the
compression flow path 22 on the rear stage side flows from the
radially inner side toward the radially outer side.
[0085] Furthermore, a gap is formed between a cover upstream
surface 43B facing the upstream side of the cover 43 and a casing
upstream surface 3B facing the cover upstream surface 43B. The gap
is a flow path F2 which will be described later. In the flow path
F2, as indicated by an arrow B in FIG. 2, a high-pressure fluid
flowing through the diffuser flow path 23 flows from the radially
outer side toward the radially inner side.
[0086] Here, between the impeller 4 as the rotating body R and the
casing 3 as the stationary body S, a frictional resistance (disk
friction loss) is generated via the fluid flowing through the flow
path F1 and the flow path F2. In particular, in a case of the
centrifugal compressor 100, since the outer diameter of the
impeller 4 increases as the lifting height increases, it is known
that the disk friction loss increases.
[0087] Here, in the present embodiment, as shown in FIG. 3, the
disk back surface 41A of the impeller 4 is provided with a rotation
side projection portion 80 (hereinafter, referred to as a
projection portion 80) for controlling the flow of the fluid
flowing through the flow path F1. In FIG. 3, the periphery of the
disk back surface 41A and the casing back surface 3A is shown in a
simplified manner, and in order to generalize the description, the
disk back surface 41A is referred to as a first facing surface P1,
and the casing back surface 3A is referred to as a second facing
surface P2. A space between the first facing surface P1 and the
second facing surface P2 corresponds to the above-described flow
path F1. The projection portion 80 is provided on the outer side of
the position of 50% of the radius of the first facing surface
P1.
[0088] The projection portion 80 projects in the direction of the
axis O from the first facing surface P1 toward the second facing
surface P2. The dimension of the projection portion 80 in the
radial direction gradually decreases going from the first facing
surface P1 side toward the second facing surface P2 side.
Accordingly, the projection portion 80 has a tapered shape in a
sectional view including the axis O. A clearance C is formed
between a tip end of the projection portion 80 and the second
facing surface P2.
[0089] The first facing surface P1 is partitioned into a first
inner region P11 on the radially inner side and a first outer
region P12 on the radially outer side with the projection portion
80 as a standard. The first inner region P11 is parallel to the
second facing surface P2 in a sectional view including the axis O.
The first outer region P12 is positioned on the side spaced apart
from the second facing surface P2 further than the first inner
region P11 in the direction of the axis O. In other words, the
distance between the first outer region P12 and the second facing
surface P2 is larger than the distance between the first inner
region P11 and the second facing surface P2. In addition, the
distance between the first outer region P12 and the second facing
surface P2 may be the same as the distance between the first inner
region P11 and the second facing surface P2. Further, the distance
between the first outer region P12 and the second facing surface P2
may be smaller than the distance between the first inner region P11
and the second facing surface P2.
[0090] The end edge on the radially outer side of the second facing
surface P2 is connected to an outer wall surface P3 that widens in
the direction of the axis O. The outer wall surface P3 corresponds
to a casing inner circumferential surface 3D which is an inner
circumferential surface of the casing facing the end edge on the
radially outer side of the impeller 4 in FIG. 2.
[0091] Next, the behavior of the fluid in the above-described flow
path F1 will be described. As shown in FIG. 3, the fluid flowing
toward the radially outer side in the flow path F1 flows toward the
second facing surface P2 along the projection portion 80 provided
on the first facing surface P1. In other words, the flow of the
fluid is peeled off from the first facing surface P1 and flows to
the stationary body S side. Thereafter, the fluid passes through
the clearance C between the projection portion 80 and the second
facing surface P2. At this time, a flow velocity of the fluid
increases. From the flow of the fluid having a high flow velocity,
some components are separated toward the rotating body R side (that
is, the first facing surface P1 side). The peeled flow forms a
vortex (stagnation) in a region close to the first facing surface
P1 and on the radially outer side of the projection portion 80.
More specifically, the vortex flows toward the radially outer side,
and then flows from the radially outer side toward the projection
portion 80 along the first facing surface P1. By forming such a
vortex constantly, the remaining flow components except for the
vortex are inhibited by the vortex and flow toward the radially
outer side at a position close to the stationary body S side
(second facing surface P2 side). As a result, a friction loss
between the first facing surface P1 and the second facing surface
P2 can be reduced.
[0092] Furthermore, according to the configuration, the first outer
region P12 positioned on the radially outer side nipping the
projection portion 80 widens to the position further away from the
second facing surface P2 than the first inner region P11 positioned
on the radially inner side. Therefore, the region where the vortex
is formed on the first outer region P12 side can be enlarged.
Accordingly, as the remaining flow components except for the vortex
are inhibited by the vortex, the remaining flow components flow
toward the radially outer side at a position close to the
stationary body S side (second facing surface P2 side). As a
result, a friction loss between the first facing surface P1 and the
second facing surface P2 can further be reduced.
[0093] In addition, in the configuration, the projection portion 80
is provided on the outer side of the position of 50% of the radius
of the first facing surface P1. Here, as the position is on the
radially outer side of the first facing surface P1 that is the
rotating body R, the speed in the rotational direction with respect
to the stationary body S increases, and thus, the friction at the
position increases. According to the configuration, since the
projection portion 80 is provided at a position where the friction
is large in this manner, the friction reduction by the projection
portion 80 can be realized more effectively.
[0094] The first embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, the first inner
region P11 and the first outer region P12 may have the same
position in the direction of the axis O. According to the
configuration, the first inner region P11 and the first outer
region P12 can be formed only by providing the projection portion
80 on the first facing surface P1 formed in advance in a planar
shape. Accordingly, the cost and time required for manufacturing
the apparatus can be reduced.
Second Embodiment
[0095] Next, a second embodiment of the present invention will be
described with reference to FIG. 4. In addition, the same
configuration elements as those of the first embodiment will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 4, in the present
embodiment, a configuration of a first outer region P12' is
different from that of the first embodiment. The first outer region
P12' extends in the direction gradually spaced apart from the
second facing surface P2 as going from the radially inner side
toward the radially outer side in a sectional view including the
axis O. In other words, the first outer region P12' is inclined
with respect to the second facing surface P2. Further, an end edge
on the radially inner side of the first outer region P12' is
positioned on the side spaced apart from the second facing surface
P2 further than the first inner region P11 in the direction of the
axis O.
[0096] According to the configuration, the first outer region P12'
extends in the direction gradually spaced apart from the second
facing surface P2 as going toward the radially outer side in a
sectional view including the axis O. Therefore, the region where
the vortex is formed on the first outer region P12' side can
further be enlarged. Accordingly, as the remaining flow components
except for the vortex are inhibited by the vortex, the remaining
flow components flow toward the radially outer side at a position
close to the stationary body S side (second facing surface P2
side). As a result, a friction loss between the first facing
surface P1 and the second facing surface P2 can further be
reduced.
[0097] The second embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, it is also possible
to adopt a configuration shown in FIG. 5. In the example of the
same drawing, the second outer region P21 which is a region on the
radially outer side of the projection portion 80 on the second
facing surface P2 extends in a direction gradually spaced apart
from the first facing surface P1 as going from the radially inner
side toward the radially outer side in a sectional view including
the axis O. According to such a configuration, the flow path
sectional area between the second outer region P21 and the first
facing surface P1 is gradually enlarged toward the radially outer
side in the radial direction, and accordingly an effect as a
diffuser is achieved. As a result, the flow velocity of the fluid
that flows through the second outer region P21 decreases, and the
formation of the vortex on the first outer region P12' side can be
promoted.
Third Embodiment
[0098] Next, a third embodiment of the present invention will be
described with reference to FIG. 6. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 6, in the present
embodiment, a stationary side projection portion 90 is provided at
a position facing the projection portion 80 on the second facing
surface P2. The stationary side projection portion 90 projects from
the second facing surface P2 toward the first facing surface P1
side. The stationary side projection portion 90 has a rectangular
sectional shape in a sectional view including the axis O. In other
words, the end surface facing the first facing surface P1 side in
the stationary side projection portion 90 is formed in a planar
shape that widens in a plane intersecting the axis O. The clearance
C is formed between the stationary side projection portion 90 and
the projection portion 80.
[0099] According to the configuration, the stationary side
projection portion 90 which projects toward the projection portion
80 is provided at the position facing the projection portion 80 on
the second facing surface P2. By providing the stationary side
projection portion 90, the position of the clearance C formed
between the projection portion 80 and the stationary side
projection portion 90 in the direction of the axis O can be
adjusted. Accordingly, the position of the region where the vortex
is formed can be adjusted appropriately.
[0100] Furthermore, according to the configuration, the end surface
of the stationary side projection portion 90 is formed in a planar
shape that widens in a plane intersecting the axis O. Therefore,
for example, even in a case where the projection portion 80 is
relatively displaced in the radial direction with respect to the
stationary side projection portion 90, it is possible to reduce a
possibility that the size or the opening direction of the clearance
C between the projection portion 80 and the stationary side
projection portion 90 changes.
[0101] The third embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, the stationary side
projection portion 90 described in the third embodiment can also be
configured as shown in FIGS. 7 and 8. In the example of the
drawings, a plurality of stationary side projection portions 90B is
provided at intervals in the circumferential direction with respect
to the axis O. Furthermore, each stationary side projection portion
90B has an airfoil shape that extends toward a front side in a
rotational direction Dr of the rotating body R as going from the
radially inner side toward the radially outer side when viewed from
the direction of the axis O. According to the configuration, when
the fluid passes between the plurality of stationary side
projection portions 90B, a swirl flow component toward the front
side in a rotational direction Dr of the rotating body R can be
added to the fluid. As a result, the peeling of the flow from the
second facing surface P2 is promoted, and an increase in the
circumferential velocity component of the vortex on the first
facing surface P1 side can be promoted.
Fourth Embodiment
[0102] Next, a fourth embodiment of the present invention will be
described with reference to FIG. 9. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 9, in the present
embodiment, a second outer region P21' which is a region on the
radially outer side from the projection portion 80 on the second
facing surface P2 extends in a direction gradually spaced apart
from the first facing surface P1 starting from an end edge of the
stationary side projection portion 90 on the first facing surface
P1 side as going from the radially inner side toward the radially
outer side in a sectional view including the axis O. In other
words, the second outer region P21' is inclined with respect to the
first facing surface P1.
[0103] According to the configuration, the second outer region P21'
on the second facing surface P2 extends in the direction gradually
spaced apart from the first facing surface P1 starting from the end
edge of the projection portion 80 as going toward the radially
outer side in a sectional view including the axis O. Accordingly,
as the flow path sectional area between the second outer region
P21' and the first facing surface P1 is gradually enlarged as going
toward the radially outer side, an effect as a diffuser can be
achieved. As a result, the flow velocity of the fluid that flows
along the second outer region P21' decreases, and the formation of
the vortex in the vicinity of the second outer region side P21' can
be promoted.
[0104] The fourth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Fifth Embodiment
[0105] Next, a fifth embodiment of the present invention will be
described with reference to FIG. 10. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 10, in the present
embodiment, a plurality (two) of projection portions 80 are
provided at intervals in the radial direction on the first facing
surface P1. The two projection portions 80 have the same shape.
[0106] According to the configuration, since the plurality of
projection portions 80 are provided at intervals in the radial
direction on the first facing surface P1, in a wider region on the
first facing surface P1, the friction loss between the rotating
body R side and the stationary body S side can be reduced
uniformly.
[0107] The fifth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, in the fifth
embodiment, an example in which the two projection portions 80 are
provided at intervals in the radial direction has been described.
However, the number of the provided projection portions 80 is not
limited to the description above, and may be three or more.
Sixth Embodiment
[0108] Next, a sixth embodiment of the present invention will be
described with reference to FIG. 11. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. In the present embodiment, the periphery
of the cover upstream surface 43B and the casing upstream surface
3B described with reference to FIG. 2 in the first embodiment will
be described. In FIG. 11, the periphery of the cover upstream
surface 43B and the casing upstream surface 3B is shown in a
simplified manner, and in order to generalize the description, the
cover upstream surface 43B is referred to as the first facing
surface P1 and the casing upstream surface 3B is referred to as a
second facing surface P2. A space between the first facing surface
P1 and the second facing surface P2 corresponds to the flow path F2
described in the first embodiment. In the flow path F2, as
indicated by an arrow B in FIG. 2, a high-pressure fluid flowing
through the diffuser flow path 23 flows from the radially outer
side toward the radially inner side.
[0109] Here, between the impeller 4 as the rotating body R and the
casing 3 as the stationary body S, a frictional resistance (disk
friction loss) is generated via the fluid flowing through the
above-described flow path F2. In particular, in a case of the
centrifugal compressor 100, since the outer diameter of the
impeller 4 increases as the lifting height increases, it is known
that the disk friction loss increases. Here, in the present
embodiment, as shown in FIG. 11, on the first facing surface P1, a
projection portion 80B is provided for controlling the flow of the
fluid flowing through the flow path F2.
[0110] The projection portion 80B is provided at a position on the
most radially outer side on the first facing surface P1. The
projection portion 80B projects toward the second facing surface P2
and has an annular shape around the axis O. The projection portion
80B faces the second facing surface P2 with a clearance C
therebetween.
[0111] According to the configuration, the fluid that flows toward
the radially inner side in the flow path F2 flows toward the second
facing surface P2 side along the projection portion 80B provided on
the first facing surface P1. In other words, the flow of the fluid
is peeled off from the first facing surface P1 and flows to the
stationary body S side. Thereafter, the fluid passes through the
clearance C between the projection portion 80B and the second
facing surface P2. At this time, a flow velocity of the fluid
increases. From the flow of the fluid having a high flow velocity,
some components are separated toward the rotating body R side (that
is, the first facing surface P1 side). The peeled flow forms a
vortex (stagnation) in a region close to the first facing surface
P1 and on the radially inner side of the projection portion 80B.
More specifically, the vortex flows toward the radially inner side,
and then flows from the radially outer side to the radially inner
side toward the projection portion 80B along the first facing
surface P1. By forming such a vortex constantly, the remaining flow
components except for the vortex are inhibited by the vortex and
flow toward the radially inner side at a position close to the
stationary body S side (second facing surface P2 side). As a
result, a friction loss between the first facing surface P1 and the
second facing surface P2 can be reduced.
[0112] The sixth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Seventh Embodiment
[0113] Next, a seventh embodiment of the present invention will be
described with reference to FIG. 12. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 12, in the present
embodiment, a recess portion 10 is formed at the position adjacent
to the radially inner side of the projection portion 80B on the
first facing surface P1. The recess portion 10 is recessed in a
direction spaced apart from the second facing surface P2. In a
sectional view including the axis O, the recess portion 10 has a
rectangular sectional shape. A recess portion bottom surface P4
which is a bottom surface (the surface facing the second facing
surface P2) of the recess portion 10 widens in the radial direction
with respect to the axis O.
[0114] According to the configuration, the recess portion 10 is
formed adjacent to the radially inner side of the projection
portion 80B. By providing the recess portion 10, the region where
the vortex is formed can be enlarged. Accordingly, as the remaining
flow components except for the vortex are inhibited by the vortex,
the remaining flow components flow toward the radially inner side
at a position close to the stationary body S side (second facing
surface P2 side). As a result, a friction loss between the first
facing surface P1 and the second facing surface P2 can further be
reduced.
[0115] The seventh embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Eighth Embodiment
[0116] Next, an eighth embodiment of the present invention will be
described with reference to FIG. 13. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 13, in the present
embodiment, the bottom surface (recess portion bottom surface P4')
of the recess portion 10 described in the seventh embodiment is
inclined with respect to the radial direction of the axis O. More
specifically, the recess portion bottom surface P4' extends in the
direction gradually spaced apart from the second facing surface P2
as going from the radially inner side toward the radially outer
side in a sectional view including the axis O.
[0117] According to the configuration, the recess portion bottom
surface P4' extends in the direction gradually spaced apart from
the second facing surface P2 as going toward the radially outer
side in a sectional view including the axis O. Therefore, the
region where the vortex is formed can be further enlarged.
Accordingly, as the remaining flow components except for the vortex
are inhibited by the vortex, the remaining flow components flow
toward the radially inner side at a position close to the
stationary body S side (second facing surface P2 side). As a
result, a friction loss between the first facing surface P1 and the
second facing surface can further be reduced.
[0118] The eighth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Ninth Embodiment
[0119] Next, a ninth embodiment of the present invention will be
described with reference to FIG. 14. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 14, in the present
embodiment, a stationary side recess portion 11 is provided in the
region facing the recess portion 10 on the second facing surface
P2. The stationary side recess portion 11 is recessed in a
direction spaced apart from the first facing surface P1. The bottom
surface (recess portion bottom surface P5) of the stationary side
recess portion 11 extends in the direction gradually spaced apart
from the first facing surface P1 as going from the radially outer
side toward the radially inner side in a sectional view including
the axis O. In other words, the recess portion bottom surface P5 is
inclined with respect to the first facing surface P1. Furthermore,
the end edge on the radially inner side of the recess portion
bottom surface P5 is connected to the end edge on the radially
outer side of the second facing surface P2 that widens in the
radial direction.
[0120] According to the configuration, the stationary side recess
portion 11 is formed in the region facing the recess portion 10 on
the second facing surface P2. Furthermore, the bottom surface
(recess portion bottom surface P5) of the stationary side recess
portion 11 extends in the direction gradually spaced apart from the
first facing surface P1 as going toward the radially inner side in
a sectional view including the axis O. Accordingly, as the flow
path sectional area between the recess portion 10 and the
stationary side recess portion 11 is gradually enlarged as going
toward the radially inner side, an effect as a diffuser can be
achieved. As a result, the flow velocity of the fluid that flows
into the recess portion 10 decreases, and the formation of the
vortex in the recess portion 10 can be promoted.
[0121] The ninth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Tenth Embodiment
[0122] Next, a tenth embodiment of the present invention will be
described with reference to FIG. 15. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and a detailed description
thereof will be omitted. As shown in FIG. 15, in the present
embodiment, the stationary side projection portion 90B is provided
at a position facing the projection portion 80B on the second
facing surface P2. The stationary side projection portion 90B
projects toward the projection portion 80B. The stationary side
projection portion 90B projects from the second facing surface P2
toward the first facing surface P1 side. The stationary side
projection portion 90B has a rectangular sectional shape in a
sectional view including the axis O. In other words, the end
surface facing the first facing surface P1 side in the stationary
side projection portion 90B is formed in a planar shape that widens
in a plane intersecting the axis O. The clearance C is formed
between the stationary side projection portion 90B and the
projection portion 80B.
[0123] According to the configuration, the stationary side
projection portion 90B which projects toward the projection portion
80B is provided at the position facing the projection portion 80B
on the second facing surface P2. By providing the stationary side
projection portion 90B, the position of the clearance C formed
between the projection portion 80B and the stationary side
projection portion 90B in the direction of the axis O can be
adjusted. Accordingly, the position of the region where the vortex
is formed can be adjusted appropriately.
[0124] Furthermore, according to the configuration, the end surface
of the stationary side projection portion 90B is formed in a planar
shape that widens in a plane intersecting the axis O. Therefore,
for example, even in a case where the projection portion 80B is
relatively displaced in the radial direction with respect to the
stationary side projection portion 90B, it is possible to reduce a
possibility that the size or the opening direction of the clearance
C between the projection portion 80B and the stationary side
projection portion 90B changes.
[0125] The tenth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, the stationary side
projection portion 90B in the tenth embodiment can also be
configured as described with reference to FIGS. 7 and 8 as a
modification example of the above-described fourth embodiment. In
other words, a configuration in which the plurality of stationary
side projection portions 90B are arranged at intervals in the
circumferential direction, and each stationary side projection
portion 90B extends toward the front side in a rotational direction
Dr of the rotating body R as going from the radially outer side
toward the radially inner side, can be employed.
Eleventh Embodiment
[0126] Next, an eleventh embodiment of the present invention will
be described with reference to FIG. 16. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 16, the region facing the
recess portion 10 on the second facing surface P2 (recess portion
facing surface P6) extends in a direction gradually spaced apart
from the first facing surface P1 as going from the radially outer
side toward the radially inner side in a sectional view including
the axis O. More specifically, the recess portion facing surface P6
extends radially inward starting from the tip end of the stationary
side projection portion 90B.
[0127] According to the configuration, the recess portion facing
surface P6 facing the recess portion 10 on the second facing
surface P2 extends in the direction gradually spaced apart from the
first facing surface P1 as going toward the radially inner side in
a sectional view including the axis O. Accordingly, as the flow
path sectional area between the second facing surface P2 and the
recess portion 10 is gradually enlarged as going toward the
radially inner side, an effect as a diffuser can be achieved. As a
result, the flow velocity of the fluid that flows between the
second facing surface P2 and the recess portion 10 decreases, and
the formation of the vortex in the recess portion 10 can be
promoted.
[0128] The eleventh embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention.
Twelfth Embodiment
[0129] Next, a twelfth embodiment of the present invention will be
described with reference to FIG. 17. In addition, the same
configuration elements as those of each of the embodiments will be
given the same reference numerals, and the detailed description
thereof will be omitted. As shown in FIG. 17, in the present
embodiment, the plurality (two) of projection portions 80B are
provided at intervals in the radial direction on the first facing
surface P1. The two projection portions 80B have the same
shape.
[0130] According to the configuration, since the plurality of
projection portions 80 are provided at intervals in the radial
direction on the first facing surface P1, in a wider region on the
first facing surface P1, the friction loss between the rotating
body R side and the stationary body S side can be reduced
uniformly.
[0131] The twelfth embodiment of the present invention has been
described above. In addition, various changes and modifications can
be made to the above-described configuration without departing from
the gist of the present invention. For example, in the twelfth
embodiment, an example in which the two projection portions 80 are
provided at intervals in the radial direction has been described.
However, the number of the provided projection portions 80 is not
limited to the description above, and may be three or more.
EXPLANATION OF REFERENCES
[0132] 100 centrifugal compressor (rotating machinery) [0133] 1
rotating shaft [0134] 2 fluid flow path [0135] 3 casing [0136] 3A
casing back surface [0137] 3B casing upstream surface [0138] 3D
casing inner circumferential surface [0139] 4 impeller [0140] 5
journal bearing [0141] 6 thrust bearing [0142] 7 intake port [0143]
8 exhaust port [0144] 10 recess portion [0145] 11 stationary side
recess portion [0146] 21 suction flow path [0147] 22 compression
flow path [0148] 23 diffuser flow path [0149] 24 return bend
portion [0150] 25 guide flow path [0151] 41 disk [0152] 41A disk
back surface [0153] 42 blade [0154] 43 cover [0155] 43B cover
upstream surface [0156] 50 return vane [0157] 80, 80B projection
portion (rotation side projection portion) [0158] 90, 90B
stationary side projection portion [0159] Dr front side in
rotational direction [0160] F1, F2 flow path [0161] O axis [0162]
P1 first facing surface [0163] P11 first inner region [0164] P12,
P12' first outer region [0165] P2 second facing surface [0166] P21,
P21' second outer region [0167] P3 outer wall surface [0168] P4,
P4', P5 recess portion bottom surface [0169] P6 recess portion
facing surface [0170] R rotating body [0171] S stationary body
* * * * *