U.S. patent application number 15/039312 was filed with the patent office on 2017-06-15 for impeller and centrifugal compressor.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION, MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Shinji IWAMOTO, Ryosuke SAITO.
Application Number | 20170167501 15/039312 |
Document ID | / |
Family ID | 53681066 |
Filed Date | 2017-06-15 |
United States Patent
Application |
20170167501 |
Kind Code |
A1 |
SAITO; Ryosuke ; et
al. |
June 15, 2017 |
IMPELLER AND CENTRIFUGAL COMPRESSOR
Abstract
The present invention is provided with: a disk (2) that rotates
around an axis (O); and, on the surface of one axial (O) side of
the disk (2), a plurality of blades (3) that are provided at
intervals in the circumferential direction and demarcate a channel
(10) in which a fluid that flows in from one side in the axial (O)
direction is discharged toward the outer side in the radial
direction. Therein, holes (H) are formed in the blades (3), said
holes communicating with a pressure surface (p) that faces the
front side in the rotational direction, and with a suction surface
(n) that faces the rear side in the rotational direction.
Inventors: |
SAITO; Ryosuke; (Tokyo,
JP) ; IWAMOTO; Shinji; (Hiroshima-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD.
MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION |
Tokyo
Tokyo |
|
JP
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION
Tokyo
JP
|
Family ID: |
53681066 |
Appl. No.: |
15/039312 |
Filed: |
July 23, 2014 |
PCT Filed: |
July 23, 2014 |
PCT NO: |
PCT/JP2014/069451 |
371 Date: |
May 25, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 17/12 20130101;
F04D 17/122 20130101; F04D 29/682 20130101; F04D 29/684 20130101;
F04D 29/681 20130101; F04D 29/30 20130101; F04D 29/667 20130101;
F04D 29/284 20130101 |
International
Class: |
F04D 29/30 20060101
F04D029/30; F04D 29/66 20060101 F04D029/66; F04D 17/12 20060101
F04D017/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2014 |
JP |
2014-009680 |
Claims
1. An impeller comprising: a disk which rotates around an axis; and
a plurality of blades which are provided at intervals therebetween
in a circumferential direction on one side surface in an axial
direction of the disk, and demarcate a channel through which a
fluid flowing in from the one side in the axial direction is
discharged toward the outside in a radial direction, wherein a hole
is formed in the blade, and the hole communicates with a pressure
surface facing a front side in a rotational direction and a suction
surface facing a rear side in the rotational direction.
2. The impeller according to claim 1, wherein the hole extends
toward a downstream side of the channel as the hole is directed
from the pressure surface side to the suction surface side.
3. The impeller according to claim 1 or 2, wherein a plurality of
holes are arranged so as to be separated from each other from the
inside in the radial direction toward the outside in the radial
direction.
4. The impeller according to claim 1, wherein an opening area of
the hole increases from the pressure surface side toward the
suction surface side.
5. The impeller according to claim 1, wherein the opening area of
the hole decreases from the pressure surface side toward the
suction surface side.
6. The impeller according to claim 1, wherein the hole has a groove
which is spirally formed on an inner peripheral surface of the
hole.
7. The impeller according to claim 1, wherein the hole includes one
inflow port which is provided on the pressure surface side, and a
plurality of injection ports which communicate with the inflow port
and are provided on the suction surface side.
8. A centrifugal compressor comprising the impeller according to
claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to an impeller and a
centrifugal compressor.
[0002] Priority is claimed on Japanese Patent Application No.
2014-009680, filed Jan. 22, 2014, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] In general, in a centrifugal compressor or a diagonal
compressor which is used in a rotary machine such as an industrial
compressor, a turbo chiller, or a small gas turbine, performance
improvement is required, and particularly, performance improvement
of an impeller which is a key component of the compressors is
required. In addition, in recent years, various means for improving
the performance of the impeller have been suggested.
[0004] PTL 1 discloses that cross bleed holes penetrating both
surface of a shroudless blade are provided on the shroudless blade
which is used in a fan of a compressor or an axial flow gas
turbine. The cross bleed holes are provided in the vicinity of a
tip of the blade.
CITATION LIST
Patent Literature
[0005] [PTL 1] Specification of US Unexamined Patent Application
Publication No. 2010/0329848
SUMMARY OF INVENTION
Technical Problem
[0006] However, in the shroudless blade of PTL 1, since a swirl is
formed due to a secondary flow at a region on the outside in a
radial direction on a suction surface side of the blade, a low
energy fluid stays in the region, and energy loss of an impeller
occurs.
[0007] The present invention is made to solve the above-described
problem and is to provide an impeller in which energy loss
decreases and efficiency increases.
Solution to Problem
[0008] In order to solve the problem, in an impeller and a
centrifugal compressor according to a first aspect of the present
invention, the following means is adopted.
[0009] According to a first aspect of the present invention, there
is provided an impeller including: a disk which rotates around an
axis; and a plurality of blades which are provided at intervals
therebetween in a circumferential direction on one side surface in
an axial direction of the disk, and demarcate a channel through
which a fluid flowing in from the one side in the axial direction
is discharged toward the outside in a radial direction, in which a
hole is formed in the blade, and the hole communicates with a
pressure surface facing a front side in a rotational direction and
a suction surface facing a rear side in the rotational
direction.
[0010] According to this configuration, a portion of the fluid
flowing into the inner portion of the channel is injected to the
inner portion of the channel of the suction surface side as a jet
stream via the hole. It is possible to dissipate a secondary flow
and a swirl generated in the suction surface side of the blade by
the jet stream.
[0011] In addition, in the impeller according to a second aspect of
the present invention, in the first aspect, the hole may extend
toward a downstream side of the channel as the hole is directed
from the pressure surface side to the suction surface side.
[0012] According to this configuration, since the jet stream
injected from the hole flows in approximately the same direction as
that of a main stream of the fluid on the suction surface side of
the channel, it is possible to dissipate the secondary flow and the
swirl without interfering with the flow of the main stream.
[0013] Moreover, in the impeller according to a third aspect of the
present invention, in the first or second aspect, a plurality of
holes may be arranged so as to be separated from each other from
the inside in the radial direction of a duct toward the outside in
the radial direction.
[0014] According to this configuration, since a flow rate of the
jet stream injected from the hole increases and the jet stream is
injected to a wider region on the suction surface side, it is
possible to more effectively dissipate the secondary flow and the
swirl generated on the suction surface side.
[0015] In addition, in the impeller according to a fourth aspect of
the present invention, in any one of the first to third aspects, an
opening area of the hole may increase from the pressure surface
side toward the suction surface side.
[0016] According to this configuration, it is possible to
appropriately adjust a pressure of the jet stream injected from the
hole so as to be decreased. Accordingly, the jet stream is
appropriately adjusted so as not to interfere with the flow of the
main stream, and it is possible to effectively dissipate the
secondary flow and the swirl.
[0017] Moreover, in the impeller according to a fifth aspect of the
present invention, in any one of the first to fourth aspects, the
opening area of the hole may decrease from the pressure surface
side toward the suction surface side.
[0018] According to this configuration, it is possible to
appropriately adjust a pressure of the jet stream injected from the
hole so as to be increased. Accordingly, the jet stream is
appropriately adjusted so as not to interfere with the flow of the
main stream, and it is possible to effectively dissipate the
secondary flow and the swirl.
[0019] In addition, in the impeller according to a sixth aspect of
the present invention, in any one of the first to fifth aspects,
the hole may have a groove which is spirally formed on an inner
peripheral surface of the hole.
[0020] According to this configuration, due to the spiral groove,
swirling components are applied to the jet stream injected from the
hole. Since the fluid including the swirling components collides
with the secondary flow and the swirl, it is possible to more
effectively dissipate the secondary flow and the swirl.
[0021] Moreover, in the impeller according to a seventh aspect of
the present invention, in any one of the first to fifth aspects,
the hole may have one inflow port which is provided on the pressure
surface side, and may have a plurality of injection ports which
communicate with the inflow port and are provided on the suction
surface side.
[0022] According to this configuration, since the plurality of
injection ports are provided on the suction surface side while one
inflow port is provided on the pressure surface side, the jet
stream is injected to a wider region on the suction surface side,
and it is possible to more effectively dissipate the secondary flow
and the swirl generated on the suction surface side.
[0023] In addition, according to an eight aspect of the present
invention, there is provided a centrifugal compressor including the
impeller according to any one of the first to seventh aspects.
Advantageous Effects of Invention
[0024] According to the impeller of the present invention, it is
possible to provide an impeller in which energy loss decreases and
efficiency increases.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a sectional view showing an outline of a
centrifugal compressor according to the present invention.
[0026] FIG. 2 is a circumferential sectional view of an impeller
according to a first embodiment of the present invention.
[0027] FIG. 3 is a sectional view taken along line A-A of FIG. 1 in
a blade according to the first embodiment of the present
invention.
[0028] FIG. 4 is a view showing a region in which a hole H
according to each embodiment of the present invention is
provided.
[0029] FIG. 5 is a sectional view of a blade according to a second
embodiment of the present invention.
[0030] FIG. 6 is a sectional view showing a modification example of
the blade according to the second embodiment of the present
invention.
[0031] FIG. 7 is a sectional view of a blade according to a third
embodiment of the present invention.
[0032] FIG. 8 is a sectional view showing a modification example of
the blade according to the third embodiment of the present
invention.
[0033] FIG. 9 is a sectional view of a blade according to a fourth
embodiment of the present invention.
[0034] FIG. 10 is a sectional view of a blade according to a fifth
embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0035] Next, an impeller of a rotary machine in embodiments of the
present invention will be described with reference to the drawings.
In the embodiments, an impeller of a centrifugal compressor which
is a rotary machine will be described as an example.
First Embodiment
[0036] As shown in FIG. 1, for example, a centrifugal compressor
100 which is a rotary machine of the present embodiment is mainly
configured of a shaft 102 which rotates around an axis O, impellers
1 which are attached to the shaft 102 and compress a process gas
(gas) G using centrifugal force, and a casing 105 which rotatably
supports the shaft 102 and in which a channel 104 through which the
process gas G flows from an upstream side to a downstream side is
formed.
[0037] The casing 105 is formed so as to have an approximately
columnar outline and the shaft 102 is disposed so as to penetrate
the center of the casing 105. Journal bearings 105a are provided on
both ends of the casing 105 in the axial direction of the shaft
102, and a thrust bearing 105b is provided on one end. The journal
bearings 105a and the thrust bearing 105b rotatably support the
shaft 102. That is, the shaft 102 is supported by the casing 105
via the journal bearings 105a and the thrust bearing 105b.
[0038] Moreover, an intake port 105c through which the process gas
G flows in from the outside is provided on one end side of the
casing 105 in the axial direction, and an exhaust port 105d through
which the process gas G is discharged to the outside is provided on
the other end side. An internal space, which communicates with each
of the intake port 105c and the exhaust port 105d and in which an
increase in a diameter and a decrease in the diameter are repeated,
is provided in the casing 105. The internal space functions as a
space for accommodating the impellers 1 and functions as the
channel 104.
[0039] That is, the intake port 105c and the exhaust port 105d
communicate with each other via the impellers 1 and the channel
104.
[0040] The plurality of impellers 1 are arranged with intervals
therebetween in the axial direction of the shaft 102. In addition,
in FIG. 1, six impellers 1 are provided. However, at least one or
more impeller may be provided.
[0041] As shown in FIGS. 2 to 4, the impeller 1 is configured so as
to include a disk 2 and a plurality of blades 3. The disk 2 is
formed in an approximately circular shape in a front view, and is
rotatable around the shaft about the above-described axis O. In the
disk 2, a disk surface 4 is curvedly formed from a predetermined
position S on the inside in the radial direction slightly separated
toward the outside in the radial direction from the axis O toward
the outside in the radial direction. In the curvedly formed disk
surface 4, the surface positioned on the inside in the radial
direction is formed along the axis O, and is formed so as to be
gradually concaved in the radial direction toward the outside in
the radial direction. That is, the thickness of the disk 2 in the
axial direction decreases from one (upstream side) of the end
surfaces in the axial direction as the disk 2 is directed from the
position S on the inside in the radial direction which is slightly
separated from the axis O toward the outside in the radial
direction, and a decrease amount in the thickness of the disk 2 in
the axial direction becomes larger as the position of the thickness
moves inward and the decrease amount becomes smaller as the
position of the thickness moves outward.
[0042] In the above-described disk surface 4, the plurality of
blades 3 are approximately radially disposed and are erected so as
to be approximately perpendicular to the disk surface 4. The
thickness of each of the blades 3 is approximately uniformly formed
from an end portion of the blade of the disk surface 4 side to the
end portion of the tip side opposite to the disk surface 4
side.
[0043] In addition, when the blade 3 is viewed from the direction
of the axis O, the blade 3 has a shape which is curved so as to be
a slightly convex surface in a rotational direction of the disk 2
from the end portion on the inside in the radial direction to the
end portion on the outside in the radial direction. When the
impeller 1 rotates, in blade surfaces of the concave surface side
and the convex surface side of the curved blade 3, the blade
surface of the concave surface side which is the rear side of the
convex surface becomes a suction surface n while the blade surface
of the convex surface side becomes a pressure surface p.
[0044] FIG. 2 is a view showing a section taken along line A-A of
FIG. 1. In addition, line A-A is a line which passes through an
intermediate position in a height direction of the blade 3 based on
the disk surface 4. As shown in FIG. 2, a tip end t of the blade 3
is formed so as to be curved from the inside in the radial
direction of the disk 2 to the outside in the radial direction.
More specifically, similarly to the above-described disk surface 4,
the tip end is formed along the axis O as it is positioned on the
inside in the radial direction, and the tip end is formed so as to
be gradually concaved along the radial direction toward the outside
in the radial direction. In addition, the height of the blade 3
based on the disk surface 4 becomes high as the position of the
height is positioned further on the inside in the radial direction
of the disk 2, and the height becomes low as the position of the
height is positioned further on the outside in the radial
direction.
[0045] In the impeller 1, the tip end t side of the blade 3 is
covered by the casing 105 (refer to FIG. 1), and an impeller
channel 10 of the impeller 1 is configured of a shroud surface 5
which is configured by the casing 105, the pressure surface p and
the suction surface n of the blade 3 which are adjacent to each
other, and the disk surface 4 between the pressure surface p and
the suction surface n. That is, two impeller channels 10 and 10 are
configured so as to be adjacent to each other via one blade 3.
[0046] In addition, a hole H which penetrates the blade 3 from the
pressure surface p toward the suction surface n is formed in the
middle of the extension of the blade 3. The hole H is formed to
penetrate the blade 3 so as to have a predetermined angle with
respect to the thickness direction of the blade 3. In other words,
in the hole H, a position of an inflow port H1 on the pressure
surface p side and a position of an injection port H2 on the
suction surface n side are formed so as to be deviated from each
other when viewed in the circumferential direction of the disk 2,
and the inflow port H1 and the injection port H2 are formed so as
to linearly communicate with each other. That is, the impeller
channels 10 and 10 adjacent to each other via the blade 3
communicate with each other by the hole H.
[0047] Moreover, in the present embodiment, when viewed in the
circumferential direction of the impeller 1, the penetrating
direction of the hole H is set so as to be approximately the same
as a line which connects intermediate positions in the height
direction of the blade 3 based on the disk surface 4 in the axial
direction.
[0048] A sectional shape of the hole H when viewed in the
penetrating direction of the hole H is circular. Here, an opening
size of the hole H is approximately determined according to design.
However, in the present embodiment, the opening size of the inflow
port H1 of the hole H is the same as that of the injection port H2
of the hole H.
[0049] Next, in a case where the blade 3 is viewed from the
pressure surface p side, the position at which the hole H (inflow
port H1) is provided will be described with reference to FIG. 4.
That is, the position at which the hole H is provided is inside a
region A in FIG. 4. The region A is a region which is surrounded by
a virtual curve L1 along a flow direction of a fluid on the surface
of the blade 3, virtual curves L2 and L3 orthogonal to the virtual
curve L1, and the disk surface 4.
[0050] As described above, the virtual curve L1 is curved along the
flow direction of the fluid, and is set so as to pass through
approximately 60% of the positions of the height from the disk
surface 4 to the tip end t of the blade 3. Moreover, the virtual
curve L2 is set so as to pass through approximately 20% of the
positions of the dimension from an end edge of an inlet 6 side of
the impeller channel 10 to an end edge of an outlet 7 side in the
blade 3. Similarly, the virtual curve L3 is set so as to pass
through approximately 60% of the positions of the dimension from
the end edge of the inlet 6 side to the end edge of the outlet 7
side. That is, the region A is an approximately rectangular region
which includes the pair of long sides formed arcuately and the pair
of short sides connecting the long sides, and similarly to the disk
surface 4, the region A is formed along the axis O as it is
positioned on the inside in the radial direction, and the region A
is formed so as to be gradually concaved along the radial direction
as it is directed the outside in the radial direction. In addition,
the height of the blade 3 based on the disk surface 4 becomes
higher as the position of the height is positioned on the inside in
the radial direction of the disk 2, and the height becomes lower as
the position of the height is positioned on the outside in the
radial direction.
[0051] Moreover, in the above description, the position at which
the inflow port H1 is provided on the pressure surface p side is
described. However, similarly to the inflow port H1, the injection
port H2 is also formed so as to be included inside the region
A.
[0052] As described above, in the impeller 1, the tip end t side of
the blade 3 is covered by the casing 105 (refer to FIG. 1), and the
impeller channel 10 of the impeller 1 is configured of the shroud
surface 5 which is configured by the casing 105, the pressure
surface p and the suction surface n of the blade 3 which are
adjacent to each other, and the disk surface 4 between the pressure
surface p and the suction surface n. Accordingly, by rotating the
impeller 1, a fluid flows in from the inlet 6 of the impeller
channel 10 positioned on the inside in the radial direction of the
disk 2, and the fluid flows to the outside from the outlet 7
positioned on the outside in the radial direction by centrifugal
force. That is, as shown in FIG. 2, the fluid forms a main stream
F. Moreover, the main stream F follows the curved direction of the
disk surface 4. In addition, the main stream F exists over the
entire height direction of the blade 3. However, in FIG. 2, a
representative direction of the main stream F is shown by one
arrow.
[0053] Here, the state of the main stream F in a case where the
hole H is not provided in the blade 3 is described. That is, the
flow direction is gradually changed from the axial direction to the
radial direction as the impeller channel 10 is directed from the
inside in the radial direction of the disk 2 to the outside in the
radial direction, and as described above, the impeller channel 10
is curvedly formed from the inlet 6 toward the outlet 7. Due to the
impeller channel 10 being curvedly formed and centrifugal force
toward the outside in the radial direction being generated
according to the rotation of the impeller 1, in the impeller
channel 10, a secondary flow F2 shown by a dashed arrow in FIG. 2
is formed in addition to the main stream F. In the case where the
hole H is not formed in the blade 3, the secondary flow F2 reaches
a region k of the shroud surface 5 side close to the suction
surface n of a latter half portion 11 of the outlet 7 side of the
impeller channel 10, and forms a swirl. That is, the secondary flow
F2 stays in the region k as a fluid having low energy.
[0054] However, in the present embodiment, the hole H penetrating
the blade 3 from the pressure surface p toward the suction surface
n is formed in the middle of the extension of the blade 3. In this
case, a portion of the fluid flowing in from the inlet 6 of the
impeller channel flows into the hole H from the inflow port H1 of
the pressure surface p side, and is injected toward the adjacent
impeller channel 10 (the impeller channel 10 positioned on the rear
side in the rotational direction of the impeller 1) via the blade 3
from the injection port H2 of the suction surface n. In addition,
the fluid injected from the injection port H2 forms a jet stream
FJ. As described above, the hole H penetrates the blade 3 in the
same direction as the extension direction of the line which
connects the intermediate positions in the height direction of the
blade 3 based on the disk surface 4. That is, the direction of the
hole H is approximately the same as the direction of the main
stream F flowing in the vicinity of the hole H. Accordingly, the
flow direction of the jet stream FJ injected from the hole H is
approximately the same as the direction of the main stream F.
[0055] Accordingly, the jet stream FJ having approximately the same
directional components as those of the main stream F collides with
the secondary flow F2 having directional components different from
those of the flow direction of the main stream F. Here, since an
opening volume of the hole H is sufficiently smaller than a volume
of the impeller channel 10, the jet stream FJ passing through the
hole H has a higher pressure than that of the vicinity of the jet
stream FJ. In other words, the jet stream FJ has a higher flow rate
than that of the secondary flow F2.
[0056] Accordingly, the secondary flow F2 is deviated by the jet
stream FJ, flows in approximately the same direction as that of the
jet stream FJ, that is, in the approximately the same direction as
that of the main stream F, and the directional components of the
secondary flow F2 directing the region k decrease.
[0057] As described above, in the impeller 1 according to the
present embodiment, the hole H, which communicates with the
pressure surface p facing the front side in the rotational
direction and the suction surface n facing the rear side in the
rotational direction, is formed in the blade 3.
[0058] Accordingly, the swirl generated in the region k due to the
secondary flow F2 decreases by the jet stream FJ injected from the
hole H, and components staying in the region k as a fluid having
low energy decrease. That is, in the impeller 1, pressure loss due
to the secondary flow F2 decreases, and it is possible to obtain
high efficiency.
[0059] In addition, the hole H extends toward the downstream side
of the impeller channel 10 as the hole is directed from the
pressure surface p side toward the suction surface n side.
[0060] Accordingly, with respect to the secondary flow F2 having
directional components different from those of the flow direction
of the main stream F, it is possible to form the jet stream FJ
having approximately the same directional components as those of
the main stream F.
Second Embodiment
[0061] Next, a second embodiment of the present invention will be
described with reference to FIG. 5. Moreover, the same reference
numerals are assigned to the same components as those of the first
embodiment, and detailed descriptions thereof are omitted.
[0062] FIG. 5 is a view showing the blade 3 of the impeller 1
according to the present embodiment. As shown in FIG. 5, in the
blade 3 according to the present embodiment, the opening area of
the injection port H2 provided on the suction surface n side is
larger than the opening area of the inflow port H1 provided on the
pressure surface p side. That is, the hole H is formed such that
the opening area increases from the pressure surface p side toward
the suction surface n side.
[0063] According to this configuration, unlike the case where the
hole H is formed in a linear tube shape, it is possible to adjust
the pressure of the jet stream FJ passing through the hole H so as
to be decreased. That is, it is possible to decrease the flow rate
of the jet stream FJ. Accordingly, it is possible to more
effectively decrease the secondary flow F2.
[0064] In addition, as shown in FIG. 6, in the blade 3 according to
the present embodiment, the hole H may be formed such that opening
area of the injection port H2 provided on the suction surface n
side is smaller than the opening area of the inflow port H1
provided on the pressure surface p side. That is, the hole H may be
formed such that the opening area decreases from the pressure
surface p side toward the suction surface n side.
[0065] According to this configuration, unlike the case where the
hole H is formed in a linear tube shape, it is possible to adjust
the pressure of the jet stream FJ passing through the hole H so as
to be increased. That is, it is possible to increase the flow rate
of the jet stream FJ. Accordingly, it is possible to more
effectively decrease the secondary flow F2.
Third Embodiment
[0066] Next, a third embodiment of the present invention will be
described with reference to FIG. 7. Moreover, the same reference
numerals are assigned to the same components as those of the above
described embodiments, and detailed descriptions thereof are
omitted.
[0067] As shown in FIG. 7, in the blade 3 according to the present
embodiment, the plurality of holes H are provided so as to be
separated from each other from the inside in the radial direction
of the disk 2 toward the outside in the radial direction. In FIG.
7, three holes H are shown. The three holes H are approximately
linearly arranged so as to be separated from the disk surface 4
from the hole H positioned on the inside in the radial direction
toward the hole H positioned on the outside in the radial
direction. In addition, all three holes are formed inside the
region A shown in FIG. 4.
[0068] According to this configuration, unlike a case where only
one hole H is provided, it is possible to inject the jet stream FJ
in a wider range. Therefore, it is possible to more effectively
decrease the secondary flow F2.
[0069] In addition, as shown in FIG. 8, three holes H may be
arranged along the height direction of the blade 3 based on the
disk surface 4. In addition, according to this configuration, it is
possible to inject the jet stream FJ in a wider range, and it is
possible to more effectively decrease the secondary flow F2.
Fourth Embodiment
[0070] Next, a fourth embodiment of the present invention will be
described with reference to FIG. 9. Moreover, the same reference
numerals are assigned to the same components as those of the above
described embodiments, and detailed descriptions thereof are
omitted.
[0071] As shown in FIG. 9, in the blade 3 according to the present
embodiment, the hole H has a spiral groove C on the inner
peripheral surface of the hole H. The groove C is formed so as to
draw a circle along the inner peripheral surface of the hole H from
the pressure surface p side toward the suction surface n side. That
is, the groove C has a female screw shape. In addition, the
circumference direction of the groove C may be the clockwise
direction or the counterclockwise direction.
[0072] According to this configuration, it is possible to apply
swirling components based on the circumference direction of the
groove C to the jet stream FJ passing through the hole H.
Accordingly, when the jet stream FJ collides with the secondary
flow F2, since the flow including the swirling components diffuses
the secondary flow F2, it is possible to more effectively decrease
the secondary flow F2.
Fifth Embodiment
[0073] Next, a fifth embodiment of the present invention will be
described with reference to FIG. 10. Moreover, the same reference
numerals are assigned to the same components as those of the above
described embodiments, and detailed descriptions thereof are
omitted.
[0074] As shown in FIG. 10, in the blade 3 according to the present
embodiment, the hole H includes one inflow port H1 which is
provided on the pressure surface p side and a plurality of
injection ports H2 which are provided on the suction surface n
side. FIG. 10 shows a configuration in which three injection ports
H2 are provided. Each of the three injection ports H2 communicates
with one inflow port H1. In addition, the three injection ports H2
are arranged so as to be separated from each other from the inside
in the radial direction of the disk 2 toward the outside in the
radial direction. That is, three channels are formed inside the
hole H toward the injection ports H2 with the inflow path H1 as the
starting point. In addition, the channel which is positioned in the
innermost side in the radial direction among the three channels
linearly communicates with the inflow port H1.
[0075] According to this configuration, after the jet stream FJ
introduced from one inflow port H1 is divided into three streams
toward the three channels, the divided jet stream is injected from
the three injection ports H2 to the suction surface n side.
Accordingly, it is possible to supply the jet stream FJ to the
suction surface n side in a wide range. Moreover, since only one
inflow port H1 is provided on the pressure surface p side, the
components of the flow extracted from the main stream F so as to
form the jet stream FJ may decrease.
[0076] Accordingly, it is possible to more effectively decrease the
secondary flow F2, and it is possible to decrease the influence of
the jet stream FJ applied to the main stream F.
[0077] Hereinbefore, the embodiments of the present invention are
described with reference to the drawings. However, specific
configurations are not limited to the embodiments, and include
design modifications or the like within a scope which does not
depart from the gist of the present invention.
[0078] For example, in the above-described embodiments, the opening
shape of the hole H is circular. However, the opening shape of the
hole H is not limited to this, and may be a rectangular slit shape,
or a polygon such as a triangular shape. In addition, the opening
shape may be an elliptical shape.
INDUSTRIAL APPLICABILITY
[0079] According to the impeller of the present invention, it is
possible to provide an impeller in which energy loss decreases and
efficiency increases. It is possible to apply the impeller
according to the present invention to a rotary machine such as a
centrifugal compressor.
REFERENCE SIGNS LIST
[0080] 1: impeller [0081] 2: disk [0082] 3: blade [0083] 4: disk
surface [0084] 5: shroud surface [0085] 6: impeller channel inlet
[0086] 7: impeller channel outlet [0087] 10: impeller channel
[0088] 100: centrifugal compressor [0089] 102: shaft [0090] 104:
channel [0091] 105: casing [0092] F: main stream [0093] F2:
secondary flow [0094] FJ: jet stream [0095] H: hole
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