U.S. patent application number 14/649882 was filed with the patent office on 2015-11-05 for centrifugal gas compressor or pump comprising a toothed ring and a cowl.
This patent application is currently assigned to THY ENGINEERING. The applicant listed for this patent is LIEBHERR-AEROSPACE TOULOUSE SAS, THY ENGINEERING. Invention is credited to Stephan Aubin, Viviane Ciais, Mathieu Roumeas.
Application Number | 20150316071 14/649882 |
Document ID | / |
Family ID | 47714332 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150316071 |
Kind Code |
A1 |
Aubin; Stephan ; et
al. |
November 5, 2015 |
CENTRIFUGAL GAS COMPRESSOR OR PUMP COMPRISING A TOOTHED RING AND A
COWL
Abstract
A centrifugal gas compressor or pump comprising a body, a wheel
rotatably mounted within the body around a wheel axis, the wheel
comprising a hub, a set of blades fastened to the hub, the body
comprising a diffuser placed on the periphery of the wheel and a
fluid intake placed facing the hub, the blades comprising a first
edge facing the intake and a second edge facing the diffuser so
that a fluid travels from the intake to the diffuser, the second
edges being located inside a blade-enveloping cylinder centred on
the wheel axis. The wheel comprises a toothed ring fastened to the
wheel, which extends radially past the enveloping cylinder to form
a diffuser wall.
Inventors: |
Aubin; Stephan;
(MONTPELLIER, FR) ; Ciais; Viviane; (TOULOUSE,
FR) ; Roumeas; Mathieu; (ONDES, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THY ENGINEERING
LIEBHERR-AEROSPACE TOULOUSE SAS |
Ruitz
Toulouse |
|
FR
FR |
|
|
Assignee: |
THY ENGINEERING
RUITZ
FR
|
Family ID: |
47714332 |
Appl. No.: |
14/649882 |
Filed: |
December 4, 2013 |
PCT Filed: |
December 4, 2013 |
PCT NO: |
PCT/FR2013/052934 |
371 Date: |
June 4, 2015 |
Current U.S.
Class: |
415/204 ;
415/203 |
Current CPC
Class: |
F01D 5/34 20130101; F04D
29/284 20130101; F04D 17/10 20130101; F04D 29/441 20130101; F04D
1/00 20130101; F04D 29/22 20130101; F04D 29/445 20130101; F02C 6/12
20130101 |
International
Class: |
F04D 29/44 20060101
F04D029/44; F04D 29/28 20060101 F04D029/28; F04D 29/22 20060101
F04D029/22; F04D 1/00 20060101 F04D001/00; F04D 17/10 20060101
F04D017/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 4, 2012 |
FR |
1261612 |
Claims
1. A centrifugal gas compressor or pump comprising a body, a wheel
rotatively mounted in the body around a wheel axis the wheel
comprising a hub, a set of blades in attached to the hub, the body
comprising as diffuser placed on the periphery of the wheel and a
fluid intake placed opposite the hub, the blades comprising as
first edge opposite the intake and a second edge opposite the
diffuser so that a fluid circulates from the intake to the
diffuser, the second edges being located inside a blade-enveloping
cylinder centered on the wheel axis, wherein the wheel comprises at
least one ring, attached to the wheel and which extends radially
beyond the blade-enveloping cylinder to form a wall of the
diffuser.
2. A compressor or pump according to claim 1, wherein the body
comprises a volute around the diffuser.
3. A compressor or pump according to claim 2, wherein the ring is
inserted with play into a bore of the compressor body and is placed
in such a way that its diffuser side face is in the same plane as
the wall of the volute at this level.
4. A compressor or pump according to claim 1, wherein the ring
extends from the hub.
5. A compressor or pump according to claim 1, wherein the wheel
comprises as cowl attached to the blades.
6. A compressor or pump according to claim 5, wherein the ring
extends from the cowl.
7. A compressor or pump according to claim 4, wherein the cowl and
the blades are in one piece.
8. A compressor or pump according to claim 4, wherein the ring
forms one piece with the wheel extending from the hub.
Description
RELATED APPLICATIONS
[0001] This application is a National Phase entry of PCT
Application No. PCT/FR2013/052934, filed Dec. 4, 2013, which claims
priority from FR Application No. 1261612, filed Dec. 4, 2012, the
disclosures of which are hereby incorporated by referenced herein
in their entirety.
TECHNICAL FIELD
[0002] The invention relates to a rotating machine such as a
compressor of a centrifugal type for a gaseous fluid or a pump for
a liquid. In particular, it concerns the diffusion system of such a
machine.
BACKGROUND ART
[0003] Rotating machines such as a compressor of a centrifugal type
or a pump are widely used in industry, in particular in the field
of combustion engines. In particular, a turbine coupled on the same
shaft to a compressor is used to form a turbocompressor. The
turbine is supplied by the exhaust gases of an engine and drives
the compressor which compresses the fresh air to supercharge the
engine. Certain compressors are driven by an electric motor.
[0004] FIGS. 6 and 7 show a centrifugal compressor 11 according to
the prior art. The compressor 11 includes a compressor body 111 and
a rotating part rotatively mounted in the compressor body 111
around a wheel axis A. The rotating part comprises a compressor
wheel 112 mounted on a rotating shaft 114 in a bearing 113 of the
compressor body 111. The compressor wheel 112 comprises a hub 1120
and a set of blades 1121 attached to the hub. The compressor body
111 also comprises an axial opening placed opposite the hub 1120
and which comprises an intake 1110. The compressor body 111
comprises a volute 1112 around the compressor wheel 112. The volute
1112 comprises a peripheral opening placed on the periphery of the
compressor wheel 112 and leads to an outlet 1113 which extends
substantially in a direction tangent to the compressor wheel 112.
The peripheral opening is called a diffuser 1111. The blades 1121
comprise a first edge 11211, called a leading edge, opposite the
axial opening 1110 and a second edge 11212, called a trailing edge,
opposite the diffuser 1111 so that the gases circulate from the
axial opening 1110 to the diffuser 1111 being driven by the
compressor wheel 112. The shape of the blades 1121 is designed so
that the gases receive mechanical energy by the compressor wheel
112, that principally being accelerated, the kinetic energy thus
obtained then being converted into pressure in the volute.
[0005] Certain compressor wheel versions are cowled and comprise
for this purpose a cowl attached to the blades, the section of
which mates with that of the guide wall.
[0006] Machines of the same type can be used for a fluid no longer
gaseous, but liquid. In this case, the term pump is used instead of
compressor.
[0007] The speed of the fluid at the diffuser is high such that the
friction losses along the diffuser wall related to the viscosity of
the fluid are high. At this level, the tangential component of the
speed of the fluid is very high and often predominant. The aim of
the invention is to reduce these friction losses.
DETAILED DESCRIPTION
[0008] With these targets in mind, the object of the invention is a
centrifugal gas compressor or pump comprising a body, a wheel
rotatively mounted in the body around a wheel axis, the wheel
comprising a hub, a set of blades attached to the hub, the body
comprising a diffuser placed on the periphery of the wheel and a
fluid intake placed opposite the hub, the blades comprising a first
edge opposite the axial opening and the second edge opposite the
diffuser so that a fluid circulates from the intake to the
diffuser, the second edges being located inside a blade-enveloping
cylinder centered on the wheel axis, the wheel comprising at least
one ring attached to the wheel and which extends radially beyond
the blade-enveloping cylinder to form a diffuser wall.
[0009] A result of the ring is that the diffuser zone comprises a
wall which rotates at the same speed as that of the wheel. The
difference between the average speed of the fluid and this wall is
greatly reduced which allows the friction losses at this level to
be greatly reduced. Thus, less losses on the kinetic energy of the
fluid are obtained in the diffuser and, therefore, on the energy
supplied in the form of pressure at the volute outlet. It can also
be seen that the wheel is submitted to pressure forces the
resultant of which is an axial force. In particular, the pressure
which is presented on the face of the wheel which carries the
blades is in general very different to the one opposed to it. The
modification in the size of this face which results from adding the
ring beyond the first edge of the blades also modifies this result.
Thus, it is possible to adjust this result, in particular in the
case of a turbocompressor where the turbine wheel and the
compressor wheel exert axial forces in opposite directions.
[0010] In a particular manner, the ring is inserted with play in a
bore of the compressor body and is placed in such a way that its
diffuser side face is in the same plane as the wall of the volute
at this level. The gas flow which leaves the ring continues to be
guided without discontinuity by the wall of the volute thus
avoiding the creation of load losses.
[0011] According to an additional characteristic, the body
comprises a volute around the diffuser.
[0012] According to an embodiment, the ring extends from the
hub.
[0013] In a particular embodiment, the wheel comprises a cowl
attached to the blades. According to an improvement, the ring
extends from the cowl. Thus, the diffuser zone comprises a wall
possibly additional which rotates at the same speed as that of the
wheel. This ring can be alone. In combination with the ring in the
extension of the hub, the flow of the fluid is entirely channelled
in this zone by the walls which substantially move at the same
speed as the flow of the fluid, thus greatly reducing the friction
losses. The balance of the pressure forces can be exerted in a
direction opposite to that of the configuration with the ring in
the extension of the hub.
[0014] In a particular embodiment, the cowl and the blades are in
one piece.
[0015] According to another arrangement, the ring and the wheel in
the extension of the hub are in one piece. Thus the wheel is
provided with high mechanical strength. Manufacture requires only a
few modifications in the manufacturing technique.
BRIEF DESCRIPTION OF THE FIGURES
[0016] The invention will be better understood and other features
and advantages of the invention will become apparent on reading the
following description, the description making reference to the
appended drawings:
[0017] FIG. 1 is a longitudinal cross-sectional view of a machine
fulfilling the function of compressor in accordance with a first
embodiment of the invention;
[0018] FIG. 2 is a detailed view taken along the lines II of FIG.
1;
[0019] FIG. 3 is a longitudinal cross-sectional view of a
turbocompressor comprising a turbine and a compressor in accordance
with the invention;
[0020] FIGS. 4 and 5 are views similar to FIG. 2 of a compressor
wheel, but according to a third and a fourth embodiment of the
invention;
[0021] FIG. 6 is a longitudinal cross-sectional view through line
VI-VI of FIG. 7 of a centrifugal compressor according to the prior
art; and
[0022] FIG. 7 is a view of the compressor, the body being shown by
a cross-sectional view through line VII-VII of FIG. 6.
DETAILED DESCRIPTION
[0023] A compressor 21 in accordance with a first embodiment of the
invention, such as shown on FIGS. 1 and 2, includes a compressor
body 211 and a rotating part rotatively mounted in the compressor
body 211 around a wheel axis A. The rotating part includes a
compressor wheel 212 mounted on a rotating shaft 214 on a bearing
of the compressor body 211. The compressor wheel 212 comprises a
hub 2120 and a set of blades 2121 attached to the hub 2120. The
compressor body 211 also includes an axial opening placed opposite
the hub 2120 and which comprises an intake 2110. The compressor
body 211 includes a volute 2112 around the compressor wheel 212.
The volute 2112 includes a peripheral opening forming a diffuser
2111, placed on the periphery of the compressor wheel 212 and
leading to an outlet 2113 which substantially extends in a
direction tangential to the compressor wheel 212. The blades 2121
include a first edge 21211 opposite the gas intake and a second
edge 21212 opposite the diffuser 2111. The gases circulate from the
intake 2110 to the diffuser 2111 being driven by the compressor
wheel 212. The shape of the blades 2121 is designed so that the
gases accelerate when passing through the compressor wheel 212 by
means of the energy supplied by the wheel. The second edges 21212
extend substantially parallel to the wheel axis A and are contained
in a virtual cylinder called blade-enveloping cylinder C.
[0024] In compliance with the invention, the hub 2120 extends
beyond the fictive cylinder C in the form of a ring 21201. The ring
21201 thus delimits the diffuser 2111 on one of its sides. The ring
21201 is inserted with play in a bore 2114 of the compressor body
211 and is placed in such a way that its diffuser 211 side face is
in the same plane as the wall of the volute 2112 at this level.
[0025] In operation, the shaft 214 is rotationally driven by drive
means, not shown, at a speed which can be higher than 200,000
revolutions per minute. A gas flow is established between the gas
inlet 2110 and the outlet 2113. The speed of the gas at the outlet
of the wheel, at the second edge of the blades, has a tangential
component generally higher than the radial component. The relative
speed between the ring and the gas flow is essentially the radial
component and is therefore much lower than the speed of the gas
flow against the fixed wall of the diffuser according to prior art.
It can be seen that the losses related to the friction along the
wall rendered rotative are substantially divided by two in relation
to the fixed wall case, or even more in certain operating modes
where the gas speed has a dominant tangential component.
[0026] In the embodiment shown on FIG. 3, a turbocompressor
comprises a turbine 30 and a compressor 31 in compliance with the
invention. The wheels 302, 312 of the turbine 30 and of the
compressor 31 are mounted on the same shaft 32, which is rotatively
mounted by means of a bearing 33 placed between the body of the
compressor 311 and the body of the turbine 301. The bearing 33 is
formed, in this example, by two ball bearings.
[0027] The turbine 30 includes a turbine body 301 and a rotating
part rotatively mounted on the turbine body 301 around the wheel
axis A. The rotating part includes a turbine wheel 302 which
comprises a hub 3020 and a set of blades 3021 attached to the hub
3020. The turbine body 301 includes a turbine volute 3012 around
the turbine wheel 302. The volute 3012 comprises an intake 3013
which extends substantially in a tangential direction and leads to
a nozzle 3011 placed on the periphery of the turbine wheel 302. The
turbine body 301 also comprises an axial opening placed opposite
the hub 3020 and which acts as an outlet 3010 for the gases. The
turbine body 301 comprises a guide wall 3014 opposite the blades
3021 of the turbine wheel 302 in such a way as to leave only a
small space between the blades 3021 and the turbine body 301. The
purpose of the nozzle 3011 is to channel the gases which enter by
the intake 3013 into the turbine volute 3012 to be directed to the
blades 3021 of the turbine wheel 302 with an appropriate direction
and speed. The shape of the blades 3021 is designed so that the
gases are decompressed by passing through the turbine wheel 302 and
restore energy to it.
[0028] In the same way as for compressor 31, the turbine wheel 302
includes a ring 30201 extending from the hub 3020 beyond the
blade-enveloping cylinder C'. The ring 30201 forms one of the walls
of the nozzle 3011.
[0029] According to a third embodiment, shown on FIG. 4, the wheel
402 of a compressor also comprises a cowl 4022 attached to the
blades 4021 and channelling the gases between the cowl and the hub
4020. The cowl 4022 forms one piece with the blades 4021 but can be
attached by other means. In compliance with the invention, the cowl
is extended by a second ring 40220 opposite the ring 40201 which
extends the hub. Thus, the diffuser 4011 comprises two walls which
delimit it and are rotative to limit the friction losses.
[0030] According to a fourth embodiment, shown on FIG. 5, the wheel
502 of a compressor also includes a fixed cowl 5022 on the blades
5021, but only in the most peripheral part of the wheel 502. The
cowl 5022 forms one piece with the blades 5021, but can be attached
by other means. In compliance with the invention, the cowl is
extended by a second ring 50220, substantially parallel to the ring
50201 which extends the hub. Thus, the diffuser 5011 comprises two
walls which delimit it and which are rotative to limit the friction
losses.
[0031] The invention is not limited to the embodiments described
above which are provided only as an example. For instead, the ring
could equip only the cowl, the machines can circulate a liquid
instead of a gaseous fluid.
* * * * *