U.S. patent application number 14/842567 was filed with the patent office on 2016-03-03 for radial compressor stage.
This patent application is currently assigned to MAN DIESEL & TURBO SE. The applicant listed for this patent is Yves BIDAUT, Philipp JENNY, Thomas MOKULYS, Samuel SCHNEIDER, Christof SEEBASS-LINGGI. Invention is credited to Yves BIDAUT, Philipp JENNY, Thomas MOKULYS, Samuel SCHNEIDER, Christof SEEBASS-LINGGI.
Application Number | 20160061219 14/842567 |
Document ID | / |
Family ID | 53765155 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160061219 |
Kind Code |
A1 |
MOKULYS; Thomas ; et
al. |
March 3, 2016 |
RADIAL COMPRESSOR STAGE
Abstract
A radial compressor stage includes an impeller with multiple
impeller blades on the rotor side and a diffuser with multiple
guide blades on the stator side positioned downstream of the
impeller. Between the impeller and the stator an impeller side gap
is formed. Flow inlet edges of the guide blades on the stator side
lie on a first circle contour such that the flow inlet edges of all
guide blades on the stator side have an identical spacing to the
flow inlet edges of the respective adjacent guide blades. Flow
outlet edges of the guide blades on the stator side lie on a second
circle contour such that in at least one first circumferential
position the flow outlet edge of the respective guide blade on the
stator side has a spacing to the flow outlet edge of at least one
adjacent guide blade other than in second circumferential
positions.
Inventors: |
MOKULYS; Thomas; (Xanten,
DE) ; JENNY; Philipp; (Ennetburgen, CH) ;
SEEBASS-LINGGI; Christof; (Wettingen, CH) ; BIDAUT;
Yves; (Reutlingen, CH) ; SCHNEIDER; Samuel;
(Zurich, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MOKULYS; Thomas
JENNY; Philipp
SEEBASS-LINGGI; Christof
BIDAUT; Yves
SCHNEIDER; Samuel |
Xanten
Ennetburgen
Wettingen
Reutlingen
Zurich |
|
DE
CH
CH
CH
DE |
|
|
Assignee: |
MAN DIESEL & TURBO SE
|
Family ID: |
53765155 |
Appl. No.: |
14/842567 |
Filed: |
September 1, 2015 |
Current U.S.
Class: |
415/211.2 |
Current CPC
Class: |
F04D 29/444 20130101;
F04D 29/668 20130101; F04D 29/284 20130101; F04D 17/10 20130101;
F04D 29/666 20130101 |
International
Class: |
F04D 29/44 20060101
F04D029/44; F04D 29/28 20060101 F04D029/28; F04D 17/10 20060101
F04D017/10 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2014 |
DE |
102014012765.6 |
Claims
1. A radial compressor stage comprising: a stator; a rotor; an
impeller having a plurality of impeller blades on the rotor side
rotating relative to a stator; a diffuser having a plurality of
guide blades on a stator side positioned in a flow direction
downstream of the impeller; and an impeller side gap formed between
the impeller and the stator, wherein flow inlet edges of the
plurality of guide blades lie on a first circle contour such that
the flow inlet edges of the plurality of guide blades have a
substantially identical spacing to the flow inlet edges of a
respective adjacent guide blades; and wherein flow outlet edges of
the plurality of guide blades lie on a second circle contour such
that, in at least one first circumferential position, a respective
flow outlet edge of a respective guide blade on the stator side has
a spacing to the flow outlet edge of at least one adjacent guide
blade other than in second circumferential positions.
2. The radial compressor stage according to claim 1, wherein in the
second circumferential positions the respective guide blades all
have identical second stepping angles; and in first circumferential
position the respective guide blades on the stator side have a
first stepping angle that deviates from the second stepping
angle.
3. The radial compressor stage according to claim 2, wherein the
first stepping angle deviates from the second stepping angle by
.+-.10.degree..
4. A radial compressor stage, comprising: a stator; an impeller
having a plurality of impeller blades on a rotor side rotating
relative to the stator; a diffuser with a plurality of guide blades
on a stator side positioned in flow direction downstream of the
impeller; an impeller side gap formed between the impeller and the
stator, wherein at least one guide blade has a curvature that
deviates from the other guide blades on the stator side.
5. A radial compressor stage, comprising: a stator; an impeller
with a plurality of impeller blades on a rotor side that rotates
relative to the stator; a diffuser with a plurality of guide blades
on the stator side positioned in flow direction downstream of the
impeller; an impeller side gap formed between the impeller and the
stator; and a diffuser flow channel section formed between adjacent
guide blades on the stator side in at least one first
circumferential position has a flow cross section deviating from
diffuser flow channel sections formed in second circumferential
positions.
6. The radial compressor stage according to claim 5, wherein
relative to the second circumferential positions in the at least
one first circumferential position between the adjacent guide
blades on the stator side at least one side wall bounding the
diffuser flow channel section subject to reducing the flow cross
section is curved towards an inside into the diffuser flow channel
section and/or subject to enlarging the flow cross section towards
an outside into the stator.
7. The radial compressor stage according to claim 2, wherein the
first stepping angle deviates from the second stepping angle by
.+-.7.degree..
8. The radial compressor stage according to claim 2, wherein the
first stepping angle deviates from the second stepping angle by
.+-.5.degree..
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a radial compressor stage for a
radial compressor.
[0003] 2. Description of the Related Art
[0004] From DE 195 02 808 C2 the fundamental construction of a
radial compressor having at least one radial compressor stage is
known. Accordingly, it is disclosed in this prior art that the or
each radial compressor stage of a radial compressor comprises an
impeller rotating with respect to a stator, wherein the impeller
comprises a hub and multiple impeller blades on the rotor side.
Each impeller blade of the impeller comprises a flow inlet edge and
a flow outlet edge. Between the flow inlet edge and the flow outlet
edge of each impeller blade a suction side, a pressure side, and an
outer surface facing the stator extends. The outer surface of the
respective impeller blade borders the stator and serves for sealing
relative to the stator. Such an impeller of a radial compressor, in
which the outer surfaces of the impeller blades directly border the
stator, does not comprise a shroud and is also called open
impeller. The impeller blades are positioned in an impeller flow
channel that is bounded by the hub of the impeller and the
stator.
[0005] Furthermore it is known from DE 195 02 808 C2 that the
radial compressor stage comprises a diffuser positioned downstream
of the impeller that comprises multiple guide blades on the stator
side. Each guide blade of the diffuser has a flow inlet edge and a
flow outlet edge. Between the flow inlet edge and the flow outlet
edge of each guide blade a suction side and a pressure side
extends. The guide blades are positioned in a diffuser flow channel
bounded by the stator.
[0006] From DE 195 02 802 C2 it is evident that between the
impeller and the stator of the radial compressor stage shown there,
a so-called impeller side gap is formed, namely between a back side
of the impeller and the stator. This impeller side gap is connected
to an intermediate flow channel that extends between the impeller
flow channel and the diffuser flow channel.
[0007] A further radial compressor stage with such an impeller side
gap is known from DE 10 2007 019 264 A1.
[0008] From EP 2 014 925 A1 a radial compressor stage with a
diffuser is known, in which the angular spacing of flow inlet edges
of two guide elements arranged adjacent to one another differs from
the angular spacing of flow inlet edges of two other guide elements
arranged adjacent to one another.
[0009] During the operation of a radial compressor, the radial
compressor stages are exposed to mechanical excitations and
oscillations that can cause damage to the radial compressor stage,
in particular to the impeller blades of the impeller of the radial
compressor stage. Such mechanical excitations can be based on
synchronous excitation mechanisms and on asynchronous excitation
mechanisms.
[0010] In particular, three-dimensional and unsteady flow phenomena
are generated through the interaction of rotating and stationary
components. Under certain conditions, pressure fluctuations
develop, which have a character rotating in direction of rotation
or in a direction that is opposite to the direction of rotation.
The number and the rotating speed of these pressure fluctuations
are arbitrary.
[0011] This phenomenon is the basis of an asynchronous excitation
of open impellers in radial compressors. Up to now, no methods are
known with the help of which such asynchronous excitations can be
specifically counteracted in order to avoid a critical vibration
excitation in particular of the impeller blades of the
impeller.
SUMMARY OF THE INVENTION
[0012] There is a need for a radial compressor stage for a radial
compressor, in which the impeller blades of the impeller are
exposed to low vibration excitation through such asynchronous
excitations.
[0013] One embodiment of the present invention is based on creating
a radial compressor stage for a radial compressor that fulfils the
above requirements and accordingly is exposed to a low vibration
excitation in particular through such asynchronous excitations.
[0014] According to a first aspect of the invention, this object is
solved through a radial compressor stage. Accordingly, the flow
inlet edges of the guide blades of the diffuser on the stator side
lie on a first circle contour namely in such a manner that the flow
inlet edges of all guide blades on the stator side have an
identical spacing from the flow inlet edges of the respective
adjacent guide blades. The flow outlet edges of the guide blades of
the diffuser on the stator side lie on a second circle contour,
namely in such a manner that in at least one first circumferential
position the flow outlet edge of the respective guide blade on the
stator side has a spacing from the flow outlet edge of at least one
adjacent guide blade other than in second circumferential
positions.
[0015] According to one embodiment of the invention, a radial
compressor stage includes, at least one guide blade of the diffuser
on the stator side that has a curvature which deviates from the
other guide blades on the stator side.
[0016] According to a one embodiment of the invention a radial
compressor stage wherein, in at least one first circumferential
position, a diffuser flow channel section formed between adjacent
guide blades of the diffuser on the stator side has a flow cross
section which deviates from the diffuser flow channel sections
formed on second circumferential positions.
[0017] With each of the above aspects according to the invention,
asynchronous excitations of open impellers in radial compressors
can be easily and reliably counteracted, as a result of which the
vibration excitation in particular for the impeller blades of the
impeller of the radial compressor stage can be reduced.
[0018] Here, the above aspects according to the invention can be
employed on a radial compressor stage either alone or preferably
combined with multiple such aspects according to the invention.
[0019] The above aspects according to the invention altogether
relate to measures for the design configuration of the
diffuser.
[0020] Other objects and features of the present invention will
become apparent from the following detailed description considered
in conjunction with the accompanying drawings. It is to be
understood, however, that the drawings are designed solely for
purposes of illustration and not as a definition of the limits of
the invention, for which reference should be made to the appended
claims. It should be further understood that the drawings are not
necessarily drawn to scale and that, unless otherwise indicated,
they are merely intended to conceptually illustrate the structures
and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Preferred further developments of the invention are obtained
from the subclaims and the following description. Exemplary
embodiments of the invention are explained in more detail with the
help of the drawing without being restricted to this. It shows:
[0022] FIG. 1: is a meridional section through a radial compressor
stage according to the invention according to a first aspect of the
invention;
[0023] FIG. 2: is an axial section through the radial compressor
stage of FIG. 1;
[0024] FIG. 3: is an axial section through a radial compressor
stage according to a second aspect of the invention; and
[0025] FIG. 4: is a meridional section through a radial compressor
stage according to the invention according to a third aspect of the
invention.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0026] The present invention relates to a radial compressor with at
least one radial compressor stage.
[0027] FIG. 1 shows a detail of a radial compressor stage according
to the invention in meridional section according to a first aspect
of the invention, and FIG. 2 shows an axial section through the
radial compressor stage of FIG. 1.
[0028] The radial compressor stage of FIG. 1 comprises an impeller
10 with multiple impeller blades 11 on the rotor side. The impeller
10 rotates relative to the stator 12. The stator 12 can be a
housing or a stator ring or the like. The impeller blades 11 are
positioned in an impeller flow channel 13 bounded by a hub contour
14 on the rotor side and a stator contour 15. Each impeller blade
12 comprises a flow inlet edge 16 and a flow outlet edge 17.
Between the flow inlet edge 16 and the flow outlet edge 17 of each
impeller blade 11 a pressure side, a suction side and radially
outside on the impeller blade 11 an outer surface 18 of the
respective impeller blade 11 facing the stator 12 extends. The
outer surface 18 of the impeller blade 11 borders the stator 12 and
serves for sealing relative to the stator 12. Such an impeller 10,
in the case of which the outer surfaces 18 of the impeller blades
11 indirectly border the stator 12 does not have a shroud and is
also called an open impeller.
[0029] According to FIG. 1, a diffuser 19 on the stator side is
positioned downstream of the impeller 10. The diffuser 19 comprises
multiple guide blades 20 on the stator side. The guide blades 20 of
the diffuser 19 on the stator side are positioned in a diffuser
flow channel 21 bounded by the stator 12. Each of the guide blades
20 of the diffuser 19 on the stator side comprises a flow inlet
edge 22 and a flow outlet edge 23. Between the flow inlet edge 22
and the flow outlet edge 23 of the respective guide blade 20 on the
stator side a suction side 24 and a pressure side 25 of the
respective guide blade extends.
[0030] Between the impeller flow channel 13, in which the impeller
blades 11 of the impeller 10 on the rotor side are positioned, and
the diffuser flow channel 21, in which the guide blades 20 of the
diffuser 19 on the stator side are positioned, an intermediate flow
channel 26 extends, via which medium compressed in the radial
compressor stage starting out from the impeller 10 can flow in the
direction of the diffuser 16. According to FIG. 1, a impeller side
gap 28 is formed between a back side 27 of the impeller 10 and the
stator 12, wherein this impeller side gap 28 according to FIG. 1 is
coupled to the intermediate flow channel 26 via a gap 34.
[0031] The invention relates to such details of a radial compressor
stage with the help of which the danger of unsteady flow phenomena,
which can lead to asynchronous excitation of the open impellers,
can be reduced.
[0032] According to a first aspect of the invention, which is
described in the following making reference to FIGS. 1 and 2, all
flow inlet edges 22 of all guide blades 20 of the diffuser 19 on
the stator side lie on a first circle contour 29.
[0033] Here, the flow inlet edges 22 of the guide blades 20 of the
diffuser 19 on the stator side lie on the first circle contour 29
in such a manner that the flow inlet edges 22 of all guide blades
20 on the stator side have an identical spacing from the flow inlet
edges 22 of the respective adjacent guide blades 20. The flow inlet
edges 22 of the guide blades 20 of the diffuser 19 located seen in
circumferential direction of the diffuser flow channel 21 next to
one another are accordingly evenly distributed seen in
circumferential direction, so that accordingly all flow inlet edges
22, which lie on the first circle contour 29, have identical
circumferential spacings to adjacent flow inlet edges 22.
[0034] According to the first advantageous further development of
the first aspect and/or second aspect of the invention it is
provided, furthermore, that the flow outlet edges 23 of the guide
blades 20 of the diffuser 19 on the stator side lie on a second
circle contour 30.
[0035] The flow outlet edges 23 of the guide blades 20 of the
diffuser 19 on the stator side lie on the second circle contour 30
such that in at least one first circumferential position of the
diffuser flow channel 21 the flow outlet edge 23 of the respective
guide blade 20 on the stator side positioned there has a spacing
from the flow outlet edge of at least one adjacent guide blade 20
other than in second circumferential positions of the diffuser flow
channel 21.
[0036] In the region of the flow outlet edges 23, no equal
distribution of the flow outlet edges 23 is provided seen in
circumferential direction of the diffuser flow channel 21. In
contrast the equal distribution of the flow outlet edges 23, which
all lie on the second circle contour 30, is preferentially
cancelled in the first circumferential positions in order to
thereby reduce the risk of unsteady flow phenomena, which can lead
to an asynchronous excitation of the open impellers.
[0037] According to the first advantageous further development of
the first aspect and/or second aspect of the invention it is
possible in a first extreme case that the corresponding flow outlet
edge 23 in a single circumferential position of the diffuser flow
channel 21 has another spacing from the respective adjacent flow
outlet edges 23, that by contrast in the other circumferential
positions the flow outlet edges 23 with respect to their
circumferential positions are equally distributed.
[0038] It is likewise possible according to the first advantageous
further development of the first aspect and/or second aspect of the
invention in a second extreme case that in all circumferential
positions of the diffuser flow channel 21 the flow outlet edges 23
have different spacings in each case from the respective adjacent
flow outlet edges 23.
[0039] In the second circumferential positions of the diffuser flow
channel 21, the respective guide blades 20 of the diffuser 19 on
the stator side preferentially all have identical, second stepping
angles.
[0040] The guide blades 20 on the stator side positioned in the or
each first circumferential position by contrast preferentially have
a first stepping angle, which deviates from the second stepping
angle, in particular by plus minus .+-.10.degree., preferably by
plus minus .+-.7.degree., particularly preferably by .+-.5.degree.,
most preferably by .+-.3.degree..
[0041] According to the first advantageous further development of
the first aspect and/or second aspect of the invention it is
accordingly proposed for reducing the danger of unsteady flow
phenomena, which can lead to an asynchronous excitation of the open
impellers, to reposition the flow outlet edges 23 of selected guide
blades 20 of the diffuser 19 on the stator side in circumferential
direction, preferentially subject to cancelling or interrupting the
flow outlet edges 23 which seen in circumferential direction of the
diffuser flow channel 21 are otherwise equally distributed.
[0042] In an extreme case, the flow outlet edges 23 of all guide
blades 20 of the diffuser 19 on the stator side can have different
spacings from the respective adjacent flow outlet edges 23.
[0043] As is evident in FIG. 2, a flow outlet edge 23'' (see dashed
line course of the in FIG. 2 right guide blade) in the direction of
the pressure side 25 of the respective adjacent guide blade 20 or a
flow outlet edge 23' (see dashed line course of the in FIG. 5 left
guide blade) be relocated in circumferential direction in the
direction of the suction side 24 of the respective adjacent guide
blade 20 namely in such a manner that all flow outlet edges 23 as
before still lie on the second circle contour.
[0044] This corresponds to a change of the stepping angle of the
guide blades 20 of the diffuser 19 on the stator side in selected
circumferential positions. In selected second circumferential
positions of the diffuser 19, the respective guide blades 20 on the
stator side have deviating stepping angles.
[0045] Those selected guide blades 20, which compared with the
remaining guide blades 20 on the stator side, have a different
stepping angle are characterized in that their stepping angle
deviates in particular by .+-.10.degree., particularly preferably
by .+-.5.degree. from the stepping angles of the remaining guide
blades 20 of the diffuser 19.
[0046] Through the above measures of the first advantageous further
development of the first aspect and/or second aspect of the
invention, a slightly higher or a slightly lower loading can be
imposed on the guide blades 20 of the diffuser 19 in defined
circumferential positions at uneven circumferential spacings. The
danger of unsteady flow phenomena which can lead to an asynchronous
excitation of the open impellers can thereby be further
reduced.
[0047] According to a second aspect of the invention shown in FIG.
3, it is proposed for reducing the risk of unsteady flow phenomena,
which can lead to asynchronous excitation of the open impellers,
that both the flow inlet edges 22 of the guide blades 20 of the
diffuser 19 on the stator side positioned on the first circle
contour 29 as well as the flow outlet edges 23 of the guide blades
20 of the diffuser 19 on the stator side positioned on the second
circle contour 30 are equally distributed in circumferential
direction, i.e. in each case have identical circumferential
spacings.
[0048] However, according to the second aspect of the invention, at
least one guide blade 20 of the diffuser 19 on the stator side has
a deviating curvature between the flow inlet edge 22 and the flow
outlet edge 23, namely a suction side 24' and a pressure side 25'
with a curvature which deviates relative to the other guide blades
20. This is shown in FIG. 3 by the dashed course for the middle
guide blade 20.
[0049] According to the second aspect of the invention it is
possible in a first extreme case that exclusively a single guide
blade 20 of the diffuser 19 on the stator side has a deviating
curvature, that by contrast all other guide blades 20 of the
diffuser 19 on the stator side have identical curvatures.
[0050] It is likewise possible in a second extreme case according
to the second aspect of the invention that all guide blades 20 of
the diffuser 19 on the stator side have curvatures that deviate
from one another.
[0051] It is preferred to employ the first aspect of the invention
and the second aspect of the invention combined with one another
for reducing the risk of unsteady flow phenomena, which can lead to
asynchronous excitation of the open impellers, on the radial
compressor stage.
[0052] A third aspect of the present invention is discussed in the
following making reference to FIG. 4.
[0053] According to the third aspect of the invention, it is
proposed for reducing the risk of unsteady flow phenomena that can
lead to asynchronous excitation of the open impellers, to change a
diffuser flow channel section 33 formed between adjacent guide
blades 20 of the diffuser 19 on the stator side in at least one
first circumferential position of the diffuser flow channel 21 in
such a manner that the same has a deviating flow cross section
compared with the diffuser flow channel sections formed in second
circumferential positions.
[0054] Accordingly it is evident from FIG. 4 that in a first
circumferential position of the diffuser 19 between adjacent guide
blades 20 on the stator side the respective diffuser flow channel
section 33 has a reduced flow cross section, namely because of the
fact that the side walls 31, 32 on the stator side bounding the
respective diffuser flow channel section 33, are curved towards the
inside subject to reducing the flow cross section of the respective
diffuser channel section 33. It is pointed out that merely one of
these side walls 31, 32 bounding the respective diffuser flow
channel 33 can be curved into the respective diffuser flow channel
33. It is likewise possible, in selected circumferential positions,
to expand the respective diffuser flow channel section with respect
to its flow cross section, wherein at least one of these side walls
31, 32 is then curved towards the outside into the stator 12.
[0055] According to the third aspect it is possible in a first
extreme case that exclusively in a single circumferential position
of the diffuser flow channel 21 the corresponding diffuser flow
channel section 33 has a deviating flow cross section, that by
contrast all other diffuser flow channel sections 33 have identical
flow cross sections.
[0056] It is likewise possible according to the third aspect of the
invention in a second extreme case that in all circumferential
positions of the diffuser flow channel 21 the diffuser flow channel
sections 33 each have different flow cross sections.
[0057] The measures of the third aspect can be employed combined
with the measures of the first aspect and/or the measures of the
second aspect. Preferably, the measures of the third aspect are
employed on a radial compressor stage combined with the measures of
the first aspect and with the measures of the second aspect.
[0058] Thus, while there have shown and described and pointed out
fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *