U.S. patent application number 15/075321 was filed with the patent office on 2016-09-29 for impeller with offset splitter blades.
This patent application is currently assigned to DRESSER-RAND COMPANY. The applicant listed for this patent is Mark J. Kuzdzal, Pascal Lardy, James M. Sorokes. Invention is credited to Mark J. Kuzdzal, Pascal Lardy, James M. Sorokes.
Application Number | 20160281732 15/075321 |
Document ID | / |
Family ID | 56975051 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160281732 |
Kind Code |
A1 |
Lardy; Pascal ; et
al. |
September 29, 2016 |
IMPELLER WITH OFFSET SPLITTER BLADES
Abstract
An impeller includes a hub mountable to a rotary shaft and
configured to rotate about a center axis. The impeller may include
a plurality of main blades and splitter blades arranged
equidistantly and circumferentially about the center axis. A
splitter blade having a leading edge and a trailing edge may be
positioned between first and second adjacent main blades and canted
such that the leading edge is displaced from a blade position
equidistant the first and second adjacent main blades a first
percentage amount of one half an angular distance between the first
and second adjacent main blades. The trailing edge may be displaced
from the blade position equidistant the first and second adjacent
main blades a second percentage amount of one half the angular
distance between the first and second adjacent main blades. The
second percentage amount may be greater or less than the first
percentage amount.
Inventors: |
Lardy; Pascal; (Notre Dame
du Bec, FR) ; Sorokes; James M.; (Olean, NY) ;
Kuzdzal; Mark J.; (Allegany, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lardy; Pascal
Sorokes; James M.
Kuzdzal; Mark J. |
Notre Dame du Bec
Olean
Allegany |
NY
NY |
FR
US
US |
|
|
Assignee: |
DRESSER-RAND COMPANY
Olean
NY
|
Family ID: |
56975051 |
Appl. No.: |
15/075321 |
Filed: |
March 21, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62139032 |
Mar 27, 2015 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/4213 20130101;
F04D 29/058 20130101; F05D 2250/51 20130101; F04D 25/06 20130101;
F04D 29/284 20130101; F04D 29/30 20130101; F04D 29/462
20130101 |
International
Class: |
F04D 29/30 20060101
F04D029/30; F04D 29/42 20060101 F04D029/42; F04D 25/06 20060101
F04D025/06; F04D 29/28 20060101 F04D029/28 |
Goverment Interests
STATEMENT OF GOVERNMENT INTEREST
[0002] This invention was made with government support under
Government Contract No. DOE-DE-FE0000493 awarded by the U.S.
Department of Energy. The government has certain rights in the
invention.
Claims
1. An impeller for a compressor, comprising: a hub mountable to a
rotary shaft of the compressor and configured to rotate about a
center axis, the hub comprising a first meridional end portion and
a second meridional end portion; a plurality of main blades mounted
to or integral with the hub, the plurality of main blades arranged
equidistantly and circumferentially about the center axis; and a
plurality of splitter blades mounted to or integral with the hub,
the plurality of splitter blades arranged equidistantly and
circumferentially about the center axis, each splitter blade
comprising a leading edge meridionally spaced from the first
meridional end portion and a trailing edge proximal the second
meridional end portion, wherein a splitter blade is positioned
between a first adjacent main blade and a second adjacent main
blade and canted such that the leading edge of the splitter blade
is displaced from a blade position equidistant the first adjacent
main blade and the second adjacent main blade a first percentage
amount of one half an angular distance between the first adjacent
main blade and the second adjacent main blade, and the trailing
edge of the splitter blade is displaced from the blade position
equidistant the first adjacent main blade and the second adjacent
main blade a second percentage amount of one half the angular
distance between the first adjacent main blade and the second
adjacent main blade, the second percentage amount being greater or
less than the first percentage amount.
2. The impeller of claim 1, wherein the splitter blade is
positioned between the first adjacent main blade and the second
adjacent main blade such that the splitter blade is
circumferentially offset from the blade position equidistant the
first adjacent main blade and the second adjacent main blade.
3. The impeller of claim 1, wherein each main blade of the
plurality of main blades comprises: a leading edge proximal the
first meridional end portion; a trailing edge proximal the second
meridional end portion; a pressure surface side extending between
the leading edge and the trailing edge; and a suction surface side
opposing the pressure surface side and extending between the
leading edge and the trailing edge, wherein the splitter blade is
positioned between a pressure surface side of the first adjacent
main blade and a suction surface side of the second adjacent main
blade such that the splitter blade is circumferentially offset from
the blade position equidistant the first adjacent main blade and
the second adjacent main blade.
4. The impeller of claim 3, wherein the splitter blade is
circumferentially offset in a direction toward the pressure surface
side of the first adjacent main blade.
5. The impeller of claim 3, wherein: a first flow passage is formed
between the splitter blade and the pressure surface side of the
first adjacent main blade; and a second flow passage is formed
between the splitter blade and the suction surface side of the
second adjacent main blade, such that the first flow passage and
the second flow passage are configured to receive substantially
equal mass flow therethrough.
6. The impeller of claim 5, wherein the splitter blade comprises: a
pressure surface side extending between the leading edge and the
trailing edge of the splitter blade; and a suction surface side
opposing the pressure surface side and extending between the
leading edge and the trailing edge of the splitter blade, wherein
the first flow passage is formed between the suction surface side
of the splitter blade and the pressure surface side of the first
adjacent main blade, and the second flow passage is formed between
the pressure surface side of the splitter blade and the suction
surface side of the second adjacent main blade.
7. The impeller of claim 1, wherein the plurality of main blades
and the plurality of splitter blades are equal in number.
8. The impeller of claim 1, wherein the respective leading edges of
the main blades and the respective leading edges of the splitter
blades are arranged in an meridionally-staggered pattern with
respect to one another.
9. The impeller of claim 1, wherein the splitter blade is
positioned between the first adjacent main blade and the second
adjacent main blade and canted such that the second percentage
amount is greater than the first percentage amount.
10. The impeller of claim 1, wherein the splitter blade is
positioned between the first adjacent main blade and the second
adjacent main blade and canted such that the second percentage
amount is less than the first percentage amount.
11. A compressor comprising: a housing; an inlet coupled to or
integral with the housing and defining an inlet passageway
configured to receive and flow a process fluid; a rotary shaft
configured to be driven by a driver; a centrifugal impeller coupled
with the rotary shaft and fluidly coupled to the inlet passageway,
the centrifugal impeller configured to rotate about a center axis
and impart energy to the process fluid received via the inlet
passageway, the centrifugal impeller comprising: a hub defining a
borehole through which a coupling member or the rotary shaft of the
compressor extends, the hub comprising a first meridional end
portion having an annular portion and a second meridional end
portion forming a disc-shaped portion; and a plurality of blades
mounted to or integral with the hub, the plurality of blades
arranged equidistantly and circumferentially about the center axis
and comprising a splitter blade positioned between a first adjacent
main blade and a second adjacent main blade and canted with respect
to the first adjacent main blade and the second adjacent main
blade; a static diffuser circumferentially disposed about the
centrifugal impeller and configured to receive the process fluid
from the centrifugal impeller and convert the energy imparted to
pressure energy; and a collector fluidly coupled to and configured
to collect the process fluid exiting the static diffuser, wherein
the compressor is configured to provide a compression ratio of at
least about 8:1.
12. The compressor of claim 11, wherein: the splitter blade
comprises a leading edge meridionally spaced from the first
meridional end portion and a trailing edge proximal the second
meridional end portion, and the splitter blade is positioned
between the first adjacent main blade and the second adjacent main
blade and canted such that the leading edge of the splitter blade
is displaced from a blade position equidistant the first adjacent
main blade and the second adjacent main blade a first percentage
amount of one half an angular distance between the first adjacent
main blade and the second adjacent main blade, and the trailing
edge of the splitter blade is displaced from the blade position
equidistant the first adjacent main blade and the second adjacent
main blade a second percentage amount of one half the angular
distance between the first adjacent main blade and the second
adjacent main blade, the second percentage amount being greater or
less than the first percentage amount.
13. The compressor of claim 11, wherein the splitter blade is
positioned between the first adjacent main blade and the second
adjacent main blade such that the splitter blade is
circumferentially offset from the blade position equidistant the
first adjacent main blade and the second adjacent main blade.
14. The compressor of claim 11, wherein each main blade of the
plurality of main blades comprises: a leading edge proximal the
first meridional end; a trailing edge proximal the second
meridional end; a pressure surface side extending from the leading
edge to the trailing edge; and a suction surface side opposing the
pressure surface side and extending from the leading edge to the
trailing edge, wherein the splitter blade is positioned between a
pressure surface side of the first adjacent main blade and a
suction side surface of the second adjacent main blade such that
the splitter blade is circumferentially offset from the blade
position equidistant the first adjacent main blade and the second
adjacent main blade.
15. The compressor of claim 14, wherein the splitter blade is
circumferentially offset in a direction toward the pressure surface
side of the first adjacent main blade.
16. The compressor of claim 14, wherein: a first flow passage is
formed between the splitter blade and the pressure surface side of
the first adjacent main blade; and a second flow passage is formed
between the splitter blade and the suction surface side of the
second adjacent main blade, such that the first flow passage and
the second flow passage are configured to receive substantially
equal mass flow therethrough.
17. The compressor of claim 11, wherein: the process fluid
comprises carbon dioxide; the compressor is configured to provide a
compression ratio of at least about 10:1; and the second meridional
end portion of the centrifugal impeller is configured to discharge
the process fluid therefrom in at least a partially radial
direction at an absolute Mach number of about 1.3 or greater.
18. The compressor of claim 17, wherein the centrifugal impeller is
configured to rotate via the rotary shaft at a rotational speed of
about 500 meters per second or greater.
19. A compression system comprising: a driver comprising a drive
shaft, the driver configured to provide the drive shaft with
rotational energy; a supersonic compressor operatively coupled to
the driver via a rotary shaft integral with or coupled with the
drive shaft and configured to rotate about a center axis, the
supersonic compressor comprising: a compressor chassis; an inlet
defining an inlet passageway configured to flow a process fluid
therethrough, the process fluid having a first velocity and a first
pressure energy; a centrifugal impeller coupled with the rotary
shaft and fluidly coupled to the inlet passageway, the centrifugal
impeller having a tip and configured to increase the first velocity
and the first pressure energy of the process fluid received via the
inlet passageway and discharge the process fluid from the tip in at
least a partially radial direction having a second velocity and a
second pressure energy, the second velocity being a supersonic
velocity having an absolute Mach number of about one or greater,
wherein the centrifugal impeller comprises: a hub defining a
borehole through which a coupling member or the rotary shaft of the
supersonic compressor extends, the hub comprising a first
meridional end portion having an annular portion and a second
meridional end portion forming the tip; and a plurality of blades
mounted to or integral with the hub, the plurality of blades
arranged equidistantly and circumferentially about the center axis
and comprising a splitter blade positioned between a first adjacent
main blade and a second adjacent main blade and canted with respect
to the first adjacent main blade and the second adjacent main
blade; a static diffuser circumferentially disposed about the tip
of the centrifugal impeller and defining an annular diffuser
passageway configured to receive and reduce the second velocity of
the process fluid to a third velocity and increase the second
pressure energy to a third pressure energy, the third velocity
being a subsonic velocity; and a discharge volute fluidly coupled
to the annular diffuser passageway and configured to receive the
process fluid flowing therefrom, wherein the supersonic compressor
is configured to provide a compression ratio of at least about
8:1.
20. The compression system of claim 19, wherein: the process fluid
comprises carbon dioxide; the second velocity has an absolute Mach
number of about 1.3 or greater; the supersonic compressor is
configured to provide a compression ratio of at least about 10:1;
and the splitter blade is positioned between the first adjacent
main blade and the second adjacent main blade such that the
splitter blade is circumferentially offset from a blade position
equidistant the first adjacent main blade and the second adjacent
main blade, the splitter blade being circumferentially offset in a
direction toward a pressure surface side of the first adjacent main
blade.
Description
BACKGROUND
[0001] This application claims the benefit of U.S. Provisional
Patent Application having Ser. No. 62/139,032, which was filed Mar.
27, 2015. The aforementioned patent application is hereby
incorporated by reference in its entirety into the present
application to the extent consistent with the present
application.
[0003] Compressors and systems including compressors have been
developed and are utilized in a myriad of industrial processes
(e.g., petroleum refineries, offshore oil production platforms, and
subsea process control systems) to compress gas, typically by
applying mechanical energy to the gas in a low pressure environment
and transporting the gas and compressing the gas to a higher
pressure environment. The compressed gas may be utilized to perform
work or as an element in the operation of one or more downstream
process components. As conventional compressors are increasingly
used in offshore oil production facilities and other environments
facing space constraints, there is an ever-increasing demand for
smaller, lighter, and more compact compressors. In addition to the
foregoing, it is desirable for commercial purposes that the compact
compressors achieve higher compression ratios (e.g., 10:1 or
greater) while optimizing efficiency and maintaining a compact
arrangement.
[0004] In view of the foregoing, skilled artisans have proposed
approaches to improve the efficiency of the compact compressors,
many of which in the case of compact centrifugal compressors relate
to the blading of one or more impellers operating therein. One such
approach has included the use of splitter blades mounted to the
impeller, such that each splitter blade is disposed equidistantly
between adjacent full blades mounted to and extending from the hub
of the impeller; however, such an approach has been determined to
result in unequal mass flow in channels formed between the splitter
blades and the adjacent full blades, thus resulting in efficiency
losses.
[0005] What is needed, therefore, is an efficient compression
system that provides increased compression ratios in a compact
arrangement that is economically and commercially viable.
SUMMARY
[0006] Embodiments of the disclosure may provide an impeller for a
compressor. The impeller may include a hub mountable to a rotary
shaft of the compressor and configured to rotate about a center
axis. The hub may include a first meridional end portion and a
second meridional end portion. The impeller may also include a
plurality of main blades mounted to or integral with the hub. The
plurality of main blades may be arranged equidistantly and
circumferentially about the center axis. The impeller may further
include a plurality of splitter blades mounted to or integral with
the hub. The plurality of splitter blades may be arranged
equidistantly and circumferentially about the center axis. Each
splitter blade may include a leading edge meridionally spaced from
the first meridional end portion and a trailing edge proximal the
second meridional end portion. A splitter blade may be positioned
between a first adjacent main blade and a second adjacent main
blade and canted such that the leading edge of the splitter blade
is displaced from a blade position equidistant the first adjacent
main blade and the second adjacent main blade a first percentage
amount of one half an angular distance between the first adjacent
main blade and the second adjacent main blade. The trailing edge of
the splitter blade may be displaced from the blade position
equidistant the first adjacent main blade and the second adjacent
main blade a second percentage amount of one half the angular
distance between the first adjacent main blade and the second
adjacent main blade. The second percentage amount may be greater or
less than the first percentage amount.
[0007] Embodiments of the disclosure may further provide a
compressor. The compressor may include a housing and an inlet
coupled to or integral with the housing and defining an inlet
passageway configured to receive and flow a process fluid. The
compressor may also include a rotary shaft configured to be driven
by a driver, and a centrifugal impeller coupled with the rotary
shaft and fluidly coupled to the inlet passageway. The centrifugal
impeller may be configured to rotate about a center axis and impart
energy to the process fluid received via the inlet passageway. The
centrifugal impeller may include a hub defining a borehole through
which a coupling member or the rotary shaft of the supersonic
compressor extends. The hub may include a first meridional end
portion having an annular portion and a second meridional end
portion forming a disc-shaped portion. The centrifugal impeller may
also include a plurality of blades mounted to or integral with the
hub. The plurality of blades may be arranged equidistantly and
circumferentially about the center axis and include a splitter
blade positioned between a first adjacent main blade and a second
adjacent main blade and canted with respect to the first adjacent
main blade and the second adjacent main blade. The compressor may
further include a static diffuser circumferentially disposed about
the centrifugal impeller and configured to receive the process
fluid from the centrifugal impeller and convert the energy imparted
to pressure energy. The compressor may also include a collector
fluidly coupled to and configured to collect the process fluid
exiting the static diffuser, such that the compressor is configured
to provide a compression ratio of at least about 8:1.
[0008] Embodiments of the disclosure may further provide a
compression system. The compression system may include a driver
including a drive shaft. The driver may be configured to provide
the drive shaft with rotational energy. The compression system may
also include a supersonic compressor operatively coupled to the
driver via a rotary shaft integral with or coupled with the drive
shaft and configured to rotate about a center axis. The supersonic
compressor may include a compressor chassis and an inlet defining
an inlet passageway configured to flow a process fluid
therethrough. The process fluid may have a first velocity and a
first pressure energy. The supersonic compressor may further
include a centrifugal impeller coupled with the rotary shaft and
fluidly coupled to the inlet passageway. The centrifugal impeller
may have a tip and may be configured to increase the first velocity
and the first pressure energy of the process fluid received via the
inlet passageway and discharge the process fluid from the tip in at
least a partially radial direction having a second velocity and a
second pressure energy. The second velocity may be a supersonic
velocity having an absolute Mach number of about one or greater.
The centrifugal impeller may include a hub defining a borehole
through which a coupling member or the rotary shaft of the
supersonic compressor extends. The hub may include a first
meridional end portion having an annular portion and a second
meridional end portion forming the tip. The centrifugal impeller
may also include a plurality of blades mounted to or integral with
the hub. The plurality of blades may be arranged equidistantly and
circumferentially about the center axis and include a splitter
blade positioned between a first adjacent main blade and a second
adjacent main blade and canted with respect to the first adjacent
main blade and the second adjacent main blade. The supersonic
compressor may also include a static diffuser circumferentially
disposed about the tip of the centrifugal impeller and defining an
annular diffuser passageway configured to receive and reduce the
second velocity of the process fluid to a third velocity and
increase the second pressure energy to a third pressure energy, the
third velocity being a subsonic velocity. The supersonic compressor
may further include a discharge volute fluidly coupled to the
annular diffuser passageway and configured to receive the process
fluid flowing therefrom, such that the supersonic compressor is
configured to provide a compression ratio of at least about
8:1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present disclosure is best understood from the following
detailed description when read with the accompanying Figures. It is
emphasized that, in accordance with the standard practice in the
industry, various features are not drawn to scale. In fact, the
dimensions of the various features may be arbitrarily increased or
reduced for clarity of discussion.
[0010] FIG. 1 illustrates a schematic view of an exemplary
compression system, according to one or more embodiments.
[0011] FIG. 2 illustrates a cross-sectional view of an exemplary
compressor, which may be included in the compression system of FIG.
1, according to one or more embodiments.
[0012] FIG. 3A illustrates a perspective view of an exemplary
impeller, which may be included in the compressor of FIG. 2,
according to one or more embodiments.
[0013] FIG. 3B illustrates a front view of the impeller of FIG. 3A,
according to one or more embodiments.
DETAILED DESCRIPTION
[0014] It is to be understood that the following disclosure
describes several exemplary embodiments for implementing different
features, structures, or functions of the invention. Exemplary
embodiments of components, arrangements, and configurations are
described below to simplify the present disclosure; however, these
exemplary embodiments are provided merely as examples and are not
intended to limit the scope of the invention. Additionally, the
present disclosure may repeat reference numerals and/or letters in
the various exemplary embodiments and across the Figures provided
herein. This repetition is for the purpose of simplicity and
clarity and does not in itself dictate a relationship between the
various exemplary embodiments and/or configurations discussed in
the various Figures. Moreover, the formation of a first feature
over or on a second feature in the description that follows may
include embodiments in which the first and second features are
formed in direct contact, and may also include embodiments in which
additional features may be formed interposing the first and second
features, such that the first and second features may not be in
direct contact. Finally, the exemplary embodiments presented below
may be combined in any combination of ways, i.e., any element from
one exemplary embodiment may be used in any other exemplary
embodiment, without departing from the scope of the disclosure.
[0015] Additionally, certain terms are used throughout the
following description and claims to refer to particular components.
As one skilled in the art will appreciate, various entities may
refer to the same component by different names, and as such, the
naming convention for the elements described herein is not intended
to limit the scope of the invention, unless otherwise specifically
defined herein. Further, the naming convention used herein is not
intended to distinguish between components that differ in name but
not function. Additionally, in the following discussion and in the
claims, the terms "including" and "comprising" are used in an
open-ended fashion, and thus should be interpreted to mean
"including, but not limited to." All numerical values in this
disclosure may be exact or approximate values unless otherwise
specifically stated. Accordingly, various embodiments of the
disclosure may deviate from the numbers, values, and ranges
disclosed herein without departing from the intended scope.
Furthermore, as it is used in the claims or specification, the term
"or" is intended to encompass both exclusive and inclusive cases,
i.e., "A or B" is intended to be synonymous with "at least one of A
and B," unless otherwise expressly specified herein.
[0016] FIG. 1 illustrates a schematic view of an exemplary
compression system 100, according to one or more embodiments. The
compression system 100 may include one or more compressors 102 (one
is shown) configured to pressurize a process fluid. In an exemplary
embodiment, the compression system 100 may have a compression ratio
of at least about 6:1 or greater. For example, the compression
system 100 may compress the process fluid to a compression ratio of
about 6:1, about 6.1:1, about 6.2:1, about 6.3:1, about 6.4:1,
about 6.5:1, about 6.6:1, about 6.7:1, about 6.8:1, about 6.9:1,
about 7:1, about 7.1:1, about 7.2:1, about 7.3:1, about 7.4:1,
about 7.5:1, about 7.6:1, about 7.7:1, about 7.8:1, about 7.9:1,
about 8:1, about 8.1:1, about 8.2:1, about 8.3:1, about 8.4:1,
about 8.5:1, about 8.6:1, about 8.7:1, about 8.8:1, about 8.9:1,
about 9:1, about 9.1:1, about 9.2:1, about 9.3:1, about 9.4:1,
about 9.5:1, about 9.6:1, about 9.7:1, about 9.8:1, about 9.9:1,
about 10:1, about 10.1:1, about 10.2:1, about 10.3:1, about 10.4:1,
about 10.5:1, about 10.6:1, about 10.7:1, about 10.8:1, about
10.9:1, about 11:1, about 11.1:1, about 11.2:1, about 11.3:1, about
11.4:1, about 11.5:1, about 11.6:1, about 11.7:1, about 11.8:1,
about 11.9:1, about 12:1, about 12.1:1, about 12.2:1, about 12.3:1,
about 12.4:1, about 12.5:1, about 12.6:1, about 12.7:1, about
12.8:1, about 12.9:1, about 13:1, about 13.1:1, about 13.2:1, about
13.3:1, about 13.4:1, about 13.5:1, about 13.6:1, about 13.7:1,
about 13.8:1, about 13.9:1, about 14:1, or greater.
[0017] The compression system 100 may also include, amongst other
components, a driver 104 operatively coupled to the compressor 102
via a drive shaft 106. The driver 104 may be configured to provide
the drive shaft 106 with rotational energy. In an exemplary
embodiment, the drive shaft 106 may be integral with or coupled
with a rotary shaft 108 of the compressor 102, such that the
rotational energy of the drive shaft 106 is imparted to the rotary
shaft 108. The drive shaft 106 may be coupled with the rotary shaft
108 via a gearbox (not shown) including a plurality of gears
configured to transmit the rotational energy of the drive shaft 106
to the rotary shaft 108 of the compressor 102, such that the drive
shaft 106 and the rotary shaft 108 may spin at the same speed,
substantially similar speeds, or differing speeds and rotational
directions.
[0018] The driver 104 may be a motor and more specifically may be
an electric motor, such as a permanent magnet motor, and may
include a stator (not shown) and a rotor (not shown). It will be
appreciated, however, that other embodiments may employ other types
of electric motors including, but not limited to, synchronous
motors, induction motors, and brushed DC motors. The driver 104 may
also be a hydraulic motor, an internal combustion engine, a steam
turbine, a gas turbine, or any other device capable of driving the
rotary shaft 108 of the compressor 102 either directly or through a
power train.
[0019] In an exemplary embodiment, the compressor 102 may be a
direct-inlet centrifugal compressor. In other embodiments, the
compressor 102 may be a back-to-back compressor. The direct-inlet
centrifugal compressor may be, for example, a version of a
Dresser-Rand Pipeline Direct Inlet (PDI) centrifugal compressor
manufactured by the Dresser-Rand Company of Olean, New York. The
compressor 102 may have a center-hung rotor configuration or an
overhung rotor configuration, as illustrated in FIG. 1. In an
exemplary embodiment, the compressor 102 may be an axial-inlet
centrifugal compressor. In another embodiment, the compressor 102
may be a radial-inlet centrifugal compressor. As previously
discussed, the compression system 100 may include one or more
compressors 102. For example, the compression system 100 may
include a plurality of compressors (not shown). In another example,
illustrated in FIG. 1, the compression system 100 may include a
single compressor 102. The compressor 102 may be a supersonic
compressor or a subsonic compressor. In at least one embodiment,
the compression system 100 may include a plurality of compressors
(not shown), and at least one compressor of the plurality of
compressors is a subsonic compressor. In another embodiment,
illustrated in FIG. 1, the compression system 100 includes a single
compressor 102, and the single compressor 102 is a supersonic
compressor.
[0020] The compressor 102 may include one or more stages (not
shown). In at least one embodiment, the compressor 102 may be a
single-stage compressor. In another embodiment, the compressor 102
may be a multi-stage centrifugal compressor. Each stage (not shown)
of the compressor 102 may be a subsonic compressor stage or a
supersonic compressor stage. In an exemplary embodiment, the
compressor 102 may include a single supersonic compressor stage. In
another embodiment, the compressor 102 may include a plurality of
subsonic compressor stages. In yet another embodiment, the
compressor 102 may include a subsonic compressor stage and a
supersonic compressor stage. Any one or more stages of the
compressor 102 may have a compression ratio greater than about 1:1.
For example, any one or more stages of the compressor 102 may have
a compression ratio of about 1.1:1, about 1.2:1, about 1.3:1, about
1.4:1, about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about
1.9:1, about 2:1, about 2.1:1, about 2.2:1, about 2.3:1, about
2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about
2.9:1, about 3:1, about 3.1:1, about 3.2:1, about 3.3:1, about
3.4:1, about 3.5:1, about 3.6:1, about 3.7:1, about 3.8:1, about
3.9:1, about 4:1, about 4.1:1, about 4.2:1, about 4.3:1, about
4.4:1, about 4.5:1, about 4.6:1, about 4.7:1, about 4.8:1, about
4.9:1, about 5:1, about 5.1:1, about 5.2:1, about 5.3:1, about
5.4:1, about 5.5:1, about 5.6:1, about 5.7:1, about 5.8:1, about
5.9:1, about 6:1, about 6.1:1, about 6.2:1, about 6.3:1, about
6.4:1, about 6.5:1, about 6.6:1, about 6.7:1, about 6.8:1, about
6.9:1, about 7:1, about 7.1:1, about 7.2:1, about 7.3:1, about
7.4:1, about 7.5:1, about 7.6:1, about 7.7:1, about 7.8:1, about
7.9:1, about 8.0:1, about 8.1:1, about 8.2:1, about 8.3:1, about
8.4:1, about 8.5:1, about 8.6:1, about 8.7:1, about 8.8:1, about
8.9:1, about 9:1, about 9.1:1, about 9.2:1, about 9.3:1, about
9.4:1, about 9.5:1, about 9.6:1, about 9.7:1, about 9.8:1, about
9.9:1, about 10:1, about 10.1:1, about 10.2:1, about 10.3:1, about
10.4:1, about 10.5:1, about 10.6:1, about 10.7:1, about 10.8:1,
about 10.9:1, about 11:1, about 11.1:1, about 11.2:1, about 11.3:1,
about 11.4:1, about 11.5:1, 11 3.6:1, about 11.7:1, about 11.8:1,
about 11.9:1, about 12:1, about 12.1:1, about 12.2:1, about 12.3:1,
about 12.4:1, about 12.5:1, about 12.6:1, about 12.7:1, about
12.8:1, about 12.9:1, about 13:1, about 13.1:1, about 13.2:1, about
13.3:1, about 13.4:1, about 13.5:1, about 13.6:1, about 13.7:1,
about 13.8:1, about 13.9:1, about 14:1, or greater. In an exemplary
embodiment, the compressor 102 may include a plurality of
compressor stages, where a first stage (not shown) of the plurality
of compressor stages may have a compression ratio of about 1.75:1
and a second stage (not shown) of the plurality of compressor
stages may have a compression ratio of about 6.0:1.
[0021] FIG. 2 illustrates a cross-sectional view of an embodiment
of the compressor 102, which may be included in the compression
system 100 of FIG. 1. As shown in FIG. 2, the compressor 102
includes a housing 110 forming or having an axial inlet 112
defining an inlet passageway 114, a static diffuser 116 fluidly
coupled to the inlet passageway 114, and a collector 117 fluidly
coupled to the static diffuser 116. Although illustrated as an
axial inlet in FIG. 2, in one or more other embodiments, the inlet
112 may be a radial inlet. The driver 104 may be disposed outside
of (as shown in FIG. 1) or within the housing 110, such that the
housing 110 may have a first end, or compressor end, and a second
end (not shown), or driver end. The housing 110 may be configured
to hermetically seal the driver 104 and the compressor 102 within,
thereby providing both support and protection to each component of
the compression system 100. The housing 110 may also be configured
to contain the process fluid flowing through one or more portions
or components of the compressor 102.
[0022] The drive shaft 106 of the driver 104 and the rotary shaft
108 of the compressor 102 may be supported, respectively, by one or
more radial bearings 118, as shown in FIG. 1 in an overhung
configuration. The radial bearings 118 may be directly or
indirectly supported by the housing 110, and in turn provide
support to the drive shaft 106 and the rotary shaft 108, which
carry the compressor 102 and the driver 104 during operation of the
compression system 100. In one embodiment, the radial bearings 118
may be magnetic bearings, such as active or passive magnetic
bearings. In other embodiments, however, other types of bearings
(e.g., oil film bearings) may be used. In addition, at least one
axial thrust bearing 120 may be provided to manage movement of the
rotary shaft 108 in the axial direction. In an embodiment in which
the driver 104 and the compressor 102 are hermetically-sealed
within the housing 110, the axial thrust bearing 120 may be
provided at or near the end of the rotary shaft 108 adjacent the
compressor end of the housing 110. The axial thrust bearing 120 may
be a magnetic bearing and may be configured to bear axial thrusts
generated by the compressor 102.
[0023] As shown in FIG. 2, the axial inlet 112 defining the inlet
passageway 114 of the compressor 102 may include one or more inlet
guide vanes 122 of an inlet guide vane assembly configured to
condition a process fluid flowing therethrough to achieve
predetermined or desired fluid properties and/or fluid flow
attributes. Such fluid properties may include flow pattern (e.g.,
swirl distribution), velocity, mass flow rate, pressure,
temperature, and/or any suitable fluid property and fluid flow
attribute to enable the compressor 102 to function as described
herein. The inlet guide vanes 122 may be disposed within the inlet
passageway 114 and may be static or moveable, i.e., adjustable. In
an exemplary embodiment, a plurality of inlet guide vanes 122 may
be arranged about a circumferential inner surface 124 of the axial
inlet 112 in a spaced apart orientation, each extending into the
inlet passageway 114. The spacing of the inlet guide vanes 122 may
be equidistant or may vary depending on the predetermined process
fluid property and/or fluid flow attribute desired. With reference
to shape, the inlet guide vanes 122 may be airfoil shaped,
streamline shaped, or otherwise shaped and configured to at least
partially impart the one or more fluid properties and/or fluid flow
attributes on the process fluid flowing through the inlet
passageway 114.
[0024] In one or more embodiments, the inlet guide vanes 122 may be
moveably coupled to the housing 110 and disposed within the inlet
passageway 114 as disclosed in U.S. Pat. No. 8,632,302, the subject
matter of which is incorporated by reference herein to the extent
consistent with the present disclosure. The inlet guide vanes 122
may be further coupled to an annular inlet guide vane actuation
member (not shown), such that upon actuation of the annular inlet
vane actuation member, each of the inlet guide vanes 122 coupled to
the annular inlet guide vane actuation member may pivot about the
respective coupling to the housing 110, thereby adjusting the flow
incident on components of the compressor 102. As configured, the
inlet guide vanes 122 may be adjusted without disassembling the
housing 110 in order to adjust the performance of the compressor
102. Doing so without disassembly of the compressor 102 saves time
and effort in optimizing the compressor 102 for a particular
operating condition. Furthermore, the impact of alternate vane
angles on overall flow range and/or peak efficiency may be assessed
and optimized for increased performance, and a matrix of inlet
guide vane angles may be produced on a relatively short cycle time
relative to conventional compressors such that the data may be
analyzed to determine the best combination of inlet guide vane
angles for any given application.
[0025] The compressor 102 may include a centrifugal impeller 126
configured to rotate about a center axis 128 within the housing
110. In an exemplary embodiment, the centrifugal impeller 126
includes a hub 130 and is open or "unshrouded." In another
embodiment, the centrifugal impeller 126 may be a shrouded
impeller. The hub 130 may include a first meridional end portion
132, generally referred to as the eye of the centrifugal impeller
126, and a second meridional end portion 134 having a disc shape,
the outer perimeter of the second meridional end portion 134
generally referred to as the tip 136 of the centrifugal impeller
126. The disc-shaped, second meridional end portion 134 may taper
inwardly to the first meridional end portion 132 having an annular
shape. The hub 130 may define a bore 138 configured to receive a
coupling member 140, such as a tiebolt, to couple the centrifugal
impeller 126 to the rotary shaft 108. In another embodiment, the
bore 138 may be configured to receive the rotary shaft 108
extending therethrough.
[0026] As shown in FIG. 2, the compressor 102 may include a balance
piston 142 configured to balance an axial thrust generated by the
centrifugal impeller 126 during operation. In an exemplary
embodiment, the balance piston 142 may be integral with the
centrifugal impeller 126, such that the balance piston 142 and the
centrifugal impeller 126 are formed from a single or unitary piece.
In another embodiment, the balance piston 142 and the centrifugal
impeller 126 may be separate components. For example, the balance
piston 142 and the centrifugal impeller 126 may be separate annular
components coupled with one another. One or more seals, e.g.,
labyrinth seals, may be implemented to isolate the balance piston
142 from external contaminants or lubricants.
[0027] The centrifugal impeller 126 may be operatively coupled to
the rotary shaft 108 such that the rotary shaft 108, when acted
upon by the driver 104 via the drive shaft 106, rotates, thereby
causing the centrifugal impeller 126 to rotate such that process
fluid flowing into the inlet passageway 114 is drawn into the
centrifugal impeller 126 and accelerated to the tip 136, or
periphery, of the centrifugal impeller 126, thereby increasing the
velocity of the process fluid. In one or more embodiments, the
process fluid at the tip 136 of the centrifugal impeller 126 may be
subsonic and have an absolute Mach number less than one. For
example, the process fluid at the tip 136 of the centrifugal
impeller 126 may have an exit absolute Mach number less than one,
less than 0.9, less than 0.8, less than 0.7, less than 0.6, or less
than 0.5. Accordingly, in such embodiments, the compressor 102
discussed herein may be "subsonic," as the centrifugal impeller 126
may be configured to rotate about the center axis 128 at a speed
sufficient to provide the process fluid at the tip 136 thereof with
an exit absolute Mach number of less than one.
[0028] In one or more embodiments, the process fluid at the tip 136
of the centrifugal impeller 126 may be supersonic and have an exit
absolute Mach number of one or greater. For example, the process
fluid at the tip 136 of the centrifugal impeller 126 may have an
exit absolute Mach number of at least one, at least 1.1, at least
1.2, at least 1.3, at least 1.4, or at least 1.5. Accordingly, in
such embodiments, the compressor 102 discussed herein may be
"supersonic," as the centrifugal impeller 126 may be configured to
rotate about the center axis 128 at a speed sufficient to provide
the process fluid at the tip 136 thereof with an exit absolute Mach
number of one or greater or with a fluid velocity greater than the
speed of sound. In a supersonic compressor or a stage thereof, the
rotational or tip speed of the centrifugal impeller 126 may be
about 500 meters per second (mis) or greater. For example, the tip
speed of the centrifugal impeller 126 may be about 510 m/s, about
520 m/s, about 530 m/s, about 540 m/s, about 550 m/s, about 560
m/s, or greater.
[0029] Referring now to FIGS. 3A and 3B, with continued reference
to FIG. 2, FIGS. 3A and 3B illustrate a perspective view and a
front view, respectively, of the centrifugal impeller 126 that may
be included in the compressor 102, according to one or more
embodiments. As shown in FIG. 2 and more clearly in FIGS. 3A and
3B, the centrifugal impeller 126 may include a plurality of
aerodynamic surfaces or blades 144a,b coupled or integral with the
hub 130 and configured to increase the velocity and energy of the
process fluid. As illustrated in FIGS. 3A and 3B, the blades 144a,b
of the centrifugal impeller 126 may be curved, such that the
process fluid may be urged in a tangential and radial direction by
the centrifugal force through a plurality of flow passages 146, 148
formed by the blades 144a,b and discharged from the blade tips of
the centrifugal impeller 126 (cumulatively, the tip 136 of the
centrifugal impeller 126) in at least partially radial directions
that extend 360 degrees around the centrifugal impeller 126. It
will be appreciated that the contour or amount of curvature of the
blades 144a,b is not limited to the shaping illustrated in FIGS. 3A
and 3B and may be determined based, at least in part, on desired
operating parameters.
[0030] The plurality of blades 144a,b may include main blades 144a
spaced equidistantly apart and circumferentially about the center
axis 128. Each main blade 144a may extend from a leading edge 150
disposed adjacent the first meridional end portion 132 of the
centrifugal impeller 126 to a trailing edge 152 disposed adjacent
the second meridional end portion 134 of the centrifugal impeller
126. Further, based on rotation of the centrifugal impeller 126,
each main blade 144a may define a pressure surface on one side 154
of the main blade 144a and a suction surface on the opposing side
156 of the main blade 1144a. As shown in FIGS. 3A and 3B, the
centrifugal impeller 126 may include thirteen main blades 144a;
however, other embodiments including more than or less than
thirteen main blades 144a are contemplated herein. The number of
main blades 144a may be determined based, at least in part, on
desired operating parameters.
[0031] The plurality of blades 144a,b may also include one or more
splitter blades 144b configured to reduce aerodynamic choking
conditions that may occur in the compressor 102 depending on the
number of blades 144a,b employed with respect to the centrifugal
impeller 126. The splitter blades 144b may be spaced equidistantly
apart and circumferentially about the center axis 128. Each
splitter blade 144b may extend from a leading edge 158,
meridionally spaced and downstream from the first meridional end
portion 132, to a trailing edge 160 disposed adjacent the second
meridional end portion 134 of the centrifugal impeller 126. The
leading edge 158 of each splitter blade 144b may be disposed
meridionally outward from the leading edges 150 of the main blades
144a such that the respective leading edges 150, 158 of the main
blades 144a and splitter blades 144b are staggered and not
coplanar. Further, based on rotation of the centrifugal impeller
126, each splitter blade 144b may define a pressure surface on one
side 162 of the splitter blade 144b and a suction surface on the
opposing side 164 of the splitter blade 144b.
[0032] As most clearly illustrated in FIGS. 2 and 3A, each of the
main blades 144a and the splitter blades 144b extends meridionally
from the second meridional end portion 134 of the centrifugal
impeller 126 toward the first meridional end portion 132 thereof.
The configuration of the respective meridional extents of the main
blades 144a and the splitter blades 144b may be substantially
similar proximal the respective trailing edges 152, 160 of the main
blades 144a and the splitter blades 144b. The configuration of the
respective meridional extents of the main blades 144a and the
splitter blades 144b may differ from the second meridional end
portion 134 to the respective leading edges 150, 158 of the main
blades 144a and the splitter blades 144b. In an exemplary
embodiment, the meridional extent of each of the main blades 144a
may be greater than the meridional extent of each of the splitter
blades 144b, such that the respective leading edges 158 of the
splitter blades 144b may be disposed meridionally offset toward the
second meridional end portion 134 of the centrifugal impeller 126
from the respective leading edges 150 of the main blades 144a.
[0033] The splitter blades 144b and main blades 144a may be
arranged circumferentially about the center axis 128 in a pattern
such that a splitter blade 144b is disposed between adjacent main
blades 144a. As arranged, each splitter blade 144b may be disposed
between the pressure surface side 154 of an adjacent main blade
144a and the suction surface side 156 of the other adjacent main
blade 144a. Further, the splitter blades 144b may be "clocked" with
respect to the main blades 144a, such that each splitter blade 144b
is circumferentially offset or not equidistant from the respective
adjacent main blades 144a and thus is not circumferentially
centered between the adjacent main blades 144a. By clocking the
splitter blades 144b, e.g., displacing the splitter blades 144b
from a position equidistant from the adjacent main blades 144a, the
operating characteristics of the centrifugal impeller 126 may be
improved.
[0034] In one or more embodiments, the splitter blades 144b and
main blades 144a may be arranged circumferentially about the center
axis 128 in a pattern such that a plurality of splitter blades 144b
may be disposed between adjacent main blades 144a. Accordingly, in
one embodiment, at least two splitter blades 144b are disposed
between adjacent main blades 144a. The leading edges 158 of the
respective splitter blades 144b may be offset meridionally from one
another such that the respective leading edges 158 of the splitter
blades 144b are staggered and not coplanar.
[0035] As positioned between the adjacent main blades 144a, each
splitter blade 144b may be oriented such that the splitter blade
144b is canted, such that the leading edge 158 of the splitter
blade 144b is circumferentially offset from a position equidistant
from the adjacent main blades 144a a different percentage amount
than the trailing edge 160 of the splitter blade 144b. Accordingly,
in an exemplary embodiment, the leading edge 158 of the splitter
blade 144b may be displaced from a position equidistant from the
adjacent main blades 144a by a distance of a first percentage
amount of one half the angular distance .theta. between the
adjacent main blades 144a. The trailing edge 160 of the splitter
blade 144b may be displaced from the position equidistant the
adjacent main blades 144a by a distance of a second percentage
amount of one half the angular distance 8 between the adjacent main
blades 144a.
[0036] In an exemplary embodiment, the first percentage amount may
be greater than the second percentage amount. In another
embodiment, the first percentage amount may be less than the second
percentage amount. For example, the difference in displacement
between the leading edge 158 and the trailing edge 160 from the
position equidistant the adjacent main blades 144a may be a
percentage amount of at least about one percent, about two percent,
about three percent, about four percent, about five percent, about
ten percent, about fifteen percent, or about twenty percent. In
another example, the difference in displacement between the leading
edge 158 and the trailing edge 160 from the position equidistant
the adjacent main blades 144a may be a percentage amount of between
about one percent and about two percent, about three percent and
about five percent, about five percent and about ten percent, or
about ten percent and about twenty percent. The differences in
distance related to the percentage amounts, e.g., the amount the
splitter blade 144b is canted, may be determined based, at least in
part, on desired operating parameters.
[0037] As shown in FIGS. 3A and 3B, a plurality of flow passages
146, 148 may be formed between the splitter blades 144b and the
adjacent main blades 144a as arranged about the center axis 128. In
an exemplary embodiment, the plurality of flow passages 146, 148
may include a first flow passage 146 formed between the pressure
surface side 162 of the splitter blade 144b and the suction surface
side 156 of one of the adjacent main blades 144a and a second flow
passage 148 between the suction surface side 164 of the splitter
blade 144b and the pressure surface side 154 of the other adjacent
main blade 144a. The mass flow of the process fluid through the
first and second flow passages 146, 148 may be determined based on
the displacement of the splitter blade 144b in relation to the
adjacent main blades 144a. For example, it has been determined that
disposing the splitter blade 144b equidistantly between the
adjacent main blades 144a may not result in equal mass flow through
the first flow passage 146 and the second flow passage 148.
Accordingly, in an exemplary embodiment, the splitter blade 144b
may be circumferentially offset from a position centered between
adjacent main blades 144a, such that the suction surface side 164
of the splitter blade 144b is disposed in a direction closer to the
pressure surface side 154 of one of the adjacent main blades 144a
and further from the suction surface side 156 of the other adjacent
main blade 144a, thereby substantially equalizing the mass flow
through the respective flow passages 146, 148.
[0038] As will be appreciated by those of skill in the art, the
desired displacement of the splitter blades 144b may depend on
various factors, such as the shape of the blades 144a,b, the angle
of incidence of the blades 144a,b, the size of the blades 144a,b
and of the centrifugal impeller 126, the operating speed range,
etc. However, the displacement necessary to equalize the mass flow
through the first flow passage 146 and the second flow passage 148
may be determined for a given design of the centrifugal impeller
126 and corresponding blades 144a,b by measurement of the mass
flow, such as by use of a mass flow meter.
[0039] As shown in FIG. 2, the compressor 102 may include a shroud
170 coupled to the housing 110 and disposed adjacent the plurality
of blades 144a,b of the centrifugal impeller 126. In particular, a
surface 172 of the shroud 170 may include an abradable material and
may be contoured to substantially align with the silhouette of the
plurality of blades 144a,b, thus substantially reducing leakage
flow of the process fluid in a gap defined therebetween. The
abradable material is arranged on the surface 172 of the shroud 170
and configured to be deformed and/or removed therefrom during
incidental contact of the rotating centrifugal impeller 126 with
the abradable material of the stationary shroud 170 during axial
movement of the rotary shaft 108, thereby preventing damage to the
blades 144a,b and resulting in a loss of a sacrificial amount of
the abradable material.
[0040] In an embodiment, illustrated most clearly in FIG. 2, the
compressor 102 may include the static diffuser 116 fluidly coupled
to the axial inlet 112 and configured to receive the radial process
fluid flow exiting the tip 136 of the centrifugal impeller 126. As
shown in FIG. 2, the static diffuser 116 may be a vaneless
diffuser. The static diffuser 116 may be configured to convert
kinetic energy of the process fluid from the centrifugal impeller
126 into increased static pressure. In an exemplary embodiment, the
static diffuser 116 may be located downstream of the centrifugal
impeller 126 and may be statically disposed circumferentially about
the periphery, or tip 136, of the centrifugal impeller 126.
[0041] The static diffuser 116 may be coupled with or integral with
the housing 110 of the compressor 102 and may form an annular
diffuser passageway 174 having an inlet end adjacent the tip 136 of
the centrifugal impeller 126 and a radially outer outlet end. In an
exemplary embodiment, the annular diffuser passageway 174 may be
formed, at least in part, by portions of the housing 110, namely a
shroud wall 180 and a hub wall 182, forming the confining sidewalls
of the static diffuser 116. The shroud wall 180 and the hub wall
182 may each be a straight wall or a contoured wall, such that the
annular diffuser passageway 174 may be formed from straight walls,
contoured walls, or a combination thereof. In addition, the annular
diffuser passageway 174 may have a reduced width as the shroud wall
180 and the hub wall 182 extend radially outward. Such a "pinched"
diffuser may provide for lower choke and surge limits and, thus,
improve the efficiency of the centrifugal impeller 126.
[0042] In another embodiment, the static diffuser 116 may be a
vaned diffuser. Accordingly, the static diffuser 116 may have a
plurality of diffuser vanes (not shown) arranged in a plurality of
concentric rings (not shown) about the center axis 128 and
extending from the shroud wall 180 and/or the hub wall 182 of the
static diffuser 116. In an exemplary embodiment, the diffuser vanes
are arranged in tandem, such that a first ring of diffuser vanes is
disposed radially inward from a second ring of diffuser vanes.
Respective leading edges of the diffuser vanes of the second ring
may be displaced radially outward from trailing edges of the
diffuser vanes of the first ring. The diffuser vanes of the first
ring may have a lower solidity, or chord to pitch ratio, than the
diffuser vanes of the second ring. In another embodiment, the
static diffuser may include a third ring of diffuser vanes, wherein
the diffuser vanes of the third ring may have a lower solidity than
the diffuser vanes of the second ring. Each of the diffuser vanes
may be airfoils or shaped substantially similar thereto.
[0043] A vaneless space (not shown) may be provided between the tip
136 of the centrifugal impeller 126 and the diameter formed by
leading edges of the diffuser vanes of the first ring. Similarly, a
vaneless space (not shown) may be provided between the diameter
formed by the trailing edges of the diffuser vanes of the first
ring and the leading edges of the diffuser vanes of the second
ring. In one or more embodiments, the incidence of the diffuser
vanes of the first ring may be determined for controlling the Mach
number and reducing supersonic flow introduced at the inlet end of
the static diffuser 116 to a subsonic flow at the trailing edges of
the first ring. As configured, shock waves created by the leading
edges of the first ring do not propagate to the diffuser vanes of
the second ring; however, the leading edges of the first ring
provide for a communication path from the downstream portion of the
static diffuser 116 toward an upstream portion of the centrifugal
impeller 126 to back pressure the centrifugal impeller 126, thereby
obtaining a wider range. The incidence of the diffuser vanes of the
second ring may be determined by placing the second ring in the
"shadow" or flow path of the first ring. Accordingly, the diffuser
vanes may be arranged such that two diffuser vanes of the second
ring are provided in the wake of each diffuser vane of the first
ring and are provided to alter the direction of the process fluid
flow.
[0044] As discussed above, in one or more embodiments, the
compressor 102 provided herein may be referred to as "supersonic"
because the centrifugal impeller 126 may be designed to rotate
about the center axis 128 at high speeds such that a moving process
fluid encountering the inlet end 176 of the static diffuser 116 is
said to have a fluid velocity which is above the speed of sound of
the process fluid being compressed. Thus, in an exemplary
embodiment, the moving process fluid encountering the inlet end 176
of the static diffuser 116 may have an exit absolute Mach number of
about one or greater. However, to increase total energy of the
fluid system, the moving process fluid encountering the inlet end
176 of the static diffuser 116 may have an exit absolute Mach
number of at least about 1.1, at least about 1.2, at least about
1.3, at least about 1.4, or at least about 1.5. In another example,
the process fluid at the tip 136 of the centrifugal impeller 126
may have an exit absolute Mach number from about 1.1 to about 1.5,
or about 1.2 to about 1.4.
[0045] The process fluid flow leaving the outlet end of the static
diffuser 116 may flow into the collector 117, as most clearly seen
in FIG. 2. The collector 117 may be configured to gather the
process fluid flow from the static diffuser 116 and to deliver the
process fluid flow to a downstream pipe and/or process component
(not shown). In an exemplary embodiment, the collector 117 may be a
discharge volute or specifically, a scroll-type discharge volute.
In another embodiment, the collector 117 may be a plenum. The
collector 117 may be further configured to increase the static
pressure of the process fluid flow by converting the kinetic energy
of the process fluid to static pressure. The collector 117 may have
a round tongue (not shown). In another embodiment, the collector
may have a sharp tongue (not shown). It will be appreciated that
the tongue of the collector 117 may form other shapes known to
those of ordinary skill in the art without varying from the scope
of this disclosure.
[0046] One or more exemplary operational aspects of the compression
system 100 will now be discussed with continued reference to FIGS.
1-3B. A process fluid may be provided from an external source (not
shown), having a low pressure environment, to the compression
system 100. The compression system 100 may include, amongst other
components, the compressor 102 having the centrifugal impeller 126
coupled with the rotary shaft 108 and the static diffuser 116
disposed circumferentially about the rotating centrifugal impeller
126. The process fluid may be drawn into the axial inlet 112 of the
compressor 102 with a velocity ranging, for example, from about
Mach 0.05 to about Mach 0.40. The process fluid may flow through
the inlet passageway 114 defined by the axial inlet 112 and across
the inlet guide vanes 122 extending into the inlet passageway 114.
The process fluid flowing across the inlet guide vanes 122 may be
provided with an increased velocity and imparted with at least one
fluid property (e.g., swirl) prior to be being drawn into the
rotating centrifugal impeller 126. The inlet guide vanes 122 may be
adjusted in order to vary the one or more fluid properties imparted
to the process fluid.
[0047] The process fluid may be drawn into the rotating centrifugal
impeller 126 and may contact the curved centrifugal impeller blades
144a,b, such that the process fluid may be accelerated in a
tangential and radial direction by centrifugal force through the
first flow passages 146 and the second flow passages 148 and may be
discharged from the blade tips of the centrifugal impeller 126
(cumulatively, the tip 136 of the centrifugal impeller 126) in at
least partially radial directions that extend 360 degrees around
the rotating centrifugal impeller 126. The rotating centrifugal
impeller 126 increases the velocity and static pressure of the
process fluid, such that the velocity of the process fluid
discharged from the blade tips (cumulatively, the tip 136 of the
centrifugal impeller 126) may be supersonic in some embodiments and
have an exit absolute Mach number of at least about one, at least
about 1.1, at least about 1.2, at least about 1.3, at least about
1.4, or at least about 1.5.
[0048] The static diffuser 116 may be disposed circumferentially
about the periphery, or tip 136, of the centrifugal impeller 126
and may be coupled with or integral with the housing 110 of the
compressor 102. The radial process fluid flow discharged from the
rotating centrifugal impeller 126 may be received by the static
diffuser 116 such that the velocity of the flow of process fluid
discharged from the tip 136 of the rotating centrifugal impeller
126 is substantially similar to the velocity of the process fluid
entering the inlet end of the static diffuser 116. Accordingly, the
process fluid may enter the inlet end of the static diffuser 116
with a supersonic velocity having, for example, an exit absolute
Mach number of at least one, and correspondingly, may be referred
to as supersonic process fluid.
[0049] The velocity of the supersonic process fluid flowing into
the inlet end of the static diffuser 116 decreases with increasing
radius of the annular diffuser passageway 174 as the process fluid
flows from the inlet end to the radially outer outlet end of the
static diffuser 116 as the velocity head is converted to static
pressure. In some embodiments, the tangential velocity of the
supersonic process fluid may decelerate from supersonic to subsonic
velocities across the diffuser vanes of the first ring without
shock losses. Accordingly, the static diffuser 116 may reduce the
velocity and increase the pressure energy of the process fluid.
[0050] The process fluid exiting the static diffuser 116 may have a
subsonic velocity and may be fed into the collector 117 or
discharge volute. The collector 117 may increase the static
pressure of the process fluid by converting the remaining kinetic
energy of the process fluid to static pressure. The process fluid
may then be routed to perform work or for operation of one or more
downstream processes or components (not shown).
[0051] The process fluid pressurized, circulated, contained, or
otherwise utilized in the compression system 100 may be a fluid in
a liquid phase, a gas phase, a supercritical state, a subcritical
state, or any combination thereof. The process fluid may be a
mixture, or process fluid mixture. The process fluid may include
one or more high molecular weight process fluids, one or more low
molecular weight process fluids, or any mixture or combination
thereof. As used herein, the term "high molecular weight process
fluids" refers to process fluids having a molecular weight of about
30 grams per mole (g/mol) or greater. Illustrative high molecular
weight process fluids may include, but are not limited to,
hydrocarbons, such as ethane, propane, butanes, pentanes, and
hexanes. Illustrative high molecular weight process fluids may also
include, but are not limited to, carbon dioxide (CO.sub.2) or
process fluid mixtures containing carbon dioxide. As used herein,
the term "low molecular weight process fluids" refers to process
fluids having a molecular weight less than about 30 g/mol.
Illustrative low molecular weight process fluids may include, but
are not limited to, air, hydrogen, methane, or any combination or
mixtures thereof.
[0052] In an exemplary embodiment, the process fluid or the process
fluid mixture may be or include carbon dioxide. The amount of
carbon dioxide in the process fluid or the process fluid mixture
may be at least about 80%, at least about 85%, at least about 90%,
at least about 95%, at least about 96%, at least about 97%, at
least about 98%, at least about 99%, or greater by volume.
Utilizing carbon dioxide as the process fluid or as a component or
part of the process fluid mixture in the compression system 100 may
provide one or more advantages. For example, the high density and
high heat capacity or volumetric heat capacity of carbon dioxide
with respect to other process fluids may make carbon dioxide more
"energy dense." Accordingly, a relative size of the compression
system 100 and/or the components thereof may be reduced without
reducing the performance of the compression system 100.
[0053] The carbon dioxide may be of any particular type, source,
purity, or grade. For example, industrial grade carbon dioxide may
be utilized as the process fluid without departing from the scope
of the disclosure. Further, as previously discussed, the process
fluids may be a mixture, or process fluid mixture. The process
fluid mixture may be selected for one or more desirable properties
of the process fluid mixture within the compression system 100. For
example, the process fluid mixture may include a mixture of a
liquid absorbent and carbon dioxide (or a process fluid containing
carbon dioxide) that may enable the process fluid mixture to be
compressed to a relatively higher pressure with less energy input
than compressing carbon dioxide (or a process fluid containing
carbon dioxide) alone.
[0054] It should be appreciated that all numerical values and
ranges disclosed herein are approximate valves and ranges, whether
"about" is used in conjunction therewith. It should also be
appreciated that the term "about," as used herein, in conjunction
with a numeral refers to a value that is +/-5% (inclusive) of that
numeral, +/-10% (inclusive) of that numeral, or +/-15% (inclusive)
of that numeral. It should further be appreciated that when a
numerical range is disclosed herein, any numerical value falling
within the range is also specifically disclosed.
[0055] Certain embodiments and features have been described using a
set of numerical upper limits and a set of numerical lower limits.
It should be appreciated that ranges including the combination of
any two values, e.g., the combination of any lower value with any
upper value, the combination of any two lower values, and/or the
combination of any two upper values are contemplated unless
otherwise indicated.
[0056] The foregoing has outlined features of several embodiments
so that those skilled in the art may better understand the present
disclosure. Those skilled in the art should appreciate that they
may readily use the present disclosure as a basis for designing or
modifying other processes and structures for carrying out the same
purposes and/or achieving the same advantages of the embodiments
introduced herein. Those skilled in the art should also realize
that such equivalent constructions do not depart from the spirit
and scope of the present disclosure, and that they may make various
changes, substitutions and alterations herein without departing
from the spirit and scope of the present disclosure.
* * * * *