SUPERSONIC COMPRESSOR ROTOR AND
METHOD OF COMPRESSING A FLUID
BACKGROUND OF THE INVENTION
[0001] The subject matter described herein relates generally to
supersonic compressor rotors and, more particularly, to a method of operating a
supersonic compressor rotor to compress a fluid.
[0002] At least some known supersonic compressor systems include
a drive assembly, a drive shaft, and at least one supersonic compressor rotor for
compressing a fluid. The drive assembly is coupled to the supersonic compressor
rotor with the drive shaft to rotate the drive shaft and the supersonic compressor rotor.
[0003] Known supersonic compressor rotors include a plurality of
strakes coupled to a rotor disk. Each strake is oriented circumferentially about the
rotor disk and defines an axial flow channel between adjacent strakes. At least some
known supersonic compressor rotors include a stationary supersonic compression
ramp that is coupled to the rotor disk. Known supersonic compression ramps are
positioned at a fixed location within the axial flow path and are configured to form a
compression wave within the flow path.
[0004] During operation of known supersonic compressor systems,
the drive assembly rotates the supersonic compressor rotor at a high rotational speed.
A fluid is channeled to the supersonic compressor rotor such that the fluid is
characterized by a velocity that is supersonic with respect to the supersonic
compressor rotor at the flow channel. In known supersonic compressor rotors, a
normal Shockwave may be formed upstream of the supersonic compressor ramp. As
fluid passes through the normal Shockwave, a velocity of the fluid is reduced to
subsonic with respect to the supersonic compressor rotor. As a velocity of fluid is
reduced through the normal Shockwave, fluid energy is also reduced. The reduction
in fluid energy through the flow channel may reduce an operating efficiency of known
supersonic compressor systems. Known supersonic compressor systems are described
in, for example, United States Patents numbers 7,334,990 and 7,293,955 filed March
28, 2005 and March 23, 2005 respectively, and United States Patent Application
2009/0196731 filed January 16, 2009.
BRIEF DESCRIPTION OF THE INVENTION
[0005] In one aspect, a supersonic compressor rotor is provided. A
supersonic compressor rotor includes a substantially cylindrical disk body that
includes an upstream surface, a downstream surface, and a radially outer surface that
extends generally axially between the upstream surface and the downstream surface.
The disk body defines a centerline axis. A plurality of vanes are coupled to the
radially outer surface. Adjacent vanes form a pair and are oriented such that a flow
channel is defined between each pair of adjacent vanes. The flow channel extends
generally axially between an inlet opening and an outlet opening. At least one
supersonic compression ramp is positioned within the flow channel. The supersonic
compression ramp is selectively positionable at a first position, at a second position,
and at any position therebetween.
[0006] In another aspect, a supersonic compressor system is
provided. A supersonic compressor system includes a casing that includes an inner
surface that defines a cavity that extends between a fluid inlet and a fluid outlet. A
drive shaft is positioned within the casing. The drive shaft is rotatably coupled to a
driving assembly. A supersonic compressor rotor is coupled to the drive shaft. The
supersonic compressor rotor is positioned between the fluid inlet and the fluid outlet
for channeling fluid from the fluid inlet to the fluid outlet. The supersonic
compressor rotor includes a substantially cylindrical disk body that includes an
upstream surface, a downstream surface, and a radially outer surface that extends
generally axially between the upstream surface and the downstream surface. The disk
body defines a centerline axis. A plurality of vanes are coupled to the radially outer
surface. Adjacent vanes form a pair and are oriented such that a flow channel is
defined between each pair of adjacent vanes. The flow channel extends generally
axially between an inlet opening and an outlet opening. At least one supersonic
compression ramp is positioned within the flow channel. The supersonic compression
ramp is selectively positionable at a first position, at a second position, and at any
position therebetween.
[0007] In yet another aspect, the present invention provides a method
of compressing a fluid using a supersonic compressor employing a supersonic
compressor rotor provided by the present invention. The method includes (a)
introducing a fluid to be compressed into an inlet opening of a rotating supersonic
compressor rotor, said supersonic compressor rotor comprising (i) a substantially
cylindrical disk body comprising an upstream surface, a downstream surface, and a
radially outer surface that extends generally axially between said upstream surface
and said downstream surface, said disk body defining a centerline axis; (ii) a plurality
of vanes coupled to said radially outer surface, adjacent said vanes forming a pair and
oriented such that a flow channel is defined between each said pair of adjacent vanes,
said flow channel extending generally axially between the inlet opening and an outlet
opening; and (iii) at least one supersonic compression ramp positioned within said
flow channel, said supersonic compression ramp being selectively positionable at a
first position, at a second position, and at any position therebetween; (b) operating the
supersonic compressor rotor with the supersonic compressor ramp positioned in the
first position until a normal shock wave forms downstream of a throat region defined
by a trailing edge of the supersonic compressor ramp; and (c) positioning the
supersonic compressor ramp in the second position, said second position being
characterized by a minimum cross-sectional area which is smaller than a
corresponding minimum cross-sectional area characteristic of the first position; and
(d) operating the supersonic compressor rotor with the supersonic compressor ramp
positioned in the second position to produce a compressed fluid.
BRIEF DESCRIPTION OF THE DRAWING
[0008] These and other features, aspects, and advantages of the
present invention will become better understood when the following detailed
description is read with reference to the accompanying drawings in which like
characters represent like parts throughout the drawings, wherein:
[0009] Fig. 1 is a schematic view of an exemplary supersonic
compressor system;
[0010] Fig. 2 is a perspective view of an exemplary supersonic
compressor rotor that may be used with the supersonic compressor system shown in
Fig. 1;
[001 1] Fig. 3 is an enlarged top view of a portion of the supersonic
compressor rotor shown in Fig. 2 along sectional line 3-3;
[0012] Fig. 4 is a cross-sectional view of the supersonic compressor
rotor shown in Fig. 2 along sectional line 4-4, including the supersonic compressor
ramp shown in a first position;
[0013] Fig. 5 is a cross-sectional view of the supersonic compressor
rotor shown in Fig. 4, including the supersonic compressor ramp shown in a second
position;
[0014] Fig. 6 is a block diagram of an exemplary control system
suitable for use with the supersonic compressor system in Fig. 1;
[0015] Fig. 7 is a flow chart illustrating an exemplary method of
operating the supersonic compressor system shown in Fig. 1.
[0016] Unless otherwise indicated, the drawings provided herein are
meant to illustrate key inventive features of the invention. These key inventive
features are believed to be applicable in a wide variety of systems comprising one or
more embodiments of the invention. As such, the drawings are not meant to include
all conventional features known by those of ordinary skill in the art to be required for
the practice of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] In the following specification and the claims, which follow,
reference will be made to a number of terms, which shall be defined to have the
following meanings.
[0018] The singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise.
[0019] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the description
includes instances where the event occurs and instances where it does not.
[0020] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative representation
that could permissibly vary without resulting in a change in the basic function to
which it is related. Accordingly, a value modified by a term or terms, such as "about"
and "substantially", are not to be limited to the precise value specified. In at least
some instances, the approximating language may correspond to the precision of an
instrument for measuring the value. Here and throughout the specification and
claims, range limitations may be combined and/or interchanged, such ranges are
identified and include all the sub-ranges contained therein unless context or language
indicates otherwise.
[0021] As used herein, the term "supersonic compressor rotor" refers
to a compressor rotor comprising a supersonic compression ramp disposed within a
fluid flow channel of the supersonic compressor rotor. Supersonic compressor rotors
are said to be "supersonic" because they are designed to rotate about an axis of
rotation at high speeds such that a moving fluid, for example a moving gas,
encountering the rotating supersonic compressor rotor at a supersonic compression
ramp disposed within a flow channel of the rotor, is said to have a relative fluid
velocity which is supersonic. The relative fluid velocity can be defined in terms of
the vector sum of the rotor velocity at the supersonic compression ramp and the fluid
velocity just prior to encountering the supersonic compression ramp. This relative
fluid velocity is at times referred to as the "local supersonic inlet velocity", which in
certain embodiments is a combination of an inlet gas velocity and a tangential speed
of a supersonic compression ramp disposed within a flow channel of the supersonic
compressor rotor. The supersonic compressor rotors are engineered for service at very
high tangential speeds, for example tangential speeds in a range of 300 meters/second
to 800 meters/second.
[0022] The exemplary systems and methods described herein
overcome disadvantages of known supersonic compressor assemblies by providing a
supersonic compressor rotor that facilitates the passage of a normal Shockwave
formed at a first location within a flow channel of the supersonic compressor rotor
during a start-up mode to a second location within the flow channel, the normal shock
wave passing through a minimum cross-sectional area of the flow channel during its
transit from the first location to the second location. Thereafter the supersonic
compressor rotor provided by the present invention provides for greater efficiency of
operation during a compression mode of operation. The supersonic compressor rotor
described herein includes a supersonic compression ramp that is selectively
positionable between the first position and the second position to control the size of
the minimum cross-sectional area of the flow channel, at times herein referred to as
the throat region. By adjusting the size of the minimum cross-sectional area the
supersonic compressor rotor may be operated more efficiently than supersonic
compressor rotors comprising supersonic compressor ramps which are stationary (i.e.
the supersonic compressor ramps are not positionable at a first position in the flow
channel, a second position in the flow channel, or any position therein between).
[0023] Fig. 1 is a schematic view of an exemplary supersonic
compressor system 10. In the exemplary embodiment, supersonic compressor system
10 includes an intake section 12, a compressor section 14 coupled downstream from
intake section 12, a discharge section 16 coupled downstream from compressor
section 14, and a drive assembly 18. Compressor section 14 is coupled to drive
assembly 18 by a rotor assembly 20 that includes an inner drive shaft 22 configured to
drive a first supersonic compressor rotor 44, and an outer drive shaft 23 configured to
drive a second supersonic compressor rotor. A control system 24 is coupled in
operative communication with compressor section 14 and drive assembly 18 for
controlling an operation of compressor section 14 and drive assembly 18. In the
exemplary embodiment, each of intake section 12, compressor section 14, and
discharge section 16 are positioned within a compressor housing 26. More
specifically, compressor housing 26 includes a fluid inlet 28, a fluid outlet 30, and an
inner surface 32 that defines a cavity 34. Cavity 34 extends between fluid inlet 28
and fluid outlet 30 and is configured to channel a fluid from fluid inlet 28 to fluid
outlet 30. Each of intake section 12, compressor section 14, and discharge section 16
are positioned within cavity 34. Alternatively, intake section 12 and/or discharge
section 16 may not be positioned within compressor housing 26.
[0024] During operation, supersonic compressor system 10 is
monitored by several sensors 36 that detect various conditions of intake section 12,
compressor section 14, discharge section 16, and drive assembly 18. Sensors 36 may
include gas sensors, temperature sensors, flow sensors, speed sensors, pressure
sensors and/or any other sensors that sense various parameters relative to the
operation of supersonic compressor system 10. As used herein, the term "parameters"
refers to physical properties whose values can be used to define the operating
conditions of supersonic compressor system 10, such as temperatures, pressures, and
gas flows at defined locations.
[0025] In the exemplary embodiment, fluid inlet 28 is configured to
channel a flow of fluid from a fluid source 38 to intake section 12. The fluid may be
any fluid such as, for example a liquid, a gas, a gas mixture, and/or a liquid-gas
mixture. Intake section 12 is coupled in flow communication with compressor section
14 for channeling fluid from fluid inlet 28 to compressor section 14. Intake section 12
is configured to condition a fluid flow having one or more predetermined parameters,
such as a velocity, a mass flow rate, a pressure, a temperature, and/or any suitable
flow parameter. In the exemplary embodiment, intake section 12 includes an inlet
guide vane assembly 40 that is coupled between fluid inlet 28 and compressor section
14 for channeling fluid from fluid inlet 28 to compressor section 14. Inlet guide vane
assembly 40 includes one or more stationary inlet guide vanes 42 which may be
coupled to compressor housing 26 and are stationary with respect to compressor
section 14.
[0026] Compressor section 14 is coupled between intake section 12
and discharge section 16 for channeling at least a portion of fluid from intake section
12 to discharge section 16. Generally, compressor section 14 includes at least one
supersonic compressor rotor 44 that is rotatably coupled to drive shaft 22. Supersonic
compressor rotor 44 is configured to increase a pressure of fluid, reduce a volume of
fluid, and/or increase a temperature of fluid being channeled to discharge section 16.
In the exemplary embodiment, compressor section 14 includes at least one pressure
sensor 46 that is configured to sense a pressure of fluid being channeled through
supersonic compressor rotor 44 and transmit a signal indicative of fluid pressure to
control system 24.
[0027] Discharge section 16 includes an outlet guide vane assembly
48 comprising stationary outlet guide vanes 42 that is disposed between supersonic
compressor rotor 44 and fluid outlet 30 for channeling fluid from supersonic
compressor rotor 44 to fluid outlet 30. Fluid outlet 30 is configured to channel fluid
from outlet guide vane assembly 48 and/or supersonic compressor rotor 44 to an
output system 50 such as, for example, a turbine engine system, a fluid treatment
system, and/or a fluid storage system. Drive assembly 18 is configured to rotate drive
shaft 22 to cause a rotation of supersonic compressor rotor 44. In the embodiment
shown in Fig. 1 the supersonic compressor system 10 comprises a pair of counterrotating
supersonic compressor rotors 44. Drive assembly 20 powers each of the two
supersonic compressor rotors 44 which are independently coupled to one of a pair of
partially concentric drive shafts 22 and 23 (concentricity shown in Fig. 1) configured
to rotate in opposite directions. In the exemplary embodiment, compressor section 14
includes at least one velocity sensor 52 that is coupled to supersonic compressor rotor
44. Velocity sensor 52 is configured to sense a rotational velocity of supersonic
compressor rotor 44 and transmit a signal indicative of the rotational velocity to
control system 24.
[0028] During operation, intake section 12 channels fluid from fluid
source 38 towards compressor section 14. Compressor section 14 compresses the
fluid and discharges the compressed fluid towards discharge section 16. Discharge
section 16 channels the compressed fluid from compressor section 14 to output
system 50 through fluid outlet 30.
[0029] Fig. 2 is a perspective view of an exemplary supersonic
compressor rotor 44. Fig. 3 is a sectional view of supersonic compressor rotor 44
taken along sectional line 3-3 shown in Fig. 2. Fig. 4 is a cross-sectional view of a
portion of supersonic compressor rotor 44 taken along sectional line 4-4 shown in Fig.
2. Fig. 5 is a cross-sectional view of a portion of supersonic compressor rotor 44
taken along sectional line 4-4 shown in Fig. 2. Identical components shown in Figs.
3-5 are labeled with the same reference numbers used in Fig. 2. In the exemplary
embodiment, supersonic compressor rotor 44 includes a plurality of vanes 54 that are
coupled to a rotor disk 56. Rotor disk 56 includes an annular disk body 58 that
defines an inner cylindrical cavity 60 extending generally axially through disk body
58 along a centerline axis 62. Disk body 58 includes a radially inner surface 64 and a
radially outer surface 66. Radially inner surface 64 defines inner cylindrical cavity
60. Inner cylindrical cavity 60 has a substantially cylindrical shape and is oriented
about centerline axis 62. Inner cylindrical cavity 60 is sized to receive drive shaft 22
or 23 (shown in Fig. 1) therethrough. Rotor disk 56 also includes an upstream surface
68 and a downstream surface 70. Each upstream surface 68 and downstream surface
70 extends between radially inner surface 64 and radially outer surface 66 in a radial
direction 72 that is generally perpendicular to centerline axis 62. Each upstream
surface 68 and downstream surface 70 includes a radial width 74 that is defined
between radially inner surface 64 and radially outer surface 66. Radially outer surface
66 is coupled between upstream surface 68 and downstream surface 70, and includes
an axial distance 76 (Fig. 3) defined between upstream surface 68 and downstream
surface 70 in an axial direction 78 that is generally parallel to centerline axis 62.
[0030] In the exemplary embodiment, each vane 54 is coupled to
radially outer surface 66 and extends outwardly from radially outer surface 66. Each
vane 54 extends circumferentially about rotor disk 56 in a helical shape. Each vane
54 includes an inlet edge 80, an outlet edge 82, and a sidewall 84 that extends
between inlet edge 80 and outlet edge 82. Inlet edge 80 is positioned adjacent
upstream surface 68. Outlet edge 82 is positioned adjacent downstream surface 70.
In the exemplary embodiment, adjacent vanes 54 form a pair 86 of vanes 54 (Fig. 2).
Each pair 86 is oriented to define a flow channel 88 between adjacent vanes 54. Flow
channel 88 extends between an inlet opening 90 and an outlet opening 92, and defines
a flow path, represented by arrow 94, that extends from inlet opening 90 to outlet
opening 92. Flow path 94 is oriented generally parallel to adjacent vanes 54 and to
radially outer surface 66. Flow path 94 is defined in axial direction 78 along radially
outer surface 66 from inlet opening 90 to outlet opening 92. Flow channel 88 is sized,
shaped, and oriented to channel fluid along flow path 94 from inlet opening 90 to
outlet opening 92 in axial direction 78. Inlet opening 90 is defined between inlet edge
80 and adjacent sidewall 84. Outlet opening 92 is defined between outlet edge 82 and
adjacent sidewall 84. Each sidewall 84 extends outwardly from radially outer surface
66 in radial direction 72. Sidewall 84 includes an outer surface 96 and an opposite
inner surface 98. Sidewall 84 extends between outer surface 96 and inner surface 98
to define a radial height 100 of flow channel 88. Each vane 54 is spaced axially from
an adjacent vane 54 such that flow channel 88 is oriented generally in axial direction
78 between inlet opening 90 and outlet opening 92. Flow channel 88 includes a width
106 that is defined between adjacent sidewalls 84 and such width 106 is defined as
being perpendicular to flow path 94.
[0031] Referring to Fig. 4, in the exemplary embodiment, a shroud
assembly 108 extends circumferentially about radially outer surface 66 such that flow
channel 88 is defined between shroud assembly 108 and radially outer surface 66.
Shroud assembly 108 includes one or more shroud plates 110. Each shroud plate 110
is coupled to outer surface 96 (Fig. 2) of each vane 54. Alternatively, supersonic
compressor rotor 44 does not include shroud assembly 108. In such an embodiment,
a diaphragm assembly (not shown) may be positioned adjacent outer surface 96 of
each vane 54 such that the diaphragm assembly at least partially defines flow channel
88. In one embodiment, the inner surface 32 of the compressor housing (together
with vanes 54, radially outer surface 66 and supersonic compressor ramp 112) serves
to define the flow channel 88, in which instance the supersonic compressor rotor is
configured such that the distance between outer surface 96 of vanes 54 and the inner
surface 32 is minimized. Those of ordinary skill in the art will appreciate that such
close tolerances between moving and stationary surfaces may be achieved using art
recognized techniques.
[0032] In the exemplary embodiment, at least one supersonic
compression ramp 112 is coupled to rotor disk 56 and is positioned within flow
channel 88. Supersonic compression ramp 112 is positioned between inlet opening 90
and outlet opening 92, and is sized, shaped, and oriented to enable one or more
compression waves to form within flow channel 88. During operation of supersonic
compressor rotor 44, intake section 12 (shown in Fig. 1) channels a fluid 116 towards
inlet opening 90 of flow channel 88. Fluid 116 includes a first velocity, i.e. an
approach velocity, just prior to entering inlet opening 90. Drive assembly 18 (shown
in Fig. 1) rotates supersonic compressor rotor 44 about centerline axis 62 at a second
velocity, i.e. a rotational velocity, represented by arrow 118, such that fluid 116
entering flow channel 88 has a third velocity, i.e. an inlet velocity at inlet opening 90
that is supersonic relative to vanes 54. As fluid 116 contacts supersonic compression
ramp 112 compression waves are formed within flow channel 88 to facilitate
compressing fluid 116 and increase a fluid pressure, increase a fluid temperature,
and/or reduce a fluid volume.
[0033] In the exemplary embodiment, flow channel 88 includes a
cross-sectional area 120 (Fig. 3) that varies along flow path 94. Cross-sectional area
120 of flow channel 88 is defined perpendicularly to flow path 94 and is equal to
width 106 of flow channel 88 multiplied by height 100 of flow channel 88. Flow
channel 88 includes a first area, i.e. an inlet cross-sectional area 122 at inlet opening
90, a second area, i.e. an outlet cross-sectional area 124 at outlet opening 92, and a
third area, i.e. a minimum cross-sectional area 126 that is defined between inlet
opening 90 and outlet opening 92. In the exemplary embodiment, minimum crosssectional
area 126 is less than inlet cross-sectional area 122 and outlet cross-sectional
area 124.
[0034] In the exemplary embodiment, supersonic compression ramp
112 is coupled to rotor disk 56 and is disposed partly within rotor disk 56 and partly
within flow channel 88. As such, radially outer surface 66 defines at least one
perforation through which supersonic compression ramp 112 extends into flow
channel 88. Supersonic compression ramp 112 defines a throat region 128 of flow
channel 88. Throat region 128 defines minimum cross-sectional area 126 of flow
channel 88. Supersonic compression ramp 112 includes a compression surface 130
and a diverging surface 132. Compression surface 130 extends axially between
adjacent vanes 54 and extends along a portion of flow channel 88 defined between
inlet opening 90 and outlet opening 92. Compression surface 130 includes a first
edge, i.e. a leading edge 134 and a second edge, i.e. a trailing edge 136. Leading edge
134 is positioned closer to inlet opening 90 than trailing edge 136. Compression
surface 130 extends into flow channel 88 between leading edge 134 and trailing edge
136 and is oriented at an oblique angle 138 from radially outer surface 66 towards
trailing edge 136 and shroud assembly 108. Trailing edge 136 extends into flow
channel 88 a radial distance 160 (Fig. 4) from radially outer surface 66. Compression
surface 130 converges towards shroud assembly 108 such that a compression region
142 is defined between leading edge 134 and trailing edge 136. Compression region
142 includes a converging cross-sectional area 144 of flow channel 88 that is reduced
along flow path 94 from leading edge 134 to trailing edge 136. Trailing edge 136 of
compression surface 130 (together with sidewalls 84 and shroud assembly 108)
defines throat region 128.
[0035] Diverging surface 132 is coupled to compression surface 130
and extends downstream from compression surface 130 towards outlet opening 92.
Diverging surface 132 includes a first end 146 and a second end 148 that is closer to
outlet opening 92 than first end 146. First end 146 of diverging surface 132 is
coupled to trailing edge 136 of compression surface 130. Diverging surface 132
extends between first end 146 and second end 148 and is oriented at an oblique angle
150 (Fig. 5) from radially outer surface 66 towards trailing edge 136 of compression
surface 130. Diverging surface 132 defines a diverging region 152 that includes a
diverging cross-sectional area 154 (Fig. 4) that increases from trailing edge 136 of
compression surface 130 to outlet opening 92. Diverging region 152 extends from
throat region 128 toward outlet opening 92.
[0036] In the exemplary embodiment, supersonic compression ramp
112 is selectively positionable between a first position 156 (Fig. 4) and a second
position 158 (Fig. 5). In first position 156, supersonic compression ramp 112 extends
into flow channel 88 a first radial distance 160 that is defined between radially outer
surface 66 and trailing edge 136. Moreover, in first position 156, trailing edge 136
defines throat region 128 having a first minimum cross-sectional area 126 and
referred to in in the embodiment shown in Fig 4 as minimum cross-sectional area 162.
In second position 158 (Fig.5), supersonic compression ramp 112 extends into flow
channel 88 a second radial distance 164 from radially outer surface 66 to trailing edge
136. Second radial distance 164 is larger than first radial distance 160 such that
trailing edge 136 defines throat region 128 having a second minimum cross-sectional
area 166 (126) that is smaller than first minimum cross-sectional area 162 (126).
[0037] In the exemplary embodiment, supersonic compressor rotor
44 includes an actuator assembly 168 that is operatively coupled to supersonic
compression ramp 112 for moving supersonic compression ramp 112 with respect to
radially outer surface 66, and between first position 156 and second position 158.
Control system 24 is coupled in operative communication with actuator assembly 168
for controlling an operation of actuator assembly 168, and moving supersonic
compression ramp 112 between first position 156 and second position 158.
[0038] In the exemplary embodiment, supersonic compressor rotor
44 is configured to selectively operate in a first mode, i.e. a start-up mode, and a
second mode, i.e. a compression mode. As used herein, the term "start-up mode"
refers to a mode of operation in which the velocity of the supersonic compressor rotor
is initially insufficient to establish a normal shock wave 170 downstream of the throat
region 128. In start-up mode the supersonic compression ramp 112 is positioned
within flow channel 88 to facilitate the passage of a normal Shockwave 170
established upstream of the throat region to a position downstream of the throat
region. For example, the supersonic compressor ramp may be positioned to facilitate
the passage of a normal Shockwave 170 from a first location 172 (Fig. 4) within flow
channel 88 that is upstream from throat region 128, and between inlet opening 90 and
throat region 128 to a second location 174 (Fig. 5) which is downstream of throat
region 128. Normal Shockwave 170 is oriented perpendicular to flow path 94 and
extends across flow path 94. As used herein, the term "compression mode" refers to a
mode of operation in which the velocity of the rotor is sufficient to establish a normal
shock wave downstream of the throat region, and which includes steady state
operation of the supersonic compressor. It should be noted that the supersonic
compressor rotor may be operated in compression mode under non-steady state
conditions as well, as when, for example, one or more operating parameters (e.g.
temperature, fluid composition) vary continuously during operation. .
[0039] In one embodiment, during operation of supersonic
compressor rotor 44 in start-up mode, supersonic compression ramp 112 is in first
position 156 (Fig. 4). During start-up mode, fluid 116 enters flow channel 88 of
supersonic compressor rotor 44 in which supersonic compressor ramp 112 is in first
position 156, in which mode a normal Shockwave 170 forms upstream of throat region
128. As the velocity of the supersonic compressor rotor increases, normal Shockwave
170 moves downstream along flow path 94 and becomes established downstream of
throat region 128, and the supersonic compressor rotor 44 transitions from start-up
mode to compression mode. It should be noted that passage of the normal shock
wave through the throat region is facilitated by a relatively large throat region crosssectional
area associated with first position 156 (Fig. 4). Once compression mode has
been established, the supersonic compressor rotor may be operated with greater
efficiency by further reducing the cross-sectional area 126 of the throat region (the
minimum cross-sectional area of flow path 88). To this end supersonic compression
ramp 112 may be shifted from first position 156 to second position 158 (Fig. 5). As
supersonic compression ramp 112 moves from first position 156 to second position
158, minimum cross-sectional area 126 of throat region 128 decreases from first
minimum cross-sectional area 162 (126) to second minimum cross-sectional area 166
(126). As minimum cross-sectional area 126 of flow channel 88 decreases to an
appropriate cross-sectional area 166 (which may be determined simulations or
experimentally by those of ordinary skill in the art), the supersonic compressor rotor
may be operated more efficiently.
[0040] In one embodiment, in compression mode, supersonic
compression ramp 112 is selectively positioned between first position 156 and second
position 158 to cause a system 176 (Fig. 5) of compression waves to form within
flow channel 88. System 176 includes a first and second oblique Shockwaves 178 and
180. First oblique shock wave 178 is formed as fluid 116 encounters the leading edge
134 of supersonic compression ramp 112 and is channeled through compression
region 142. Compression surface 130 causes first oblique Shockwave 178 to be
formed at leading edge 134 of compression surface 130. First oblique Shockwave 178
extends across flow path 94 from leading edge 134 to shroud plate 110, and is
oriented at an oblique angle with respect to flow path 94. First oblique Shockwave
178 contacts shroud plate 110 and forms a second oblique Shockwave 180 that is
reflected from shroud plate 110 towards trailing edge 136 of compression surface 130
at an oblique angle with respect to flow path 94. Supersonic compression ramp 112 is
configured to cause each first oblique Shockwave 178 and second oblique Shockwave
180 to form within compression region 142. As will be appreciated by those of
ordinary skill in the art, fluid flow through each of oblique shock waves 178 and 180
is supersonic and remains supersonic until the fluid encounters and passes through
normal shock wave 170 (Fig. 5).
[0041] As fluid 116 passes through compression region 142, a
velocity of fluid is reduced (but as noted, remains supersonic) as fluid passes through
each first oblique Shockwave 178 and second oblique Shockwave 180. In addition, a
pressure of fluid 116 is increased, and a volume of fluid 116 is decreased. As fluid
116 passes through throat region 128, a velocity of fluid 116 is increased downstream
of throat region 128 to normal Shockwave 170. As fluid passes through normal
Shockwave 170, a velocity of fluid 116 is decreased to a subsonic velocity with
respect to rotor disk 56.
[0042] In the exemplary embodiment, rotor disk 56 defines a disk
cavity 184 (Fig. 2). Actuator assembly 168 is positioned within disk cavity 184 and
may be coupled to an inner surface 182 (Fig. 2) of annular disk body 58 or some other
suitable surface defining disk cavity 184. In the exemplary embodiment, actuator
assembly 168 is a hydraulic piston-type mechanism, and includes a hydraulic pump
assembly 186, a hydraulic cylinder 188, and a hydraulic piston 190. Hydraulic pump
assembly 186 is coupled in flow communication with hydraulic cylinder 188 for
adjusting a pressure of hydraulic fluid contained within hydraulic cylinder 188.
Hydraulic piston 190 is positioned within hydraulic cylinder 188 and is configured to
move with respect to hydraulic cylinder 188. A biasing mechanism 192 is coupled to
hydraulic piston 190 and to hydraulic cylinder 188 to bias hydraulic piston 190
radially inward toward centerline axis 62. Hydraulic piston 190 is coupled to
supersonic compression ramp 112 to move supersonic compression ramp 112 from
first position 156 to second position 158, and from second position 158 to first
position 156. In the exemplary embodiment, actuator assembly 168 is configured to
selectively position supersonic compression ramp 112 at first position 156, at second
position 158, and any position between first position 156 and second position 158.
[0043] In the exemplary embodiment, control system 24 is coupled
in operative communication with hydraulic pump assembly 186 for controlling an
operation of hydraulic pump assembly 186. During operation, hydraulic pump
assembly 186 increases a hydraulic pressure within hydraulic cylinder 188 to move
hydraulic piston 190 towards radially outer surface 66 along radial direction 72. As
hydraulic pressure is increased, hydraulic piston 190 causes supersonic compression
ramp 112 to move from first position 156 towards second position 158. As hydraulic
pressure is decreased within hydraulic cylinder, biasing mechanism 192 moves
hydraulic piston radially inwardly that causes supersonic compression ramp to move
from second position 158 towards first position 156. In the embodiment shown in
Fig. 4 and Fig. 5, supersonic compressor ramp 112 moves radially outward from
position 156 and pivots slightly to attain position 158, said radially outward
movement and said pivoting being induced and controlled by actuator assembly 168.
[0044] Fig. 6 is a block diagram illustrating an exemplary control
system 24. In the exemplary embodiment, control system 24 is a real-time controller
that includes any suitable processor-based or microprocessor-based system, such as a
computer system, that includes microcontrollers, reduced instruction set circuits
(RISC), application-specific integrated circuits (ASICs), logic circuits, and/or any
other circuit or processor that is capable of executing the functions described herein.
In one embodiment, control system 24 is a microprocessor that includes read-only
memory (ROM) and/or random access memory (RAM), such as, for example, a 32 bit
microcomputer with 2 Mbit ROM and 64 Kbit RAM. As used herein, the term "real
time" refers to outcomes occurring at a substantially short period of time after a
change in the inputs affect the outcome, with the time period being a design parameter
that may be selected based on the importance of the outcome and/or the capability of
the system processing the inputs to generate the outcome.
[0045] In the exemplary embodiment, control system 24 includes a
memory area 200 configured to store executable instructions and/or one or more
operating parameters representing and/or indicating an operating condition of
supersonic compressor system 10. Operating parameters may represent and/or
indicate, without limitation, a fluid pressure, a rotational velocity, a vibration, and/or a
fluid temperature. Control system 24 further includes a processor 202 that is coupled
to memory area 200 and is programmed to determine an operation of one or more
supersonic compressor system control devices 204, for example, supersonic
compressor rotor 44, based at least in part on one or more operating parameters. In
one embodiment, processor 202 includes a processing unit, such as, without
limitation, an integrated circuit (IC), an application specific integrated circuit (ASIC),
a microcomputer, a programmable logic controller (PLC), and/or any other
programmable circuit. Alternatively, processor 202 may include multiple processing
units (e.g., in a multi-core configuration).
[0046] In the exemplary embodiment, control system 24 includes a
sensor interface 206 that is coupled to at least one sensor 36 such as, for example,
velocity sensor 52, and/or pressure sensor 46 for receiving one or more signals from
sensor 36. Each sensor 36 generates and transmits a signal corresponding to an
operating parameter of supersonic compressor system 10. Moreover, each sensor 36
may transmit a signal continuously, periodically, or only once, for example, though
other signal timings are also contemplated. Furthermore, each sensor 36 may transmit
a signal either in an analog form or in a digital form. Control system 24 processes the
signal(s) by processor 202 to create one or more operating parameters. In some
embodiments, processor 202 is programmed (e.g., with executable instructions in
memory area 200) to sample a signal produced by sensor 36. For example, processor
202 may receive a continuous signal from sensor 36 and, in response, periodically
(e.g., once every five seconds) calculate an operation mode of supersonic compressor
rotor 44 based on the continuous signal. In some embodiments, processor 202
normalizes a signal received from sensor 36. For example, sensor 36 may produce an
analog signal with a parameter (e.g., voltage) that is directly proportional to an
operating parameter value. Processor 202 may be programmed to convert the analog
signal to the operating parameter. In one embodiment, sensor interface 206 includes
an analog-to-digital converter that converts an analog voltage signal generated by
sensor 36 to a multi-bit digital signal usable by control system 24.
[0047] Control system 24 also includes a control interface 208 that is
configured to control an operation of supersonic compressor system 10. In some
embodiments, control interface 208 is operatively coupled to one or more supersonic
compressor system control devices 204, for example, supersonic compressor rotor 44.
[0048] Various connections are available between control interface
208 and control device 204 and between sensor interface 206 and sensor 36. Such
connections may include, without limitation, an electrical conductor, a low-level
serial data connection, such as Recommended Standard (RS) 232 or RS-485, a highlevel
serial data connection, such as Universal Serial Bus (USB) or Institute of
Electrical and Electronics Engineers (IEEE) 1394 (a/k/a FIREWIRE), a parallel data
connection, such as IEEE 1284 or IEEE 488, a short-range wireless communication
channel such as BLUETOOTH, and/or a private (e.g., inaccessible outside supersonic
compressor system 10) network connection, whether wired or wireless.
[0049] Referring again to Fig. 4, in the exemplary embodiment,
pressure sensor 46 is coupled to supersonic compressor rotor 44 and is configured to
sense a pressure within flow channel 88. In one embodiment, pressure sensor 46 is
positioned upstream of throat region 128 for sensing a pressure within compression
region 142 of flow channel 88. Alternatively, pressure sensor 46 may be positioned at
any suitable location to enable control system 24 to function as described herein. In
the exemplary embodiment, velocity sensor 52 is coupled to supersonic compressor
rotor 44 for sensing a rotational velocity of rotor disk 56.
[0050] During operation of supersonic compressor system 10,
control system 24 receives from velocity sensor 52 signals indicative of a rotational
velocity of supersonic compressor rotor 44 and receives from pressure sensor 46
signals indicative of a pressure of fluid 116 within flow channel 88. Control system
24 is configured to calculate a location of normal Shockwave 170 within flow channel
88 based at least in part on the rotational velocity of supersonic compressor rotor 44
and the fluid pressure within flow channel 88. Control system 24 is further
configured to selectively position supersonic compression ramp 112 between first
position 156 and second position 158 based on the calculated location of normal
Shockwave 170. In one embodiment, control system 24 is configured to compare the
calculated location of normal Shockwave 170 with a predefined location and
determine whether normal Shockwave 170 is at first location 172 or second location
174. In the exemplary embodiment, control system 24 selectively positions
supersonic compression ramp 112 at first position 156, at second position 158, and at
any position therebetween based upon determining whether normal Shockwave 170 is
at first location 172 or second location 174. In an alternative embodiment, control
system 24 is configured to compare a sensed fluid pressure with a predefined pressure
and/or a predefined range of pressure values. If the sensed fluid pressure is different
than a predefined pressure and/or is not within a predefined range of pressure values,
control system 24 operates supersonic compression ramp 112 to adjust minimum
cross-sectional area 126 of throat region 128 until the sensed fluid pressure is
substantially equal to a predefined pressure or is within a predefined range of pressure
values.
[0051] Fig. 7 is a flow chart illustrating an exemplary method 300 of
operating supersonic compressor rotor 44 to compress a fluid. In the exemplary
embodiment, method 300 includes transmitting 302 a first monitoring signal
indicative of a rotational velocity of supersonic compressor rotor 44 from velocity
sensor 52 to control system 24. A second monitoring signal indicative of a pressure
within flow channel 88 is transmitted 304 from pressure sensor 46 to control system
24. A location of normal Shockwave 170 is calculated 306 by control system 24
based at least in part on the first monitoring signal and the second monitoring signal.
Control system 24 determines 308 whether normal Shockwave 170 is positioned
downstream of throat region 128 based on the calculated location. Control system 24
positions 310 supersonic compression ramp 112 at one of first position 156 and
second position 158 based on whether normal Shockwave 170 is positioned
downstream of throat region 128.
[0052] An exemplary technical effect of the system, method, and
apparatus described herein includes at least one of: (a) transmitting, from a first sensor
to the control system, a first signal indicative of a rotational velocity of the supersonic
compression rotor; (b) transmitting, from a second sensor to the control system, a
second signal indicative of a pressure within a flow channel; (c) calculating the
location of a normal Shockwave based at least in part on the first signal and the second
signal; (d) determining whether the normal Shockwave is positioned downstream of
the throat region based on the calculated location; and (e) positioning a supersonic
compression ramp at one of a first position and a second position based on the
determination of whether the normal Shockwave is positioned downstream of a throat
region.
[0053] The above-described supersonic compressor rotor provides a
cost effective and reliable method for increasing an efficiency in performance of
supersonic compressor systems. Moreover, the supersonic compressor rotor
facilitates increasing the operating efficiency of the supersonic compressor system by
adjusting the minimal cross-sectional area in the throat region once the desired
operation condition has been attained, as indicated by the location of a normal
Shockwave that is formed within a flow channel downstream of the throat region.
More specifically, the supersonic compressor rotor described herein includes a
supersonic compression ramp that is selectively positionable between a first position
and a second position to facilitate adjusting a minimum cross-sectional area of the
flow channel. By adjusting the minimum cross-sectional area, the supersonic
compressor rotor facilitates improving the operating efficiency of the supersonic
compressor system. As such, the cost of operating and maintaining the supersonic
compressor system may be reduced.
[0054] Exemplary embodiments of systems and methods for
assembling a supersonic compressor rotor are described above in detail. The system
and methods are not limited to the specific embodiments described herein, but rather,
components of systems and/or steps of the method may be utilized independently and
separately from other components and/or steps described herein. For example, the
systems and methods may also be used in combination with other rotary engine
systems and methods, and are not limited to practice with only the supersonic
compressor system as described herein. Rather, the exemplary embodiment can be
implemented and utilized in connection with many other rotary system applications.
[0055] Although specific features of various embodiments of the
invention may be shown in some drawings and not in others, this is for convenience
only. Moreover, references to "one embodiment" in the above description are not
intended to be interpreted as excluding the existence of additional embodiments that
also incorporate the recited features. In accordance with the principles of the
invention, any feature of a drawing may be referenced and/or claimed in combination
with any feature of any other drawing.
[0056] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person skilled in the art to
practice the invention, including making and using any devices or systems and
performing any incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to those skilled in
the art. Such other examples are intended to be within the scope of the claims if they
have structural elements that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial differences from the
literal languages of the claims.
WHAT IS CLAIMED IS:
1. A supersonic compressor rotor comprising:
a substantially cylindrical disk body comprising an upstream surface, a
downstream surface, and a radially outer surface that extends generally axially
between said upstream surface and said downstream surface, said disk body defining
a centerline axis;
a plurality of vanes coupled to said radially outer surface, adjacent said
vanes forming a pair and oriented such that a flow channel is defined between each
said pair of adjacent vanes, said flow channel extending generally axially between an
inlet opening and an outlet opening; and
at least one supersonic compression ramp positioned within said flow
channel, said supersonic compression ramp being selectively positionable at a first
position, at a second position, and at any position therebetween.
2. A supersonic compressor rotor in accordance with Claim 1,
wherein said at least one supersonic compression ramp defines a throat region of said
flow channel, said throat region having a minimum cross-sectional area of said flow
channel, said supersonic compression ramp configured to adjust a cross-sectional area
of said throat region.
3. A supersonic compressor rotor in accordance with Claim 1,
further comprising an actuator coupled to said at least one supersonic compression
ramp, said actuator configured to position said supersonic compression ramp at said
first position, at said second position, and at any position therebetween.
4. A supersonic compressor rotor in accordance with Claim 1,
further comprising a control system operatively coupled to said at least one supersonic
compression ramp to facilitate moving said supersonic compression ramp at said first
position, at said second position, and at any position therebetween.
5. A supersonic compressor rotor in accordance with Claim 4,
further comprising at least a first sensor configured to sense a rotational velocity of
said rotor disk and to generate at least a first monitoring signal indicative of the
sensed rotational velocity, said control system communicatively coupled to said first
sensor for receiving the generated first monitoring signal from said first sensor, said
control system configured to calculate a location of a normal Shockwave within said
flow channel based on the received first monitoring signal.
6. A supersonic compressor rotor in accordance with Claim 5,
further comprising at least a second sensor configured to sense a pressure within said
flow channel and to transmit to said control system at least a second monitoring signal
indicative of the sensed pressure, said control system configured to calculate the
location of the normal Shockwave based on the first monitoring signal and the second
monitoring signal.
7. A supersonic compressor rotor in accordance with Claim 5,
wherein said control system is configured to position said supersonic compression
ramp based on the calculated location of the normal Shockwave.
8. A supersonic compressor rotor in accordance with Claim 7,
wherein said control system is configured to move said supersonic compression ramp
upon determining that the sensed pressure is different than a predetermined pressure.
9. A supersonic compressor system comprising:
a casing comprising an inner surface defining a cavity extending
between a fluid inlet and a fluid outlet;
a drive shaft positioned within said casing, said drive shaft rotatably
coupled to a driving assembly; and
a supersonic compressor rotor coupled to said drive shaft, said
supersonic compressor rotor positioned between said fluid inlet and said fluid outlet
for channeling fluid from said fluid inlet to said fluid outlet, said supersonic
compressor rotor comprising:
a substantially cylindrical disk body comprising an upstream surface, a
downstream surface, and a radially outer surface that extends generally axially
between said upstream surface and said downstream surface, said disk body defining
a centerline axis;
a plurality of vanes coupled to said radially outer surface, adjacent said
vanes forming a pair and oriented such that a flow channel is defined between each
said pair of adjacent vanes, said flow channel extending generally axially between an
inlet opening and an outlet opening; and
at least one supersonic compression ramp positioned within
said flow channel, said supersonic compression ramp selectively positionable at a first
position, at a second position, and at any position therebetween.
10. A supersonic compressor system in accordance with Claim 9,
wherein said at least one supersonic compression ramp defines a throat region of said
flow channel, said throat region having a minimum cross-sectional area of said flow
channel, said supersonic compression ramp configured to adjust a cross-sectional area
of said throat region.
11. A supersonic compressor system in accordance with Claim 9,
further comprising an actuator coupled to said at least one supersonic compression
ramp, said actuator configured to position said supersonic compression ramp at said
first position, at said second position, and at any position therebetween.
12. A supersonic compressor system in accordance with Claim 9,
further comprising a control system operatively coupled to said at least one supersonic
compression ramp to facilitate moving said supersonic compression ramp at said first
position, at said second position, and at any position therebetween.
13. A supersonic compressor system in accordance with Claim 12,
further comprising at least a first sensor configured to sense a rotational velocity of
said rotor disk and to generate at least a first monitoring signal indicative of the
sensed rotational velocity, said control system communicatively coupled to said first
sensor for receiving the generated first monitoring signal from said first sensor, said
control system configured to calculate a location of a normal Shockwave within said
flow channel based on the received first monitoring signal.
14. A supersonic compressor system in accordance with Claim 13,
further comprising at least a second sensor configured to sense a pressure within said
flow channel and to transmit to said control system at least a second monitoring signal
indicative of the sensed pressure, said control system configured to calculate the
location of the normal Shockwave based on the first monitoring signal and the second
monitoring signal.
15. A supersonic compressor system in accordance with Claim 13,
wherein said control system is configured to position said supersonic compression
ramp based on the calculated location of the normal Shockwave.
16. A supersonic compressor system in accordance with Claim 15,
wherein said control system is configured to position said supersonic compression
ramp upon determining that the sensed pressure is different than a predetermined
pressure.
17. A method of compressing a fluid, said method comprising:
(a) introducing a fluid to be compressed into an inlet opening of a
rotating supersonic compressor rotor, said supersonic compressor rotor comprising (i)
a substantially cylindrical disk body comprising an upstream surface, a downstream
surface, and a radially outer surface that extends generally axially between said
upstream surface and said downstream surface, said disk body defining a centerline
axis; (ii) a plurality of vanes coupled to said radially outer surface, adjacent said
vanes forming a pair and oriented such that a flow channel is defined between each
said pair of adjacent vanes, said flow channel extending generally axially between the
inlet opening and an outlet opening; and (iii) at least one supersonic compression
ramp positioned within said flow channel, said supersonic compression ramp being
selectively positionable at a first position, at a second position, and at any position
therebetween;
(b) operating the supersonic compressor rotor with the supersonic
compressor ramp positioned in the first position until a normal shock wave forms
downstream of a throat region defined by a trailing edge of the supersonic compressor
ramp;
(c) positioning the supersonic compressor ramp in the second position,
said second position being characterized by a minimum cross-sectional area which is
smaller than a corresponding minimum cross-sectional area characteristic of the first
position; and
(d) operating the supersonic compressor rotor with the supersonic
compressor ramp positioned in the second position to produce a compressed fluid.
18. A method in accordance with Claim 17, further comprising:
transmitting, from a first sensor to a control system, a first signal
indicative of a rotational velocity of the supersonic compressor rotor; and,
calculating the location of the normal Shockwave based at least in part
on the first signal.
19. A method in accordance with Claim 17, further comprising:
transmitting, from a second sensor to a control system, a second signal
indicative of a pressure within the flow channel; and,
calculating the location of the normal Shockwave based at least in part
on the first signal and the second signal.
20. A method in accordance with Claim 19, further comprising
determining whether the normal Shockwave is positioned downstream
of the throat region based on the calculated location; and,
positioning the supersonic compression ramp at the first position, the
second position, and any position therebetween based on the determination of whether
the normal Shockwave is positioned downstream of the throat region.