U.S. patent application number 12/939740 was filed with the patent office on 2012-05-10 for motor driven cabin air compressor with variable diffuser.
This patent application is currently assigned to HAMILTON SUNDSTRAND CORPORATION. Invention is credited to Craig M. Beers, Christopher McAuliffe.
Application Number | 20120114463 12/939740 |
Document ID | / |
Family ID | 46019789 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120114463 |
Kind Code |
A1 |
Beers; Craig M. ; et
al. |
May 10, 2012 |
MOTOR DRIVEN CABIN AIR COMPRESSOR WITH VARIABLE DIFFUSER
Abstract
An air cycle machine is provided and includes a compressor
section having a variable area diffuser, a turbine section having
an inlet nozzle with a variable size, a motor to drive the
compressor and a common rotating shaft on which the compressor
section, the turbine section and the motor are mounted, the turbine
section driving rotation of the shaft to drive the compressor
section with the motor.
Inventors: |
Beers; Craig M.;
(Wethersfield, CT) ; McAuliffe; Christopher;
(Windsor, CT) |
Assignee: |
HAMILTON SUNDSTRAND
CORPORATION
Windsor Locks
CT
|
Family ID: |
46019789 |
Appl. No.: |
12/939740 |
Filed: |
November 4, 2010 |
Current U.S.
Class: |
415/151 |
Current CPC
Class: |
F04D 25/0606 20130101;
F04D 29/462 20130101 |
Class at
Publication: |
415/151 |
International
Class: |
F04D 29/46 20060101
F04D029/46 |
Claims
1. An air cycle machine, comprising: a compressor section having a
variable area diffuser; a turbine section having an inlet nozzle
with a variable size; a motor to drive the compressor; and a common
rotating shaft on which the compressor section, the turbine section
and the motor are mounted, the turbine section driving rotation of
the shaft to drive the compressor section with the motor.
2. The air cycle machine according to claim 1, wherein the
compressor section, the turbine section and the motor are each
supported on air bearings.
3. The air cycle machine according to claim 1, wherein the variable
size of the inlet nozzle is set according to operation of a
predefined number of packs.
4. The air cycle machine according to claim 1, wherein the motor
comprises an integrally cooled motor.
5. The air cycle machine according to claim 4, further comprising a
heat exchanger coupled to the motor.
6. The air cycle machine according to claim 5, wherein a first
cooling flow is tapped from an inlet of the compressor section and
exited downstream form the heat exchanger.
7. The air cycle machine according to claim 5, wherein a second
cooling flow is tapped from an outlet of the compressor section for
air bearing cooling.
8. An air cycle machine, comprising: a compressor section having a
variable area diffuser to compress inlet air; a turbine section
having an inlet nozzle with a variable size to receive the
compressed air from the compressor section and to expand the air
for use in an aircraft cabin; a motor to drive the compressor; and
a common rotating shaft on which the compressor section, the
turbine section and the motor are operably mounted, the turbine
section driving rotation of the shaft to provide additional drive
power to the compressor section along with that of the motor.
9. The air cycle machine according to claim 8, wherein the
compressor section, the turbine section and the motor are each
supported on air bearings.
10. The air cycle machine according to claim 8, wherein the
variable size of the inlet nozzle is set according to operation of
a predefined number of packs.
11. The air cycle machine according to claim 8, wherein the motor
comprises an integrally cooled motor.
12. The air cycle machine according to claim 11, further comprising
a heat exchanger coupled to the motor.
13. The air cycle machine according to claim 12, wherein a first
cooling flow is tapped from an inlet of the compressor section and
exited downstream form the heat exchanger.
14. The air cycle machine according to claim 12, wherein a second
cooling flow is tapped from an outlet of the compressor section for
air bearing cooling.
15. An air cycle machine for use in a RAM engine in an aircraft,
comprising: a compressor section having a variable area diffuser to
compress RAM inlet air; a turbine section having an inlet nozzle
with a variable size to receive the compressed air from the
compressor section and to expand the air for use in a cabin of the
aircraft; a motor to drive the compressor; and a common rotating
shaft on which the compressor section, the turbine section and the
motor are operably mounted, the turbine section driving rotation of
the shaft to provide additional drive power to the compressor
section along with that of the motor.
16. The air cycle machine according to claim 15, wherein the
compressor section, the turbine section and the motor are each
supported on air bearings.
17. The air cycle machine according to claim 15, wherein the
variable size of the inlet nozzle is set according to operation of
a predefined number of packs.
18. The air cycle machine according to claim 15, wherein the motor
comprises an integrally cooled motor.
19. The air cycle machine according to claim 18, further comprising
a heat exchanger coupled to the motor.
20. The air cycle machine according to claim 19, wherein a first
cooling flow is tapped from an inlet of the compressor section and
exited downstream form the heat exchanger and a second cooling flow
is tapped from an outlet of the compressor section for air bearing
cooling.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to a motor
driven cabin air compressor with a variable diffuser.
[0002] Aircraft environmental control systems incorporate
turbomachines, commonly referred to as air cycle machines (ACMs),
to help facilitate cooling and dehumidifying air for supply to a
cabin of an aircraft. Air cycle machines can include two or more
wheels having at least one compressor and at least one turbine
disposed axially along the same shaft. On aircraft powered by gas
turbine engines, the air to be conditioned in the air cycle machine
is generally either compressed air bled from one or more of the
compressor stages of the gas turbine engine or air diverted from
another location on the aircraft. With either system, the air is
passed through the compressor(s) of the air cycle machine where it
is further compressed and then passed through a heat exchanger to
cool the compressed air sufficiently to condense moisture
therefrom. The dehumidified air continues through the environmental
control system back to the turbine(s) of the air cycle machine. In
the turbine(s), the air is expanded to both extract energy from the
compressed air so as to drive the shaft and the compressor(s)
coupled thereto and cool the air for use in the cabin as
conditioned cooling air.
[0003] To meet required specifications for providing fresh air and
maintain pressurization to the cabin during flight, environmental
control systems on larger aircraft employ two separate (dual) air
conditioning packs. Unfortunately, operating dual air conditioning
packs may not be necessary or efficient in some circumstances such
as when the plane is on the tarmac. In this instance and others,
operating only a single air conditioning pack could accomplish the
conditioning of air for the cabin.
BRIEF DESCRIPTION OF THE INVENTION
[0004] According to one aspect of the invention, an air cycle
machine is provided and includes a compressor section having a
variable area diffuser, a turbine section having an inlet nozzle
with a variable size, a motor to drive the compressor and a common
rotating shaft on which the compressor section, the turbine section
and the motor are mounted, the turbine section driving rotation of
the shaft to drive the compressor section with the motor.
[0005] According to another aspect of the invention, an air cycle
machine is provided and includes a compressor section having a
variable area diffuser to compress inlet air, a turbine section
having an inlet nozzle with a variable size to receive the
compressed air from the compressor section and to expand the air
for use in an aircraft cabin, a motor to drive the compressor and a
common rotating shaft on which the compressor section, the turbine
section and the motor are operably mounted, the turbine section
driving rotation of the shaft to provide additional drive power to
the compressor section along with that of the motor.
[0006] According to yet another aspect of the invention, an air
cycle machine for use in a RAM engine in an aircraft is provided
and includes a compressor section having a variable area diffuser
to compress RAM inlet air, a turbine section having an inlet nozzle
with a variable size to receive the compressed air from the
compressor section and to expand the air for use in a cabin of the
aircraft, a motor to drive the compressor and a common rotating
shaft on which the compressor section, the turbine section and the
motor are operably mounted, the turbine section driving rotation of
the shaft to provide additional drive power to the compressor
section along with that of the motor.
[0007] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0009] FIG. 1 is a schematic view of an air cycle machine for an
environmental control system of an aircraft;
[0010] FIG. 2A is an enlarged view of a turbine inlet nozzle of the
air cycle machine with a poppet member in a first position;
[0011] FIG. 2B is an enlarged view of the turbine inlet nozzle of
the air cycle machine with the poppet member in a second
position;
[0012] FIG. 3 is a partially broken view of a variable area
diffuser in the direction of arrows 2-2 of FIG. 4;
[0013] FIG. 4 is an enlarged cross-sectional view of a variable
area diffuser; and
[0014] FIG. 5 is a schematic illustration of the air cycle
machine.
[0015] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0016] FIG. 1 shows a schematic view of an environmental control
system (ECS) 10. The environmental control system 10 includes an
air cycle machine 12 that receives air 14 that is conditioned by
various devices symbolically indicated as 16A, 16B, and 16C to
produce air flow at a desired temperature and pressure for aircraft
cabin C. The air cycle machine 12 includes a compressor section 18,
a shaft 20, and a turbine section 22. The compressor section 18 has
a compressor inlet 24, a compressor wheel 26 and a compressor
outlet 28. The turbine section 22 includes a turbine inlet 30,
turbine inlet nozzle 32, turbine wheel 34 and turbine outlet
36.
[0017] System air 14 is bled from one or more of the compressor
stages of the gas turbine engines of the aircraft or directed from
an air source at another location on the aircraft. One or more
devices 16A can condition (e.g., preheat, acoustically treat) the
air 14 prior to its entry into the air cycle machine 12. The air 14
enters the air cycle machine 12 at the compressor section 18
through the compressor inlet 24. The air 14 is compressed to a
higher pressure by the compressor wheel 26, which is mounted on the
shaft 20 for rotation about axis A. The compressed air 14 is output
to the remainder of the environmental control system 10 via the
compressor outlet 28. Air 14 output from the compressor section 18
is conditioned by various devices 16B to change the characteristics
of the air 14 that enters the turbine section 22 via the turbine
inlet 30. These devices 16B can include heat exchangers,
condensers, and/or water extractors/collectors that condition the
air 14 to a desired pressure and temperature.
[0018] The turbine inlet nozzle 32 receives air 14 entering the air
cycle machine 12 through the inlet 30 and is disposed adjacent the
turbine wheel 34 to direct the flow of air 14 thereto. As will be
discussed subsequently, the air cycle machine 12 is configured with
a valve to vary the size of turbine inlet nozzle 32 as desired to
better optimize the efficiency of the environmental control system
10. In particular, the selectively variable turbine inlet nozzle 32
disclosed herein allows the power consumption of the environmental
control system 10 to be reduced, for example, by operating only a
single air conditioning pack to condition the cabin rather than
operating two air conditioning packs in some instances.
[0019] The turbine wheel 34 is mounted on the shaft 20 to drive
rotation of the shaft 20 and compressor wheel 26 about axis A.
After passing through the turbine inlet nozzle 32 the air 14 is
expanded to both extract energy from the air 14 so as to drive the
shaft 20 and the compressor wheel 26 (in combination with a motor
38 mounted along the shaft 20 in some embodiments) and to cool the
air 14 to prepare it for the cabin. After expansion, the air 14
passes through the turbine outlet 36 out of the air cycle machine
12. The air 14 can pass through one or more devices 16C (e.g., heat
exchangers, compact mixers, and/or acoustic treatment devices)
before reaching the cabin C at the desired temperature and
pressure.
[0020] FIG. 2A is an enlarged view of the turbine section 22 with a
poppet member 40 disposed in a first position extending into the
turbine inlet nozzle 32. In addition to the turbine inlet 30, the
turbine inlet nozzle 32, the turbine wheel 34, the turbine outlet
36, and the poppet member 40, the turbine section 22 includes a
shroud 42, a first cavity 44, a valve body 46, and a second cavity
48. The shroud 42 has a passage 50. The poppet member 40 includes a
main body 52 and seals 41A and 41B. An arcuate plate 54 is fixed
within the turbine inlet nozzle 32.
[0021] As illustrated in FIG. 2A, the poppet member 40 is slidably
mounted on the stator shroud 42 and is configured to seal the first
cavity 44 from the turbine inlet nozzle 32. In particular, seals
41A and 41B are disposed between the poppet member 40 and the
shroud 42 to allow for pressurization of the first cavity 44. The
first cavity 44 serves as an annular plenum that is defined by
portions of the shroud 42, the poppet member 40, the valve body 46,
and other portions of the casing of the air cycle machine 12. The
valve body 46 is mounted in fluid communication with the first
cavity 44.
[0022] The valve body 46 can be any valve commonly known in the art
for selectively communicating air from two ports (two pressure
sources) to a third port. The valve body 46 can be controlled to
move a member between a first position that blocks a first of the
three ports and allows the second and third ports to be in fluid
communication, and a second position that blocks the second port
and allows the first and third ports to be in fluid communication.
The valve body 46 is controlled to vary the pressure in the first
cavity 44 between a first pressure P.sub.1, equal to or about equal
to the pressure P.sub.t within the turbine inlet 30 (illustrated in
FIG. 2A), and a second lower pressure P.sub.2, equal to or about
equal to an ambient pressure P.sub.a external to the environmental
control system 10 and air cycle machine 12 (illustrated in FIG.
2B). Thus, the valve body 46 is selectively controlled to allow for
fluid communication between the first cavity 44 and either the
turbine inlet 30 or the ambient air source external to the air
cycle machine 12. In the first position shown in FIG. 2A, the first
cavity 44 is in fluid communication with the turbine inlet 30. The
higher first pressure P.sub.1 that results from this arrangement
forces the poppet member 40 outward expanding the volume of the
first cavity 44. Thus, in the first position, the poppet member 40
extends from the first cavity 44 into the turbine inlet nozzle 32
to reduce the size (volume and/or cross-sectional area) of the
inlet turbine nozzle 32 that receives air 14 from the turbine inlet
30. In this position, the poppet member 40 restricts the flow of
air 14 to the turbine wheel 34. The reduced air flow to the turbine
wheel 34 maybe desirable in some instances, for example, if it is
necessary to operate both air conditioning packs to maintain the
cabin at a desired pressure and temperature.
[0023] The second cavity 48 is defined by the shroud 42 and the
poppet member 40 and is positioned radially outward of the turbine
wheel 34 with respect to axis A. The poppet member 40 separates the
first cavity 44 from the second cavity 48. The passage 50 through
shroud 42 allows the second cavity 48 to be in fluid communication
with the turbine inlet nozzle 32 immediately adjacent to the
turbine wheel 34. This arrangement allows the second cavity 48 to
be maintained at or about the static pressure experienced within
the turbine inlet nozzle 32 immediately adjacent to the turbine
wheel 34. This static pressure is lower than the pressure at the
turbine inlet 30 (and selectively the pressure of the first cavity
44) but greater than the ambient pressure external to the air cycle
machine 12 (and selectively the pressure of the first cavity 44),
which allows for actuation of the poppet valve 40.
[0024] The poppet valve 40 includes a main body 52 that is mounted
on the shroud 42 and configured to seal and separate the first
cavity 44 from the second cavity 48. The main body 52 is actuated
as discussed to slide relative to shroud 42. In the first position
shown in FIG. 2A, the main body 52 extends from the first cavity 44
and shroud 42 into the turbine inlet nozzle 32. The arcuate plate
54 is fixed to the turbine inlet nozzle 32 and divides the turbine
inlet nozzle into two sections. The plate 54 is aligned within the
turbine inlet nozzle 32 so as to minimally interfere with the
direction of airflow toward the turbine wheel 34. In particular,
the plate 54 is configured with a small cross-sectional area
interfacing the airflow and has a larger surface that extends
generally parallel to one of the walls of the turbine inlet nozzle
32. The plate 54 extends generally radially to immediately adjacent
the turbine wheel 34, thereby, dividing the turbine inlet nozzle 32
into a primary section (through which air 14 flows when the poppet
member 40 is in the first position illustrated in FIG. 2A) and a
secondary section (through which air 14 generally does not pass
when the poppet member 40 is in the first position).
[0025] FIG. 2B is an enlarged view of the turbine section 22 with
the poppet member 40 disposed in a second position. In the second
position, the first cavity 44 is in fluid communication with the
ambient air source external to the air cycle machine 12. As a
result of this arrangement, the pressure within the second cavity
48 (the static pressure) exceeds the second pressure P.sub.2 within
the first cavity 44 and the poppet member 40 moves decreasing the
volume of the first cavity 44 and increasing the volume of the
second cavity 48. The movement of the main body 52 of the poppet
member 40 within the first cavity 44 retracts main body 52 from at
least a portion of the turbine inlet nozzle 32, allowing airflow
through the secondary section of the turbine inlet nozzle 32,
thereby increasing the size (volume and/or cross sectional area) of
the turbine inlet nozzle 32 through which air 14 flows to the
turbine wheel 34. Thus, in the second position shown in FIG. 2B
virtually the entire airflow passes through the turbine inlet
nozzle 32 unrestricted by the poppet member 40 to the turbine wheel
34.
[0026] By varying the pressure of the first cavity 44 in the manner
disclosed to selectively move the poppet member 40 within the
turbine inlet nozzle 32, the efficiency of the environmental
control system 10 can be improved. In particular, selectively
moving the poppet member 40 to vary the size of the turbine inlet
nozzle 32 when desired allows the power consumption of the
environmental control system 10 to be reduced, for example, by
operating only a single air conditioning pack to condition the
cabin rather than operating both air conditioning packs.
[0027] Referring to FIGS. 3 and 4, the compressor section 18 may
include a variable area diffuser 322 with an actuator 323 (see FIG.
1) to vary the inlet throat 352 (see FIG. 3) to vary a flow rate
through the ECS 10. The variable area diffuser 322 includes a
backing plate 328 that is isolated from deflection, D. In
conventional devices, the backing plate 328 would be secured
directly to the housing 316 contributing to the diffuser vanes
binding. Instead, the inventive diffuser 322 employs a mounting
plate 330 that supports the backing plate 328. The inner and outer
periphery of the backing plate 328 is supported by the mounting
plate 330, but is also permitted to move axially independently of
the mounting plate 330.
[0028] A shroud 336 is supported by the housing 316 and may deflect
axially under load. Multiple vanes 338 are retained between the
backing plate 328 and shroud 336 and, typically, a few thousandths
of an inch of clearance is provided between the vane 338 and the
backing plate 328 and shroud 336. In the example system shown,
there are 323 vanes that are modulated between full open and 40% of
full open.
[0029] The vanes 338 include an inlet end 348 and an outlet end
350. The inlet end 348 provides an adjustable throat 352, shown in
FIG. 2, which is provided by pivoting the vanes 338. To provide
improved containment, the present invention includes an aperture
344 arranged between the inlet and outlet ends 348 and 350. The
aperture is elongated in the direction of the length of the vane
338. Protrusions 346 extend from the backing plate 328 through the
aperture 344. In the example shown, the protrusions 346 are
integral with the backing plate 328 and extend to engage the shroud
336. Bolts 340, shown in FIG. 2, extend through the aperture 344 to
secure the vane 338 between the shroud 336 and backing plate 328.
The additional bolts 340 and protrusions 346 of the present
invention provide improved containment of the vanes 338 in the
event of a failure.
[0030] The mounting plate 330 includes a boss 342 for each vane
338. Each vane 338 includes a hole 355 for receiving a pivot pin
354. The pivot pin 354 extends through an opening in the shroud to
the mounting plate 330 to secure the vane 338 between the shroud
336 and backing plate 328. An end of the pivot pin 354 is secured
into the boss 342. Openings in the backing plate 328, vane 338 and
shroud 336 are in a slip fit relationship relative to the pivot pin
354 to permit the shroud 336 and backing plate 328 to deflect
axially without binding the vane 338.
[0031] The shroud 336 is shown broken along planes J, K and L in
FIG. 3 to better illustrate the interrelationship of diffuser
components. The vanes 338 include a slot that receives a drive pin
358. The drive pins 358 are mounted on a drive ring 356 that is
rotated by the actuator 323 to rotate the vanes 338 about the pivot
pins 354. The drive ring 356 includes a bearing 357 supporting the
drive ring 356 in the housing 316. The drive pin 358 is received in
a slot in the shroud 336 that defines the positional limits of the
vanes 338.
[0032] With reference to FIG. 5, the turbine section 22, the
compressor section 18 and the motor 38 are each mounted on the
shaft 20, which acts as a common rotating shaft, and each is
supported on foil air bearings 500 (see FIG. 1). The compressor
section 18 may have a continuously variable area diffuser 322 used
to provide compressed air utilized for aircraft cabin
pressurization and the turbine section 22 may includes a dual
nozzle turbine, as described above, with control not limited to
turbine pressure ratio in which the poppet member 40 actuates to
control turbine nozzle area based upon whether 1 or 2 packs are in
operation. Expansion through the turbine section 22 may be utilized
for supply of cooling air to aircraft cabin C and to generate shaft
power to assist the motor 38 in driving the compressor section
18.
[0033] As shown in FIG. 5, the motor 38 may include an integrally
cooled motor that is disposed in communication with a RAM heat
exchanger 501 whereby a pressure differential across the RAM heat
exchanger 501 is used to generate cooling flow. A cooling flow may
be tapped from the compressor inlet 24 upstream of the RAM heat
exchanger 501 and exited to the RAM ducting downstream of the RAM
heat exchanger 501. Also, bearing cooling supply air may be tapped
from the compressor outlet 28 and/or after cooling through the RAM
heat exchanger 501.
[0034] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
* * * * *