FIRST STAGE TURBINE HOUSING FOR AN AIR CYCLE MACHINE

A housing of an air cycle machine includes a static seal portion, a main bore housing portion, a shroud pilot housing portion, and a thrust plate housing portion. The static seal portion is arranged about a central axis and defines static seal radius D1. The main bore housing portion is arranged about the central axis and circumscribes the shaft arranged along the central axis. The main bore housing defines central bore inner radius D2. The shroud pilot housing radius is arranged about the central axis and defines shroud pilot radius D3. The thrust plate housing portion is arranged about the central axis and defines insulator seal plate radius D4. A ratio D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838.

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Description
BACKGROUND

The present invention relates to Air Cycle Machines (ACMs). ACMs may be used to compress air in a compressor section. The compressed air is discharged to a downstream heat exchanger and further routed to a turbine. The turbine extracts energy from the expanded air to drive the compressor. The air output from the turbine may be utilized as an air supply for a vehicle, such as the cabin of an aircraft. ACMs may be used to achieve a desired pressure, temperature, and humidity in the air that is transferred to the environmental control system of the aircraft.

ACMs often have a three-wheel or four-wheel configuration. In a three-wheel ACM, a turbine drives both a compressor and a fan which rotate on a common shaft. In a four-wheel ACM, two turbine sections drive a compressor and a fan on a common shaft.

Airflow from one working fluid must be directed through a ram circuit consisting of a heat exchanger and the fan section of the ACM. Airflow from a second working fluid must be directed into the compressor section, away from the compressor section towards the heat exchanger, from the heat exchanger to the turbine or turbines, and from the final turbine stage out of the ACM. In at least some of these transfers, it is desirable to direct air radially with respect to the central axis of the ACM. To accomplish this, rotating nozzles may be used to generate radial in-flow and/or out-flow.

ACMs often have more than one housing section. The housings used in an ACM are used to contain airflow routed through the ACM, as well as rotating parts. Often, housing components are configured adjacent to seals and/or other housing components to achieve airflow containment.

SUMMARY

A housing of an air cycle machine includes a static seal portion, a main bore housing portion, a shroud pilot housing portion, and a thrust plate housing portion. The static seal portion is arranged about a central axis and defines static seal radius D1. The main bore housing portion is arranged about the central axis and circumscribes the shaft arranged along the central axis. The main bore housing defines central bore inner radius D2. The shroud pilot housing radius is arranged about the central axis and defines shroud pilot radius D3. The thrust plate housing portion is arranged about the central axis and defines insulator seal plate radius D4. A ratio D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838.

An air cycle machine includes a fan section arranged around a shaft. The fan section is capable of routing a first working fluid. A compressor section is arranged next to the fan section and positioned around the shaft and is capable of compressing a second working fluid. A turbine section is arranged next to the compressor section and positioned around the shaft. The turbine section is capable of converting potential energy of the second working fluid into rotational energy. A heat exchanger is capable of exchanging heat between the first working fluid and the second working fluid. A housing of an air cycle machine includes a static seal portion, a main bore housing portion, a shroud pilot housing portion, and a thrust plate housing portion. The static seal portion is arranged about a central axis and defines static seal radius D1. The main bore housing portion is arranged about the central axis and circumscribes the shaft arranged along the central axis. The main bore housing defines central bore inner radius D2. The shroud pilot housing radius is arranged about the central axis and defines shroud pilot radius D3. The thrust plate housing portion is arranged about the central axis and defines insulator seal plate radius D4. A ratio D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an air cycle machine.

FIG. 2 is a perspective view of a housing of the air cycle machine.

 DETAILED DESCRIPTION

The dimensions of an air cycle machine housing are selected in order to achieve several goals. Reduced drag of rotating shaft on static shaft seal minimizes friction losses and transfers more turbine power to the compressor and fan. Seal clearance is desirably minimized, in order to minimize compressor inlet flow lost through the seal. Shaft excursions, such as seals, result in intimate contact between shaft seal teeth and associated seal lands. The seal clearance losses are balanced against the frictional losses of seal drag during shaft excursions. Clearance is maintained between the rotating shaft teeth and the seal land to reduce or eliminate sub-synchronous vibrations in foil bearings of the air cycle machine. Further, the leakage from excursions such as seals is prevented from dumping into part of the bearing cooling flow path. Excessive leakage into this flowpath could result in a blockage of cooling flow. Seal sizing prevents the excessive leakage that could cause reduced bearing cooling flow and over-temperature of the bearing surfaces.

Optimizing performance of a compressor and a turbine can be quite different. For a compressor, the inlet air is at a lower pressure than the outlet air, but the opposite is true for a turbine. Also, the compressor inlet air contains a high temperature, and the compressor discharge temperature is even greater. For the turbine, the inlet air is at a cool temperature and the outlet is at an even colder temperature. When the compressor and turbine parts are optimized, different methodologies are required for the turbine and compressor. If the turbine were designed using an the incorrect optimization technique, either the clearance would be too loose and cause poor turbine performance or the seal clearance would be too tight and cause a side loading of the foil bearings. In the specific instance of the seal clearance being too tight, the foil bearings would be excessively side loaded and result in poor reliability or reduced load capability. One feature of this ACM is the use of the bearing clearances and seal sizes to prevent excessively side-loading the bearings without having any negative impact on turbine performance or additional bearing cooling.

FIG. 1 is a cross-sectional view of ACM 2, which is a four-wheel ACM. As shown in FIG. 1, ACM 2 includes fan section 4, compressor section 6, first stage turbine section 8, and second stage turbine section 10, which are all connected to shaft 12. Shaft 12 rotates about central axis 14.

Fan section 4, compressor section 6, first stage turbine section 8, and second stage turbine section 10 are also connected to one another via shaft 12. Shaft 12 runs along central axis 14, and is connected to at least compressor nozzle 26, first stage turbine nozzle 32, and second stage turbine nozzle 38. Fan blades 20 may also be connected to shaft 12.

When working fluid passes through ACM 2, it is first compressed in compressor section 6, and then expanded in first stage turbine section 8 and second stage turbine section 10. Often, a first working fluid is heated or cooled in a heat exchanger (not shown) through which working fluid is routed as it passes between compressor section 6 and first stage turbine section 8. First stage turbine section 8 and second stage turbine section 10 extract energy from the working fluid, turning shaft 12 about central axis 14. Meanwhile, a second working fluid is routed through the same heat exchanger by fan section 4. For example, the first working fluid may be routed from a bleed valve of a gas turbine engine through compressor section 6, to a heat exchanger, to first stage turbine section 8, then to second stage turbine section 10, and then to the environmental control system of an aircraft. The second working fluid may be ram air that is pulled by fan section 4 through the same heat exchanger to cool the first working fluid to a desired temperature before routing of the first working fluid to the turbine sections 8 and 10. By compressing, heating, and expanding the working fluid, the output provided at the second stage turbine 10 may be adjusted to a desired temperature, pressure, and/or relative humidity.

Fan section 4 includes fan inlet 16 and fan outlet 18. Fan inlet 16 is an opening in ACM 2 that receives working fluid from another source, such as a ram air scoop. Fan outlet 18 allows working fluid to escape fan section 4. Fan blades 20 may be used to draw working fluid into fan section 4.

Compressor section 6 includes compressor inlet 22, compressor outlet 24, compressor nozzle 26, and compressor blades 27. Compressor inlet 22 is a duct defining an aperture through which working fluid to be compressed is received from another source. Compressor outlet 24 allows working fluid to be routed to other systems after it has been compressed. Compressor nozzle 26 is a nozzle section that rotates through working fluid in compressor section 6. Compressor nozzle 26 directs working fluid from compressor inlet 22 to compressor outlet 24 via compressor blades 27. Compressor nozzle 26 is a radial out-flow rotor.

First stage turbine section 8 includes first stage turbine inlet 28, first stage turbine outlet 30, first stage turbine nozzle 32, and first stage turbine blades 33. First stage turbine inlet 28 is a duct defining an aperture through which working fluid passes prior to expansion in first stage turbine section 8. First stage turbine outlet 30 is a duct defining an aperture through which working fluid (which has expanded) departs first stage turbine section 8. First stage turbine nozzle 32 is a nozzle section that rotates through working fluid in first stage turbine section 8. First stage turbine nozzle 32 cooperates with first stage turbine blades 33 to extract energy from working fluid passing therethrough, driving the rotation of first stage turbine section 8 and attached components, including shaft 12, fan section 4, and compressor section 6. First stage turbine nozzle 32 is a radial in-flow rotor.

Second stage turbine section 10 includes second stage turbine inlet 34, second stage turbine outlet 36, second stage turbine nozzle 38, and second stage turbine blades 39. Second stage turbine inlet 34 is a duct defining an aperture through which working fluid passes prior to expansion in second stage turbine section 10. Second stage turbine outlet 36 is a duct defining an aperture through which working fluid (which has expanded) departs second stage turbine section 10. Second stage turbine nozzle 38 is a nozzle section that cooperates with second stage turbine blades 39 to extract energy from working fluid passing therethrough, driving the rotation of second stage turbine section 10 and attached components, including shaft 12, fan section 4, and compressor section 6. In particular, second stage turbine nozzle 38 is a radial out-flow rotor. Working fluid passes from second stage turbine inlet 34 to cavity 35, where it is incident upon second stage turbine nozzle 38. Working fluid then passes between nozzle blades (not shown). Turbine nozzle 38 is stationary, and the nozzle vanes guide the flow for optimum entry into the turbine rotor. The flow of causes turbine blades 39 to rotate and turn shaft 12.

Shaft 12 is a rod, such as a titanium tie-rod, used to connect other components of ACM 2. Shaft 12 includes a seal portion arranged partway along its length. Central axis 14 is an axis with respect to which other components may be arranged.

Fan section 4 is connected to compressor section 6. In particular, fan outlet 18 is coupled to compressor inlet 22. Working fluid is drawn through fan inlet 16 and discharged through fan outlet 18 by fan blades 20. Working fluid from fan outlet 18 is routed to compressor inlet 22 for compression in compressor section 6. Similarly, compressor section 6 is coupled with first stage turbine section 8. Working fluid from compressor outlet 24 is routed to first stage turbine inlet 28.

Fan section 4 and compressor section 6 share housing 40. Housing 40 encloses the moving parts and air paths through fan section 4 and compressor section 6. The size and geometry of housing 40 define the flow of air through ACM 2. For example, housing 40 is arranged about shaft 12 so as to prevent excessive airflow around shaft 12. In particular, a static seal portion is included in shaft 12, directly adjacent to static seal portion 44. The outer radius of the seal portion is set such that a seal is formed with static seal portion 44 of housing 40. Thus, the outer radius of shaft 12 at the static seal portion is equal to or slightly less than static seal radius D1.

Housing 40 has specific dimensions to coordinate with adjacent housing sections, such as the housing surrounding turbine section 8. Housing 40 includes main bore housing portion 42, static seal portion 44, shroud pilot housing 46, and thrust plate 48.

Static seal portion 44 is the portion of housing 40 that circumscribes shaft 12 at the longitudinal are at which shaft 12 includes a seal. In this way, static seal portion 44 prevents flow of fluid between housing 40 and shaft 12. The radius of housing 40 from central axis 14 to static seal portion 44 is illustrated as static seal radius D1. Static seal radius D1 is between 2.0724 cm and 2.07365 cm (0.8159 in. and 0.8164 in.).

Main bore housing portion 42 is the portion of housing 40 that circumscribes shaft 12 so as to prevent excessive airflow around shaft 12. The radius of housing 40 from central axis 14 to main bore housing portion 42 is illustrated as central bore inner radius D2. Central bore inner radius D2 is between 2.4638 cm and 2.4689 cm (0.9700 in. and 0.9720 in.).

Shroud pilot housing 46 defines a portion of housing 40 at the point where the radial distance between central axis 14 and housing 40 is at a local minimum. Shroud pilot housing portion 46 is configured to mate with a complimentary feature, turbine housing 50. By coupling with turbine housing 50, shroud pilot housing 46 prevents working fluid passing through the compressor inlet 22 from intermixing with compressed fluid at the compressor outlet 24. The radius of housing 40 from central axis 14 to shroud pilot housing 46 is illustrated as shroud pilot housing radius D3. Shroud pilot housing radius D3 is between 4.79805 cm and 4.80315 cm (1.8890 in. and 1.8910 in.).

Thrust plate 48 is a portion of housing 40 that extends between first stage turbine section 8 and second stage turbine section 10. Thrust plate 48 separates second stage turbine inlet 34 and cavity 35. The radius from central axis 14 to thrust plate 48 is illustrated as thrust plate radius D4. Thrust plate housing radius D4 is between 8.22705 cm and 8.23215 cm (3.2390 in. and 3.2410 in.).

The ratios between static seal radius D1, central bore inner radius D2, shroud pilot housing radius D3, and thrust plate housing radius D4 can also be set to reach optimized bearing cooling and seal leakage throughout ACM 2. Optimized clearance of seals in ACM 2 also permits proper operation of the shaft/rotor system. The following ratios are preferable as between D1, D2, D3, and D4: D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838

FIG. 2 is a perspective view of housing 40, illustrating static seal radius D1, central bore inner radius D2, shroud pilot housing radius D3, and thrust plate radius D4. Components of ACM 2 of FIG. 1, including the adjacent housing of turbine section 8 and shaft 12, have been removed to more clearly illustrate the specific dimensions of housing 40. As previously described with respect to FIG. 1, a static seal portion D1, main bore housing radius D2, shroud pilot housing radius D3, and thrust plate housing radius D4 have specific ranges of dimensions that are optimal.

Discussion of Possible Embodiments

The following are non-exclusive descriptions of possible embodiments of the present invention.

A housing of an air cycle machine may include a static seal portion arranged about a central axis and configured to circumscribe a static seal defined by a shaft arranged along the central axis. The static seal portion defines a static seal radius D1. A main bore housing portion is arranged about the central axis and positioned longitudinally adjacent to the static seal portion. The main bore housing is configured to circumscribe the shaft. The main bore housing defines a central bore inner radius D2. A shroud pilot housing portion is arranged about the central axis. The shroud pilot housing portion defines a shroud pilot radius D3. A thrust plate housing portion is arranged about the central axis and is configured to mate with an adjacent turbine section component. The thrust plate housing portion defining an insulator seal plate radius D4. The ratios as between D1, D2, D3, and D4 include D1/D2 between 0.8394 to 0.8416, D1/D3 between 0.4315 to 0.4322, D1/D4 between 0.2517 to 0.2521, D2/D3 between 0.5130 to 0.5146, D2/D4 between 0.2993-0.3001, and D3/D4 between 0.5828-0.5838.

The housing of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components.

The static seal radius may be between 2.0724 cm and 2.07365 cm. The main bore housing radius may be between 2.4638 cm and 2.4689 cm. The shroud pilot housing radius may be between 4.79805 cm and 4.80315 cm. The thrust plate housing radius may be between 8.22705 cm and 8.23215 cm. The turbine section component may be a turbine section housing. The turbine section component may be a first stage turbine section housing. The shroud housing pilot portion may be configured to mate with the adjacent turbine section component.

An air cycle machine may include a shaft. The air cycle machine may further include a fan section arranged around a portion of the shaft. The fan section is capable of routing a first working fluid. The air cycle machine includes a compressor section arranged adjacent to the fan section and positioned around the shaft. The compressor section is capable of compressing a second working fluid. The turbine section is arranged adjacent to the compressor section and positioned around the shaft. The turbine section is capable of converting potential energy of the second working fluid to rotational energy. A heat exchanger is capable of exchanging heat between the first working fluid and the second working fluid. A housing forms a part of both the fan section and the compressor section. The housing includes a static seal portion arranged about a central axis and configured to circumscribe a static seal defined by a shaft arranged along the central axis. The static seal portion defines a static seal radius D1. A main bore housing portion is arranged about the central axis and positioned longitudinally adjacent to the static seal portion. The main bore housing is configured to circumscribe the shaft. The main bore housing defines a central bore inner radius D2. A shroud pilot housing portion is arranged about the central axis. The shroud pilot housing portion defines a shroud pilot radius D3. A thrust plate housing portion is arranged about the central axis and is configured to mate with an adjacent turbine section component. The thrust plate housing portion defining an insulator seal plate radius D4. The ratios as between D1, D2, D3, and D4 include D1/D2 between 0.8394 to 0.8416, D1/D3 between 0.4315 to 0.4322, D1/D4 between 0.2517 to 0.2521, D2/D3 between 0.5130 to 0.5146, D2/D4 between 0.2993-0.3001, and D3/D4 between 0.5828-0.5838.

The housing of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components.

The second working fluid may pass through the heat exchanger located between the compressor section and the turbine section. The fan section, the compressor section, and the turbine section may be connected by the shaft to form a single spool. The static seal radius may be between 0.8159 in. and 0.8164 in. The main bore housing radius may be between 0.9700 in. and 0.9720 in. The shroud pilot housing radius may be between 1.8890 in. and 1.8910 in. The thrust plate housing radius may be between 3.2390 in. and 3.2410 in.

While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A housing of an air cycle machine, the housing comprising:

a static seal portion arranged about a central axis and configured to circumscribe a static seal defined by a shaft arranged along the central axis, the static seal portion defining a static seal radius D1;
a main bore housing portion arranged about the central axis and positioned longitudinally adjacent to the static seal portion, the main bore housing configured to circumscribe the shaft, the main bore housing defining a central bore inner radius D2;
a shroud pilot housing portion arranged about the central axis, the shroud pilot housing portion defining a shroud pilot radius D3; and
an insulator seal plate housing portion arranged about the central axis and configured to mate with an adjacent turbine section component, the insulator seal plate housing portion defining an insulator seal plate radius D4, wherein a ratio D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838.

2. The housing of claim 1 wherein the static seal radius is between 2.0724 cm and 2.07365 cm.

3. The housing of claim 1 wherein the main bore housing radius is between 2.4638 cm and 2.4689 cm.

4. The housing of claim 1 wherein the shroud pilot housing radius is between 4.79805 cm and 4.80315 cm.

5. The housing of claim 1 wherein the insulator seal plate housing radius is between 8.22705 cm and 8.23215 cm.

6. The housing of claim 1, wherein the turbine section component is a turbine section housing.

7. The housing of claim 1, wherein the turbine section component is a first stage turbine section housing.

8. The housing of claim 1, wherein the shroud housing pilot portion is configured to mate with an adjacent turbine section component.

9. An air cycle machine comprises:

a shaft;
a fan section arranged around a portion of the shaft, the fan section capable of routing a first working fluid;
a compressor section arranged adjacent to the fan section and positioned around the shaft, the compressor section capable of compressing a second working fluid;
a turbine section arranged adjacent to the compressor section and positioned around the shaft, the turbine section capable of converting potential energy of the second working fluid to rotational energy;
a heat exchanger capable of exchanging heat between the first working fluid and the second working fluid; and
a housing comprising: a static seal portion arranged about a central axis and configured to circumscribe a static seal defined by a shaft arranged along the central axis, the static seal portion defining a static seal radius D1; a main bore housing portion arranged about the central axis and positioned longitudinally adjacent to the static seal portion, the main bore housing configured to circumscribe the shaft, the main bore housing defining a central bore inner radius D2; a shroud pilot housing portion arranged about the central axis, the shroud pilot housing portion defining a shroud pilot radius D3; and an insulator seal plate housing portion arranged about the central axis and configured to mate with an adjacent turbine section component, the insulator seal plate housing portion defining an insulator seal plate radius D4, wherein a ratio D1/D2 is 0.8394 to 0.8416, a ratio D1/D3 is 0.4315 to 0.4322, a ratio D1/D4 is 0.2517 to 0.2521, a ratio D2/D3 is 0.5130 to 0.5146, a ratio D2/D4 is 0.2993-0.3001, and a ratio D3/D4 is 0.5828-0.5838.

10. The air cycle machine of claim 9, wherein the second working fluid passes through the heat exchanger between the compressor section and the turbine section.

11. The air cycle machine of claim 9, wherein the fan section, the compressor section, and the turbine section are connected by the shaft to form a single spool.

12. The housing of claim 9 wherein the static seal radius is between 0.8159 in. and 0.8164 in.

13. The housing of claim 9 wherein the main bore housing radius is between 0.9700 in. and 0.9720 in.

14. The housing of claim 9 wherein the shroud pilot housing radius is between 1.8890 in. and 1.8910 in.

15. The housing of claim 9 wherein the insulator seal plate housing radius is between 3.2390 in. and 3.2410 in.

Patent History
Publication number: 20150233386
Type: Application
Filed: Feb 14, 2014
Publication Date: Aug 20, 2015
Applicant: Hamilton Sundstrand Corporation (Windsor Locks, CT)
Inventors: Craig M. Beers (Wethersfield, CT), Seth E. Rosen (Middletown, CT)
Application Number: 14/180,777
Classifications
International Classification: F04D 29/40 (20060101);