Patent US3843277A successfully refreshed from Google Patents.
US3843277A
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Sound attenuating inlet duct
Assignee: General Electric Co
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Filing: 1973-02-14
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Granted: 1974-10-22
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Expires: 1993-02-14
Abstract
Abstract A sound attenuating inlet duct is provided for a gas turbine engine wherein the inlet duct includes a casing which defines an extended length, minimum cross-sectional throat area through which the inlet airflow is accelerated to a velocity less than the speed of sound to provide the equivalent sound attenuation of a conventional sound attenuating inlet duct which accelerates the inlet air flow to or above the speed of sound in a plane perpendicular to the inlet duct center axis.
Inventors
- 👤 F Ehrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:44
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; F02C7/045; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
150 words
In a gas turbine engine of the type having compressor means, combustion means, and turbine means in serial flow relation, there is provided a sound attenuating inlet duct comprising: an outer casing extending forward of the compressor means and open at opposing ends to accommodate an inlet airflow to the compressor means wherein the inlet cross-sectional area enveloped by the casing initially converges to a minimum crosssectional throat area intermediate the ends thereof and thereafter diverges outward to an increased diameter at the interface with the compressor means, said throat area remaining substantially constant for an extended length through which the airflow is accelerated to a speed less than the speed of sound, thus remaining subchoked to provide sound attenuation equivalent to a totally choked inlet duct where the inlet airflow is accelerated to at least the speed of sound in a plane perpendicular to the inlet duct center axis.
Claim 2
Dependent Claim
150 words
In a gas turbine engine of the type having compressor means, combustion means, and turbine means in serial flow relation, there is provided a sound attenuating inlet duct comprising: an outer casing extending forward of the compressor means and open at opposing ends to accommodate an inlet airflow to the compressor means wherein the inlet cross-sectional area enveloped by the casing initially converges to a minimum crosssectional throat area intermediate the ends thereof and thereafter diverges outward to an increased diameter at the interface with the compressor means, said throat area remaining substantially constant for an extended length through which the airflow is accelerated to a speed less than the speed of sound, thus remaining subchoked to provide sound attenuation equivalent to a totally choked inlet duct where the inlet airflow is accelerated to at least the speed of sound in a plane perpendicular to the inlet duct center axis.
Claim 3
Dependent Claim
38 words
The sound attenuating inlet duct of claim 1 wherein the outer casing is generally circular in cross-section and the ratio of the extended length of the minimum cross-sectional throat area to the throat diameter is greater than 0.1.
Claim 4
Dependent Claim
49 words
The sound attenuating inlet duct of claim 2 wherein there is further included a centerbody centrally disposed within the casing such that the effective cross-sectional area of the sound attenuating inlet is a function of the cross-sectional area enveloped by the casing minus the cross-sectional area of the centerbody.
Claim 5
Dependent Claim
62 words
The sound attenuating inlet duct of claim 2 wherein the inside surface of the casing diverges outward along a portion of the longitudinal length of the minimum cross-sectional throat area with the centerbody extending centrally into said portion such that the effective cross-sectional area of the sound attenuating inlet remains substantially constant throughout the extended length of the minimum cross-sectional throat area.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |