US3637041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sound suppression system for fan jet engines
Assignee: Rohr Inc
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Filing: 1970-09-02
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Granted: 1972-01-25
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Expires: 1990-09-02
Abstract
Abstract System is intended for use with a jet engine having an engine separator sleeve for discharging turbine exhaust gases, and an engine casing surrounding and spaced from the separator sleeve to form therewith an annular flow path for fan air rearwardly around the exhaust gas stream. A tail pipe is attached to and forms a continuation of the engine casing and defining a discharge zone to receive and control the turbine exhaust gas and fan airstreams. A series of partitions extend generally inwardly in alternately arranged pairs from the tailpipe in fore-and-aft planes to define a peripherally arranged series of flow passages for gas and air. A guide vane pivotally mounted in each passage has a stowed position aligned with the separator sleeve to form a continuation thereof and segregate turbine exhaust gas and fan airflow. The vanes swing in unison, but in alternately opposite directions about transverse axes to cause their leading ends to swing radially in and out in alternation about the periphery so that one set of vanes directs fan air into the engine exhaust gas flow path, and the other set of alternately interposed vanes directs turbine exhaust gas into the fan airflow path. The result is a thorough intermixing of air and exhaust gas before leaving the engine nozzle, thereby reducing the temperature and velocity of the mixture and lowering the total jet noise.
Inventors
- 👤 Jack H Hilbig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:29
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/38; F02K1/386
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
201 words
A sound suppression system for use in combination with a fan jeT engine having a rearwardly discharging primary tailpipe for the exhaust gas stream and a secondary tailpipe surrounding the primary tailpipe and radially spaced therefrom for rearward flow of the fan airstream around the exhaust gas stream, comprising: a shroud connected to the secondary tailpipe and forming a continuation thereof and defining a discharge zone to receive and control the gas and airstreams; a plurality of partitions located within the shroud and arranged in peripherally spaced relationship; the partitions lying in fore-to-aft planes extending generally radially inward from the inner wall of the shroud to define a plurality of axially directed flow passages for the primary gas and secondary air; guide vanes located in said passages and having stowed positions in which they form virtual continuations of the wall of the primary tailpipe and substantially separate the air and gas streams; some of the vanes being movable to deployed positions in which they direct some of the airstream inwardly to mix with the gas stream; and some of the vanes being movable to deployed positions in which they direct some of the gas stream outwardly to mix with the airstream.
Claim 2
Dependent Claim
201 words
A sound suppression system for use in combination with a fan jeT engine having a rearwardly discharging primary tailpipe for the exhaust gas stream and a secondary tailpipe surrounding the primary tailpipe and radially spaced therefrom for rearward flow of the fan airstream around the exhaust gas stream, comprising: a shroud connected to the secondary tailpipe and forming a continuation thereof and defining a discharge zone to receive and control the gas and airstreams; a plurality of partitions located within the shroud and arranged in peripherally spaced relationship; the partitions lying in fore-to-aft planes extending generally radially inward from the inner wall of the shroud to define a plurality of axially directed flow passages for the primary gas and secondary air; guide vanes located in said passages and having stowed positions in which they form virtual continuations of the wall of the primary tailpipe and substantially separate the air and gas streams; some of the vanes being movable to deployed positions in which they direct some of the airstream inwardly to mix with the gas stream; and some of the vanes being movable to deployed positions in which they direct some of the gas stream outwardly to mix with the airstream.
Claim 3
Dependent Claim
81 words
A system as claimed in claim 1; a first set of vanes comprising those vanes which are deployed to direct some of the airstream inwardly and being spaced peripherally around the inner wall of the shroud; and a second set of vanes comprising those vanes which are deployed to direct some of the gas stream outwardly and being spaced peripherally around the inner wall of the shroud; each vane of each set being located between two vanes of the other set.
Claim 4
Dependent Claim
58 words
A system as claimed in claim 2; the vanes being pivotally mounted to their adjacent partitions on transverse axes spaced aft of their leading edges; the leading edges of the first set being swingable outward toward the wall of the shroud; and the leading edges of the second set being swingable inward toward the center of the shroud.
Claim 5
Dependent Claim
31 words
A system as claimed in claim 2; the axes of the pivotal mountings of the vanes being aft of their leading edges a distance of approximately two thirds of their length.
Claim 6
Dependent Claim
36 words
A system as claimed in claim 3; the aft ends of the vanes being convergent rearwardly and in deployed position alternately extending inwardly and outwardly to produce turbulence and increased mixing of the gas and air.
Claim 7
Dependent Claim
59 words
A system as claimed in claim 3; and a bullet extending coaxially aft of the primary nozzle and of smaller diameter and defining the inner wall of the gas flow passage; the partitions adjacent their forward ends extending radially from the shroud inner wall substantially to the bullet to define discrete entrances to the passages formed by the partitions.
Claim 8
Dependent Claim
40 words
A system as claimed in claim 3; and a support ring connected to the primary nozzle and forming a continuation thereof; the partitions being secured to the support ring at their forward ends to retain them in their proper relation.
Claim 9
Dependent Claim
213 words
A system as claimed in claim 3; the partitions being arranged in pairs; the two partitions of each pair being laterally spaced from and parallel to a fore to aft plane extending radially from the axis of the shroud to form a passage of generally rectangular cross section; a partition of each pair meeting the adjacent partition of the next succeeding pair at an angle to form a passage having a generally triangular cross section with an inner apex and a base at the shroud wall; the inner edges of the partitions diverging rearwardly from the shroud axis to form rearwardly diverging openings at the inner sides of the triangular passages; the vanes of the first set being generally rectangular in planform and swingable to deployed position to substantially fully block rearward air flow through the radially outer portions of their respective passages and direct the air inwardly to mix with the gas in the radially inner portions of their respective passages; the vanes of the second set in planform converging forwardly from their pivotal mounting axes in cOnformance with the openings in their passages and being swingable to deployed position to substantially fully block the openings in their respective passages and direct the gas flow outward to mix with the fan air.
Claim 10
Dependent Claim
46 words
A system as claimed in claim 8; the vanes of the second set being triangular in cross section throughout at least the major portion of their length with a radially inner apex and outer base to conform generally with the cross section of their respective passages.
Claim 11
Dependent Claim
64 words
A system as claimed in claim 8; the deployed position of the second set of vanes producing a gradual rearward reduction in flow area of the triangular passages; and the outer edges of the partitions being cut away in a rearwardly convergent direction to provide lateral flow paths for the excess gas and air mixture to flow laterally into the adjacent rectangular flow passages.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |