# US 8,770,921 B2 · Systems and methods for reducing noise from jet engine exhaust

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,770,921 B2
- Document ID: US8770921B2
- Status: Granted
- Kind: B2
- Application number: 12/935,450
- Filed: 2009-03-31
- Published: 2011-02-03
- Granted: 2014-07-08
- Earliest claimed: 2008-03-31
- Assignees: Airbus Operations GmbH; Centre National de la Recherche Scientifique (CNRS); Universite De Poitiers
- Applicants: Jerome Huber; Jean-Paul Bonnet; Joel Delville; Peter Jordan; Francois Strekowski
- Inventors: Jerome Huber; Jean-Paul Bonnet; Joel Delville; Peter Jordan; Francois Strekowski
- Web page: https://patentgrep.com/patent/US8770921B2

## CPC

- F02K 1/34: for attenuating noise
- F02K 1/46: Nozzles having means for adding air to the jet or for augmenting the mixing region between the jet and the ambient air, e.g. for silencing (F02K1/28, F02K1/36, F02K1/38 take precedence)
- F05D 2240/40: Use of a multiplicity of similar components
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An aircraft jet engine with a longitudinal axis, including a wall enclosing a gas flow ejected from a downstream end of the wall in the longitudinal axis, plural ducts being distributed around the periphery of the downstream end of the wall each including a terminal section, including an outlet opening. Each duct can eject a fluid jet through the outlet opening thereof. The ducts are configured to eject the fluid jets essentially parallel to each other, each fluid jet ejected through the corresponding outlet opening forming a lateral angle with the longitudinal axis in a projection view in a plane with the longitudinal axis.

## Claims

### Claim 1

An aircraft jet engine with a longitudinal axis comprising:
a wall surrounding a gas stream that is ejected at a downstream end of the wall along the longitudinal axis;
plural ducts distributed around the periphery of the downstream end of the wall and each comprising a terminal portion comprising an outlet opening, each duct configured to eject a fluid jet through its outlet opening,
wherein the ducts are configured to eject fluid jets more or less parallel to each other, each fluid jet ejected through the corresponding outlet opening forming a lateral angle with the longitudinal axis along a projection view in a plane containing the longitudinal axis, and
wherein the ducts include primary ducts that are spaced apart from each other and the ducts include at least one secondary duct added adjacent and parallel to each primary duct to form clusters of ducts having a same orientation.

### Claim 2 (depends on 1)

A jet engine according to claim 1, wherein the ducts are configured to eject each fluid jet slanted toward the longitudinal axis along a penetration angle.

### Claim 3 (depends on 2)

A jet engine according to claim 2, wherein the penetration angle is between 8 and 60°.

### Claim 4 (depends on 1)

A jet engine according to claim 1, wherein the lateral angle is formed by orientation of the terminal portion of a duct with the longitudinal axis, while the penetration angle is formed by a slant of the outlet opening of the duct toward the longitudinal axis.

### Claim 5 (depends on 1)

A jet engine according to claim 1, wherein the lateral angle is formed by orientation of the outlet opening of a duct with the longitudinal axis while the penetration angle is formed by a slant of the terminal portion of a duct toward the longitudinal axis.

### Claim 6 (depends on 1)

A jet engine according to claim 1, wherein the lateral angle is between 40 and 70°.

### Claim 7 (depends on 1)

A jet engine according to claim 1, wherein the downstream end of the wall comprises a plurality of chevrons distributed around a periphery thereof to form a mechanical acoustic attenuation device.

### Claim 8 (depends on 7)

A jet engine according to claim 7, wherein the ducts are associated with the chevrons that impart to the downstream end of the wall a jagged shape comprising a succession of peaks and valleys.

### Claim 9 (depends on 1)

An aircraft comprising at least one aircraft jet engine according to claim 1.