Modified acoustic secondary nozzle

Patent metadata

Field	Value
Publication number	US-11149685-B2
Application number	US-201816640198-A
Country	US
Kind code	B2
Filing date	Aug 21, 2018
Priority date	Aug 21, 2017
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

An assembly for the rear of a bypass turbomachine ( 10 ) comprises a primary nozzle ( 11 ) comprising a trailing edge defining a primary flow path portion and a secondary nozzle ( 110 ) defining a secondary flow path portion, defined about a longitudinal axis (X), said secondary nozzle being configured to eject a mixture of the flows coming from a secondary flow path (Vs) and from a primary flow path (Vp) of the turbomachine ( 10 ), the secondary nozzle being of convergent-divergent shape with a throat ( 112 ) corresponding to a minimum cross section of the nozzle ( 110 ), the secondary nozzle ( 110 ) comprising, at the throat ( 112 ), a periodic succession of lobes ( 116, 118 ) which are situated along the internal circumference of the secondary nozzle ( 110 ). The assembly also comprises a lobed mixer ( 130 ) at the downstream end of the primary nozzle ( 11 ), this having an alternation of hot lobes ( 134 ) extending inside the secondary flow path and of cold lobes ( 132 ) extending inside the primary flow path. The lobes of the nozzle ( 110 ) which are concave ( 118 ), which is to say radially towards the outside, and respectively which are convex ( 116 ), which is to say radically towards the inside, if the longitudinal offset is disregarded, radically face the respectively hot lobes ( 134 ) and cold lobes ( 132 ) of the mixer ( 130 ).

First claim

The invention claimed is:

1. An assembly for a rear of a turbomachine with a longitudinal axis, the assembly comprising:
a primary nozzle comprising a trailing edge and defining a primary flowpath portion,
a secondary nozzle defining a secondary flowpath portion, said secondary nozzle being configured to eject a mixture of flows derived from a secondary flowpath and a primary flowpath of the turbomachine, the secondary nozzle being of convergent-divergent shape with a throat corresponding to a minimum section of the secondary nozzle,
a lobed mixer, at a downstream end of the primary nozzle and having an alternation of hot lobes extending inside the secondary flowpath and cold lobes extending inside the primary flowpath,
wherein:
the secondary nozzle comprises, at the throat, a periodic succession of convex and concave lobes located along an inner circumference of the secondary nozzle, and
the lobes of the secondary nozzle are, to within a longitudinal offset, radially facing the hot lobes and the cold lobes of the lobed mixer,
and there are as many concave lobes as there are the hot lobes and as many convex lobes as there are the cold lobes.

2. The assembly according to claim 1 , wherein each of the lobes of the secondary nozzle extends axially over part of the secondary nozzle by a certain distance from the throat to a trailing edge of the secondary nozzle.

3. The assembly according to claim 2 , wherein the certain distance is smaller than an average diameter of the secondary nozzle at the throat.

4. The assembly according to claim 3 , wherein, in sections orthogonal to the longitudinal axis, an amplitude of the lobes of the secondary nozzle between successive sections along an upstream and/or downstream direction of the throat gradually decreases until reaching zero.

5. The assembly according to claim 2 , wherein, in sections orthogonal to the longitudinal axis, an amplitude of the lobes of the secondary nozzle between successive sections along an upstream and/or downstream direction of the throat gradually decreases until reaching zero.

6. The assembly according to claim 1 , wherein the lobes of the secondary nozzle are formed directly in a material of the secondary nozzle.

7. The assembly according to claim 1 , wherein a ratio between a section at a trailing edge of the secondary nozzle and a section at the throat of the secondary nozzle is comprised between 1 and 1.05.

8. The assembly according to claim 1 , wherein a section of a trailing edge of the secondary nozzle is circular.

9. A double-flow turbomachine comprising the assembly according to claim 8 .

10. The assembly according to claim 1 , wherein the periodic succession of the lobes of the secondary nozzle is defined, at least on a portion of the inner circumference of the secondary nozzle, by the following equation:
R ( x ,θ)= R ref ( x )+ L ( x )·cos( N ·θ)

and
π R 2 ref ( x throat )=π∫ 0 2π R 2 ( x throat ,θ) dθ

where R is a radius of the secondary nozzle as a function of a circumferential position and of an abscissa along the longitudinal axis of the turbomachine, x throat is an abscissa of the throat, R ref is a radius of a circular reference section, L is an amplitude function depending on the abscissa of the throat, N is a number of periods.

11. The assembly according to claim 10 , wherein the periodic succession of the lobes of the secondary nozzle is defined on more than 75% of the inner circumference of the secondary nozzle.

Assignees

• Safran Aircraft Engines

Inventors

• Gonzalez Jérémy Paul Francisco
• Bodard Guillaume
• Jodet Norman Bruno André
• Mardjono Jacky Novi

Classifications

• F02K3/06

  with front fan · CPC title

• F02K1/48 Primary

  Corrugated nozzles · CPC title

• F02K3/04

  the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type · CPC title

• F02K1/46 Primary

  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) · CPC title