Sound reducer

Abstract

A sound reducer includes an inlet opening for gases to be propagated in the sound reducer, an expansion chamber and a channel in communication with the expansion chamber and extending along an axis of the channel from the expansion chamber to an outlet opening through which the gases leave the reducer. An axis of revolution of the inlet opening of the reducer and an axis of revolution of the outlet opening of the reducer are perpendicular to a plane that is perpendicular to the axis of the channel. The reducer includes an absorption region for absorbing a sound wave which at least partially encases the channel. The absorption region at least partially formed of a one-piece architectured material and is arranged such that a portion of the gases flow from the channel through the architectured material to an outer wall of the architectured material delimiting the absorption region.

1 . A sound reducer, called a reducer, comprising: an inlet opening for gases, called gases, intended to propagate in the sound reducer; an expansion chamber and a channel communicating with said expansion chamber and extending, along an axis, called channel axis, from the expansion chamber to an outlet opening for the gases from the reducer; an axis of revolution of the reducer inlet opening and an axis of revolution of the reducer outlet opening are parallel to the channel axis; the reducer further comprises an absorption zone for a sound wave produced by the gases, said absorption zone enveloping, at least in part, said channel; the sound wave absorption zone is constituted, at least in part, by a one-piece architectured material and is arranged so that a part of the gases flow from the channel through the architectured material to an outer wall of the architectured material delimiting the absorption zone; the one-piece architectured material comprises a set of elementary patterns, called patterns, forming the one-piece structure of the architectured material, at least some of the patterns:
 are closed and delimited by a wall forming a cavity; and   comprise at least two openings through which the cavity of each of the patterns of the at least one part of the patterns communicates with the outside of the cavity of each of the patterns of the at least one part of the patterns.   
     
     
         2 . The reducer according to  claim 1 , wherein a distance, extending in a plane perpendicular to the channel axis, between the channel and at least part of the outer wall of the architectured material, varies along the channel axis. 
     
     
         3 . The reducer according to  claim 1 , wherein each of the patterns has a three-dimensional structure and at least some of the patterns have a hollow three-dimensional structure; the absorption zone is arranged so that a part of the gases flows through the openings and cavities of the patterns of the at least some of the patterns of the absorption zone. 
     
     
         4 . The reducer according to  claim 1 , wherein the channel extends through a succession of patterns of the architectured material. 
     
     
         5 . The reducer according to  claim 4 , wherein the channel is formed by a series of apertures in the wall of each of the patterns of the succession of patterns through which the channel extends. 
     
     
         6 . The reducer according to  claim 3 , wherein a plurality of patterns of the succession of patterns through which the channel extends comprise at least one opening; the openings of the patterns of the succession of patterns are arranged such that a part of the gases flowing in the channel enter the absorption zone. 
     
     
         7 . The reducer according to  claim 3 , wherein a plurality of patterns of the succession of patterns through which the channel extends comprise at least two openings; the at least two openings of a given pattern of the succession of patterns are arranged so that a part of the gases flowing through the channel penetrate at least two distinct patterns of the absorption zone. 
     
     
         8 . The reducer according to  claim 3 , wherein a plurality of patterns of the at least part of the patterns of the absorption zone comprise six openings and:
 an axis of revolution of an opening of one of the patterns of the at least part of the patterns of the absorption zone and an axis of revolution of an opening of another of the patterns of the at least part of the patterns of the absorption zone form an angle of between 0 and 45° with respect to an axis parallel to the channel axis, and   an axis of revolution of an opening of one of the patterns of the at least one part of the patterns of the absorption zone and an axis of revolution of an opening of another of the patterns of the at least one part of the patterns of the absorption zone form an angle of between 0 and 45° with respect to an axis, known as the longitudinal axis, perpendicular to the axis of the channel,   an axis of revolution of an opening of one of the patterns of the at least part of the patterns of the absorption zone and an axis of revolution of an opening of another of the patterns of the at least part of the patterns of the absorption zone form an angle of between 0 and 45° with respect to an axis, known as the vertical axis, perpendicular to the longitudinal axis and perpendicular to the axis of the channel.   
     
     
         9 . The reducer according to  claim 1 , comprising at least one recess extending between the outer wall of the architectured material and an outer wall of the sound reducer. 
     
     
         10 . The reducer according to  claim 1 , comprising at least two vents extending between the absorption zone or between the channel or between the expansion zone and an outer wall of the sound reducer, each of the vents being arranged such that a portion of the gases intended to flow in the channel is discharged, out of the sound reducer, through the at least two vents. 
     
     
         11 . The reducer according to  claim 10 , wherein the at least two vents extend through patterns in the architectured material. 
     
     
         12 . The reducer according to  claim 10 , wherein the at least two vents comprise two consecutive walls, along an axis parallel to the channel axis, facing each other; a tangent at a distal end of at least one of the two consecutive walls of a given vent forms an angle less than 90° and greater than 0° with a plane normal to the channel axis intersecting the tangent at the distal end of the at least one of the two consecutive walls of the given vent. 
     
     
         13 . The reducer according to  claim 10 , wherein for at least one of the vents and at each point on the outlet surface of the at least one of the given vents through which gases are expelled from the reducer, a tangent at a point on the outlet surface of the at least one of the given vents forms an angle β, known as the projection angle, with a straight line extending along the channel axis from an intersection of the tangent with the channel axis to the gas outlet opening which is greater than 0° and less than 90°. 
     
     
         14 . The reducer according to  claim 10 , wherein a distance, extending along an axis parallel to the channel axis, separating two consecutive walls, along an axis parallel to the channel axis, of a vent, called a vent cross-section, increases and/or decreases, for at least one of the vents, in a direction wherein the at least one vent mainly extends from the absorption zone or from the channel or from the expansion chamber towards the outer wall of the sound reducer. 
     
     
         15 . The reducer according to  claim 10 , wherein a distance, extending along an axis parallel to the channel axis, separating two consecutive walls, along an axis parallel to the channel axis, facing a vent, called a vent cross-section, increases between two consecutive vents in a direction connecting the gas inlet opening and the gas outlet opening.