Low noise aeroengine inlet system

Abstract

An aeroengine includes an inlet duct having a section including opposed and substantially flat first and second peripheral walls, a first deformable wall providing a portion of the first peripheral wall and a second deformable wall providing a portion of the second peripheral wall. The deformable walls are deformable between undeployed and deployed positions, and each include panels pivotally connected one to another to allow pivotal movement of the panels relative to respective adjacent panels about respective parallel axes oriented transverse to a direction of the air flow. The deformable walls in the undeployed position each being substantially flat to substantially avoid interfering with the air flow, and in the deployed position each projecting into the inlet duct from the respective peripheral wall to reduce an effective cross-sectional area of the inlet duct to reduce line-of-sight noise propagation.

1 . An aeroengine comprising: an inlet duct for directing an air flow from an intake opening to a compressor, the inlet duct having a section including opposed and substantially flat first and second peripheral walls, a first deformable wall providing a portion of the first peripheral wall and a second deformable wall providing a portion of the second peripheral wall, the first and second deformable walls being deformable between undeployed and deployed positions, the first and second deformable walls each including a plurality of panels pivotally connected one to another to allow pivotal movement of the panels relative to respective adjacent ones of the panels about respective parallel axes oriented transverse to a direction of the air flow, the first and second deformable walls in the undeployed position each being substantially flat to substantially avoid interfering with the air flow and the first and second deformable walls in the deployed position each projecting into the inlet duct from a respective one of the first and second peripheral walls to reduce an effective cross-sectional area of the inlet duct to reduce line-of-sight noise propagation. 
     
     
         2 . The aeroengine as defined in  claim 1 , wherein the plurality of panels includes a panel located at one end of each of the first and second deformable walls movably supported on a respective track to allow the first and second deformable walls to project into the inlet duct. 
     
     
         3 . The aeroengine as defined in  claim 1  wherein the panels are identical. 
     
     
         4 . The aeroengine as defined in  claim 1  wherein the panels are different in one dimension thereof. 
     
     
         5 . The aeroengine as defined in  claim 1  wherein each of the first and second deformable walls comprises a first surface exposed to the air flow and a second surface opposite to the first surface, a plurality of holes extending through the respective first and second deformable walls between the first and second surfaces, in communication with respective acoustic cells attached to the second surface of the respective first and second deformable walls. 
     
     
         6 . The aeroengine as defined in  claim 1  wherein the respective first and second deformable walls each form a respective ridge extending substantially perpendicular to a direction of the air flow. 
     
     
         7 . The aeroengine as defined in  claim 6  wherein the first and second deformable walls form the respective ridge in a sequence in the direction of the air flow.