POROUS CORE COWLING FOR A TURBOJET ENGINE
A core cowling for a bypass turbojet engine consisting of an internal wall ( 7 ) bathed in the main airflow ( 1 ) of said turbojet engine and an outer wall ( 6 ) bathed in the secondary airflow ( 2 ) thereof, the two walls between them forming a cavity ( 5 ) which receives the ventilation airflow originating from the hot parts of the turbojet engine to be injected into the secondary airflow through said outer wall, wherein said outer wall is pierced with multiple perforations ( 8 ) which are uniformly distributed on the circumference of said barrel and spread longitudinally along said outer wall in the direction of flow of the secondary airflow ( 2 ), so as to connect said cavity that receives the ventilation airflow to said secondary flow along at least two parallel circles of perforations.
1 . A core cowling for a bypass turbojet engine consisting of an internal wall bathed in the main airflow of said turbojet engine and an outer wall bathed in the secondary airflow thereof, the two walls between them forming a cavity which receives a ventilation airflow originating from the hot parts of the turbojet engine to be injected into the secondary airflow through said outer wall,
wherein said outer wall is pierced with multiple perforations which are uniformly distributed on the circumference of said barrel and spread longitudinally along said outer wall in the direction of flow of the secondary airflow, so as to connect said cavity that receives the ventilation airflow to said secondary flow along at least two parallel circles of perforations.
2 . The core cowling as claimed in claim 1 , in which the repeat pattern for the positioning of the perforations is a square, the perforations situated upstream being aligned, in the direction of flow of the secondary airflow, with the perforations situated further downstream.
3 . The core cowling as claimed in claim 1 , in which the repeat pattern for the positioning of the perforations is a diamond, the major axis of the diamond being aligned with the direction of flow of the secondary airflow.
4 . The core cowling as claimed in claim 1 , in which the repeat pattern for the positioning of the perforations is a quincunce, the sides of the quincunce being aligned with the direction of flow of the secondary airflow.
5 . The core cowling as claimed in claim 1 , in which the perforations are cylinders of revolution, their axis of symmetry being inclined by an angle smaller than 30° with respect to the plane tangential to said outer wall at the relevant point.
6 . The core cowling as claimed in claim 5 , in which the angle by which the axis of symmetry is inclined is smaller than 20°.
7 . The core cowling as claimed in claim 1 , in which the longest dimension of at least some of the perforations is shorter than 1 cm.
8 . The core cowling as claimed in claim 1 , in which the longest dimension of at least some of the perforations is shorter than 1 mm.
9 . The core cowling as claimed in claim 1 , in which the longest dimension of the perforations is constant from upstream to downstream in the direction of flow of the secondary airflow.
10 . A bypass turbojet engine comprising a core cowling as claimed in claim 1 .