Patent ID: 7827802

Claim:
A variable-section flow mixer for a double-flow turbojet for a supersonic airplane, the mixer comprising: a central annular body about a longitudinal axis; a primary annular cover coaxially surrounding the central body to co-operate therewith to define a primary annular channel; a secondary annular cover coaxially surrounding the primary cover to co-operate therewith to define a secondary annular channel coaxial with the primary channel; and an annular nozzle centered on the longitudinal axis and placed longitudinally in line with the secondary cover, the nozzle including a plurality of external-air admission openings distributed around its entire circumference, opening out into a convergence zone between the flows coming from the primary and secondary channels, and within which lobes are mounted that are movable between two different positions: a closed position in which they obstruct the nozzle openings; and a deployed position in which they disengage said openings and deploy radially into the nozzle so as to enable external air to be admitted into the convergence zone; the lobes all presenting a common azimuth component in a common direction so as to impart gyratory motion to the external air that is admitted into the convergence zone when the lobes are in the second position; the mixer further including a plurality of longitudinal grooves occupying at least a portion of the central body, the grooves all presenting a common azimuth component in a common direction that is opposite to the direction of the azimuth component of the lobes.