ANNULAR FLOW DUCT FOR A TURBOMACHINE THROUGH WHICH A MAIN FLOW CAN FLOW IN THE AXIAL DIRECTION

摘要

The invention relates to an annular flow duct for a turbomachine, said flow duct being arranged concentrically about a machine axis running in the axial direction and being defined by a boundary wall of circular cross section for directing a main flow, wherein the boundary wall has a plurality of return flow passages which are distributed over its circumference and through which in each case a partial flow which can be detached from the main flow at a bleed position can be returned to the main flow at a feed position situated upstream of the bleed position, and having aerofoils, arranged radially in the flow duct, of a blade ring, the aerofoil tips of which lie opposite the boundary wall, with a gap being formed in each case, wherein the aerofoils are movable in a predetermined rotation direction along the circumference of the boundary wall. In order to specify a compressor which is insensitive to pumping and flow separations, it is proposed that - as viewed in rotation direction - the bleed position of each return flow passage lie upstream of the corresponding feed position.