Device for the reduction of secondary losses in a bladed flow duct

Claim 1

An arrangement for the reduction of secondary flow losses in a bladed flow duct of a turbomachine having a plurality of turbine blades arranged circumferentially therearound along a circumferential direction, with each turbine blade being mounted upon a separate platform, and each turbine blade having opposite convex and concave sides, with the concave side defining a pressure side of the blade and the convex side defining a suction side of the blade, such that the convex suction side of each turbine blade faces a concave pressure side of an adjacent blade, and the concave pressure side of each turbine blade faces a convex suction of an adjacent blade, said bladed flow duct defining a duct wall having a boundary layer step between circumferentially adjacent blades, said boundary layer step being directed towards the concave pressure side of an adjacent turbine blade, said boundary layer step extending obliquely, relative to said circumferential direction, in a direction along a approximately parallel with the suction side of the blade, and the boundary layer step in the longitudinal direction thereof having a convex shape and having a zero height at the beginning and at the end thereof.