Patent ID: 8382438

Claim:
A stator/rotor blade for a fluid-flow machine, the blade having a free blade end blade area adjacent to a tip clearance gap positioned between a blade tip and a main gas path boundary of one of a hub and a casing, and a fixed blade end blade area structurally connected to the main gas path boundary of one of the hub and the casing, the blade transmitting energy to the working fluid and being cambered to turn flow from high relative whirl to lower relative whirl, the blade being defined by flow line profile sections with a leading edge and a trailing edge which establish a forward end point and a rearward end point, respectively, each given by a tangent normal to and intersecting with a respective profile chord, with a distance between these end points being a respective profile depth, and the free end blade area and the fixed end blade area meeting at a central meridional flow line profile of the blade, the blade having an enlargement of the profile depth at the free blade end blade area which, in relation to a profile depth of the blade at a central meridional flow line of the blade, is at least +10 percent at a tip of the free blade end blade area and decreases to zero by the central meridional flow line of the blade, with the enlargement values being ≧0 throughout, the profile depth enlargement being provided across substantially all of a length of the free blade end blade area and continuously increasing in a continuous concave curve from the central meridional flow line to the tip of the free end blade area on each of the leading edge and the trailing edge to provide structural stress and aerodynamic loading continuity across the blade length, the profile depth enlargement sized to avoid local distortion of the blade leading edge and trailing edge shape meridional projections, the profile depth enlargement at the trailing edge of the tip of the free blade end blade area being >0.