Gas turbine engine and a gas turbine engine component

A gas turbine engine component comprising an inner part and an outer part forming between them a gas flow passage, which gas flow passage surrounds the inner part, the inner part presenting an inner passage surface, wherein the trace of the inner passage surface in a cross-section perpendicular to a central axis of the component presents at least one substantially straight portion, wherein the inner passage surface presents in the cross-section a plurality of crests, and that the at least one substantially straight portion of the trace is positioned between two adjacent crests, wherein ridges, forming the crests at the cross-section, are curved so that an angle of the local orientation of the ridges to a plane being parallel with the axis of rotation varies in the direction which is parallel to the axis of rotation.

A gas turbine engine component adapted to provide a gas flow passage for at least a part of a gas flow through the gas turbine engine, which gas flow passage surrounds an inner passage surface, an outer passage surface forming an outer delimitation of the gas flow passage, a plurality of circumferentially spaced blades extending between the inner and outer passage surfaces, wherein two portions of a trace, in a cross-section perpendicular to a central axis of the component, of the outer passage surface between two adjacent blades are substantially straight and oriented in an angle in relation to each other so as to form a concavity in the gas flow passage.

The gas turbine engine component according to 14, wherein the two portions of the trace, at the cross-section of the outer passage surface between any of two adjacent blades, form a major part of a total trace between two adjacent blades.