Patent ID: 7871244

Claim:
A turbine engine ring seal segment, comprising: a turbine engine ring segment having an inner radial surface that defines a portion of a gap gas flow path; wherein the inner radial surface is formed of an abradable ceramic coating and includes a plurality of gas flow protrusions that are oriented transverse to the gap gas flow path; wherein the gas flow protrusions are formed of a plurality of peaks, each separated by depressions between two adjacent peaks, wherein the depressions have an approximate semicircular shape, a distance between two adjacent peaks is at least equal to a width of the depression, and a height of a single peak is at least six percent of the distance between two adjacent peaks; wherein vortices are induced in the gas flow in the gap gas flow path; and wherein the plurality of peaks and depressions includes at least two discontinuous series of peaks and depressions and intermittent stretches of the inner radial surface without peaks and depression in between two discontinuous series of peaks and depressions.