摘要 |
A seal segment 226 bounding a main gas path in a gas turbine engine and which opposes the free end a rotor blade, comprising: a gas path facing surface having a series of axially separated radially offset lands 236, 238 which oppose the corresponding free ends of a rotor blade in use, the radial offset being provided by a radial step 240; a circumferentially extending radial projection (figure 4, 246) which projects from the gas path facing surface towards the main gas path. A method of manufacturing a seal segment by providing an oversized seal segment blank having one or more steps, machining out a central portion of the steps to provide a land with a main gas path surface and a circumferential radial projection extending from the main surface. The projection may extend from the surface of the land by 0.25mm-1.5mm, the radial offset may be between 1mm and 6mm. The radial project can have an upstream side which is chamfered or filleted. The step of machining can be achieved by abrasively removing material, for example with an abrasive wheel. The blade maybe a shrouded blade with a plurality of offset tip fins corresponding each to a land. |