| 摘要 |
PURPOSE: To maintain optimum clearances under almost the driving conditions of an engine by interposing a plurality of shroud segments between rotor blade tips and a casing. CONSTITUTION: A plurality of shroud segments 32 mounted to a casing 20 via a plurality of support members 20 cooperate to define an annular shroud which surrounds radial outer extents of blade tips 33 of a blade array 21. Here, an upstream end 40 of each shroud segment 32 is fixed to the casing 20, whereas a down stream end 42 is free so that relative radial is possible. Consequently, when local cooling in a region of the flanges 26 and 21 is performed, corresponding local thermal contraction of the casing 20 occurs, and the downstream of the shroud segments 32 is radially inward moved. Therefore, clearances between sealing ribs 38 and abradable strips 31 are increased at upstream while reduced at downstream. Since the shroud segments 32 are pivoted in such a manner, sealing effect is improved as a whole. |
