| 摘要 |
The invention relates to a cavity constituted by a casing of a gas turbine and a moving blade with a tip shroud, by which a cavity space is made to a necessary minimum size, a main flow gas is prevented from being entrained and a pressure loss is reduced. A tip shroud (6) is mounted on a tip end portion of a moving blade (4), a fin (7) is mounted thereon, a recess-like cavity (15) narrower than the conventional one is formed by portions (12a) and (12b) of a casing (12) and the fin (7), and further a projecting portion (16) is provided to an upstream end portion of the tip shroud (6). The projecting portion (16) is at a position (13a) at a time of a cold start and is at a position (13b) at a time of a hot start run, even if a thermal expansion occurs, thus the projecting portion (16) is not in contact with the recess portion, a main flow gas (1) is less entrained within the cavity (15), and a pressure loss is reduced because of no swirl, so that a performance of the gas turbine is enhanced.
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