| 摘要 |
<p>In this turbine (1), with regards to the distal-end portion of a blade (50) or a portion of the partition plate outer ring (11) corresponding to the distal-end portion of the blade (50), a step portion (52) having a step surface (53) is provided to one of the portions so as to protrude towards the other. A seal fin (15) extending out with respect to the step portion (52) and forming a minute gap (H) with respect to the step portion (52) is provided to the other portion. A cavity (C) forming a principal vortex is formed on the upstream side of the seal fin (15). The step portion (52) facing the seal fin (15) bulges out that the principal vortex forms a counter vortex. The cavity (C) is formed so that the axial-direction-width dimension (W) and the radial-direction-height dimension (D) satisfy the following formula (1). (1): 0.45 <= D/W <= 2.67</p> |
