| 摘要 |
Turbine nozzles and turbine moving blades of an axial-flow turbine are provided which are capable of reducing a secondary flow loss with a simple structure. A nozzle blade passage formed by nozzle blades, an outer diaphragm ring and an inner diaphragm ring is structured in such a manner that the shapes of inner and outer walls of the nozzle blades are made to be irregular so that stepped portions (h1 at the root and h2 at the tip) each having curvature R are formed. The nozzle blades are formed in such a manner that ends (Zr, Zp and Zt) of a trailing edge of the nozzle blades are positioned at the most downstream position at the central portion of the nozzle blades. Moreover, relationships Zt<Zr<Zp are satisfied. Similarly to the nozzle blade passage, the moving blades are formed in such a manner that stepped portions h3 and h4 each having curvature R are formed in the moving blade passage. The central portion of the lengthwise direction of the moving blades is made to be lower than a straight line connecting a trailing edge of the root and a trailing edge of the tip to each other. Thus a moving blade passage is formed in which the distance from the line connecting the trailing edge and the outer surface of the trailing edge is a maximum length.
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