| 摘要 |
PROBLEM TO BE SOLVED: To increase the damping effect of moving blade vibration by setting a shroud gap while a turbine is in a static stage so as to cause a ratio be a friction force between shrouds and an exciting force applied on a moving blade to take a specified value and using the most of friction force between the shrouds. SOLUTION: A friction force between shroud contact surfaces and an exciting force applied on a moving blade are respectively indicated by expression: (friction force)=(coefficient of dynamic friction)×(should reaction force), and (exciting force)=(exciting force factor)×(stationary force). Herein, (shroud reaction force) is a force applied in a direction orthogonal to the shroud contact surface by a centrifugal force, and (stationary force) is a fluid force decided by the heat condition of a turbine. (Exciting force factor) is an experimentally obtained factor. A ratio between a friction force applied to the contact surface of a shroud 1 and an exciting force applied from a fluid on the moving blade, i.e., a friction force ratio is set in the range of 1 to 100. Fore obtaining the damping effect of a damper, an initial gap A-A between the shrouds is set such that an initial friction force is about 10.
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