Abstract
Partial admission has been applied to steam turbine because it produces high turbine efficiency at low loads. The shock load caused by partial admission generates excitation force on a blade, and the vibratory stress of the blade may become a cause of HCF. Therefore, in designing a steam turbine blade, the vibratory stress caused by partial admission should be exactly predicted. This paper, first, presents the analysis method to calculate the vibratory stress of the blade caused by partial admission. And the vibration response characteristics to shock load is explained, using some calculated results of simplified blade models. Secondary, the response analysis is carried out for the actual grouped blade and the integral shroud blade, and the results are evaluated from the viewpoint of blade reliability.
