Abstract
Under the low load and low condenser vacuum operation, the rotating end-blade of the low-pressure steam turbine is vibrated by the random excitation forces due to an inverse flow, a flow separation, and so on. These excitation forces can cause the excessive random vibration and the stall flutter to the blade. In order to research the vibratory characteristics of the integral shroud blade (ISB) structure under the low load and low condenser vacuum operation, the model turbine test is carried out and the vibratory stress of the blade is measured under various operating conditions. From the test results, it is confirmed that the vibratory stress of the ISB structure is much smaller than the conventional grouped blades and shows the excellent stability to the self-excited vibration due to the higher blade damping.
