Analysis and safety evaluation of steam turbine last stage blade vortex-induced response under deep peak shaving conditions
BIAN Long
FAN Zhifei
ZHU Mingliang
XUAN Fuzhen
Abstract：To compensate for the intermittency of renewable energy generation,coal-fired power units are required to operate under low-load conditions over a long time,which causes the last stage blades of steam turbine low-pressure cylinders under small flow conditions persistently,leading to increased dynamic stresses and fatigue damage in the blades.To evaluate the safety of these last-stage blades,the fluid-structure interaction analysis of the last two-stage flow path and last stage rotating blades were conducted for a 660 MW air-cooled steam turbine under typical operating conditions.The results demonstrate that as the load decreases,both the maximum equivalent stress and deformation of the last stage rotating blades gradually diminish first,then slightly increasing.The maximum equivalent stress of the last stage rotating blades remains consistently below the material's yield strength,indicating that the blades are in the stage of elastic deformation and no plastic deformation has occurred.Using the Goodman curve analysis method for the high-cycle fatigue life assessment of the last stage rotating blades,the dynamic stress levels of the last stage rotating blades fall within the safe zone of the Goodman curve,indicating that there is no risk of fatigue damage to the blades.
Keywords：Steam turbineLast stage bladeFluid-structure interactionTypical operating conditionSafety assessment
Publication Date：2025-09-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 197-204 )