Fatigue Analysis of ۳۲۰ MW Steam Turbine Last Stage Blade

In this paper, the last stage blade of a ۳۲۰ MW Steam Turbine is analyzed under static centrifugal load and fluctuating pressure load obtained from steady CFD analysis by FEM. For fatigue analysis, first of all the mean stresses are determined by preforming static structural analysis of the row under centrifugal load exerted by applying rotational speed. Then, modal analysis is carried out to calculate natural frequencies of the bladed-disk system by considering the stress stiffening. The endurance limit of the blade is also calculated by the procedure described in machine design references. Finally, harmonic analysis is performed after applying pressure obtained from CFD analysis on each blade. The pressure loads are exerted by phase angle to excite the mode of the study and accordingly to obtain resonant stresses.

کلیدواژه ها:

High Cycle Fatigue (HCF) ، Finite Element Method (FEM) ، Modal Analysis ، Last Stage Steam Turbine Blade ، Lacing Wire