Aeroelasticity Analysis of Unsteady Rotor Blade Forces and Displacements in LP Last Stage Steam Turbine with Various Pressure Distributions the Stage Exit

作者：Rzadkowski, R.^*; Gnesin, V; Kolodyazhnaya, L.

来源：Journal of Vibration Engineering & Technologies, 2018, 6(5): 333-337.

DOI：10.1007/s42417-018-0049-9

• Steam turbines
• Unsteady forces
• Blade vibration

Background Several high vibration amplitude problems have been reported regarding the slender last stage blading of commercial LP steam turbines. This paper analyses rotor blade unsteady forces and displacements in the last stage of a low pressure steam turbine with symmetrical and non-symmetrical (exhaust hood induced) pressure distributions behind the rotor blades.
Method The FSI partially integrated method was used for the 3D ideal gas flow. 3D unsteady non-viscous flow was analysed using the Godunov-Kolgan method. Non-symmetrical pressure distributions in the stage exit were taken from 3D viscous CFX ANSYS calculations, using a CFD mesh of all the stator blades, all the rotor blades (rotating and not vibrating) and the exhaust hood.
Results The non-uniform and uniform pressure distributions cause rotor blades to vibrate in different bending-torsion modes.
Conclusions Introducing blade vibration into the flow model causes the appearance of unsteady force and blade displacement harmonics that are not multiples of the rotation frequency. The unsteady rotor blade forces and blade displacements analysis shows the importance of including an exhaust hood in the CFD mesh.

• 出版日期2018-10
• 单位中国人民解放军空军电子技术研究所