Abstract

A three-dimensional analysis for aerodynamic unsteady forces of the last stage steam turbine 13K215 rotor blades and total unsteady forces acting on the shaft from considered stage, have been presented. The numerical calculations were performer for different pressure distribution (p₂=6000, 7500, 9000, 7500 Pa). The analysis of 3D transonic flow of an ideal gas through turbomachinery blade rows moving relatively one to another without taking into account the blades oscillations is presented. An ideal gas flow through the mutually moving stator and rotor blades in periodicity on the whole annulus is described by the unsteady Euler conservation equations, which are integrated using the explicit monotonous finite-volume difference sc and moving heme of Godunov-Kolgan hybrid H-H grid. The algorithm proposed alllows to calculate turbine stages with an arbitary tagential and radial directions were found. Due to non-uniform pressure distribution the low frequency excitation appeared.