The torsional vibration of turbo axis induced by unsteady aerodynamic force on rotor blade

An algorithm for computing the 3-D oscillating flow field of the blade passage under the torsional vibration of the rotor is applied to analyze the stability in turbomachines. The induced flow field responding to blade vibration is computed by Oscillating Fluid Mechanics Method and Parametric Polynomial Method. After getting the solution of the unsteady flow field, the work done by the unsteay aerodynamic force acting on the blade can be obtained. The negative or positive work is the criterion of the aeroelastic stability. Numerical results indicate that there are instabilities of the torsional vibration in some frequency bands.