A study of nonlinear vibrations in a frictionally-damped turbine bladed disc with comprehensive modelling of aerodynamic effects

A new effective method for comprehensive modelling of gas flow effects on vibration of nonlinear vibration of bladed discs has been developed for a case when effect of the gas flow on the mode shapes is significant. The method separates completely the structural dynamics calculations from the significantly more computationally expensive computational fluid dynamics (CFD) calculations while provides the high accuracy of modelling for aerodynamic effects. A comprehensive analysis of the forced response using the new method has been performed for a realistic turbine bladed disc with root-disc joints, tip and underplatform dampers. The full chain of aerodynamic and structural calculations are performed: (i) determination of boundary conditions for CFD; (ii) CFD analysis; (iii) calculation of the aerodynamic characteristics required by the new method; (iv) nonlinear forced response analysis using the MAIM. The efficiency of the friction damping devices has been studied and compared for several resonance frequencies and engine orders. Advantages of the method for aerodynamic effect modelling have been demonstrated. Copyright 2012 by ASME