Patent ID: 8286347
Filing Date: 2012-10-16
Classification: F01D,Y10T

Abstract:
1. A method for reducing vibration levels in a turbomachine comprising at least a first bladed wheel and a second bladed wheel, where the first and second wheels are moving relative to one another about an axis of rotation and a gaseous fluid is passing over the first and second wheels, due to perturbations of an aerodynamic origin that are produced by the second bladed wheel or an obstacle on the first bladed wheel, the method comprising: A—defining an initial configuration of the blades as a function of an expected performance of the turbomachine using individual aerodynamic profiles of p cross sections radially stacked between a root and a tip of said blades; B—calculating, using a computer, a synchronous forced response y(ω) on the first bladed wheel as a function of a harmonic excitation force f(ω) produced by the second bladed wheel or the obstacle from a relation y(ω)=F( C—defining a coefficient (α<1) for the reduction in a synchronous forced response y(ω); D—determining, using the computer, a geometric tangential shift value θ for each of said p stacked cross sections of one of the two wheels so as to reduce a term corresponding to the generalized aerodynamic force associated with the eigenmode ν, | E—calculating, using the computer, a synchronous forced response y′(ω) on the first bladed wheel; F—repeating the calculation in D with new geometric tangential shift values if |y′(ω)|>α|y(ω)|; and G—manufacturing at least some of the blades of said one of the first and second wheels with the new configuration if |y′(ω)|<α|y(ω)|.