Abstract:
Vibratory stresses are the main cause of failure in gas turbine engines and other rotating
machinery components. These stresses must be attenuated to an acceptable level through an
efficient process in order to prevent failures in turbine blades. Previous studies have shown that a
thin magneto mechanical coating layer can make a significant contribution to the damping and
reduction of these vibratory stresses. Previous studies on analyzing the damping characteristics
of these coatings for various applications, such as beams and turbine blades, employed general
solid mechanics loads. In this study, we numerically compute aerodynamic loads on one and a
half stage axial turbine and applied these loads on the blade via a mapping procedure in order to
bring more reality to the problem. We employ a three-dimensional finite-volume based solver to
simulate the flow in the turbine using SST model to account for turbulence effects. Sliding mesh
technique is used to allow the transfer of flow parameters across the sliding rotor/stator
interfaces. In order to model a single passage configuration, profile transformation method is
used. A free vibration analysis has been performed to obtain natural frequencies and
corresponding mode shapes to analyze resonance conditions. The computed CFD loads are then
applied to an uncoated and coated turbine blade through a finite-element analysis (FEA)
package. A forced response analysis is performed at the critical frequencies to obtain vibratory
stresses. Numerical results show suppression of vibratory stresses at various low and high
frequency vibration modes. The results are benchmarked against published data and closely
match the expected outcome. The research presents an effective procedure for suppression of
vibratory stresses in gas turbine engine component subjected to real world aerodynamic loading.
The new procedure is a significant improvement towards more realistic simulation based
solutions for vibration suppression problems.
