Aeroelastic stability evaluation of structurally enhanced low-pressure turbine blade

Abstract

Weight reduction of low-pressure turbine blades remains a critical design challenge, as it must be achieved without compromising aerodynamic efficiency or aeroelastic stability. This study aims to investigate the impact of significant mass reduction through structural modification, specifically hollow and lattice-filled designs, on the aerodynamic damping of an LPT blade. Three designs of the T106 C profile blade were analyzed: a solid baseline, a hollowed blade, and a lattice-based blade. The lattice-based design achieved a ≈33% mass reduction. Their modal parameters, derived from experimental modal analysis, were used in the numerical simulation method to compute aerodynamic damping. Aerodynamic damping coefficient was predicted over a range of reduced frequencies at an inter-blade phase angle of 0° for the first flexural mode. The results demonstrate that the lattice-based blade not only achieves the target weight reduction but also exhibits higher aeroelastic stability, showing aerodynamic damping coefficient levels approximately 21.7% higher than the solid baseline at higher exit Mach numbers. By improving the natural frequency and thus the reduced frequency, not only is weight reduction achieved but also higher aeroelastic stability.