Aero-elastic response of structurally modified turbine blades

Purpose This study aims to assess the aero-elastic response (deformation and acceleration) of two structurally modified low-pressure turbine blade models compared to the traditional solid blade by using one-way fluid-structure interaction. The structurally modified designs include a weight-reduced blade and a lattice-based blade modeled by a novel location-based lattice integration technique. Design/methodology/approach Numerical modal analysis is conducted on the three blades to determine their natural frequencies, and two of them are additively manufactured for experimental modal analysis to validate the results and calculate damping ratios. Computational fluid dynamics is performed to analyze the acting forces (steady and unsteady) based on two- and three-dimensional models, including those with and without tip clearance, at an operating flow condition, to determine the aero-elastic response of all blade designs. Findings The lattice-based blade is ∼33% lighter than the solid blade with enhanced natural frequencies for flex and torsional modes by 15.31% and 8.71%, respectively. Meanwhile, the weight-reduced turbine blade model is 35% lighter and has enhanced modes by 8.86% and 4.04%. The aero-elastic response presents the lowest deformation but the highest levels of acceleration (1.5 g’s) for the solid blade. The lattice-based design deforms slightly higher than solid with the lowest acceleration levels (0.92 g’s). Practical implications The utilization of lattice-based blades can decrease the weight of the gas turbine engine, with lesser fuel consumption having the capability of higher RPM speeds. Originality/value The comparison between the structurally modified turbine blade models based on aero-elastic response to the traditional solid high-aspect ratio blade has not been investigated earlier.