A PISTON THEORY-BASED AEROELASTIC STABILITY PREDICTION TOOLBOX FOR RADIAL TURBOMACHINERY

Aircraft intermittent combustion engines often incorporate turbochargers adapted from ground-based applications to improve their efficiency and performance. These turbochargers operate at off-design conditions and experience blade failures brought on by aerodynamically-induced blade vibrations. A previously-developed reduced-order model (ROM) leveraging piston theory to compute the stability of general fluid-structural configurations is first presented and summarized. The ROM has been applied to the high-pressure turbine of a dual-stage turbocharger and the results are reviewed as a baseline for new predictions considered in this work. For each operating condition that is investigated, a computational fluid dynamic (CFD) simulation must be performed to inform the fluid loading predicted by piston theory. Interpolation-based approaches are considered to minimize the numerical expense associated with this requirement. The Gaussian-based Kriging interpolation method is presented and explored. The method provides more accurate estimates for the non-linear behavior of the quantities of interest. Kriging also estimates uncertainty and provides confidence levels as part of the interpolation process. A graphical user interface (GUI) that automates the ROM prediction is presented. The GUI presents a rapid means to alter the turbomachine of interest, predict the aeroelastic response associated with a user-specified flight condition and quantify the uncertainty associated with the prediction.