Modeling and Validation of Tongue-Induced Unsteady Loading in Turbocharger Radial Turbine Using a 1D Approach With 3D LES

In aviation, turbochargers adapted from ground-based systems are employed in intermittent combustion engines to improve efficiency and performance. However, these units frequently operate under off-design conditions, making them vulnerable to blade failures caused by aerodynamically induced resonances. This study presents a one-dimensional (1D) modeling approach for simulating unsteady loading in turbocharger turbines. The model integrates the theoretical design of the volute with a viscous flow solver that accounts for volute curvature and the circumferentially continuous nature of the outflow. The 1D model effectively captures tongue-induced unsteady loading and shows good agreement with results from three-dimensional (3D) large eddy simulations (LES), demonstrating its capability in accurately predicting unsteady aerodynamic forces on radial turbine blades. Additionally, the study identifies the mechanisms responsible for cyclic blade loading and associated vibrations. Ongoing work focuses on further refining the 1D model for improved predictive accuracy and deepening the investigation into the influence of the volute tongue on unsteady blade loading.