Adjoint-Based Multi-Point and Multi-Objective Optimization of a Turbocharger Radial Turbine

This paper presents a gradient-based design optimization of a turbocharger radial turbine for automotive applications. The aim is to improve both the total-to-static efficiency and the moment of inertia of the turbine wheel. The search for the optimal designs is accomplished by a high-fidelity adjoint-based optimization framework using a fast sequential quadratic programming algorithm. The proposed method is able to produce improved Pareto-optimal designs in only a few iterations which are trade-offs between the two competing objectives. This is realized by redesigning the blade shape and the meridional flow channel for the respective target while satisfying imposed aerodynamic constraints. Furthermore, a comparative study with a stochastic evolutionary algorithm suggests that the gradient-based method has captured the global Pareto front at a computational cost which is about one order of magnitude lower.