Aero-thermal-structural optimization of a high-pressure turbine rotor with robustness evaluation to in-service deterioration

This paper presents a multi-disciplinary optimization conducted on the high-pressure turbine rotor of a commercial turbofan engine. The rotor geometry is parametrized using a compact orthogonal design space, and the system’s response is studied under the aerodynamic, thermal and structural aspects via high-fidelity numerical simulations. The analysis is conducted using proprietary Rolls-Royce flow and structural solvers. The objective functions considered for the aerodynamic, thermal and structural disciplines are respectively high-pressure stage isentropic efficiency, peak near-wall gas temperature and peak von Mises stress on the rotor. The optimization is constrained by rotor capacity and high-pressure stage reaction degree. On the final three-dimensional Pareto front, two designs are selected, achieving a peak stress reduction of 17.5MPa and peak temperature reduction of 27.5K respectively. The sensitivity of these optimal designs to in-service degradation is then evaluated by applying various degrees of deterioration to the nominal designs. This deterioration is intended to replicate the erosion and deformation patterns observed on in-service blades after different numbers of operational cycles. The aerothermal performance of the optima is verified at a higher fidelity by conducting unsteady simulations.