Multi-disciplinary optimisation of a compressor rotor subjected to ice impact

Abstract

Compressors of gas turbine engines are multi-disciplinary systems whereas the different disci-plines are largely considered separately. In order to produce feasible designs, the components need to be re-designed several times which is time consuming. A multi-disciplinary design pro-cess enabling an integrated approach for all discipline is described in this paper. The main disciplines considered are aerodynamics and ice impact-worthiness for the front stage interme-diate pressure compressor (IPC) rotor of a modern three-spool jet-engine. Due to long lead times, ice impact analyses are usually not carried out until the aerodynamic design is reasonably mature. Only small changes to the rotor are usually allowed in order to sat-isfy the impact requirements that may lead to sub-optimal designs. Therefore, the introduction of ice impact analysis in the earlier design stages provides higher flexibility for the designers and leads to an overall better compressor performance. A fast thick-shell approach has been developed to model the transient dynamics of the compressor rotor impacted by crystalline ice cuboids released from upstream stators. The disciplines are linked using surrogate models which are based on the Kriging method. An adaptive multi-objective, multi-disciplinary optimisation approach has been used in order to increase the accuracy of the surrogate model iteratively in the areas of interest. It allows to op-timise the performance of each discipline individually. The obtained Pareto front shows design trends in order to improve each discipline individually or both together.