Integrated multifidelity, multidisciplinary evolutionary design optimization of counterrotating compressors

In high-speed air-breathing propulsion, compact turbomachinery is essential to reduce the engine size and weight. Hence, high compression ratios are required in the compressor stages. This paper proposes an optimization-based integrated design approach, which unifies aerodynamic and structural issues and provides innovative solutions in reduced time-to-market and development cost compared to traditional design methods. The methodology consists of two successive evolutionary optimizations; the first with low-fidelity radial distributions based on experimental correlations and the second with high-fidelity aerostructural performances. The key to allow a smooth transition between the low-fidelity preliminary design phase and the high-fidelity three-dimensional rotor shape optimization is a novel geometrical parameterization based on span-wise distributions. A differential evolution algorithm is employed to confront simultaneously the concurrent multidisciplinary objectives of aerodynamic efficiency and structural integrity. The proposed methodology was demonstrated with the design of a two-stage highly loaded compact counterrotating compressor.