Potential of Surrogate Modeling in Compressor Casing Design Focusing Rapid Tip Clearance Assessments

Tip clearance-induced losses constrain decisive improvements in system efficiency and aerodynamic operational stability of aero engine axial compressors. The tendency towards even lower blade heights to compensate higher fluid densities aggravates their influence. Generally, it is emphasized to preserve the tip clearance at a minimum but large enough to prevent a collision of the blade tip and the casing during the entire engine mission. The present work concentrates on the development of a preliminary aero engine axial compressor casing design methodology involving metamodeling techniques. Previous research work at the Institute resulted in a 2D axisymmetric Finite Element model of a generic multistage high-pressure axial compressor casing. Subsequent sensitivity studies led to the identification of significant parameters important for fine tuning the tip clearance via specific flange design. This work is devoted to explore the potential of Surrogate Modeling in preliminary compressor casing design with respect to rapid tip clearance assessments and corresponding precision compared to Finite Element results. Reputed as data-driven mathematical approximation models and conceived for numerical inexpensive simulation result reproduction, Surrogate Models evolve their capacity when linked with extensive design space exploration and optimization algorithms. Compared with high-fidelity Finite Element simulations the reductions obtained in computational time amount to 99.9% in favor of the Surrogate Models. Validated via statistic methods and dependent on the training database size, the precisions of the Surrogate Models reach down to the range of manufacturing tolerances. Subsequent inclusion of the Surrogate Models in a parametric optimization process concerning tip clearance minimization rapidly returned adaptions of the geometric design variables.      «

Tip clearance-induced losses constrain decisive improvements in system efficiency and aerodynamic operational stability of aero engine axial compressors. The tendency towards even lower blade heights to compensate higher fluid densities aggravates their influence. Generally, it is emphasized to preserve the tip clearance at a minimum but large enough to prevent a collision of the blade tip and the casing during the entire engine mission. The present work concentrates on the development of a prel...     »