Aerodynamic Optimization Process for Turbocharger Compressor Impellers

Abstract

This paper presents the progression at BorgWarner Turbo Systems of the aerodynamic optimization process for radial turbocharger compressor impellers used in commercial vehicle applications. The design process was refined over several years, starting from relatively simple, single objective optimizations and moving to increasingly higher complexity with multiple operating points and objectives. CFD and numerical optimization techniques are used extensively with the aim of reducing costly gas stand testing with prototype hardware. Commercial software packages are used throughout for geometry definition, flow field evaluation, as well as an optimization scheduling providing genetic and gradient based algorithms. Design outcomes of the various developments were prototyped and tested at the BorgWarner Technical Center in Arden, NC. CFD predictions are compared with test data and discrepancies quantified. The resulting impeller designs show steady improvements with each design and methodology iteration, to the point that significant improvements in performance over conventional designs can be achieved consistently.