Multilevel optimization of the splitter blade pro le in the impeller of a centrifugal compressor

In this research, multi-level optimization of the prole of the splitter blades of a turbocharger compressor is performed using genetic algorithm in order to improve its performance. Successive corrections of the prole at hub, mid-span, and shroud of the splitter blades, with the objective of decreasing the incidence losses at the leading edge and adjustment of the blade loading at the shroud, result in an impeller having improved splitter blades. The impeller ow field analysis shows that the optimization has been successful in reducing the ow leakage at the shroud region as well as the losses in the leading edge region. Although numerical simulations predict a decrease by 0.5% in pressure ratio at design point, a 2.2-point improvement in isentropic efficiency is calculated. Based on the optimization results, a new impeller is designed, manufactured, and tested on a turbocharger test bed. Experimental results support the simulation predictions on the expected improvement in performance.