Multilevel optimization of the splitter blade profile in the impeller of a centrifugal compressor

In this research, multi-level optimization of the profile of the splitter blades of a turbocharger compressor is performed using genetic algorithm in order to improve its performance. Successive corrections of the profile 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 flow field analysis shows that the optimization has been successful in reducing the flow 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. (C) 2017 Sharif University of Technology. All rights reserved.