Numerical investigation of the three-dimensional flow in NASA low-speed centrifugal compressor impeller

The aim of this paper is to contribute to our understanding of the three-dimensional viscous flow in the NASA Large Scale Centrifugal Compressor (LSCC) impeller with vaneless diffuser. An advanced Navier-Stokes solver, EURANUS/TURBO is applied with a linear k-e model for closure. The computations were performed, st the design speed, at different tip gap sizes and with different grids for both design and off-design flow conditions, while detailed analysis is presented for the design flow condition. An excellent agreement is obtained for most of the data over a wide region of the flow passage. Tip clearance and mesh effects are addressed in the comparisons with the experimental data and some of the mechanisms leading to the formation of the throughflow wake and the 3D now structure are analyzed.