Numerical flow analysis in a subsonic vaned radial diffuser with leading edge redesign

The flow field in a subsonic vaned radial diffuser of a single-stage centri fugal compressor is numerically investigated using a three-dimensional Navi er-Stokes solver (TASCflow) and a two-dimensional analysis and inverse-desi gn software package (MISES). The vane geometry is modified in the leading e dge area (two-dimensional blade shaping) using MISES, without changing the diffuser throughflow characteristics. An analysis of the two-dimensional an d three-dimensional effects of two redesigns on the flow in each of the dif fuser subcomponents is performed in terms of static pressure recovery, tota l pressure loss production, and secondary flow reduction. The computed char acteristic lines are compared with measurements, which confirm the improvem ent obtained by the leading edge redesign in terms of increased pressure ri se and operating range.