Abstract: A transonic centrifugal compressor with wedge diffuser is designed using centrifugal compressor computer-aided integrated design system. The internal flow fields of impeller and wedge diffuser are calculated by solving three-dimensional Navier-Stokes equation method and mixed plane method. Cal-culating results illustrated that as the mass flow is at 2.45 kg/s, stage pressure ratio is 6.22, stage total to total efficiency is 75%. General secondary flow vortex structure is exhibited in impeller channel. Shock wave exist at leading edge of wedge diffuser. It was found the complex secondary flow vortex structure is formed in wedge diffuser. Secondary flow vorticex in wedge diffuser form firstly, then develop, finally diminish.

Key words: Centrifugal compressor, Three-dimensional Navier-Stokes calculation, Transonic, Wedge diffuser