Abstract: A diffuser for a centrifugal compressor in which the diffuser has a plurality of passageways that each include a diffuser inlet region, a diffuser throat region, and a diffusion region. Within the diffuser inlet region are positioned pairs of opposed ridges that disrupt the boundary layer growth and minimize aerodynamic blockage at the throat region. The diffusion region includes a first diffusion region downstream of the throat region and that has a first area expansion ratio, and the second diffusion region that includes flow dividers to allow a total area expansion rate within the second diffusion region that is about twice that of the area expansion rate in the first diffusion region.

Abstract: An internal swage fitting for swaging a tube. The fitting includes a tube connection region with one or more radial grooves and an expansion cavity at the end adjacent to the end of the tube to be swaged. The expansion cavity accommodates flowing tube material during the swaging process with minimal axial pressure on the fitting. The expansion cavity also includes a stop wall to fix the location of the tube in the fitting. The expansion cavity enables swaging of tube materials of relatively high ductility without accounting for setback. It therefore eliminates the need for a collar to establish setback during swaging.