Diffuser including a rotary stage

In a centrifugal compressor of the type having a shaft-driven rotary radial-flow impeller for delivering compressible gas at a supersonic velocity, a multistage diffuser comprising:

• a rotary stage having a pair of annular axially spaced front and back walls, each of said walls having an inner and an outer circumference, said inner circumference closely surrounding said impeller, the annular space between said walls defining a vaneless flow passage for receiving gas radially discharged from said impeller, means for rotating said rotary stage concentric with said impeller, said means comprising a disk rotatably supported on said impeller shaft, an elastic web interconnecting said disk with the back wall of said rotary stage, said web being positioned at a radius approximately equal to the radius of said impeller, and means for supporting the front wall of said rotary stage from said back wall, said means comprising a multiplicity of equi-angularly spaced struts of streamlined cross section connected between said walls at the outer peripheries thereof;
• and
• a fixed stage having a pair of axially spaced front and back walls, said walls having an inner periphery closely surrounding the outer periphery of said rotary stage, and having a plurality of symmetrically arranged vanes mounted between said spaced walls of said fixed stage;
• the annular space between said walls and said vanes defining flow passages for receiving gas discharged by said rotary stage.