Return channel forming part of centrifugal compression machine, centrifugal compression machine

摘要

A return flow channel formation part that comprises a casing (28) and a plurality of return vanes (38). The casing (28) comprises a return bend part (36) and a return flow channel (33) that has a straight flow channel (37). The straight flow channel (37) includes a hub side wall surface (W1), a shroud side wall surface (W2), and an intermediate intake port (41) that is formed in one radial-direction portion of the shroud side wall surface (W2). The angle of inclination of the hub side wall surface (W1) and/or the shroud side wall surface (W2) with respect to the radial direction in a cross-section that includes an axis line (Ar) changes at the intermediate intake port (41).