Centrifugal compressor with extended operating range

摘要

This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

主权项

1. A centrifugal compressor, comprising:
a first impeller provided in a main refrigerant flow path; a second impeller provided in the main refrigerant flow path downstream of the first impeller; a recirculation flow path provided between a first location and a second location along the main refrigerant flow path, the first location being downstream of the second impeller, the second location being downstream of the first impeller; a first vaned diffuser downstream of the first impeller, the second location adjacent the first vaned diffuser, the first vaned diffuser including a plurality of vanes having leading edges; a plurality of recirculation nozzles provided in the recirculation flow path, each of the recirculation nozzles having an outlet arranged adjacent the first vaned diffuser and downstream of the first impeller, wherein the outlets of the recirculation nozzles are arranged at least partially radially outward of the leading edges of the vanes of the first vaned diffuser with respect to a radial distance measured in a radial direction which is perpendicular to a central axis of said impeller; and wherein the recirculation flow path includes a recirculation volute adjacent inlets of the recirculation nozzles, the recirculation volute being upstream, relative to the recirculation flow path, of the recirculation nozzles.