Centrifugal compressor

A centrifugal compressor comprising:

• a revolving shaft;
• an impeller mounted to the revolving shaft;
• a casing configured to house the impeller;
• a diffuser section connected downstream of the impeller;
• and
• a volute section connected downstream of the diffuser section, and being configured to compress fluid by applying a centrifugal force to the fluid by rotating the impeller;
• a parting member configured to divide a flow channel in the diffuser section and the volute section into a plurality of channels in a direction of circulation of the fluid so as to define a hub-side flow channel and a shroud-side flow channel;
• and
• a flow rate adjuster configured to lower the flow rate of the fluid flowing in the shroud-side flow channel and enabling the fluid to flow in the hub-side flow channel at a high flow rate when the flow rate of the fluid compressed by the impeller is low and not lowering the flow rate of the fluid flowing the shroud-side flow channel to enable the fluid to flow both in the shroud-side flow channel and the hub-side flow channel when the flow rate of the fluid compressed by the impeller is high, wherein
• the diffuser section includes a hub-side diffuser section in the hub-side flow channel and a shroud-side diffuser section in the shroud-side flow channel,
• at least the hub-side diffuser section is provided with vanes, and
• a cross-sectional area of the flow channel in the shroud-side diffuser section is larger than the cross-sectional area of the flow channel in the hub-side diffuser section.