Single-stage centrifugal compressor

The invention discloses a single-stage centrifugal compressor which comprises a first centrifugal compressing portion, a second centrifugal compressing portion, a returning device and a centrifugal impeller disk body. The first centrifugal compressing portion comprises a blade on the left side of a centrifugal impeller, a first radial diffuser and an axial diffuser; the blade on the left side of the centrifugal impeller, the first radial diffuser and the axial diffuser are sequentially connected; the second centrifugal compressing portion comprises a blade on the right side of the centrifugal impeller, a second radial diffuser and a volute; and the blade on the right side of the centrifugal impeller, the second radial diffuser and the volute are sequentially connected. The returning device is connected between the first centrifugal compressing portion and the second centrifugal compressing portion, an inlet of the returning device is connected with an outlet of the axial diffuser, and an outlet of the returning device is connected with the inlet of the blade on the right side of the centrifugal impeller. The centrifugal impeller disk body comprises two opposite sides, the blade on the left side of the centrifugal impeller and the blade on the right side of the centrifugal impeller are respectively arranged on the two sides of the centrifugal impeller disk body, and the radial height of the blade on the left side of the centrifugal impeller is different from the radial height of the blade on the right side of the centrifugal impeller. According to the single-stage centrifugal compressor, the supercharge ratio can reach a larger range, the structure is more compact, and the axial length of a rotor system is shorter.