Compression closed impeller for centrifugal compressor

The invention relates to the technical field of compression closed impellers, and provides a compression closed impeller for a centrifugal compressor, which adopts a split structure, is relatively simple in casting forming, milling manufacturing and welding assembly, relatively good in practicability, relatively small in rotating load bearing of a welding part and relatively high in structural strength, and comprises a plurality of blades, an impeller and an impeller cover, the impeller is divided into a straight cylinder section, a transition section and an annular section, the left end of the straight cylinder section is fixedly connected with the right end of the transition section, the outer ring surface of the transition section is fixedly connected with the inner ring surface of the annular section, and a plurality of transition inner grooves are formed in the inner straight cylinder surface of the straight cylinder section and matched with the blades respectively; the inner gradual change face of the g