Centrifugal compressor Centrifugal compressor Divya11 (Mechanical) (OP) 3 Jun 16 05:04 Is it true that the first stage impeller of a centrifugal is always unshrouded while the other stages can have shrouded impellers? what is the reason for having an open first stage impeller? RE: Centrifugal compressor JJPellin (Mechanical) 3 Jun 16 11:59 No. Most centrifugal compressors have fully enclosed impellers in the first stage. Johnny Pellin RE: Centrifugal compressor awhicker84 (Mechanical) 14 Jul 16 19:26 The advantage of an open impeller is the reduction in stresses which helps increase the max tip speed. In other words, you could have a high head first stage. To the others: Are these open first stage impellers used mainly on high MW machines with high 1st stage flow coefficients?