| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotating machine which is made compatible in both the maintenance of high efficiency and the securement of a wide operation range.SOLUTION: A rotating machine comprises: a rotating shaft 2; a plurality of impellers 3 which are fixed to the rotating shaft 2, and rotate together with the rotating shaft 2; a diffuser passage 19 which surrounds the rotating shaft 2 and the impellers 3, and in which fluid G discharged to the outside of the radial direction from the impellers 3 circulates; and a casing 5 which defines a return passage 20 for guiding the fluid G circulating in the diffuser passage 19 toward the inside of the radial direction, and introducing the fluid into the rear-stage impeller 3. A plurality of the impellers 3 are formed smaller in flow passage cross section areas of the fluid G as they are arranged at a rear stage side, the diffuser passage 19 arranged at a front stage side out of the diffuser passages 19 corresponding to a pair of the adjacent impellers 3 is made to function as a vane-less diffuser, and the diffuser passage 19 arranged at the rear stage side is made to function as a vaned diffuser. |
