Patent ID: 7013669

Claim:
Gasdynamic arrangement for a multi-stage centrifugal turbomachine having an intake duct ( 16 ) and a discharge port ( 38 ), and comprising: a) a first impeller ( 26 ) with axial intake port and radial peripheral discharge zone, said axial intake port being in fluid communication with said intake duct; b) a second impeller ( 29 ) with axial intake port and radial peripheral discharge zone, said second impeller disposed coaxially with said first impeller, the two impellers being located at two sides of an imaginary plane crossing their common axis; c) a first means for conducting the flow from the peripheral discharge zone of the first impeller to the intake port of the second impeller along a first flow path ( 28 , C 2 ) including a plurality of first curved ducts ( 28 ) in axisymmetric arrangement; d) a second means for conducting the flow from the peripheral discharge zone of the second impeller towards said discharge port of the machine along a second flow path ( 37 , C 1 ) including a plurality of second curved ducts ( 37 ) in axisymmetric arrangement; wherein said first and said second flow paths ( 28 , 37 ) leave the respective peripheral discharge zones bending gradually towards said imaginary plane, said first and said second flow paths cross said imaginary plane in opposite directions and, after crossing said imaginary plane, the two flow paths lie entirely at different sides of the imaginary plane, and wherein said first and said second curved ducts ( 28 , 37 ) have diffuser shape with cross-section area increasing from the impeller periphery discharge zone to said imaginary plane.