REGENERATIVE ROTODYNAMIC MACHINE

in a regenerative rotodynamic machine, a portion of a disc-like impeller (11) adjacentthe impeller periphery extends radially through an annular chamber (13) in the machine casing concentric with the impeller (17), thereby dividing said chamber into two annular side channels (13A, 13B) one on each side of the impeller. The portion of the impeller lying in the annular chamber has scooped out annular cavities or recesses in its sides in which are disposed rings of aerodynamic blades (18) and fluid flow passing around the annular chamber from an inlet to an outlet is caused to circulate repeatedly, flowing radially outward through the blading in the impeller cavities and radially inward in the annular side channels alongside the impeller outside the impeller cavities. The aerodynamic blades (18) are designed so that the angle between the entry and exit flows of each blade is greater than 90°.