US Patent 10125773 Centrifugal fluid machine

In a centrifugal fluid machine, the secondary flow loss inside an impeller is reduced and the occurrence, when the flow rate decreases, of a flow separation/stall on the shroud-side suction surface near the leading edge of each impeller blade is suppressed, thereby making it possible to maintain the operating range of the impeller. For this, at the trailing edge of each impeller blade, the trailing edge of each impeller blade is inclined so that the shroud side of the impeller blade is positioned more backward in the rotation direction than the hub side thereof as the impeller is seen from the suction direction upstream of the rotary shaft of the impeller. Also, out of two adjacent impeller blades, the shroud side of one impeller blade trailing the other impeller blade in the impeller rotation direction overlaps with the other impeller blade at around the leading edge of the one impeller blade.