Ebara Corporation

Shin Konomi

Hideomi Harada

Hiroyoshi Watanabe

Kazuo Takei

Ichiro Ariga

Iciro Ariga

A centrifugal or mixed flow type turbomachine, of a vaneless diffuser type can operate stably at low flow rates below the design flow rate, by preventing the initiation of flow instability in the system. The turbomachine comprises two stabilization members disposed in two predetermined locations of the diffuser section which prevents a generation of unstable flow in the diffuser section during a low flow rate operation and reduction of head coefficient in the turbomachine.

Turbomachine

The present invention provides a centrifugal turbomachinery having a good performance which can effectively reduce the secondary flow in the flow passage of the impeller and minimize the loss caused by the secondary flow without an excessive increase in manufacturing cost. An impeller has a plurality of blades ( ) between an inlet ( ) at a central portion and an exit ( ) at a peripheral portion, and a flow passage formed between the blades for delivering fluid from the impeller inlet to the impeller exit by rotation the impeller. The blade ( ) is leaned toward a circumferential direction so that the blade at the hub side ( ) precedes the blade at the shroud side ( ) in a rotational direction of the impeller. A blade lean angle, defined as an angle between the blade and a surface perpendicular to a hub surface as viewed from the direction of the exit, shows a decreasing tendency from the inlet to the exit. A blade centerline at the hub side and a blade centerline at the shroud side as viewed from the front direction at the inlet intersect at a point where non-dimensional radius location, defined as a ratio of the radius of the intersection to the radius of the impeller exit, ranges from 0.8 to 0.95.

Centrifugal turbomachinery

A centrifugal or mixed flow type turbomachine, of a diffuser type can operate stably at low flow rates below the design flow rate, by preventing the initiation of flow instability in the system. The turbomachine comprises a stabilization member disposed in a predetermined location of the diffuser section which prevents a generation of unstable flow in the diffuser section during a low flow rate operation.

Turbomachinery

A turbomachine having variable-angle diffuser vanes operates by regulating the angle of the diffuser vanes on the basis of the sensors disposed on the pump body or pipes of a surge detection device. The onset of surge can be forecast by measuring the fluctuations in the operating parameter(s) over a measuring interval of time computed on the basis of the operating characteristics of the impeller of the turbomachine. The onset of surge is prevented by adjusting the angle of the diffuser vanes in accordance with the sampling duration for parameter fluctuations over the measuring interval of time, and by adjusting the diffuser vanes to maintain the operating parameter fluctuations of the fluid machinery below a threshold value of the turbomachine derived from the design flow rate of the turbomachine. Application of the surge detection device in combination with fluid flow guide vanes and blades of the turbomachine enables full utilization of the potential capability of the turbomachine.

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Yokohama, Japan

Shin Konomi