Air-water two-phase flow performance of centrifugal pump and dispersing effect of liquid jet on air accumulating region in impeller

摘要

It is known that an air accumulating region occurs in a centrifugal pump impeller and pump head breaks down as air flow rate is increased. Two-phase pump head might be improved by dispersing the air accumulating region with pressurized liquid jet flow. This effect is examined experimentally for a new type of impeller, consisting of tandem rotating and stationary circular cascades, which has been proposed for gas-liquid two-phase flow centrifugal pump. As the results, though a slight improvement appears by a pressurized recirculating jet from the impeller outlet in the case of vaneless diffuser, this effect is buried in an effect of suppressing the elongation of air accumulating region with the attachment of diffuser blades in the case of vaned diffuser. Then, jet dispersing effect to improve two-phase flow performance sufficiently is investigated quantitatively with a forced jet device supplying the water from the outside of pump system.