Effects of Swirling Flow Component on Discharge Coefficients of Constriction Meters : In Case of Orifice

Abstract

Discharge coefficients of pipe orifices in swirling flow were measured and the results were discussed theoretically. Differential pressure across the orifices is affected by the swirling component and its amount is found to be a function of two parameters ; the rate of constriction of orifice opening and the intensity of swirling component. In a small orifice opening the differential pressure is decreased by the swirling component, and in a larger orifice opening it is increased. Relative change of the differential pressure was calculated theoretically by using a potential flow model. Distributions of velocities and pressures were measured and changes of energy and momentum of the flow through the orifices were discussed.