An analysis of critical simultaneous gas/liquid flow through a restriction and its application to flowmetering

A theoretical analysis is presented of the mechanism of simultaneous flow of gas and liquid through a restriction at critical speed. The study shows that a relationship exists between the mass flows of gas and liquid, restriction size and upstream pressure. Comparison of this relationship with measurements showed a reasonable agreement. It has therefore been concluded that a restriction can be used as a gas/liquid flowmeter with reasonably high accuracy, provided that the flow is a critical one. Further increase of accuracy seems possible by using a restriction especially designed for the purpose.