ABSTRACT
When a vapor-liquid two phase mixture flows through a nozzle or a uniform cross section tube with the increase of the pressure difference between upstream and downstream of the nozzle, the flow rate is determined only by the upstream pressure, and it is not affected by the downstream pressure of the nozzle or the tube. The flow is named as the critical two phase flow, and the flow rate becomes maximum at the condition. When the subcooled liquid enters into a nozzle or a short tube, the flow is a single phase liquid flow at the entrance. The liquid flashes in the nozzle, and the two phase critical flow condition occurs at the nozzle exit. In this case, Zaloudek observed both upstream choke at the entrance and downstream choke at the exit. Henry and Fauske developed a critical flow model, taking into account the non-equilibrium effect in the flow in nozzles and short tubes.
