Expansion of a Very Low Quality Two-Phase Fluid Through a Convergent-Divergent Nozzle

Abstract

Flow in de Laval nozzles of high pressure, low-quality steam-water mixtures was investigated to determine the resulting mass flow rates and to acquire design criteria information. Qualities ranged from 0 to 20 percent and pressures up to 1000 psia. Comparisons of the experimental data to three simple models: (a) isentropic expansion; (b) frozen composition; and (c) slip flow, showed satisfactory correspondence at all conditions except for qualities very close to saturated liquid. Observation was made that a condition similar to shock resulted when the nozzles were overexpanded.