Analysis of flow choking of two-phase, one-component mixtures

TLDR: In this article, the authors studied the nature of flow choking in steam-water mixtures passing through a tube with ever increasing pressure gradient and found that flow regimes varied from purely entrained to annular entrained and slug entrained as quality decreased.

Abstract: The nature of flow choking has been studied as steam-water mixtures are passed through a tube with ever increasing pressure gradient. Choked flow for two-phase, one-component mixtures has been characterized with a separated flow model as resulting from maximization of the ratio of gas to liquid velocities, or slip ratio. Slip ratios at choking were measured and found to increase from 1.2 to 5.0 at 30 lb./sq.in. exit plane pressure with decrease in quality from 0.95 to 0.02. Separated models predict either 9.3 or 28.4 with no quality dependence. The difference is attributed to liquid entrainment. Flow regimes were observed to vary from purely entrained to annular entrained to slug entrained as quality decreased. Normal shock waves were observed in the free jet at qualities above 0.25. Choking flow rates were predicted with an average error of less than 2% with a stagnation energy balance model using an empirically developed slip ratio relation corrected for entrainment.