Phase Velocities in Boiling Flow Systems by Total Energy and by Diffusion

Abstract

A total energy balance is employed in a single-component boiling flow system to obtain minimum limiting values of vapor volume content and show the effects of phase velocity distributions. Results are compared to data of various investigators in steam-water systems at pressures of 115 to 1000 psia. Limiting equations are used for derivation of more accurate relationships. A correlating function and equation are derived, from the generalized diffusion velocity for momentum, which relate voids, quality, and kw/liter. These are used to correlate Argonne’s steam voids data in a boiling channel at 163 and 614 psia with velocities in the range 1.83 to 5.94 ft/sec and steam qualities between 0.008 and 0.07. A simple, semitheoretical relationship between quality, vapor fraction, and energy addition/unit boiling volume is obtained which correlates all of the 163 psia data within about 5 percent, and a limited amount of data for 614 psia equally well.