Phase Splitting Of Wet Steam in Annular Flow Through a Horizontal Branching Tee

Abstract

Summary A phase-splitting equation for flow of a two-phase fluid through a tee junction was derived. It shows that the fluid quality at an outlet of the tee is determined by the relationship between the liquid and vapor extraction ratios of the fluid through that outlet. This equation applies to any tee junction regardless of its geometry, orientation, and inclination. This paper presents its application to the flow of wet steam through a horizontal branching tee. Experimental data were for wet steam flowing through a standard branching tee of 2- and 4-in. sizes in a horizontal plane, inlet pressures from 400 to 800 psig, inlet qualities from 0.2 to 0.8, inlet vapor velocities from 40 to 120 ft/sec, and for vapor-extraction ratios in the 0.2 to 0.8 range. These data were analyzed focusing on the effect of the vapor-extraction ratio of the run stream on the liquid-extraction ratio of the same stream. A correlation between these two extraction ratios has been established with steam quality, superficial vapor velocity, and critical velocity at the inlet to the tee as controlling parameters. Using this correlation and the phase-split equation, we are able to predict steam qualities exiting from horizontal branching tees to within ± 15% of the experimental values, which is more accurate than other phase-splitting models.