Full-range drift-flux correlation for vertical flows

Abstract

An empirical drift flux correlation has been developed that eliminates the need to know the flow regime before void fraction predictions can be made. This correlation covers the full range of pressures, flows, and void fractions and has been qualified against several sets of steady state test data covering wide range of initial conditions and geometries (PWR and BWR fuel assemblies as well as large pipes up to 18 inches in diameter). This correlation should be of great value to code developers and code users in determining the drift-flux parameters (C/sub o/ and V/sub gj/) for both co-current and counter-current two-phase flows for a full range of pressures, flows and void fractions including counter current flooding limitation (CCFL) and natural circulation. The correlation is continuous throughout the full range and does not depend on flow regime maps or spline fitting. 21 refs., 39 figs., 7 tabs.