ANALYSIS OF INTERFACIAL AND MASS TRANSFER EFFECTS ON FORCED CONVECTION IN GAS-LIQUID ANNULAR TWO-PHASE FLOW

Abstract

In a gas-liquid annular two-phase flow one of the main factors influencing
the determination of heat transfer rates is the average thickness of the liquid
film. A model to accurately represent the heat transfer in such situations has
to be able of determining the average liquid film thickness to within a
reasonable accuracy. A typical physical aspect in gas-liquid annular flows is
the appearance of interface waves, which affect heat, mass and momentum
transfers. Existing models implicitly consider the wave effects in the
momentum transfer by an empirical correlation for the interfacial friction
factor. However, this procedure does not point out the difference between
interface waves and the natural turbulent effects of the system. In the
present work, the wave and mass transfer effects in the theoretical
estimation of average liquid film thickness are analyzed, in comparison to a
model that does not explicitly include these effects, as applied to the
prediction of heat transfer rates in a thermally developing flow situation.