An integral analysis of condensing annular‐mist flow

Abstract

AbstractThe application of integral techniques to the analysis of a high vapor velocity, two‐phase, annular‐mist, single‐component condensing flow system is presented. A time‐averaged annular liquid film thickness is defined, and appropriate interfacial and wall shear stress correlations are employed to account for the wavy nature of the interface between the entrainment‐laden gaseous core and the axisymmetric annular liquid film. An empirical entrainment correlation is utilized to determine the amount of liquid flowing as entrained particles in the high velocity core region. The velocity and enthalpy distributions in the gaseous core and the annular liquid film are assumed as the power‐law type. The resulting set of four nonlinear ordinary differential equations is solved numerically with the use of a digital computer. A comparison with experimental data for condensing steam is obtained. The analytical model accurately predicts the condenser length necessary for complete condensation and also predicts the dynamic quality, the heat transfer characteristics, and the static pressure distribution throughout the condensation length. The integral analysis presents some insight into the complex mechanisms and interactions which occur in high vapor velocity, two‐phase, annular‐mist flows and also indicates the need for improved experimental techniques to further this understanding.