Dynamics of Two-Phase Flows

ISBN Print: 0-8493-9925-4

NUCLEATION AND FLASHING OF INITIALLY SUBCOOLED LIQUIDS FLOWING IN NOZZLES: 2. COMPARISON WITH EXPERIMENTS USING A 5-EQUATION MODEL FOR VAPOR VOID DEVELOPMENT

DOI: 10.1615/0-8493-9925-4.290
pages 637-666

Abstract

A quasi-one-dimensional, five-equation model has been developed on a microcomputer to calculate the behavior of flowing, initially subcooled, flashing liquids. Equations for mixture and vapor mass conservation, mixture momentum conservation, liquid energy conservation, and bubble transport were discretized and linearized semi-implicitly, and solved using a successive iteration Newton method. Closure was obtained through simple constitutive equations for friction and spherical bubble growth, and a new nucleation model for wall nucleation in small nozzles combined with an existing model for bulk nucleation in large geometries. Good qualitative and quantitative agreement with experiment confirms the adequacy of the nucleation models in determining both initial size and number density of nuclei. It is shown that bulk nucleation becomes important as the volume-to-surface ratio of the geometry is increased.