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ISSN Online: 2377-424X

International Heat Transfer Conference 3
August, 7-12, 1966, Chicago, USA

VAPOR VOID FRACTION IN SUBCOOLED BOILING AND IN SATURATED BOILING SYSTEMS

Get access (open in a dialog) DOI: 10.1615/IHTC3.390
pages 24-38

Resumo

The results of an analysis for predicting the vapor void fraction in boiling systems are presented. For two phase systems in thermodynamic equilibrium it was shown (1, 20) that three effects, i.e., of flow profile, vapor concentration profile across the duct and of relative velocity must be taken into account. It is shown here that when the bulk liquid is either subcooled or superheated a fourth effect, that of the non-uniform liquid temperature distribution, must be considered. These four effects are included in an analytical expression for predicting the void fraction in saturated or subcooled boiling. A method for also taking into account the nucleating characteristics of the heated surface is given since this effect also influences the non-equilibrium void prediction. Satisfactory agreement is shown between the analytical results and experimental data.