Experimental Investigation of Bubble Departure Diameter and Bubble Departure Frequency in Subcooled Flow Boiling in a Vertical Annulus

Wall nucleation experiments have been performed in a vertical annulus test section for investigation of the bubble departure diameter and bubble departure frequency. The experimental data in forced convective subcooled boiling flow is presented as a parametric study of the effect of wall heat flux, local bulk liquid sub-cooling, liquid flow rate, and system pressure. The data is shown to extend the database currently available in literature to a wider range of system conditions. Along with the current database in forced convective flow, the available models for bubble departure size and frequency are reviewed and compared with the new data. The prediction of the bubble departure frequency is shown to require accurate modeling of the bubble departure diameter which has poor agreement with the experimental database.