Forced convective boiling of subcooled water at high velocity

This paper deals with heat transfer and critical heat flux (CHF) in subcooled flow boiling offering a fundamental study aimed at high heat flux cooling. Experiments with water at 0.12 MPa were conducted in a mass velocity range from 500 kg/m²s to 15,000 kg/m²s (velocity from 0.5 m/s to 15 m/s) and subcooling from 20 K to 60 K. A sheet of stainless steel (80 mm in heated length, 10 mm wide, and 0.2 mm thick) was mounted flush with a sidewall of a vertical rectangular channel (cross-section 20 mm by 30 mm) and heated directly using direct current. It was found that mass velocity and subcooling strongly affect CHF and heat transfer in non-boiling convection and partial nucleate boiling regimes. These two parameters have no appreciable influence in the fully developed nucleate boiling regime. In the parameter range used, CHF reached 15 MW/m². Boiling bubble behavior just prior to reaching CHF was found to vary depending on mass velocity and subcooling. 1998 Scripta Technica, Heat Trans Jpn Res, 27(5): 376–389, 1998