The Inception of Nucleate Boiling With Liquid Nitrogen

Abstract

The phenomena of patchwise boiling are discussed, and the significant parameters restricting the growth of a boiling patch are analytically determined to be: (a) a high nucleate-boiling heat-transfer coefficient, (b) a low total heat flux, (c) the absence of cavities with a trapped liquid vapor interface outside the boiling patch, (d) an appropriate value of wall thermal conductivity, and (e) a high vapor enthalpy per bubble. A qualitative agreement between theory and experiment was observed for items (a), (b), and (d). A surface finish was developed and tested in pool boiling of liquid nitrogen which eliminated the observed, stable temperature hysteresis at inception of nucleate boiling and maintained a low-temperature difference (Tw −Tsat ) for the entire nucleate-boiling curve.