Incipient Boiling Superheats in Liquid Metals

Measurements were obtained of the superheat required to initiate incipient boiling of potassium in forced convective flow. Emphasis was placed on determining the effect of preboiling, deactivation conditions on subsequent incipient-boiling superheat. Data were obtained with deactivation subcoolings of 10 to 380 deg F, boiling temperatures of 1295 to 1600 deg F, and boiling pressures of 8 to 24 psia. Measured superheats ranged from 17 to 117 deg F. Sufficient data were obtained to indicate the functional dependence of incipient-boiling superheats on each of the three independent variables: deactivation pressure, deactivation temperature, and boiling pressure. The experimental results were found to be in substantial agreement with an analytical model developed herein. The proposed correlating equation was generally correct in predicting both the magnitude of the superheat and in its functional dependence on each of the independent variables.