Quasi-steady nucleate boiling and its life caused by large stepwise heat input in saturated pool liquid He I

Abstract

Quasi-steady nucleate boiling on a horizontal cylinder in liquid He I caused by large stepwise heat input, whose height was far beyond the value corresponding to the steady critical heat flux, was investigated. It was confirmed that quasi-steady nucleate boiling exists with a certain life at the state corresponding to the point on the extension of the steady nucleate boiling curve. The correlation to express the life for the step heat input was given as a function of quasi-steady nucleate boiling heat flux. Another correlation to express the total energy transferred to the liquid from the cylinder surface before the end of quasi-steady nucleate boiling for a step heat input was also derived. It was made clear that this correlation is applicable not only to step heat input but also to the heat input which increases exponentially at first and then keeps constant (exponential step heat input). Namely, it is possible by using the correlation to predict the time when the quasi-steady nucleate boiling terminates after the addition of step and exponential step heat inputs.