Boiling-Curve Measurements From a Controlled Heat-Transfer Process

Abstract

Feedback has been introduced around a boiling heat-transfer process in such a way that stable operation of the process has been obtained in all boiling regions including the transition region, in which, as is well known, the process itself is unstable. This system makes it possible to obtain much new information concerning both the steady-state and dynamic characteristics of boiling heat-transfer processes. Pool-boiling data which were obtained by the use of this system are presented. Accurate measurements of heater voltage and current were obtained by a new technique involving the use of digital instruments. These data are presented in the form of plotted experimental points in the nucleate, transition, and film boiling regions. The new measurement technique is described. Values of n in the equation q/As = CTdn are determined for all three boiling regions, where q = Btu/hr, As is heater surface area, and Td is temperature difference between heater surface and ambient liquid. The ambient liquid is distilled water maintained at saturation temperature under atmospheric pressure.