On the effect of heating wall thickness on pool boiling burnout

The effect of the thermal properties of thin heating wall on the range of values of thickness influencing burnout heat flux was studied. Brief details are given of the experiment performed with thin metal layers of Cu, Ni, Sn, and Zn in distilled, degassed and saturated water at atmospheric pressure. The results show that over a range of values the heater thickness appreciably affects burnout. When, however, a 'limiting value', specific to each of the metals, is exceeded the influence of wall thickness becomes negligible. Under the conditions, described, the limiting values, defined to correspond to the ratio, burnout heat flux/asymptotic heat flux = 0.9, depends upon the parameter √(k p c) of the heating wall where k, p, and c are thermal conductivity, density, and specific heat. (U.K.)