Measured Variations in Local Surface Temperatures in Pool Boiling of Water

Abstract

An investigation of the surface-temperature variation during nucleate pool boiling at atmospheric pressure was conducted. The effect of surface temperature, heat flux, and heating-surface material was investigated. The temperature variation of the surface was found by a specially fabricated thermocouple placed in contact with it. The average maximum temperature variation may be found from the following equation: ΔTavgmax=c[q(f/α)1/2]−αqΔTsur−satk The exponent a is a function of surface roughness. The rate of heat flow was denoted by q in Btu/sq ft-hr, α the thermal diffusivity in sq ft/hr, f the frequency of variations in cphr, k the thermal conductivity in Btu/ft-hr-deg F, and ΔTsur−sat the temperature difference between the heating surface and the saturation temperature of water. The coefficient c and exponent a were determined experimentally for various heating-surface materials and surface finishes.