Nucleate Boling Heat Transfer of Dielectric Liquid HFE-7100 in Horizontal Layers at Various Pressures

Abstract

Experimental data are presented on nucleate boiling heat transfer of dielectric liquid HFE-7100 in horizontal layers. The liquid layer height was varied in a wide range while changing the pressure in the working chamber. The experiments were performed on a flat surface of a 120-mm outer diameter stainless-steel plate in an experimental heat-transfer vacuum setup whose working chamber was a thermal syphon. The experimental data were compared with the Yagov and Gogonin correlations which had been obtained for pool boiling. The Gogonin correlation has been demonstrated to properly generalize the experimental data in all ranges of reduced pressures and liquid layer heights. This correlation explicitly describes the influence of such parameters as the heating surface roughness and the ratio of the thermophysical properties of the liquid and the heat-transfer wall, which have a pronounced effect on the heat-transfer coefficient during boiling of dielectric liquids. Besides, this correlation is convenient since it can be used with parameters that can be monitored during the experiment. A generalization is presented of experimental data by the Pioro empirical correlation recommended for generalizing data on nucleate boiling in thin liquid layers. It has been demonstrated that the Pioro correlation with carefully selected coefficients and power exponents can generalize with an acceptable accuracy the experimental data obtained under given conditions on a heat-transfer wall exposed to a working fluid. To quantitatively assess the agreement between the computational correlations and experimental data on nucleate boiling of dielectric liquid HFE-7100 in horizontal layers, the mean error and rms deviation were used.