Experimental Investigation in Pool Boiling Heat Transfer of Pure/Binary Mixtures and Heat Transfer Correlations

Abstract

<em>Nucleate pool boiling heat transfer coefficient have been experimentally measured on a horizontal rod heater for various liquid binary mixtures. Measurements are based on more than three hundred data points on a wide range of concentrations and heat fluxes. In this investigation, it has been confirmed that the heat transfer coefficient in boiling solutions are regularly less than those in pure component liquids with same physical properties. Several reasons should be responsible for this phenomenon, but mainly it could be related to preferential evaporation of the more volatile component(s) during bubble formation. In this article, the performances of major existing correlations to the present experimental data including pure and binary mixture liquids are discussed. It is shown that it is impossible to predict the accurate value of boiling heat transfer for liquid mixtures and even pure liquids by any existing correlations over all ranges of concentrations or heat fluxes. In this investigation, the Schlünder correlation - as a model with excellent theoretical basis - has been modified; however some models provide superior performance in our experimental range. Originally, it is stated by different authors that B₀ - the ratio of the interfacial area of heat transfer to those of mass transfer as a tuning parameters in Schlünder model - is too complicated to predict and should be fitted empirically as a function of heat flux, density and pressure for any given binary system. In this investigation, B₀, the mentioned tuning parameter has been basically derived based on the analogy of the mass, heat and momentum transfer. As the results, the average error of Schlünder model in a wide range of boiling parameters has been significantly reduced.</em>