Influence of thermodynamic models on the prediction of pool boiling heat transfer coefficient of dilute binary mixtures

Abstract

In this paper, large number of experiments has been performed on saturated pool boiling heat transfer to three different dilute binary mixtures at various heat fluxes (up to 100kW/m2) and five different concentrations (1–5vol.% of heavier component). The test mixtures include water/glycerol, water/mono‐ethylene glycol (MEG), and water/di‐ethylene glycol (DEG). The effects of the main operating parameters such as heat flux, concentration, and bubble dynamics on the pool boiling heat transfer coefficient are also investigated. Furthermore, it is shown that physical properties of the mixtures have a considerable effect on the prediction of pool boiling heat transfer coefficients using the available correlations. In almost all of the existing correlations, some physical properties are strongly involved which can be estimated using different thermodynamic models. These models for the calculation of specific heat, density, heat of vaporization, and surface tension do not give exactly similar results and consequently, the heat transfer coefficient obtained from a specified predictive correlation can be tolerated according to the method used for the calculation of the physical properties. This point is usually ignored by investigators and they compare their experimental data with the correlations without reporting which thermodynamic models have to be used for the calculation of the physical properties. In this study, the prediction of Schlünder correlation has been compared with the present experimental data. Results show that the prediction ability of the Schlünder correlation is strongly dependent on the method used for the estimation of the required physical properties.