A corresponding-states correlation for predicting the critical heat flux (CHF) in pool boiling conditions is proposed, and only requires knowledge of physical property constants of the fluid at any ...fluid temperature: molar mass, critical temperature, critical pressure, and the Pitzer acentric factor. If a fourth corresponding equation of state (EoS) parameter is added, a more accurate CHF correlation is obtained and matches Kutateladze–Zuber prediction within ±10% in the reduced temperature range of 0.55–0.95. This way, CHF can be easily predicted for any reduced temperature within the range of correlation’s validity by only knowing basic properties of the fluid. Additionally, two corresponding-states correlations for determining the capillary length are proposed and also do not rely on any temperature- and pressure-dependent fluid properties. A simpler correlation only using the Pitzer acentric factor is shown to be imprecise, and a more complex correlation also accounting for the fourth corresponding EoS parameter is recommended. These correlations are fundamental for further developments, which would allow for accurate prediction of CHF values on functionalized surfaces through further studies on the influence of interactions of fluid properties with other parameters, such as wetting and active nucleation site density.
New prediction methods for four basic properties, (normal boiling point, Tb, critical temperature, Tc, critical pressure Pc and Pitzer's acentric factor, ω) are proposed, based on group contribution ...techniques. Object substances of these methods are mainly halogenated hydrocarbons (flons), which contain undeveloped substances whose chemical formulas are given. The acentric factor can be given through a new correlation with a parameter β in the Frost-Kalkwarf-Thodos vapor pressure equation. New group contribution techniques for Tb and β are developed. As for Tbr, six group increments are newly added to that of Lydersen. Furthermore, Pc can be indirectly calculated from a new empirical correlation among Pc, Tbr and ω. Average deviations (root mean square of deviations) of the proposed methods for Tb, Tc, Pc and ω are found to be about 1 %, 1 %, 3% and 3 %, respectively.
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