THE TEMPERATURE-DEPENDENT VAPORIZATION ENTHALPY IN EQUILIBRIUM VAPOR–LIQUID PHASE TRANSITIONS: ITS UNIVERSAL BEHAVIOR FOR SIMPLE FLUIDS

Abstract

In this paper, we study the universal behavior of the temperature-dependent vaporization enthalpy in equilibrium vapor–liquid phase transitions of simple fluids. We find that, under some reduction using critical data, the experimental curves of vaporization enthalpy versus the saturated temperature will overlap with each other, i.e. the universal behavior experimentally holds for the temperature-dependent vaporization enthalpy, in the temperature range from the triple point to the critical point, for simple fluids. An empirical correlation describing this universal behavior is proposed and compared with reference data and other correlations. Different from others, our correlation only needs the critical temperature as input parameters.