Review and critical comparative evaluation of moist air thermophysical properties at the temperature range between 0 and 100 ℃ for Engineering Calculations

摘要

Although a broad range of heat transfer and engineering calculations require the use of thermophysical and transport properties of humid atmospheric air at the temperature range between 0 and 100 degrees C, there is a relatively considerable gap in the scientific literature concerning their precise evaluation. Even though numerous theoretical procedures and formulas have been developed for the mixture property evaluation, relatively very few devoted to the dry air/water vapor binary mixture can be found in the literature. In an earlier publication, simple procedures were employed to evaluate and investigate their influence on the heat and mass transfer calculations, while a decade ago alternative, more refined kinetic theory procedures were presented for the calculation of moist air properties. These which were found in a fairly good agreement with the very few and incomplete earlier published measurements, were algebraically fitted to allow the evaluation of saturated mixture properties of moist air. The present investigation aims at the validation of the proposed moist air properties based on comparisons with results from numerous theoretical procedures or data derived by employing commercial computer software and more recent experimental measurements. However, since no recent experimental results have appeared in the literature in the meantime, the validation was based on extensive comparisons and critical consistency evaluation of calculated results from various developed models. It was found that the proposed moist air properties are in a fairly good agreement with data from most of the numerous calculation processes reported in the literature, while certain methods and models appear to be physically invalid. The so derived results were fitted by algebraic correlations, allowing the accurate evaluation of moist air thermophysical properties at any relative humidity ranging from dry conditions up to saturation level in 10% steps. These are recommended until new precise validating measurements appear in the literature.