0588167 - ÚT 2025 US eng A - Abstract
Vinš, Václav - Hrubý, Jan - Součková, Monika - Aminian, Ali - Celný, David - Blahut, Aleš
Current status of correlations for the surface tension of ordinary water.
2024. Twenty-Second Symposium on Thermophysical Properties and Eighteenth International Conference on the Properties of Water and Steam. Boulder, 2024.
[Symposium on Thermophysical Properties /22./ and International Conference on the Properties of Water and Steam /18./. 23.06.2024-28.06.2024, Colorado]
R&D Projects: GA ČR(CZ) GA22-03380S
Institutional support: RVO:61388998
Keywords : surface tension * correlation * international standard
OECD category: Thermodynamics
Result website:
https://thermosymposium.org/program.html

The international standard for the surface tension of ordinary water approved by IAPWS is based on the correlation by Vargaftik et al. introduced back in 1983. The IAPWS standard has been later adjusted to the International Temperature Scale of 1990 (ITS-90) and, based on the new experiments carried out under the metastable supercooled state, has been proved to provide reliable predictions even when extrapolated from 0 °C down to – 25 °C. Even though the IAPWS standard provide reliable predictions, it seems to suffer from three weaknesses: A) the uncertainty estimates appear rather high, e.g., 0.36 mN/m at 25 °C, B) in the high-temperature region reaching the critical point, the correlation is based on just two data sets published back in 1969 and 1973 by a single research group of Vargaftik, C) recent experiments carried out at temperatures down – 31 °C show slight deviation from the extrapolated IAPWS standard. In 2016, the research group of Pátek reported new experimental data from – 0.6 to 70 °C and developed new correlation for the surface tension of ordinary water with an estimated error of 0.1 mN/m. The mathematical formula is identical with the IAPWS standard. In 2015, Kalová and Mareš reviewed literature data for surface tension at 20 and 25 °C and recently developed another correlation for the surface tension of ordinary water with an additional term τ^1.76. The uncertainty is estimated between 0.1 and 0.2 mN/m depending on the temperature region. In this talk, we compare the available correlations and try to assess recent developments that could lead to a possible reduction in the uncertainty estimates of the current IAPWS standard for the surface tension of ordinary water.
Permanent Link: https://hdl.handle.net/11104/0362945