Study on Surface Tension of Fluid Helium Three

Abstract

As a standard property of helium-3, the surface tension is not only an important aspect to study the normal characteristics of this special cryogenic fluid, but also helpful to understand the Fermi quantum effects at low temperatures. After completion of studies on the thermodynamic and two typical transport properties (thermal conductivity and viscosity) of helium-3, all of the published experimental data of the surface tension of 3He have been collected. Different measurement techniques are compared and analyzed. The peculiar behavior of 3He surface tension, perhaps dominated by Fermi-Dirac quantum statistics, is analyzed and discussed at temperatures starting from zero to its critical point (3.3157 K). Based on a regular theoretical model for surface tension, a semi-empirical correlation is proposed for 3He covering the whole temperature range. The surface tension extrapolated to zero temperature by this equation is 1.5579×10−4 N · m−1. In the vicinity of the critical point, the equation could be smoothly switched to the known scaling law, which takes the critical index 1.289. Comparison for the surface-tension behavior is performed between 3He and its isotope 4He, which obeys Bose-Einstein statistics.