Surface tension of liquid3He and4He near the liquid-gas critical point

Study on Surface Tension of Fluid Helium Three

“…This is the most important criterion for us to give high weight to Iino et al's data during fitting the semi-empirical equation for the surface tension of 3 He. Compared to the early authors' results, measurements by Iino et al roughly agree with them within their own reported uncertainties above 1.5 K. However, there are apparent differences below 1 K, especially approaching 0.32 K. Iino et al [11] also measured the surface tension in the region very close to the critical point (3 × 10 −4 < τ = (T c − T )/T c < 2 × 10 −1 ), which is of great concern for determining the behavior of the equation near the critical temperature. The data point numbers, temperature range, uncertainties, etc.…”

“…Like the vapor pressure and saturated density, the surface tension should also follow the scaling law when approaching the critical point. Iino et al [11] measured the surface tension of liquid 3 He near its gas-liquid critical point and found the critical exponent to be 1.289 ± 0.015, which is close to the value of normal fluids (=1.3). Thus, the scaling law applied to the surface tension of 3 He could be expressed as…”

“…Experimentally, Esel'son and Bereznyak [6], Lovejoy [7], Zinov'eva [8,9], and Iino et al [10,11] measured the surface tension of 3 He at temperatures from 0.3 K to the vicinity of the critical point, although their data differ from each other by up to 25 %. All of the studies, except for Iino et al, used a conventional capillary rise method.…”

“…[4] (in kg · m −3 ), and the temperature (in K) is denoted by T . Based on the data analysis and filter of the measurements in Table 1, high weight was given to the high accuracy data from Iino et al [10,11]. A nonlinear least-squares fit to the model using all the reference data gives the coefficients: The maximum relative residual is 1.06 % and the average is 0.34 %, which means the uncertainty of the equation is completely within that of all the measurements.…”

“…Equation 3 could be switched to Eq. 4 at 3.065 K with no discontinuity in the function and an acceptable discontinuity in the slope to give a more accurate description of the properties in this 2.0 Lovejoy [7] Esel'son [6] Zinov'eva [8] Zinov'eva [9] Iino [10] Iino [11] Eq. Fig.…”