New Experimental Data and Reference Models for the Viscosity and Density of Squalane

Abstract

Empirical models for the density and the viscosity of squalane (C30H62; 2,6,10,15,19,23-hexamethyltetracosane) have been developed based on an exhaustive review of the data available in the literature and new experimental density and viscosity measurements carried out as a part of this work. The literature review showed there was a substantial lack of density and viscosity data at high temperature (373 to 473) K and high pressure conditions (pressures up to 200 MPa). These gaps were addressed with new experimental measurements carried out at temperatures of (338 to 473) K and at pressures of (1 to 202.1) MPa. The new data were utilized in the model development to improve the density and viscosity calculation of squalane at all conditions including high temperatures and high pressures.The model presented in this work reproduces the best squalane density and viscosity data available based on a new combined outlier and regression algorithm. The combination of the empirical models and the regression approach resulted in models which could reproduce the experimental density data with average absolute percent deviation of 0.04%, bias of 0.000%, standard deviation of 0.05%, and maximum absolute percent deviation of 0.14% and reproduce the experimental viscosity data with average absolute percent deviation of 1.4%, bias of 0.02%, standard deviation of 1.8% and maximum absolute percent deviation of 4.9% over a wide range of temperatures and pressures. Based on the data set used in the model regression (without outliers), the density model is limited to the pressure and temperature ranges of (0.1 to 202.1) MPa and (273 to 525) K, while the viscosity model is limited to the pressure and temperature ranges of (0.1 to 467.0) MPa and (273 to 473) K. These models can be used to calibrate laboratory densitometers and viscometers at relevant hightemperature, high-pressure conditions.

Probing large viscosities in glass-formers with nonequilibrium simulations

“…The approach assumes an analytic form for the shear-rate-dependent viscosity that is validated by comparing to the unusually large set of nonequilibrium and equilibrium flow measurements for squalane (19,20,(22)(23)(24)(25)(26)(27). Newtonian viscosities are obtained from two-parameter fits of this analytic form to the high-rate response.…”

Viscosity Measurements of Three Base Oils and One Fully Formulated Lubricant and New Viscosity Correlations for the Calibration Liquid Squalane

“…It is therefore essential for the calibration of the three sensors. Unfortunately, it was found that none of the three reference correlations [62,63] represents the IC data set within its estimated expanded uncertainty of 2 % [63]. Rather, the combined range of deviations from the three correlations is from −7.8 % to +7.4 %.…”

“…Mylona et al [62] published two reference correlations for the viscosity of squalane, one formulated in terms of temperature and density and one formulated in terms of temperature and pressure. Schmidt et al [63] published a third reference correlation in terms of temperature and pressure and an additional viscosity data set that was measured at Imperial College (IC), London (UK) with a vibrating wire viscometer in the temperature range from 338.2 K to 473 K with pressures up to 200 MPa. This data set is the only one that overlaps with the temperature and pressure range of the viscometer used at NIST.…”

Pressure–viscosity response in the inlet zone for quantitative elastohydrodynamics

“…The viscosity of a reference liquid, squalane, has been extensively measured to high pressure in various laboratories [34][35][36][37]. A correlation using the McEwen model in reference [34] yielded parameters at 65°C of 0  6.82 mPa·s, q  6.88 and *  14.77 GPa -1 . The deviations of this correlation from data of three publications [35][36][37] are plotted in Figure 6,…”