Liquid Viscosity and Surface Tension of n-Dodecane, n-Octacosane, Their Mixtures, and a Wax between 323 and 573 K by Surface Light Scattering

Abstract

The present contribution provides experimental data for the liquid viscosity and surface tension of n-alkane based model systems at temperatures up to 573 K. The fundamental advantage of the used surface light scattering (SLS) method lies in its application in thermodynamic equilibrium without calibration in a contactless way. The investigated systems comprise the pure fluids n-dodecane (n-C 12 H 26 ) and n-octacosane (n-C 28 H 58 ), their binary mixture at a n-C 12 H 26 mole fraction of about 0.3, and the commercially available hydrocarbon wax SX-70 representing a multicomponent mixture of n-alkanes with a broad chain length distribution. For the first time, it could be demonstrated that the SLS method can simultaneously access the liquid viscosity and surface tension of such medium-to long-chained n-alkane systems close to saturation conditions over a broad temperature range from 323 to 573 K. Typical measurement uncertainties of 2% based on a coverage factor k = 2, i.e., a level of confidence of more than 95%, were obtained. Over the entire temperature range, a simple polynomial equation for the dynamic viscosity and a modified van der Waals equation for the surface tension represent the measured data of the pure and binary systems well. The present investigations improve the data situation for hydrocarbon systems in the high-temperature range where no measurement results exist in literature.

Surface Tension and Viscosity of Binary Mixtures of the Fluorinated and Non-fluorinated Ionic Liquids [PFBMIm][PF6] and [C4C1Im][PF6] by the Pendant Drop Method and Surface Light Scattering

“…For fluids with relatively small viscosities and/or large surface or interfacial tensions, an oscillatory behavior of surface fluctuations is found by examining typically investigated wavelengths of fluctuations below about 10 µm [48][49][50]. This enables a simultaneous determination of viscosity and surface tension by SLS [48,[50][51][52][53][54]. Fluids with relatively large viscosities and/or small surface or interfacial tensions show an overdamped behavior of surface fluctuations (ω q = 0) [48,49], which holds also for all present measurements.…”

Mobility of A Water Droplet on Liquid Phase of N-Octadecane Coated Hydrophobic Surface

“…Here, S ls ( a ) is the spreading rate of liquid film on the textured surface in air. The surface energy of the liquid n-octadene is 21.6 mN/m 32 ; hence, the spreading rate corresponding to the liquid n-octadecane on the textured surface is in the order of S ls ( a ) = 2.95 mN/m, i.e. it is larger than zero.…”

“…For a small solid fraction, the slip length ( b ) can be approximated by , where μ w is the dynamic viscosity of water, μ pcm dynamic viscosity of liquid n-octadecane, and h t is the liquid film height (thickness). The dynamic viscosity of water is 0.7644 × 10 −3 Pa.s at 305 K and dynamic viscosity of liquid n-octadene at the same temperature is 3.677 × 10 −3 Pa.s 32 , and the oil film thickness is in the order of 50 μm; hence, the slip length becomes 19.65 μm. The slip velocity at the droplet bottom is related to the slip length in the form of , where τ wi is the shear stress at the interface 7 and the the interfacial shear stress for the thin film can be simplified via couette flow analogy, i.e.…”

Theoretical and numerical analysis of the evaporation of mono- and multicomponent single fuel droplets

“…(2004), Koller et al. (2017) and Wohlfarth (2008). Even though the momentum equation is not integrated and no viscous terms are included in the formulation, the liquid-phase viscosity is required in (2.9) to obtain the effective diffusivity of the species in the liquid phase.…”

“…where the viscosity of the pure species is obtained using an expression analogous to (2.14) for the experimental results of Kadlec et al (2010), Engineering ToolBox (2013), Sagdeev et al (2013), Michailidou et al (2014), Caudwell et al (2004), Koller et al (2017) and Wohlfarth (2008). Even though the momentum equation is not integrated and no viscous terms are included in the formulation, the liquid-phase viscosity is required in (2.9) to obtain the effective diffusivity of the species in the liquid phase.…”