“…The apparatus and methods used in the measurement of the density, viscosity, and thermal conductivity have been described in our previous papers. − Densities were measured using a pycnometer placed inside a constant temperature air bath and calibrated using mercury. Viscosities were measured using a capillary viscometer mounted inside a high-pressure view cell that was placed in a constant temperature air-bath.…”
Section: Methodsmentioning
confidence: 99%
“…Estimates of the expanded uncertainties ( k = 2) of the measurements are 0.2 kg·m –3 for the density, 0.04 mPa·s for the viscosity, and 0.003 W·m –1 ·K –1 for the thermal conductivity (at the 95% level of confidence). Additional details regarding the experimental apparatus and procedures can be found elsewhere. − …”
The
density, viscosity, and thermal conductivity of eight carboxylic
acids (pentanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic,
dodecanoic, and tetradecanoic acid) were measured at ambient pressure
and temperatures ranging from (290.3 to 473.4) K. The expanded uncertainties
(k = 2) of the measurements were estimated to be
0.2 kg·m–3 for the density, 0.04 mPa·s
for the viscosity, and 0.003 W·m–1·K–1 for the thermal conductivity (at the 95% level of
confidence). The data were correlated using the Rackett equation (in
the case of the density) and a modified rough hard-sphere (RHS) model
(in the case of the viscosity and thermal conductivity). Generalized
forms of the RHS model parameters are presented as functions of the
carbon number and temperature.
“…The apparatus and methods used in the measurement of the density, viscosity, and thermal conductivity have been described in our previous papers. − Densities were measured using a pycnometer placed inside a constant temperature air bath and calibrated using mercury. Viscosities were measured using a capillary viscometer mounted inside a high-pressure view cell that was placed in a constant temperature air-bath.…”
Section: Methodsmentioning
confidence: 99%
“…Estimates of the expanded uncertainties ( k = 2) of the measurements are 0.2 kg·m –3 for the density, 0.04 mPa·s for the viscosity, and 0.003 W·m –1 ·K –1 for the thermal conductivity (at the 95% level of confidence). Additional details regarding the experimental apparatus and procedures can be found elsewhere. − …”
The
density, viscosity, and thermal conductivity of eight carboxylic
acids (pentanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic,
dodecanoic, and tetradecanoic acid) were measured at ambient pressure
and temperatures ranging from (290.3 to 473.4) K. The expanded uncertainties
(k = 2) of the measurements were estimated to be
0.2 kg·m–3 for the density, 0.04 mPa·s
for the viscosity, and 0.003 W·m–1·K–1 for the thermal conductivity (at the 95% level of
confidence). The data were correlated using the Rackett equation (in
the case of the density) and a modified rough hard-sphere (RHS) model
(in the case of the viscosity and thermal conductivity). Generalized
forms of the RHS model parameters are presented as functions of the
carbon number and temperature.
“…This is followed by a progressive breakdown of overall thermal conductivity, eventually down to the atomic-level pairwise term. Each level of breakdown is followed by detailed interpretation of the effect of A comparison of the overall thermal conductivity at 300 K between the simulation models used in this work and experiment [21][22][23] . As is typical in molecular simulation, thermal conductivity is generally overestimated, and with the exception of PG-13P, relative values are maintained.…”
Section: Openmentioning
confidence: 99%
“… Figure 1 The 5 alcohol molecules studied in this work and the relation of their structures. Figure 2 A comparison of the overall thermal conductivity at 300 K between the simulation models used in this work and experiment 21 – 23 . As is typical in molecular simulation, thermal conductivity is generally over-estimated, and with the exception of PG-13P, relative values are maintained.…”
Section: Introductionmentioning
confidence: 99%
“…Having long been used as a working alcohol in antifreeze technologies, simulation studies have shown that the hydroxyl groups of EG contribute to its large thermal conductivity 16 . Adding both a carbon and hydroxyl group to ethanol (that is, to add a hydroxyl group to an internal carbon of propanol to make PG or to the end to make 13P) is also known to increase thermal conductivity compared to ethanol 23 , although not to the extent of EG. Until now, however, the atomic mechanisms responsible for such variation have remained unclear.…”
Precise control of thermophysical properties of liquids through tailor-made design of the liquid molecular structure is a goal that, if achieved, could have significant positive impacts on machine design, performance and durability. In this work we show how the breakdown of the Green–Kubo relations down to the atomic level in molecular dynamics simulation can give useful insight into the mechanisms of thermal conduction. Using a group of five small alcohols as a case study, we demonstrate how combining this level of insight with differential-structure analysis reveals the competition for conduction between carbon and hydroxyl group atoms, and show how this competition contributes to the change in thermal conductivity observed in experiment. We hope that this method will become a useful tool in the quest for molecular-structure based thermal design.
A new semi-theoretical method based on Enskog's hard sphere theory for dense fluids and the principle of corresponding states is presented for predicting viscosity of pure organic liquids. The viscosities of 75 organic liquids -37 acyclic and 38 cyclic hydrocarbonswere calculated using this method which requires critical properties and normal boiling point as input data. The predictions were compared with empirical data and other prediction methods. Highly satisfactory results were obtained over a wide range of temperatures (0.45 < T,. < 0.80).Une nouvelle methode semi-theorique, s'appuyant sur la theorie des spheres dures d'Enskog pour des fluides denses et le principe des etats correspondants, est presentee en vue de predire la viscosite des liquides organiques purs. On a calcule les viscosites de 75 liquides organiques -37 hydrocarbures acycliques et 38 cycliquesau moyen de cette methode, les proprietes critiques et le point d'ebullition normal etant utilises comme donnees d'entree. Les predictions ont ete comparees a des donnees empiriques et aux resultats d'autres methodes de prediction. Des resultats hautement satisfaisants ont ete obtenus pour une vaste gamme de temperatures (0,45 < T,. < 0,80). Keywords: organic liquid viscosity, prediction of organic liquid viscosity. iscosity of pure compounds and their mixtures is an I48 A.A.D. (%) = 6.51. M.A.D. (%) = 41.04 (observed for Cyclohexane at 287.82 K). Correlation coefficients are 0.9953 and 0.9892 for Equations (19) and (20), respectively. Results and discussion Empirical dynamic viscosity calculations of 75 organic liquids were obtained by utilizing data compiled by Viswanath and Natarajan (1989), van Velzen et al. (1972) and API Research Project 44 (1955). Results for acyclic and I52
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