Speeds of sound have been measured in ethyl myristate (C 16 H 32 O 2 ), methyl myristate (C 15 H 30 O 2 ), and methyl palmitate (C 17 H 34 O 2 ) at pressures up to 100 MPa along isotherms ranging from (293.15 to 403.15) K. The measurements were carried out using a pulse echo technique operating at 3 MHz. Additional compressed liquid density measurements were performed from (293.15 to 393.15) K with pressures from (0.1 to 100) MPa in order to evaluate isentropic compressibility using speed of sound measurements. An equation of state that represents both the density and the speed of sound temperature reported experimental data within their estimated uncertainties is given to evaluate the volume as well as its derivatives of these components.
The
knowledge of high pressure densities and speeds of sound of
biodiesel fuel is crucial for the optimization of diesel engines operation,
namely, for the injection process, to achieve a complete combustion.
However, the experimental data for these properties are still very
sparse in the literature. This work reports the densities and speeds
of sound measured at pressures from atmospheric to 200 MPa and temperatures
from (293.15 to 393.15) K for two biodiesel fuels (soybean and rapeseed).
The density data were measured only up to 100 MPa and later extrapolated
for pressures up to 200 MPa by integration of speed of sound data.
An equation of state was then proposed to describe both density and
speed of sound within their estimated uncertainties and used to assess
the density and its derivatives.
International audienceThe paper reports high pressure data of the viscosity of methyl caprate (C11H22O2) and ethyl caprate (C12H24O2). The measurements cover the temperature range from (293.15 to 353.15) K, from atmospheric pressure up to 200 MPa and were carried out by two different methods. One is based on a falling-body viscometer, whereas the other rests on a quartz crystal resonator technique. Based on the two sets of data, high pressure viscosity correlations are proposed to correlate within the experimental uncertainty the viscosity values as a function of temperature and pressure. Finally, a thermodynamic scaling method was used to describe the viscosity in terms of density and temperature
Speeds
of sound were measured for methyl oleate and methyl linoleate
(C15H30O2) at pressures up to 200
MPa along isotherms ranging from (283.15 to 393.15) K. Additional
density measurements were carried out by using a U-tube densimeter
up to 100 MPa from (293 to 393) K. From the integration of speed of
sound, density was evaluated up to 200 MPa, and the isentropic compressibility
was determined in the same p–T domain. A correlation
that represents both the density and the speed of sound within their
experimental uncertainties is reported to evaluate both the volume
and its derivatives with respect to pressure (isothermal compressibility)
and temperature (isobaric expansion).
Viscosity have been measured in ethyl myristate (C 16 H 32 O 2 ) and methyl myristate (C 15 H 30 O 2 ) at pressures up to 100 MPa along isotherms ranging from 293.15 to 403.15 K. The measurements were carried out by using a falling-body viscometer as well as a quartz crystal resonator viscometer. A comparison made between both sets of data reveals a good agreement with the different viscometers.Based on the data provided, high pressure correlations are proposed to represent viscosity in terms of density and temperature within the expanded experimental uncertainty. In addition a scaling method is given to relate the viscosity to a single thermodynamic quantity.
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