scholarly journals Modeling of density and calculations of derived volumetric properties for n-hexane, toluene and dichloromethane at pressures 0.1-60 MPa and temperatures 288.15-413.15 K

2015 ◽  
Vol 80 (11) ◽  
pp. 1423-1433 ◽  
Author(s):  
Gorica Ivanis ◽  
Aleksandar Tasic ◽  
Ivona Radovic ◽  
Bojan Djordjevic ◽  
Slobodan Serbanovic ◽  
...  

Densities data of n-hexane, toluene and dichloromethane at temperatures 288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work, were fitted to the modified Tait equation of state. The fitted temperature-pressure dependent density data were used to calculate the derived properties: the isothermal compressibility, the isobaric thermal expansivity, the difference between specific heat capacity at constant pressure and at constant volume and the internal pressure, over the entire temperature and pressure intervals specified above. In order to assess the proposed modeling procedure, a comparison of the obtained values for the isothermal compressibility and the isobaric thermal expansivity with the corresponding literature data were performed. The average absolute percentage deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric thermal expansivity: for n-hexane 1.31-4.17%, for toluene 0.71-2.45% and for dichloromethane 1.16-1.61%. By comparing the obtained deviations values with those found in the literature it can be concluded that the presented results agree good with the literature data.

2020 ◽  
Vol 34 (33) ◽  
pp. 2050382 ◽  
Author(s):  
O. Akay ◽  
H. Yurtseven

Thermodynamic functions of the thermal expansion [Formula: see text], isothermal compressibility [Formula: see text] and the difference in the heat capacity [Formula: see text] are calculated as a function of temperature ([Formula: see text] GPa) close to the transitions of [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] and [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] in the solid nitrogen. This calculation is performed by using the observed Raman frequency shifts of vibrons [Formula: see text] and [Formula: see text]. Also, by using the observed [Formula: see text]–[Formula: see text] data, those thermodynamic functions are predicted at various pressures for the fluid–solid transition in nitrogen. For both calculations, observed data are used from the literature. From the temperature and pressure dependences of the thermodynamic functions studied, the Pippard relations are examined close to the [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] transitions and also fluid–solid transition in nitrogen.We find that the thermodynamic functions can be predicted from the Raman frequency shifts and that the Pippard relations can be established for both the [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] and fluid–solid transitions in nitrogen. This method of predicting the thermodynamic functions can also be applied to some other molecular solids.


2010 ◽  
Vol 24 (19) ◽  
pp. 3749-3758
Author(s):  
E. KILIT ◽  
H. YURTSEVEN

We calculate in this study the volume of ice I as functions of temperature and pressure close to the melting point by analyzing the experimental data for the thermal expansivity. Using an approximate relation, the temperature dependence of the volume is calculated at 202.4 MPa from the thermal expansivity of ice I. The pressure dependence of the volume is also calculated at 252.3 K from the isothermal compressibility of ice I close to the melting point. The volume calculated here as functions of temperature and pressure shows critical behavior close to the melting point in ice I, which can be tested by the experimental measurements.


1976 ◽  
Vol 31 (7) ◽  
pp. 769-776 ◽  
Author(s):  
G. Goldmann ◽  
K. Tödheide

Abstract From the Tait equation an equation of state containing five adjustable parameters was developed which fits experimental density data of molten potassium chloride to 1320 K and 6 kbar with a standard deviation of 0.04%. The thermal expansion coefficient, isothermal compressibility, internal pressure, and molar heat capacities at constant pressure and constant volume were calculated as functions of pressure and temperature from the equation of state and were compared with computer simulation results. A method for an estimate of high-pressure PVT data for molten salts is suggested which yields results superior to the best computed data presently available.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3462 ◽  
Author(s):  
Samah Hamze ◽  
David Cabaleiro ◽  
Dominique Bégin ◽  
Alexandre Desforges ◽  
Thierry Maré ◽  
...  

Volumetric properties such as density and isobaric thermal expansivity, and surface tension are of paramount importance for nanofluids to evaluate their ability to be used as efficient heat transfer fluids. In this work, the nanofluids are prepared by dispersing few-layer graphene in a commercial heat transfer fluid Tyfocor® LS (40:60 wt.% propylene-glycol/water) with the aid of three different nonionic surfactants: Triton X-100, Pluronic® P-123 and Gum Arabic. The density, isobaric thermal expansivity and surface tension of each of the base fluids and nanofluids are evaluated between 283.15 and 323.15 K. The influence of the mass content in few-layer graphene from 0.05 to 0.5% on these nanofluid properties was studied. The density behavior of the different proposed nanofluids is slightly affected by the presence of graphene, and its evolution is well predicted by the weight-average equation depending on the density of each component of the nanofluids. For all the analyzed samples, the isobaric thermal expansivity increases with temperature which can be explained by a weaker degree of cohesion within the fluids. The surface tension evolution of the graphene-based nanofluids is found to be sensitive to the used surfactant, its content and the few-layer graphene concentration.


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