Compressibility, thermal expansion coefficient and heat capacity of CH4 and CO2 hydrate mixtures using molecular dynamics simulations

2015 ◽  
Vol 17 (4) ◽  
pp. 2869-2883 ◽  
Author(s):  
F. L. Ning ◽  
K. Glavatskiy ◽  
Z. Ji ◽  
S. Kjelstrup ◽  
T. J. H. Vlugt
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Molecular Dynamics Simulations ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Thermal And Mechanical Properties ◽  
Dynamics Simulations ◽  
And Storage

Understanding the thermal and mechanical properties of CH4 and CO2 hydrates is essential for the replacement of CH4 with CO2 in natural hydrate deposits as well as for CO2 sequestration and storage.

scholarly journals Thermal and Caloric Properties of Fluids from Non-equilibrium Molecular Dynamics Simulations using the Two-gradient Method

2021 ◽  
Author(s):  
Martin P. Lautenschläger ◽  
Hans Hasse
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Molecular Dynamics Simulations ◽  
Transport Properties ◽  
Thermal Expansion Coefficient ◽  
Gradient Method ◽  
Lennard Jones ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations

Transport properties of fluids can be determined efficiently from non-equilibrium molecular dynamics simulations using the two-gradient method which was introduced recently. It is shown here that also thermal and caloric properties of fluids can be determined accurately and efficiently along with the transport properties using this method. In a single run, all these properties are obtained for a series of state points at different temperatures and constant pressure. The truncated and shifted Lennard-Jones (LJTS) fluid is studied here as a test case. Data are reported for about 700 state points in the range of (T = [0:7; 8:5] and ? = [0:2; 1:0]). Besides data on the thermal conductivity, shear viscosity, and selfdiffusion the following thermal and caloric properties were measured: pressure p, internal energy u, enthalpy h, isobaric heat capacity cp and thermal expansion coefficient ?p. The results of the thermal and caloric properties agree very well with those from an accurate equation of state from the literature. Also the shear rate dependence of these properties can be studied easily with the two-gradient method. Keywords: local equilibrium; Lennard-Jones fluid; isobaric heat capacity; thermal expansion coefficient

Thermomechanical properties dependence on chain length in bulk polyethylene: Coarse-grained molecular dynamics simulations

2010 ◽  
Vol 25 (3) ◽  
pp. 537-544 ◽  
Author(s):  
Junhua Zhao ◽  
Shijo Nagao ◽  
Zhiliang Zhang
Keyword(s):  
Molecular Dynamics ◽  
Thermal Expansion ◽  
Molecular Dynamics Simulations ◽  
Thermal Expansion Coefficient ◽  
Chain Length ◽  
Expansion Coefficient ◽  
Specific Volume ◽  
Bond Number ◽  
Coarse Grained ◽  
Dynamics Simulations

Mechanical and thermodynamical properties of bulk polyethylene have been scrutinized using coarse-grained (CG) molecular dynamics simulations. Entangled but cross-link-free polymer clusters are generated by the semicrystalline lattice method for a wide range chain length of alkane modeled by CG beads, and tested under compressive and tensile stress with various temperature and strain rates. It has been found that the specific volume and volumetric thermal expansion coefficient decrease with the increase of chain length, where the specific volume is a linear function of the bond number to all bead number ratios, while the thermal expansion coefficient is a linear rational function of the ratio. Glass-transition temperature, however, does not seem to be sensitive to chain length. Yield stress under tension and compression increases with the increase of the bond number to all bead number ratio and strain rate as well as with decreasing temperature. The correlation found between chain length and these physical parameters suggests that the ratio dominates the mechanical properties of the present CG-modeled linear polymer material.

scholarly journals Measurement of Mechanical and Thermal Strains by Optical FBG Sensors Embedded in CFRP Rod

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Keunhee Cho ◽  
Sung Tae Kim ◽  
Young-Hwan Park ◽  
Jeong-Rae Cho
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Strain Sensor ◽  
Thermal And Mechanical Properties ◽  
Fbg Sensor ◽  
Thermal Test ◽  
Fbg Sensors ◽  
Thermooptic Coefficient

The present study intends to provide the photoelastic coefficient and thermal expansion coefficient needed to use an FBG-embedded CFRP rod (smart rod) as strain sensor. Due to the monolithic combination of the FBG sensor with a CFRP rod, the smart rod is likely to exhibit thermal and mechanical properties differing from those of the bare FBG sensor. A tensile test showed that the photoelastic coefficient of the smart rod is 0.204, which is about 7.3% lower than the 0.22 value of the bare optical FBG. Moreover, the thermal expansion coefficient of the smart rod obtained through a thermal test appeared to be negative with a low value of −0.190×10−6/°C. Consequently, the temperature dependence of the smart rod is mainly expressed by means of the thermooptic coefficient. Compared to the bare FBG sensor, the smart rod is easier to handle and can measure compressive strains, which make it a convenient sensor for various concrete structures.

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