scholarly journals Modeling of pure components high pressures densities using CK-SAFT and PC-SAFT equations

2018 ◽  
Vol 83 (3) ◽  
pp. 331-343
Author(s):  
Jovana Ilic-Pajic ◽  
Mirko Stijepovic ◽  
Gorica Ivanis ◽  
Ivona Radovic ◽  
Jasna Stajic-Trosic ◽  
...  
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Model Parameters ◽  
Calculated Density ◽  
Average Percentage ◽  
Pure Compounds ◽  
Density Values ◽  
Temperature And Pressure ◽  
Good Agreement

SAFT equations of state have been widely used for the determination of different thermo-physical and phase equilibria properties. In order to use these equations as predictive models it is necessary to calculate the model parameters. In this work CK-SAFT and PC-SAFT equations of state were applied for the correlation of pure compounds densities in the wide ranges of temperature and pressure (288.15?413.15 K and 0.1?60 MPa, respectively). The calculations of densities for n-hexane, n-heptane, n-octane, toluene, dichloromethane and ethanol, under high pressure conditions, were performed with the new sets of parameters determined in this paper by CK-SAFT and PC-SAFT. Very good agreement between experimental and calculated density values was achieved, having absolute average percentage deviations lower than 0.5 %.

Determination of derived volumetric properties and heat capacities at high pressures using two density scaling based equations of state. Application to dipentaerythritol hexa(3,5,5-trimethylhexanoate)

2018 ◽  
Vol 20 (5) ◽  
pp. 3531-3542 ◽  
Author(s):  
E. R. López ◽  
O. Fandiño ◽  
D. Cabaleiro ◽  
L. Lugo ◽  
J. Fernández
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Heat Capacities ◽  
Volumetric Properties ◽  
Complex Behavior ◽  
Derived Properties ◽  
Temperature And Pressure

Scaling based EoSs describe the complex behavior of derived properties for broad temperature and pressure ranges from diPEiC9 experimental densities.

Device Modeling of a-Si:H Alloy Solar Cells: Calibration Procedure for Determination of Model Input Parameters

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Zeman ◽  
R.A.C.M.M. Van Swaaij ◽  
E. Schroten ◽  
L.L.A. Vosteen ◽  
J.W. Metselaar
Keyword(s):  
Solar Cell ◽  
Material Properties ◽  
Calibration Procedure ◽  
Model Parameters ◽  
Model Input ◽  
A Value ◽  
Input Parameters ◽  
Simulated Material ◽  
Good Agreement

ABSTRACTA calibration procedure for determining the model input parameters of standard a-Si:H layers, which comprise a single junction a-Si:H solar cell, is presented. The calibration procedure consists of: i) deposition of the separate layers, ii) measurement of the material properties, iii) fitting the model parameters to match the measured properties, iv) simulation of test devices and comparison with experimental results. The inverse modeling procedure was used to extract values of the most influential model parameters by fitting the simulated material properties to the measured ones. In case of doped layers the extracted values of the characteristic energies of exponentially decaying tail states are much higher than the values reported in literature. Using the extracted values of model parameters a good agreement between the measured and calculated characteristics of a reference solar cell was reached. The presented procedure could not solve directly an important issue concerning a value of the mobility gap in a-Si:H alloys.

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: I. n-BUTANE

1938 ◽  
Vol 16b (5) ◽  
pp. 176-193 ◽  
Author(s):  
E. W. R. Steacie ◽  
I. E. Puddington
Keyword(s):  
Reaction Rate ◽  
High Pressures ◽  
The Other ◽  
First Order ◽  
Decomposition Reactions ◽  
Temperature And Pressure ◽  
Products Of Reaction ◽  
Kinetics Of ◽  
Good Agreement ◽  
Mechanism Of The Reaction

The kinetics of the thermal decomposition of n-butane has been investigated at pressures from 5 to 60 cm. and temperatures from 513 to 572 °C. The initial first order rate constants at high pressures are given by[Formula: see text]The results are in good agreement with the work of Frey and Hepp, but differ greatly from that of Paul and Marek. The reaction rate falls off strongly with diminishing pressure; this is rather surprising for a molecule as complex as butane. The first order constants in a given run fall rapidly as the reaction progresses. The last two facts suggest that chain processes may be involved.A large number of analyses of the products of reaction have been made at various pressures, temperatures, and stages of the reaction, the method being that of low-temperature fractional distillation. The products are virtually independent of temperature and pressure over the range investigated. The initial products, obtained by extrapolation to zero decomposition, are:—H2, 2.9; CH4, 33.9; C3H6, 33.9; C2H4, 15.2; C2H6, 14.1%. The mechanism of the reaction is discussed, and the results are compared with those of the other paraffin decompositions.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

scholarly journals Thermoelastic properties of magnesiowüstite, (Mg1−xFex)O: determination of the Anderson–Grüneisen parameter by time-of-flight neutron powder diffraction at simultaneous high pressures and temperatures

2008 ◽  
Vol 41 (5) ◽  
pp. 886-896 ◽  
Author(s):  
Ian G. Wood ◽  
Lidunka Vočadlo ◽  
David P. Dobson ◽  
G. David Price ◽  
A. D. Fortes ◽  
...  
Keyword(s):  
Equation Of State ◽  
Powder Diffraction ◽  
High Pressures ◽  
Equations Of State ◽  
Time Of Flight ◽  
Neutron Powder Diffraction ◽  
Grüneisen Parameter ◽  
Gruneisen Parameter ◽  
Measured State

The ability to perform neutron diffraction studies at simultaneous high pressures and high temperatures is a relatively recent development. The suitability of this technique for determiningP–V–Tequations of state has been investigated by measuring the lattice parameters of Mg1−xFexO (x= 0.2, 0.3, 0.4), in the rangeP < 10.3 GPa and 300 <T< 986 K, by time-of-flight neutron powder diffraction. Pressures were determined using metallic Fe as a marker and temperatures were measured by neutron absorption resonance radiography. Within the resolution of the experiment, no evidence was found for any change in the temperature derivative of the isothermal incompressibility, ∂KT/∂T, with composition. By assuming that the equation-of-state parameters either varied linearly or were invariant with composition, the 60 measured state points were fitted simultaneously to aP–V–T–xequation of state, leading to values of ∂KT/∂T= −0.024 (9) GPa K−1and of the isothermal Anderson–Grüneisen parameter δT= 4.0 (16) at 300 K. Two designs of simultaneous high-P/Tcell were employed during this study. It appears that, by virtue of its extended pressure range, a design using toroidal gaskets is more suitable for equation-of-state studies than is the system described by Le Godec, Dove, Francis, Kohn, Marshall, Pawley, Price, Redfern, Rhodes, Ross, Schofield, Schooneveld, Syfosse, Tucker & Welch [Mineral. Mag.(2001),65, 737–748].

Molecular dynamics approach for crystal structures of methane A and B

2017 ◽  
Vol 28 (04) ◽  
pp. 1750048 ◽  
Author(s):  
César G. Galván ◽  
José M. Cabrera-Trujillo ◽  
Ivonne J. Hernández-Hernández ◽  
Luis A. Pérez
Keyword(s):  
Molecular Dynamics ◽  
High Pressures ◽  
Force Fields ◽  
Recent Experimental Data ◽  
Reactive Force ◽  
Carbon Structures ◽  
Reactive Force Fields ◽  
Temperature And Pressure ◽  
Dynamics Simulations ◽  
Good Agreement

The carbon structures of phases A and B of methane are investigated through classical molecular dynamics simulations using optimized potentials for liquid simulations all-atom force fields as well as ReaxFF reactive force fields. Both final thermodynamic states were obtained by the proper ramping of temperature and pressure through well-known regions of methane’s phase diagram using the isothermal–isobaric (NPT) ensemble. Our calculated structures are in good agreement with very recent experimental data. The knowledge of these phases is the basis for the study of methane at high pressures.

scholarly journals Analysis of Heat Transfer through a Protective Clothing Package

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Paulina Gilewicz ◽  
Damian Obidowski ◽  
Krzysztof Sobczak ◽  
Iwona Frydrych ◽  
Agnieszka Cichocka
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Protective Clothing ◽  
Microscopic Level ◽  
Homogeneous Distribution ◽  
Model Parameters ◽  
High Quality ◽  
Measurement Results ◽  
Good Agreement

Abstract The protective clothing packages, which protect the human body against hot factors in a foundry are in continuous development to increase their resistance and comfort of use. The problem of heat transfer through textiles is the active field of research and reliable numerical modeling of this process can be helpful to design high-quality protective products. Therefore, the numerical model of heat transfer through the package based on the aluminized basalt fabric was developed. The macroscopic geometry of weft and warp threads was reproduced in agreement with samples of plain weave basalt fabric. Mapping the stochastically distributed individual monofilaments in basalt threads, as well as modeling the heat transfer between them, was impossible at the microscopic level. Therefore, the weft and warp threads were modeled as a porous material with a homogeneous distribution of basalt and air in their structure. Data from measurements of the bare and aluminized basalt fabrics by the Alambeta device were used to determine the model parameters. The model was used to simulate the heat transfer through the protective package composed of the aluminized basalt fabric, wool clothing, and cotton underwear. A good agreement of model results was found for measurement results in such a package. The presented procedure allowed for the determination of the main thermal properties of tested basalt fabrics.

Measurements of Decompression Wave Speed in Binary Mixtures of Carbon Dioxide and Impurities

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
B. Rothwell ◽  
T. Robinson
Keyword(s):  
Binary Mixtures ◽  
Wave Speed ◽  
Equations Of State ◽  
Propagation Speed ◽  
Plateau Pressure ◽  
Wave Speeds ◽  
Decompression Wave ◽  
Arrest Toughness ◽  
Good Agreement

Shock tube tests were conducted on a number of binary CO2 mixtures with N2, O2, CH4, H2, CO, and Ar impurities, from a range of initial pressures and temperatures. This paper provides examples of results from these tests. The resulting decompression wave speeds are compared with predictions made utilizing different equations of state (EOS). It was found that, for the most part (except for binaries with H2), the GERG-2008 EOS shows much better performance than the Peng–Robinson (PR) EOS. All binaries showed a very long plateau in the decompression wave speed curves. It was also shown that tangency of the fracture propagation speed curve would normally occur on the pressure plateau, and hence, the accuracy of the calculated arrest toughness for pipelines transporting these binary mixtures is highly dependent on the accuracy of the predicted plateau pressure. Again, for the most part, GERG-2008 predictions of the plateau are in good agreement with the measurements in binary mixtures with N2, O2, and CH4. An example of the determination of pipeline material toughness required to arrest ductile fracture is presented, which shows that prediction by GERG-2008 is generally more conservative and is therefore recommended. However, both GERG-2008 and PR EOS show much worse performance for the other three binaries: CO2 + H2, CO2 + CO, and CO2 + Ar, with CO2 + H2 being the worst. This is likely due to the lack of experimental data for these three binary mixtures that were used in the development of these EOS.

scholarly journals Determining gas rate distribution from temperature and pressure profiles in gas well

2012 ◽  
Vol 16 (5) ◽  
pp. 1339-1343 ◽  
Author(s):  
Emile Barrett ◽  
Imran Abbasy ◽  
Chii-Rong Wu ◽  
Zhenjiang You ◽  
Pavel Bedrikovetsky
Keyword(s):  
Inverse Problem ◽  
Flow Rate ◽  
Field Data ◽  
Pressure Data ◽  
Gas Well ◽  
Temperature Distributions ◽  
Pressure Profiles ◽  
Temperature And Pressure ◽  
Good Agreement

A simple and effective method of the gas rate prediction from temperature and pressure data is discussed in this paper. Solving the inverse problem allows determination of the flow rate by matching the gas pressure and temperature distributions with measured profiles. Results of field data treatment show good agreement with the model prediction.

Using the jominy end-quench test for validation of thermo-metallurgical model parameters

2004 ◽  
Vol 120 ◽  
pp. 571-579
Author(s):  
M. Hunkel ◽  
Th. Lübben ◽  
F. Hoffmann ◽  
P. Mayr
Keyword(s):  
Heat Transfer ◽  
Model Parameters ◽  
Simulation Testing ◽  
Peripheral Surface ◽  
Quench Test ◽  
Good Agreement

One of the most popular tests to determine the hardenability of steels is the Jominy-End-Quench-Test. Moreover this test is useful for simulation testing, too. In this paper the determination of heat transfer fluxes over the quenched surface as well as over the peripheral surface is described. The result is used for simulations of the Jominy-End-Quench-Test for two melts of SAE 52100 (100 Cr 6). One of these was taken from literature, one was used for experiments in IWT. Though transformation behaviors differ in an extreme way, the Jominy-End-Quench-Test can be simulated for both steels with good agreement between simulation and measurement.

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