The present paper proposes to use the group contribution (GC) polar perturbed-chain-statistical associating fluid theory (GC-PPC-SAFT) equation of state (EoS), that has already been used with success on various organic mixtures, and extend it to model simultaneously the liquidÀliquid equilibrium (LLE) and vaporÀliquid equilibrium (VLE) of hydrocarbons þ water systems, in wide ranges of pressure and temperature. Mixtures of water with aliphatics, aromatics, alcohols, carbon dioxide, and hydrogen sulfide have been investigated. Pure water is assumed associative (according to the 4C association scheme) and dipolar; the aromatic compounds are quadrupolar. Alcohols are autoassociative with a 3B association scheme. A cross-association between water and alcohols or H 2 S is taken into account. Cross association between water and other polar molecules (CO 2 or aromatic molecules) was also taken into account explicitly. Only one set of cross association parameters ε cross /k and k cross values were used for all the water þ aromatic mixtures considered here. ε cross /k was adjusted on experimental data, whereas k cross is set to the value found for pure water. For each system, the same binary interaction parameter k ij was used for simultaneous modeling LLE and VLE. This parameter was correlated to pseudo-ionization energy parameters for pure compounds through London's dispersion force theory, and reused from previous works [

A fully compressible four-equation model for multicomponent two-phase flow coupled with a realfluid phase equilibrium-solver is suggested. It is composed of two mass, one momentum, and one energy balance equations under the mechanical and thermal equilibrium assumptions. The multicomponent characteristics in both liquid and gas phases are considered. The thermodynamic properties are computed using a composite equation of state (EoS), in which each phase follows its own Peng-Robinson (PR) EoS in its range of convexity, and the two-phase mixtures are connected with a set of algebraic equilibrium constraints. The drawback of complex speed of sound region for the two-phase mixture is avoided using this composite EoS. The phase change is computed using a phase equilibrium-solver, in which the phase stability is examined by the Tangent Plane Distance (TPD) approach; an isoenergetic-isochoric (UVn) flash including an isothermal-isobaric (TPn) flash is applied to determine the phase change. This four-equation model has been implemented into an inhouse IFP-C3D software. Extensive comparisons between the four-equation model predictions, experimental measurements in flash boiling cases, as well as available numerical results were carried out, and good agreements have been obtained. The results demonstrated that this four-equation model can simulate the phase change and capture most real-fluid behaviors for multicomponent two-phase flows. Finally, this validated model was applied to investigate the behaviors of n-dodecane/nitrogen mixtures in one-dimensional shock and double-expansion tubes. The complex wave patterns were unraveled, and the effects of dissolved nitrogen and the volume translation in PR EoS on the wave evolutions were revealed. A three-dimensional transcritical fuel injection is finally simulated to highlight the performance of the proposed four-equation model for multidimensional flows.

The automobile industry currently faces the challenge of developing a new generation of diesel motor engines that satisfy both increasingly stringent emission regulations and reduces specific fuel consumption. The performance of diesel engines, seen in terms of emissions and specific fuel consumption, generally improves with increasing fuel-injection pressure. The design of the next generation of diesel fuel injection systems requires the knowledge of the thermophysical properties, in particular viscosity, of a wide-type of diesel fuels at pressures up to 300 MPa or more. The objective of the present work is to demonstrate that it is possible to predict the viscosity of any petroleum-based diesel fuel, using, exclusively, its molar fraction distribution as provided by multidimensional gas chromatography techniques. The precise knowledge of the fuel chemical constituents allows the understanding of the influence of the different hydrocarbon families on the fluid viscosity by means of molecular dynamics simulations. The accuracy of the Anisotropic United Atom force-field was tested and was found to be in agreement with experimental viscosities obtained with a new vibrating wire device at different temperatures and pressures up to 300 MPa. Finally, the experimental and simulated viscosities have been compared with improved group contribution method that has been coupled with gas chromatography experimental measurements for a viscosity prediction that was estimated to be of less than 18% of mean absolute deviation.

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The hydrogen solubility in 42 organic compounds including alcohols, aldehydes, carboxylic acid, esters and ethers, glycols, n-alkanes, and water is investigated. For this purpose, the Henry's constant is collected or computed from different sources. After removing incoherent data, two temperature correlations are proposed whenever possible. Their average deviation is consistent with experimental uncertainty between 5 % and 10 %. Further data reduction could then be performed by comparing the Henry's constant behavior among solvents. Monte Carlo molecular simulation is used to produce pseudoexperimental Henry's constant data at high temperature in 19 oxygen-bearing compounds such as alcohols, linear ketones, ethers, esters (573.15 K to 723.15 K) within average statistical uncertainties of 8 %. The molecular simulation results show the same trends as those of the experimental data. The database analysis shows that the hydrogen Henry's constants generally decrease with molecular weight and depend on chemical family in following way: H diols > H alcohols > H esters > H aldehydes > H ethers > H alkanes . It always decreases with temperature. The slope of ln H vs 1/T depends little on chemical family. At high temperature, a few experimental data confirm the observation of molecular simulation showing an increase of this slope.