Academic literature on the topic 'Single particle regime binary mixtures'

This study systematically investigates the pressure fluctuation in the riser of a dual interconnected circulating fluidized bed (CFB) representing a 10 kWth cold-flow model (CFM) of a chemical-looping combustion (CLC) system. Specifically, a single-species system (SSS) and a binary-mixtures system (BMS) of particles with different sizes and densities were utilized. The pressure fluctuation was analyzed using the fast Fourier transform (FFT) method. The effect of introducing a second particle, changing the inventory, composition (i.e., 5, 10 to 20 wt.%), particle size ratio, and fluidization velocity were investigated. For typical SSS experiments, the results were similar to those scarcely reported in the literature, where the pressure fluctuation intensity was influenced by varying the initial operating conditions. The pressure fluctuations of BMS were investigated in detail and compared with those obtained from SSS experiments. BMS exhibited different behaviour; it had intense pressure fluctuation in the air reactor and in the riser when compared to SSS experiments. The standard deviation (SD) of the pressure fluctuation was found to be influenced by the fluidization regime and initial operating conditions, while the power spectrum density (PSD) values were more sensitive to the presence of the particles with the higher terminal velocity in the binary mixture.

Abstract Mixed PbcSn1-c(CH3)4 samples with c = 0.0, 0.1, 0.2,0.25, 0.48, 0.5, 0.75,0.85, and 1.0 and mixed [Pb(CH3)4](.[Sn(CD3)4]1-c. samples with c = 0.02 and 0.09 were investigated by high resolution inelastic neutron scattering. Rotational tunnelling transitions are observed for energy transfers hω<100 μeV. The global features are interpreted in a single particle model. A strong matrix effect of the Pb component is attributed to changes of potential symmetry. Effects beyond the expectation of the single particle description are found

The phase separation of two-dimensional fluid mixtures was investigated with Molecular Dynamics simulations. The behavior of both single-component and binary mixtures as a function of temperature, volume fraction and average fluid density was studied. Binary systems with a size mismatch were also considered. In all cases, the diffusive coalescence of clusters is the primary mechanism of growth. In binary systems, the shape transformations of merging droplets induce important long-range flows at high volume fractions.

Fluidization behavior of binary mixtures with titanic slag particles and carbon particles had been investigated. Three solids states in the bed: fixed bed, transient fluidization and steady fluidization, emerges as increasing gas velocity. The extent of segregation of solids mixture in transient fluidization regime depended on the size difference between jetsam particles and flotsam particles. The effects of flotsam particle size, initial jetsam concentration and the superficial gas velocity on the segregation of binary solids had been measured.

Marangoni convection in a differentially heated binary mixture is studied numerically by continuation. The fluid is subject to the Soret effect and is contained in a two-dimensional small-aspect-ratio rectangular cavity with one undeformable free surface. Either or both of the temperature and concentration gradients may be destabilizing; all three possibilities are considered. A spectral-element time-stepping code is adapted to calculate bifurcation points and solution branches via Newton's method. Linear thresholds are compared to those obtained for a pure fluid. It is found that for large enough Soret coefficient, convection is initiated predominantly by solutal effects and leads to a single large roll. Computed bifurcation diagrams show a marked transition from a weakly convective Soret regime to a strongly convective Marangoni regime when the threshold for pure fluid thermal convection is passed. The presence of many secondary bifurcations means that the mode of convection at the onset of instability is often observed only over a small range of Marangoni number. In particular, two-roll states with up-flow at the centre succeed one-roll states via a well-defined sequence of bifurcations. When convection is oscillatory at onset, the limit cycle is quickly destroyed by a global (infinite-period) bifurcation leading to subcritical steady convection.

Some binary mixtures, such as specific alcohol–alkane mixtures or even water–tbutanol, exhibit two humps “camel back” shaped Kirkwood–Buff integrals (KBIs). This is in sharp contrast with the usual KBIs of binary mixtures having a single extremum. This extremum is interpreted as the region of maximum concentration fluctuations, usually occurs in binary mixtures presenting appreciable micro-segregation, and corresponds to where the mixture exhibits a percolation of the two species domains. In this paper, it is shown that two extrema occur in binary mixtures when one species forms “meta-particle” aggregates, the latter acts as a meta-species, and they have their own concentration fluctuations, hence their own KBI extremum. This “meta-extremum” occurs at a low concentration of the aggregate-forming species (such as alcohol in alkane) and is independent of the other usual extremum observed at mid-volume fraction occupancy. These systems are a good illustration of the concept of the duality between concentration fluctuations and micro-segregation.

Abstract. A series of experiments was designed and conducted in the Manchester Aerosol Chamber (MAC) to study the photo-oxidation of single and mixed biogenic (isoprene and α-pinene) and anthropogenic (o-cresol) precursors in the presence of NOx and ammonium sulfate seed particles. Several online techniques (HR-ToF-AMS, semi-continuous GC-MS, NOx and O3 analyser) were coupled to the MAC to monitor the gas and particle mass concentrations. Secondary organic aerosol (SOA) particles were collected onto a quartz-fibre filter at the end of each experiment and analysed using liquid chromatography–ultrahigh-resolution mass spectrometry (LC-Orbitrap MS). The SOA particle chemical composition in single and mixed precursor systems was investigated using non-targeted accurate mass analysis of measurements in both negative and positive ionization modes, significantly reducing data complexity and analysis time, thereby providing a more complete assessment of the chemical composition. This non-targeted analysis is not widely used in environmental science and has never been previously used in atmospheric simulation chamber studies. Products from α-pinene were found to dominate the binary mixed α-pinene–isoprene system in terms of signal contributed and the number of particle components detected. Isoprene photo-oxidation was found to generate negligible SOA particle mass under the investigated experimental conditions, and isoprene-derived products made a negligible contribution to particle composition in the α-pinene–isoprene system. No compounds uniquely found in this system sufficiently contributed to be reliably considered a tracer compound for the mixture. Methyl-nitrocatechol isomers (C7H7NO4) and methyl-nitrophenol (C7H7NO3) from o-cresol oxidation made dominant contributions to the SOA particle composition in both the o-cresol–isoprene and o-cresol–α-pinene binary systems in negative ionization mode. In contrast, interactions in the oxidation mechanisms led to the formation of compounds uniquely found in the mixed o-cresol-containing binary systems in positive ionization mode. C9H11NO and C8H8O10 made large signal contributions in the o-cresol–isoprene binary system. The SOA molecular composition in the o-cresol–α-pinene system in positive ionization mode is mainly driven by the high-molecular-weight compounds (e.g. C20H31NO4 and C20H30O3) uniquely found in the mixture. The SOA particle chemical composition formed in the ternary system is more complex. The molecular composition and signal abundance are both markedly similar to those in the single α-pinene system in positive ionization mode, with major contributions from o-cresol products in negative ionization mode.

An investigation of charging a spherical particle in partially ionized nonisothermal plasma is carried out on the basis of the numerical solution of the BGK (Bhatnagar–Gross–Krook) model kinetic equation. Stationary values of the particle charge and the electron and ion currents are calculated for various collisional regimes. It is verified that, for the strongly collisional regime, the effective potential has a Coulomb form at large distance from the particle surface. A new BGK-type model for binary gas mixtures is proposed. It is shown that this model satisfies all the basic properties of Boltzmann collision integrals including the correct exchange coefficients. A high-order implicit numerical method for solving the kinetic equations is developed. The method is conservative with respect to the collision integrals for arbitrary values of the Knudsen number.

Crystallization is fundamental to materials science and is central to a variety of applications, ranging from the fabrication of silicon wafers for microelectronics to the determination of protein structures. The basic picture is that a crystal nucleates from a homogeneous fluid by a spontaneous fluctuation that kicks the system over a single free-energy barrier. However, it is becoming apparent that nucleation is often more complicated than this simple picture and, instead, can proceed via multiple transformations of metastable structures along the pathway to the thermodynamic minimum. In this article, we observe, characterize, and model crystallization pathways using DNA-coated colloids. We use optical microscopy to investigate the crystallization of a binary colloidal mixture with single-particle resolution. We observe classical one-step pathways and nonclassical two-step pathways that proceed via a solid–solid transformation of a crystal intermediate. We also use enhanced sampling to compute the free-energy landscapes corresponding to our experiments and show that both one- and two-step pathways are driven by thermodynamics alone. Specifically, the two-step solid–solid transition is governed by a competition between two different crystal phases with free energies that depend on the crystal size. These results extend our understanding of available pathways to crystallization, by showing that size-dependent thermodynamic forces can produce pathways with multiple crystal phases that interconvert without free-energy barriers and could provide approaches to controlling the self-assembly of materials made from colloids.

2008/2009
This thesis is aimed to the study of dynamics in binary fluid mixtures by means of inelastic scattering spectroscopies. Nowadays the understanding of these dynamics is still unsatisfactory. In particular, any model is able to adequately describe collective dynamics beyond the hydrodynamic limit. In such a low momentum (k) and frequency () transfer limit, the collective dynamics is characterized by a single (adiabatic) longitudinal acoustic mode accounting for sound propagation. At frequencies above the hydrodynamics ones a transition towards a decoupled dynamic regime is expected. This is characterized by two distinct modes, namely the slow (low-) and fast (high-) sounds. The microscopic mechanisms driving such a transition, so as the related macroscopic quantities, are still unclear, even in an heuristic point of view. In this work the collective dynamics of neutral and ionic mixtures are investigated with the aim to shed light in this debated issue. He/Ne mixtures have been studied by means of Inelastic X-ray Scattering (IXS) spectroscopy. Exploiting the lack of kinematic limitations peculiar of this technique, the high frequency (>THz) dynamics has been analyzed from the mesoscopic up to the high-k range, where the dynamic response of the system can be described using the Impulse Approximation (IA). This kind of study is of particular interest for disparate mass mixtures, since inefficient kinetic energy exchanges between light and heavy particles taking place on very short time scales are expected to greatly influence the phenomenology of the aforementioned dynamic decoupling. The prototype ionic mixture, RbF, also, has been investigated by means of Inelastic Neutron Scattering (INS) spectroscopy. Ionic mixtures are particularly suited to investigate the role played by optic-like excitations (related to concentration fluctuations) in the transition from the hydrodynamics to the decoupled regime. Indeed, these kind of excitations are expected to be emphasized because of the long range Coulomb interactions. Conversely at k’s enough high, i.e. k>k* with k* dependent on the values of the electric conduction coefficient and the adiabatic sound velocity, they are expected to behave like neutral binary mixtures. The study of molten RbF has been, then, focused on the characterization of collective dynamics in the transition region, which is more difficultly accessible by IXS because of instrumental limitations. IXS data on He0.8Ne0.2 mixture have been analyzed using a generalization of the viscoelastic function, which, in our knowledge, has been applied for the first time to this purpose. This kind of data analysis permitted to extrapolate the partial dynamical structure factors related to He-He, Ne-Ne and He-Ne density fluctuations. The adiabatic and high frequency sound velocity as well as the relaxation time associated to each mixture component has been calculated from fitting parameters. The analysis of the extrapolated relaxation times permitted to define, in the probed range, two k-region depending on the behavior of such quantity. At the higher k probed the relaxation times of single components can be well described by the respective single specie collision time, indicating a complete dynamics decoupling. At lower k, conversely, the relaxation times show a deviation to respect the collisional times. The study of the same mixture in three different thermodynamic conditions, revealed a common k trend of the single component relaxation times once proper normalization, made by means of kinetic parameters, has been done. An empirical expression has then been proposed. The result can be interpreted in the framework of ‘two temperature theory’, based on the assumption that in disparate mass binary mixtures inefficient kinetic energy exchanges induce a two step process for the relaxation of density fluctuations towards the thermodynamic equilibrium. These processes are characterized by two distinct timescales: the intra-specie collision time, where each specie subsystem reaches a condition of ‘local’ equilibrium associated with a ‘local’ temperature and a characteristic time for the equilibration of the microscopic temperatures to the thermodynamic temperature trough inter-specie collisions. A further corroboration of the above picture has been found from the analysis of IXS spectra in the IA region, which allowed extrapolating the momentum distribution functions of the specie subsets. An anomalous behavior has been noticed on the He momentum distribution function, i.e. the apparent temperature associated to the momentum distribution is about 40 K higher than the macroscopic one. This striking result can be straightforwardly interpreted as a fingerprint of the peculiar ‘two temperature’ equilibration process. INS experiment on molten RbF permitted to reveal the simultaneous presence of two dispersive collective modes in the transition region. The dispersive behavior (linear with k) and the characteristic energies permitted to exclude an optic-like nature for both excitations. The performed data analysis permitted also to extrapolate the value of the electrical conduction coefficient, founding a quite low value as compared with typical values of molten salts. An estimation of k* for the studied system emphasize the possibility that at the probed k it may be isomorphous to a neutral mixture. The observed phenomenology can be thus interpreted in terms of double sound propagation phenomenon, observed in rarefied non-ionic gaseous mixtures. Finally, an alternative interpretation of these experimental results can be qualitatively provided within the frame of the generalized collective mode approach. In this case the high frequency mode is identified with the extension of the adiabatic longitudinal sound mode beyond hydrodynamic limit that, in analogy to what observed in several fluids, follows a linear dispersion with an associated sound velocity larger than the adiabatic one. The low frequency mode could instead be associated with a propagating kinetic mode related to energy fluctuations (heat waves). In conclusion, an extensive analysis of high-frequency dynamics in binary mixtures has been reported. Particular emphasis has been devoted to the study of the sound decoupling phenomenon manifesting beyond the hydrodynamic region. The experimental results indicate that such a phenomenon is manifested in both neutral and ionic disparate mass binary mixtures. It can be related to microscopic dynamics, e.g. thermalization effects related to the inefficient kinetic exchange between lighter and heavier particles.
XXI Ciclo
1978

Discrete Element Modelling has been successfully applied in combination with fluid flow solvers (CFD) to tackle important multi-phase process engineering problems. However, until recently most of the DEM-CFD studies have dealt with monodisperse particulate systems. The reason for that is that DEM requires knowledge of the force exerted by the flowing fluid on each particle. While numerous expressions are available for homogenous systems, the presence of size polydispersion or the presence of solids mixtures complicate particle-level formulations of the drag force considerably and a general model is still lacking. In the present contribution a drag force model for polydisperse system is introduced and discussed. The expression was originally proposed in the literature on the basis of lattice-Boltzmann simulation results for flow through random polydisperse systems. However, its theoretical foundations were not fully recognised. The proposed formula requires the introduction of an average diameter, whose definition will be proved to be rigorously derivable provided that appropriate consistency constraints are considered. No other fitting or adjustable parameters are involved. In the case of a binary mixture of differently sized particles the resulting drag force is shown to depend both on size ratio and local volume fraction of the solids. Such precious particle-level information is then shown to be extendable to the macroscopic scale with attractive potentialities. On this basis, solution to the (open) problem of the segregation direction in a gas-fluidized bed of binary solids endowed with contrasting density and size differences will be suggested.

This paper compares the numerically predicted steady state, laminar hydrodynamic and thermal fields of an ice slurry (water with 15% ethanol and 12.26% ice particles) and a homogeneous binary, single phase mixture (water with 17.1% ethanol) entering identical constant temperature tubes (Tw = 274.16 K) with the same temperature (T0 = 264.16 K) and Reynolds numbers (Re = 500). The isothermal length of the tube is preceded and followed by adiabatic zones. The fluids are considered to be Newtonian and the governing partial differential equations are coupled since their properties depend on the temperature and, in the case of the ice slurry, on the ice concentration which is not uniform due to heat transfer. The results show significant differences between local values of the wall shear stress, the friction factor, the bulk temperature and the Nusselt number of these two flows. Specifically, the local Nusselt number for the ice slurry is higher throughout the developing region and its bulk temperature decreases in the downstream adiabatic zone due to radial conduction and an axial increase of the bulk ice concentration.

The enthalpy-porosity technique is used in this study for numerical modeling of solidification of water and binary mixture of ammonium chloride and water (NH4Cl-H2O). A two-dimensional geometry was used to simulate the solidification process in the rectangular and trapezoidal cavities. The liquid fraction is computed based on an enthalpy balance. The mushy zone is modeled as pseudo-porous medium in which the porosity decreases from 1 (liquid) to 0 (solid) as the material solidifies. The solidification with single side cooled wall as well as both cooled side walls was investigated. The frozen layer thickness, the convective flow patterns, and the temperature distribution were obtained. The results obtained in the course of the study showed that the shape of the solid region and the convection pattern in the melt region compare well with experimental data obtained by Particle Image Velocimetry technique. The enthalpy-porosity model is predicting well the flow pattern and the thickness of the frozen layer.

Abstract In this study, two sizes of iron and stainless steel powders were binarily mixed into four groups with different weight percent fractions and the various mixtures and single-component powders were cold sprayed onto aluminum substrates. The deposition efficiencies (DE) of the powder mixtures and single-component powders were measured and are compared. The results show that the four binary mixtures exhibit different DE characteristics as a function of stainless steel wt% and that the small size mixtures have higher DE relative to the single-component iron powder. The difference is explained by particle-particle interactions (tamping and retention) that occur upon impact and only in the small size mixtures. The study also finds that changing spray parameters, such as feed rate, stand-off distance, gun travel speed, and gas temperature and pressure, has no effect on particle-particle interactions.

The hydrodynamics of fluidized beds involving gas and particle interactions are very complex and must be carefully considered when using computational fluid dynamics (CFD). Modeling particle interactions are even more challenging for binary mixtures composed of varying particle characteristics such as diameter or density. One issue is the presence of dead-zones, regions of particles that do not fluidize and accumulate at the bottom, affecting uniform fluidization. In Eulerian-Eulerian modeling, the solid phase is assumed to behave like a fluid and the presence of dead zones are not typically captured in a simulation. Instead, the entire bed mass present in an experiment is modeled, which assumes full fluidization. The paper will present modeling approaches that account for only the fluidizing mass by adjusting the initial mass present in the bed using pressure drop and minimum fluidization velocity from experiments. In order to demonstrate the fidelity of the new modeling approach, different bed materials are examined. Binary mixture models are also validated for two types of mixtures consisting of glass-ceramic and ceramic-ceramic compositions. It will be shown that adjusting the mass in the modeling of fluidized beds best represents the measured quantities of an experiment for both single-phase and binary mixtures.

Abstract In this study, 43 μm 316L stainless steel and 23 μm commercial purity Fe feedstocks were used. The following coatings were made by cold spray: single component 316L, Fe, and their binary composites with nominal compositions of 20 wt.% Fe (20Fe), 50 wt.% Fe (50Fe) and 80 wt.% Fe (80Fe). The coatings were characterized (microstructure, flattening ratio, composition) and the cold sprayability metrics (DE, porosity, coating cohesion strength) were analyzed. Results show that the single component 316L coating has a much better DE and coating cohesion strength, and a slightly lower porosity as compared with the Fe coating, whereas all the composite coatings have the similar cohesion strength. Moreover, the 20Fe coating features the highest porosity and the lowest DE; 50Fe coating features the lowest porosity; and the 80Fe coating features the highest DE. To characterize the feedstock mixture composition, in addition to the usual approach of weight or volume fraction, the ratio of the 316L and Fe particle numbers in a mixture (i.e. particle number fraction), was calculated. Using this metric, the effects of the feedstock mixing composition on the cold sprayability of bimodal size 316L/Fe powder mixtures can be better explained.

Evaporative cooling, which exploits the large latent heats associated with phase change, is of interest in a variety of thermal management technologies. Yet our fundamental understanding of thermal and mass transport remains limited. Evaporation and condensation can change the local temperature, and hence surface tension, along a liquid-vapor interface. The resulting thermocapillary stresses are dominant at small length scales in many cases. For the vast majority of single-component coolants, surface tension decreases as temperature increases, resulting in thermocapillary stresses that drive the liquid away from hot regions, leading to dryout, for example. The direction of flow driven by thermocapillary stresses is therefore consistent with that driven by buoyancy effects due to changes in the liquid density with temperature. However, a number of binary “self-rewetting fluids,” consisting of water-alcohol mixtures, have surface tensions that increase with temperature, leading to thermocapillary stresses that drive liquid towards hot regions, improving cooling performance. Although not all binary coolants are self-rewetting, all such coolants are subject to solutocapillary stresses, where differential evaporation of the two fluid components leads to changes in local species concentration at the liquid-vapor interface, and hence in surface tension. Given the lack of general models of thermal and mass transport in nonisothermal two-phase flows, experimental studies of convection in simple fluids and binary alcohol-water mixtures due to evaporation and condensation driven by a horizontal temperature gradient were performed. In these initial studies, both the simple and binary fluids have thermocapillary stresses that drive liquid away from hot regions. However, the binary fluid also has solutocapillary stresses that drive liquid towards hot regions. Particle-image velocimetry (PIV) is used to nonintrusively measure the velocity and temperature fields in a layer of liquid a few mm in depth in a 1 cm × 1 cm × 4.85 cm sealed and evacuated cuvette heated on one end and cooled on the other end.

In this study, seven drag models are examined to determine how they affect fluidization behavior of Geldart A particles of biomass and coal. Notwithstanding the notable number of numerical studies to find the best drag model for larger particles, there is a dearth of information related to drag models for finer Geldart A particles. Additionally, to our knowledge, these drag models have not been tested with a binary mixture of Geldart A particles. Computational fluid dynamics was used to model the gas and solid phases in an Eulerian-Eulerain approach to simulate the particle-particle interactions of coal-biomass mixtures and compare the predictions with experimental data. In spite of the previous findings that bode badly for using predominately Geldart B drag models for fine particles, the results of our study reveal that if static regions of mass in the fluidized beds are considered, these drag models work well with Geldart A particles. It was found that the seven drag models could be divided into two categories based on their performance. One category included the Gidaspow family of drag models (Gidaspow, Gidaspow-Blend, and Wen-Yu) and the Syamlal-O’Brien drag model; these models closely predicted the experiments for single solids phase fluidization. For binary mixtures, however, the other drag model group (BVK, HYS, Koch and Hill) yielded better predictions.

A variety of LDV experiments were conducted to assess the influence of solids loading, Reynolds number and particle size distribution on velocity fluctuations and flow behavior in gas-particle systems. This talk will summarize those experimental findings, as well as show comparisons of experimental results with multiphase CFD model predictions that utilize concepts from kinetic theory to describe particle velocity fluctuations. In order to probe solids loading effects, an axisymmetric particle-laden jet was investigated using LDV for 70 micron glass beads with solids loadings ranging from one to thirty. Dilute conditions are characterized by isotropic particle r.m.s. velocities and decreases in the magnitude of the r.m.s. velocities as the solids loading increases. Particle clustering is observed for dense conditions as well as anisotropy between axial and radial particle r.m.s. velocities. Under dense conditions, increases in the solids loading lead to increases in the axial particle r.m.s. velocity while the radial r.m.s. velocity remains at a constant level. Gas-solids flow models display good agreement between predictions and experimental measurements of mean velocities of the gas and solids as well as modulation of the gas turbulent kinetic energy by the presence of the particles. However, the gas-solid flow models based on kinetic theory concepts consistently overpredict the particle r.m.s. velocity for the range of solids loadings investigated. In addition, the same axisymmetric particle-laden jet consisting of 70-micron glass beads was investigated for a range of Reynolds numbers with a constant mass loading (m = 0.7). The presence of the solids dampens the gas turbulence intensity at the lowest value of Re investigated (8,300) compared with single-phase flow at the same Re. As the Reynolds number increases, the gas turbulence increases and for Re ≥ 15,200 the turbulence is enhanced compared with the single-phase flow at the same Re. The observed trend in turbulence modulation with Reynolds number is possibly due to the segregation of the solids and their effect on the gas mean velocity profiles. Finally, the particle-laden jet was investigated for binary mixtures of 25 and 70-micron glass beads. Specifically, the effect of a bimodal PSD on the modulation of gas-phase turbulence, the particle rms velocity, and particle segregation patterns was explored in detail. Measurements and model predictions indicate that increasing the mass fraction of the finer particles dampens the gas-phase turbulence. Changes in the random motion of the coarser particles are observed upon the addition of the finer material; clusters of fine particles arise for the largest solids loading investigated, and these clusters increase both the mean and fluctuating velocities of the coarse particles. The particles are also observed to segregate by size and volume fraction, with the coarse particles tending towards the center of the pipe.

Abstract The cyclic solvent (gas) injection has been proved as an economical and effective method to enhance oil recovery in ultratight reservoirs such as shales. However, accurate modeling of cyclic solvent injection has been challenging due to the complex nature of fluid transport in nanopores. Most models are developed based on Darcy's and Fick's laws, which do not capture some critical transport phenomena within nanopores at elevated pressure. Accordingly, we propose a predictive model encapsulating the essential transport mechanisms for cyclic solvent injection in ultratight reservoirs. The model adopts the binary friction concept to incorporate friction between different molecules as well as molecules and pore walls. The Maxwell-Stefan approach is employed to account for the friction among species. The friction between molecules and pore walls is incorporated through partial viscosity and Knudsen diffusivity. A general driving force, chemical potential gradient, and the compressibility factor are used for the high-pressure non-ideal fluid mixture. The Peng-Robinson equation of state with confinement effect is used for the phase behavior calculations. The total flux consists of multicomponent molecular diffusion flux resulting from the chemical potential gradient and pressure diffusion flux driven by the pressure gradient. The governing equations for composition and pressure are solved implicitly using the finite difference method. The developed model is validated against analytical solutions and laboratory experiments. The primary production and solvent injection process are then simulated for a trinary oil (CH4, C4H10, and C12H26) and two solvent types, including CH4 and CO2. The results show that hydrocarbon components’ transport in the vapor phase is much higher than in the liquid phase. Accordingly, light and heavy components are produced at different fluxes during primary production because the vapor phase mainly consists of lighter components. For the single-cycle solvent injection cases, both CO2 and CH4 improve hydrocarbon recovery, with CO2 slightly performing better than CH4. This is attributed to CO2's ability to extract more heavy components into the vapor phase, producing more heavy components within the vapor phase. The recovery factor of heavy components of CO2 injection (3.40%) is higher than that of CH4 injection (3.21%). For multi-cycle solvent injection cases, CO2 injection can improve hydrocarbon recovery with a 2.77% increment, slightly better than multi-cyclic CH4 injection with a 2.73% increment. The injected CO2 can extract more heavy components near the fracture. However, the injected CH4 can penetrate deeper into the matrix to extract more light components within a more extensive region.