Ion Fluid Research Articles

Transport Properties in Nanochannels: Ionic Size-, Permittivity-, and Viscosity-Related Effects

The transport properties in nanochannels are examined using a modified electrokinetic model (MEM) that takes into account the finite ion size by modeling the hydrated ions as charged dielectric spheres so that the electrolyte solution becomes a nonhomogeneous fluid characterized by permittivity and viscosity values that are both functions of the local ionic concentrations. We show that the simultaneous consideration of ionic size, permittivity, and viscosity effects always improve on the predictions of the standard electrokinetic model for point-like ions (SEM), with corrections that are significant in the nanofluidic system’s parameter range. The results reported herein are expected to provide a deeper understanding of the ion transport and fluid flow in nanofluidic devices.

Theoretical investigation of electroviscous flows in hydrophilic slit nanopores: Effects of ion concentration and pore size

Nanopores with various shapes are well developed in unconventional reservoirs, and the transport phenomena of solutions in these reservoir rocks are ubiquitous but have not yet been fully understood. This article investigates the flow characteristics of solutions in hydrophilic slit nanopores through the combination of a modified Poisson–Boltzmann (MPB) model and the modified Navier–Stokes (NS) equation. To account for the nanoconfinement effects on ion concentration and fluid viscosity, an electrochemical potential term is used in the MPB model and a varying viscosity model (VVM) is introduced in the NS equation. The model rationality is first confirmed, and then the influences of ion concentration and pore size on the transport capacities of solutions in nanopores are illuminated. In addition, the hydrodynamic features of liquids in nanopores and the limitations of this coupled model are discussed as well. The results show that the dimensionless apparent permeability of the slit increases with an increase in ion concentration and pore size. The relative contributions of the electroviscous effect (EVE) and VVM to the total flow resistance reveal different varying trends as ion concentration or pore size increases, which is greatly related to the surface charge density and the sign of the charged wall. Additionally, although the effects of EVE and VVM resulting from the nanoconfinement are considered, average velocities of fluids in nanopores exhibit a linear correlation with the pressure gradient, which cannot be used to explain the nonlinear flow mechanism occurring in tight reservoirs. Furthermore, we also compare the velocity difference between the classical PB and MPB models. We hope that the findings in this work can help improve our understanding of the characteristics of liquid flow in tight reservoirs and provide vital practical implications for diverse engineering applications.

Electrokinetic ion transport and fluid flow in a pH-regulated polymer-grafted nanochannel filled with power-law fluid.

In this article, we have discussed extensively electrokinetic ion transport and fluid flow through a slit polymer-grafted nanochannel filled with power-law fluid. The rigid walls of the channel are coated with the ion and fluid penetrable polymer layer containing a pH-regulated zwitterionic functional group (e.g., succinoglycan). The mathematical model is based on the non-linear Poisson-Boltzmann equation for electric double layer potential and the flow field within the polymer layer is governed by a modified Darcy-Brinkman equation; the Cauchy momentum equation governs the fluid flow outside of the polymer layer along with the equation of continuity for incompressible fluid. In order to consider a wide range of pertinent parameters, we adopt a finite difference based numerical tool to solve the coupled set of governing equations. We have analyzed several interesting features of electrokinetic transport phenomena through such a polymer-grafted nanochannel for a wide range of electrostatic and hydrodynamic properties of the polymer layer, parameters describing the non-Newtonian rheology of the background fluid, and the pH and concentration of the bulk electrolyte. In addition, we have also illustrated the ionic current across the undertaken nanochannel and observed that it can be either cation selective, anion selective or non-selective, depending on the critical choice of the pertinent parameters.

Modulational instability of dust-ion acoustic waves in the presence of generalized (r, q) distributed electrons

We have investigated the modulational instability (MI) of dust-ion acoustic waves in a dusty plasma model containing warm ions fluid, generalized (r, q) distributed electrons, and immobile dust grains. Using the Krylov-Bogoliubov-Mitropolsky method, the amplitude modulation of a monochromatic plane wave is analyzed through derivation of a nonlinear Schrödinger equation. The MI condition is calculated. Moreover, the effects of the plasma parameters such as the ion-to-electron temperature ratio, the wavenumber, and the unperturbed dust-to-electron number density ratio as well as the electron distribution dual parameters (r, q) are discussed. Our investigations have shown that the unstable region is bounded by two stable regions, i.e., two critical wavenumbers [kcl(lower) and kch(higher)] are found. The applications of the present theoretical study are briefly discussed in space physics whether positive or negative dust grains are enclosed.

Lactic-based Novel Amine Ionic Liquid: Synthesis and Characterization of [DEA][Lac

In this study, a novel amine ionic liquid “Diethanolamine Lactic” [DEA][Lac] was synthesized. The replacement of halogenated ion fluid was used as a modified methodology for the preparation of diethanolamine based on lactic acid. The ionic liquid was characterized using the Fourier transform infrared (FTIR) spectra and the nuclear magnetic resonance (NMR) spectroscopy. The changes in bands' wavelengths and the peaks of the participating elements and process materials have been confirmed before and after synthesis based on the results of FTIR analysis which demonstrate the successful synthesis of diethanolamine lactic. The NMR analysis also clearly confirms the synthesis of diethanolamine lactic acid. Analysis results were shown in the successful synthesis of the [diethanolamine] [lactic].

Development of hybrid low salinity water polymer flooding numerical reservoir simulator and smart proxy model for chemical enhanced oil recovery (CEOR)

A MATLAB based finite volume CEOR simulator was developed for modeling the recovery of oil by low salinity water polymer flooding (LSWPF) in a proposed geostatistical method of generating porous media. Firstly, this paper coupled ion exchange, wettability and fluid flow transport models to the proposed heterogeneous porous media to investigate LSWPF oil recovery performance. Secondly, for the first time, a new hybrid smart proxy model of particle swarm optimization artificial neural network (PSO-ANN) recovery factor (RF) correlation was derived for LSWPF oil recovery performance using the extracted weights and biases. The proposed porous media as well as stochastic multi-fractal random field and circulant embedding method (CEM) permeability field realizations did not exhibit artificial banding unlike turning bands method (TBM) realizations when compared. A fast convergence pre-conditioner solution technique of algebraic multigrid (AMG) linear solver combined with an acceleration method of biconjugate gradients stabilized method (BI-CGSTAB) was used to solve the fully implicit system of coupled linearized equations. The simulator was validated with PHREEQC geochemical package and a secondary LSWPF coreflood test with outstanding history match. Numerical 2D examples study in this paper revealed the synergetic effects of LSWPF and high salinity water polymer flooding (HSWPF) with higher oil RFs of 39% and 31%, respectively than the standalone LSWF of 23% and normal waterflood of 11% for 50 days of production. The optimal architecture of the PSO-ANN RF model is 7 inputs, 3 hidden neurons and 1 output. Also, the PSO-ANN RF model predictions were compared to the LSWPF numerical simulation results with the former remarkably having reduced computational time in seconds with training and blind testing errors <1% average absolute percentage error (AAPE) for various permeability field realizations investigated. Finally, the PSO-ANN RF model will serve as a fast-alternative reservoir management and planning tool to supplement the high-fidelity LSWPF CEOR simulator developed to minimize computational overheads, risks and uncertainties in oil recovery performance modeling.

Microscale electrodeionization: In situ concentration profiling and flow visualization

Electrodeionization (EDI) is membrane-based desalination utilizing ion exchange membranes and ion exchange resins. By combining Electrodialysis and Ion exchanger, EDI can produce ultrapure water in a continuous-flow manner. Although its theoretical mechanisms are well documented, there is no experimental platform that can provide microscopic details inside of the system. In this paper, we present microscale EDI that can visualize in situ ion concentration, pH, and fluid flows. The platform was fabricated by filling ion exchange resins as a monolayer in a transparent polydimethylsiloxane channel between cation and anion exchange membranes. According to operating voltages (0–15V), distinct behaviors of ion concentration profile, pH shift, and fluid flows were observed in Ohmic, limiting, and overlimiting regimes. It is noteworthy that overlimiting regimes can be sub-categorized as water-splitting and electroconvection regimes. In the early stage (4–8V), water-splitting is dominant with pH change near the membranes and resins; under a higher voltage (8–15V), electroconvection starts to occur even water-splitting tries to suppress the development of the extended space charge layer and corresponding electroconvective instability. Accelerated ionic migration by electroconvection can improve current efficiency up to 80%. This is a clear departure from overlimiting dynamics in electrodialysis (with electroconvection only), ion exchanger (with no distinct regime), and even from that in previous EDI experiments (with water splitting only).

Geochemical characterization of mineralized albitite from Paleoproterozoic Bhukia IOCG‐IOA deposit of Aravalli‐Delhi Fold Belt, Rajasthan, western India: Genetic linkage to the gold (±Cu ± U) mineralization

Paleoproterozoic Bhukia gold deposit is located within the Debari Group of Aravalli Supergroup, Rajasthan, northwestern India. The major lithounits that are associated with gold–graphite (±Cu ± U) mineralization exposed in Bhukia are albitite, carbonates, and quartzite which have undergone upper greenschist to amphibolite facies metamorphism. Ore mineralization viz. pyrrhotite, arsenopyrite, chalcopyrite, pyrite, graphite, magnetite, and goethite in the study area are associated with NNW–SSE trending shear zone. Nuggets of gold are identified in the thick gossan zones that occurs parallel to the shear zone. The gold–sulfide lodes of the Bhukia deposits are largely confined either to marble or albitized marble and pure monomineralic albitite. The mineralization that is associated with the albitite, follows the boundaries of albite grains which confirms the role of these weak zones for the mobilization of mineralizing fluid and concentration of metal ions. Hence, geochemical studies of albitite would help to evaluate the petrogenesis, likely magmatic affinity, tectonic setting, controls of the mineralizing fluid, source, and their linkage to the gold (±Cu ± U) metallogeny. Bhukia albitite is characterized by Na–Al–rich and K‐poor compositions along with metaluminous nature. Geochemical analysis of various key elements suggests that albitite is the product of low‐K calc‐alkaline magma series with variation in Nb/Ta ratio indicating their fractionation during the melt–rock interaction within the shear zone. Geochemical signatures suggest the role of upper continental crust in channelizing the mineralized fluids that generated albitite with felsic to intermediate composition in and around Bhukia deciphered from their low Nb/Y ratios. Lower concentration of compatible elements (Ni and Cr) and higher concentration of incompatible elements (Th, La, and Nd) with SiO2 suggest that evolution of albitite rock is related to the fractional crystallization process. Zr/Hf ratios of 9–35 with the average of 18 suggest that albitite formed under magmatic–hydrothermal transitional environment. Rare Earth Elements (REE) patterns of albitite samples are moderately fractionated showing Light Rare Earth Elements (LREE)‐enrichment with a rather steep slope and exhibit distinct negative Eu anomalies (0.42–0.71, average 0.57). The enrichment of LREE in comparison to the Heavy Rare Earth Elements (HREE) suggests a more evolved source, i.e., process of melting at shallow environments. Tectonic setting of albitite samples suggest their origin in a volcanic arc region that underwent rifting. Detailed geochemical characterization unravelled complex evolutionary history of albitite in the Bhukia area, which attests derivation of the parental melt possibly from an enriched SCLM (Sub‐continental lithospheric mantle) source similar to most of the IOCG‐IOA deposits worldwide.

Nonlinear Dynamics in Strongly Coupled Quantum Plasma

The properties of cylindrical and spherical modified ion-acoustic waves in a strongly coupled plasma (containing strongly correlated non-relativistic ions, weakly correlated relativistic (both non-relativistic and ultra-relativistic) electron and positron fluids, and positively charged static heavy ions) are investigated theoretically. The restoring force is provided by the degenerate pressure of the electron and positron fluids, whereas the inertia is provided by the mass of ions. The positively charged static heavy ions participate only in maintaining the quasi-neutrality condition at equilibrium. By using reductive perturbation method, we have derived modified Burgers and Korteweg–de Vries equations. Their shock and solitary wave solutions are also numerically analyzed to understand the localized electrostatic disturbances. The basic features of modified ion-acoustic shock and solitary waves are found to be significantly modified by the effects of degenerate pressure of electrons, positrons, and ion fluids, their number densities, and various charge states of heavy ions. It is also observed that the amplitude of these shock and solitary profiles are maximum for spherical geometry, intermediate for cylindrical geometry, and minimum for planar geometry. The present analysis can be helpful for understanding different degenerate and relativistic phenomena in dense astrophysical environments as well as laboratory plasma systems.

Generation of freak waves in non-Maxellian dusty plasmas in the domain of Gardner equation

A theoretical study has been presented to examine the properties of the nonlinear dust-ion-acoustic (DIA) rogue waves in a dusty plasma composed of positive warm ions fluid, immobile negative dust, and non-Maxwellian electrons. By utilizing reductive perturbation method, the Gardner/Extended Korteweg-de Vries equation is deduced. The Extended Korteweg-de Vries (EKdV) equation was converted to nonlinear Schrodinger equation (NLSE) by using a suitable transformation to study the regions of DIA rogue wave propagation. The alteration of the properties of the rogue waves with pertinent plasma parameters is investigated, such as the temperature ratio of the ions-to-electrons, the negative charge located on the dust grains and nonthermality/superthermality/nonextensivity of electrons. And add to that, the first- and second-order dust-ion-acoustic rogue waves nonlinear structures in the system are examined. It is confirmed that the real enforcement of our results is in laboratory experiments and in space plasma (e.g., Earth’s magnetosphere, auroral region, heliospheric environments, solar atmosphere, etc.).

Electron pairing in mirror modes: surpassing the quasi-linear limit

Abstract. The mirror mode evolving in collisionless magnetised high-temperature thermally anisotropic plasmas is shown to develop an interesting macro-state. Starting as a classical zero-frequency ion fluid instability it saturates quasi-linearly at very low magnetic level, while forming elongated magnetic bubbles which trap the electron component to perform an adiabatic bounce motion along the magnetic field. Further evolution of the mirror mode towards a stationary state is determined by the bouncing trapped electrons which interact with the thermal level of ion sound waves and generate attractive wake potentials which give rise to the formation of electron pairs in the lowest-energy singlet state of two combined electrons. Pairing preferentially takes place near the bounce-mirror points where the pairs become spatially locked with all their energy in the gyration. The resulting large anisotropy of pairs enters the mirror growth rate in the quasi-linearly stable mirror mode. It breaks the quasi-linear stability and causes further growth. Pressure balance is either restored by dissipation of the pairs and their anisotropy or inflow of plasma from the environment. In the first case new pairs will continuously form until equilibrium is reached. In the final state the fraction of pairs can be estimated. This process is open to experimental verification. To our knowledge it is the only process in which high-temperature plasma pairing may occur and has an important observable macroscopic effect: breaking the quasi-linear limit and, via pressure balance, generation of localised diamagnetism.

Obliquely propagating ion-acoustic solitary and shock waves in magnetized quantum degenerate multi-ions plasma in the presence of trapped electrons

The properties of obliquely propagating ion-acoustic waves have been investigated in multi-ions magnetized plasma comprising of inertial, positively and negatively charged ion fluids, trapped electrons, and negatively charged stationary heavy ions. The propagation of the waves is oblique to the ambient magnetic field which is along the z-direction. Only fast type of modes exists in the linear regime. The reductive perturbation method was adopted to derive the Korteweg– de Vries (KdV) and Burger equations, as well as the solitary and shock wave solutions of the evolved equations, have been used to analyze the properties of the small but finite amplitude waves. The effects of the constituent plasma parameters, namely, the trapping effect of electrons, the electron degenerate temperature and the viscosity coefficient on the dynamics of the small amplitude solitary and shock waves have been examined. The influence of the magnetic field and the obliquity parameter on the propagation characteristics of ion-acoustic waves are discussed.

Inductive Acceleration of Ions in Poynting-flux-dominated Outflows

Abstract Two-fluid (electron–positron) plasma modeling has shown that inductive acceleration can convert Poynting flux directly into bulk kinetic energy in the relativistic flows driven by rotating magnetized neutron stars and black holes. Here, we generalize this approach by adding an ion fluid. Solutions are presented in which all particles are accelerated as the flow expands, with comparable power channeled into each of the plasma components. In an ion-dominated flow, each species reaches the limiting rigidity, according to Hillas’ criterion, in a distance significantly shorter than in a lepton-dominated flow. These solutions support the hypothesis that newly born magnetars and pulsars are potential sources of ultrahigh energy cosmic rays. The competing process of Poynting flux dissipation by magnetic reconnection is shown to be ineffective in low-density flows in which the conventionally defined electron multiplicity satisfies , where L 38 × 1038 erg s−1 is the power carried by the flow in a solid angle Ω, and is the ratio of the ion to lepton power at launch.

Generation of series of electron acoustic solitary wave pulses in plasma

One-dimensional fluid simulation is used to investigate the generation of electron-acoustic solitary waves (EASWs) in three-species plasma. We consider an unmagnetized collisionless plasma consisting of cold electrons, hot electrons, and ions. The Gaussian perturbations in the equilibrium electron and ion densities are used to excite the waves in the plasma. This simulation demonstrates the generation of a series of EASW pulses in this three-species plasma through the process of wave breaking. We investigate the behavior of the ponderomotive potential, frequency, and force associated with electrons and ions during the process of the wave breaking. We observed that the ponderomotive potential of the hot electron, which is the driving species for the electron acoustic waves, peaks at the time of wave breaking. The variation of the maximum ponderomotive force acting spatially on the leading and trailing edges of the hump in the cold and hot electron and ion fluid densities shows the maximum imbalance in the magnitude of the ponderomotive force acting on both sides of the hot electron density hump at the time of wave breaking. This reveals that the imbalanced ponderomotive force acting on the hot electron fluid is responsible for the breaking of the electron acoustic wave in plasma. Furthermore, it is observed that the wave breaking process occurs at an earlier time if the hot electron temperature is increased.

Karpman-Washimi magnetization in relativistic quantum plasmas

An interesting phenomenon of ponderomotive Karpman-Washimi magnetization is investigated in ultrarelativistic degenerate plasmas. The quantum characteristics of plasma electrons are considered on incorporating the Fermi pressure and exchange-correlation potential terms into the fluid model of plasmas. The ion fluid is referred to as classically warm. The Karpman-Washimi ponderomotive magnetization MK−WStr and radiation power P¯K−WStr are derived as functions of scaled wave number k¯, scaled effective frequency ω¯∗, ratio of thermal temperature of ions to the Fermi temperature of electrons E¯i′, and fine structure constant α for two cases of streaming and nonstreaming quantum plasmas. It has been observed that the Karpman-Washimi ponderomotive magnetization MK−WStr and the Karpman-Washimi radiation power P¯K−WStr are significantly affected by the scaled streaming velocity v¯0.

Excitation and control of large amplitude standing ion acoustic waves

We study the formation of large-amplitude standing ion acoustic waves (SIAWs) by nonlinear phase-locking (autoresonance) with a weak, chirped frequency standing ponderomotive drive. These waves comprise a nonlinear two-phase solution, with each phase locked to one of the two traveling waves comprising the drive. The autoresonance in the system is guaranteed provided that the driving amplitude exceeds a threshold. The phenomenon is illustrated via water bag simulations within a nonlinear ion fluid model and analyzed using Whitham's averaged variational principle. The local ion and electron densities in the autoresonant SIAWs may significantly exceed the initial unperturbed plasma density and are only limited by kinetic wave-breaking.

Higher order corrections and temperature effects to ion acoustic shock waves in quantum degenerate electron-ion plasma

The contribution of higher-order nonlinearity and dissipation to nonlinear ion acoustic shock waves (IASWs) is investigated by using the reductive perturbation technique in dense electron-ion plasma. The model consists of degenerate electrons (being either ultrarelativistic or nonrelativistic) and nonrelativistic ion fluid. A nonlinear Burger equation and a linear inhomogeneous Burger-type equation are derived. The inclusion of the higher-order corrections results in creating new shock wave structures, humped IASWs. It is found that the kinematic viscosity and the equilibrium ion number density play important roles in the basic features of the produced IA shocks and the associated electric fields. These findings are devoted to explaining the observed waves propagating in the outer periphery of compact dense stars which mostly consists of hydrogen and degenerate electrons.

Guiding-centre theory for kinetic-magnetohydrodynamic modes in strongly flowing plasmas

A kinetic-magnetohydrodynamic model with kinetic pressure closure is derived from a consistent guiding-centre framework. Higher-order (gyroviscous) corrections to the pressure tensor are derived in complex geometry from a reduced kinetic equation. The proposed model allows for flows of the order of the thermal ion velocity, taking into account important centrifugal effects due to the E × B flow, as well as the effects of diamagnetic flows associated with finite Larmor radius corrections to both ion fluid inertia and long mean-free path contributions. Wave–particle interactions, such as toroidal drift-resonance, are retained. Furthermore, the linearised model includes a quasi-neutrality equation, allowing the effects of a parallel electric field to be studied in fast rotating tokamak plasmas.

Transport Properties of Flow-through Electrodes with Varying Composition and Particle Dimension for Electrochemical Desalination

The growing need for energy-efficient desalination has motivated research into cation intercalation as a technology to remove salt ions from water. However, Prussian Blue analogues (PBAs), a promising class of intercalation compounds with high capacity and cycle life, demonstrate low electronic conductivity [1]. A common technique to increase electronic conductivity is the use of additives such as carbon black, [2,3] however adding conductive particles reduces active particle volume fraction and overall energy density. In addition to electronic conductivity, MacMullin number and hydraulic permeability affect energy consumed by ionic conduction and electrolyte pumping, respectively. These factors can be improved through the use of macroscopic pores to increase ion transport and fluid flow at the cost of removing active material to form the pores and lowering areal capacity [4,5]. Developing practical desalination technology requires the selection of conductive additives to facilitate the electron transport with simultaneous ion transport and fluid permeation. The present work studies how the volume fraction of either C45 or Ketjen Black conductive additive affects electrodes that incorporate either insulative nanoparticles or microparticles. Here, alumina particles are chosen here as a surrogate for insulative redox-active particles. Based on electronic conductivity measurements, smaller carbon black particles were found to form a percolating path through the electrode microstructure at lower volume fractions, increasing the electrode’s bulk electronic conductivity without sacrificing active material loading. The use of smaller alumina particles showed a similar effect, as electrodes made with nanoparticles possessed orders of magnitude higher conductivity at lower carbon black volume fractions (Fig. 1). A new application of the four-point probe technique was developed to measure the in-plane MacMullin number, which showed a weak decline with increasing carbon black content. Hydraulic permeability was also measured by applying a hydraulic head onto the cross-section of an electrode. Electrodes made with smaller particles (either conductive or insulative) were less permeable due to the particles’ ability to form smaller pores at similar porosities. Particle radii and inter-particle forces played a key role in electrode solidification, an idea supported by simulations of materials used in Li-ion batteries [6]. The van der Waals forces between the carbon black particles and alumina are generally weaker than those between carbon particles themselves, and this difference is enhanced for more numerous particles of smaller radii, allowing the carbon to percolate more easily. The three transport properties were also used to predict theoretical power requirements and find the attainable area-specific adsorption rate for a given specific energy consumption in a desalination cell, as faster adsorption is expected to require more energy [7]. The size of both conductive and insulative particles correlate with these properties and determine the rate and energy cost of salt removal. Electrodes composed of similar volume fractions of conductive and insulative material but different particle sizes display dramatically different electronic conductivity, ionic conductivity, and hydraulic permeability. Applying these lessons to the fabrication of porous electrodes could reduce energy consumption and lead to efficient desalination technology. Figure 1: A) Conductivity values at varying volume fractions of carbon black for the four combinations of C45 and Ketjen Black mixed with alumina microparticles and nanoparticles. B) MacMullin Numbers for the same electrodes. C) Results of permeability tests for the four particle mixtures.

A multispecies, multifluid model for laser–induced counterstreaming plasma simulations

The interpenetration of counterstreaming plasmas is an important phenomenon in several application areas, such as astrophysical flows, design of controlled fusion devices, and laser–induced plasma experiments. Multispecies “single-fluid” codes are unable to model this phenomenon due to the single velocity representation for all the species/fluids. Kinetic codes, though capable of modeling interpenetration, are computationally prohibitive for at-scale simulations. In this paper, we propose a multifluid model that solves the fluid equations for each ion fluid or stream. This allows distinct flows that interact with each other through electrostatic and collisional forces. We introduce and describe our code, EUCLID, that uses a conservative finite-difference formulation to discretize the governing equations in space. The 5th-order Monotonicity-Preserving WENO scheme is used for the upwind approximation of the hyperbolic flux, and the explicit 4th-order Runge–Kutta scheme is used for time integration. The code is verified for several benchmark cases and manufactured solutions. We simulate one- and two-dimensional interactions of counterstreaming plasmas in vacuum as well as in the presence of gas fill, where the setups are representative of laser-induced plasma experiments.