Dusty Particle Research Articles

Enhanced heat transfer in viscoelastic fluids with periodic magnetic fields and dusty nanoparticles between two parallel plates under thermal radiation

Exploring the intricate relationship between periodic magnetic fields and dusty nanofluids within one-dimensional, unidirectional frameworks shows great potential for advancing precise control within microfluidic devices and bolstering heat transfer efficiency in nanotechnology realms. In this study, we delve into the impact of heat transfer and periodic magnetic fields on viscoelastic nanofluids laden with dust particles, confined between two parallel plates. The flow dynamics are instigated by buoyancy forces, with due consideration given to heat transfer phenomena. Employing partial differential equations, we model the flow behavior, and through the application of the Poincaré-Light Hill Technique, we attain exact solutions. Graphical representations elucidate the temperature and velocity profiles, revealing the nuanced influences of various parameters. Utilizing Mathcad-15, we generate visual depictions of the fluid and dust particle distributions. Furthermore, our analysis delves into critical fluid attributes vital for engineering applications, including skin friction and heat transfer rates, which are comprehensively examined and tabulated. This encompasses the evaluation of heat transfer rates at the wedge surface, alongside the resultant influence on surface viscous drag forces. Our findings indicate that magnetic parameters induce reductions in both base fluid and dusty particle velocities, alongside the emergence of periodic motion under the influence of periodic magnetic fields. Periodic magnetic fields generate electrical power in induction generators widely used in wind turbines, hydroelectric power plants, and other renewable energy sources.

Exploration of generalized two-phase free convection magnetohydrodynamic flow of dusty tetra-hybrid Casson nanofluid between parallel microplates

Abstract Dusty Casson fluids and tetra-hybrid nanofluids are complex phenomena that find their extensive uses in engineering and industrial applications. For instance, dusty fluids are used in gas-freezing systems and nuclear power reactors. The main objective of this article is to focus on the characterization of generalized two-phase free convection magnetohydrodynamic flow of dusty tetra-hybrid Casson nanofluid among parallel microplates: dusty Casson fluid and tetra-hybrid nanofluid exhibit free movement and electrical conductivity. The Caputo–Fabrizio fractional derivative recently discovered generalizes the partial differential equations governing the flow. Highly accurate temperature and velocity distributions can be obtained using finite sine Fourier and Laplace transform together. This study examines the relationships between temperature, dust particle velocity, and Casson fluid velocity, along with the effects of magnetic parameter, Grashof number, dusty fluid parameter, Peclet number, Reynold number, and particle mass parameter. The Mathcad-15 software provides Casson, dusty, and temperature profiles graphically. The Nusselt number and skin friction are also examined for the tetra-hybrid nanofluid. The fractional Casson fluid model is more accurate than the classical model in terms of velocity, temperature, heat transfer, and skin friction. Graphical results conclude that the fractional Casson fluid model describes a more realistic aspect of both (fluid and dust particle) velocities and temperature profiles, heat transfer rate, and skin friction than the classical Casson fluid model. Furthermore, the heat transfer rate enhanced from 0 to 39.3111% of the tetra-hybrid nanofluid.

Two-phase hydromagnetic Eyring-Powell fluid flow over a stretching sheet suspended to a dusty particle

ABSTRACT The thermophysical feature of a 2D flow of a dusty Eyring-Powell fluid caused by a stretched sheet in the presence of magnetic field was assessed in the present study. The similarity transformation had been considered for transforming the dimensionless heat and fluid flow basic partial differential equations into simple ordinary equations. After that, the Runge-Kutta-Fehlberg 45 solver utilizes numerical methods to resolve the altered equations. We study and discuss in depth the flowing and heating attributes under various parameters, including the magnetic parameter, Eyring Powell fluid parameter, fluid particle interaction parameter and Prandtl number. In order to validate the reliability of the numerical solution, the findings that were produced are contrasted with the results that were achieved in the past. It has been proven numerically that the velocity of the fluid phase and particle phase both increases when the Eyring Powell fluid parameter is increased.

A generalized magnetohydrodynamic two-phase free convection flow of dusty Casson fluid between parallel plates

This article aims to investigate the combined effects of the heat transfer and magnetic field on the electrically conducting magnetohydrodynamic two-phase free convective flow of dusty Casson fluid between parallel plates. The flow is caused by buoyancy force with heat transfer due to free convection. Moreover, the left plate moves at uniform velocity while the right plate is stationary, and all dust particles with spherical forms are scattered evenly throughout the fluid. Mathematically, the flow is described as partial differential equations. A newly introduced fractional derivative, namely Caputo-Fabrizio fractional derivative, is used to generalize the given derived system of PDEs. The problem is solved using joint applications of finite sine Fourier and Laplace transforms. Exact solutions of velocity and temperature profile are obtained. Moreover, the impact of different parameters like a magnetic parameter, Grashof number, Dusty fluid parameter, Casson parameter, Peclet number, Reynold number, and particle's mass parameter on temperature, and dust particle and Casson fluid velocity have been discussed. The graphical results for Casson fluid, dusty fluid, and temperature profiles are plotted through Mathcad-15. The behavior of Casson fluid and dusty fluid is matching for different embedded parameters. Moreover, the Nusselt number and skin friction are also determined. It is shown in Table 1 that by increasing the value of the peclet number, the rate of heat transfer decreases. Furthermore, Table 2 shows that by increasing the magnetic parameter, the skin friction decreases. Graphical results conclude that fractional Casson fluid model described a more realistic aspect of the both (Fliud and dust particle) velocities profile, temperature profile, rate of heat transfer and skin friction than the classical Casson fluid model.

Numerical model of dusty-water bridge forming between neighbor fins of fin-and-tube heat exchangers

Abstract A typical room air conditioner uses fin-and-tube heat exchanger as evaporator, and its performance may be dramatically deteriorated by the dusty-bridge between fins, which is resulted from dehumidification and dusty particle adhesion. Design of a fin-and-tube heat exchanger to avoid dusty-bridge need to predict the forming process of dusty-bridge between fins. In this paper, a numerical model is developed to simulate the dusty-water bridge formation between fins, which can well predict the shape of dusty-water bridge and mass of the dusty particles adhered by water bridges. Prediction of the dusty-water bridge shape is realized by calculating the mean curvature of the water bridge interface at first and then predicting the effect of air flow and gravity on the water bridge shape. The prediction method of the mass of the dusty particles adhered by water bridges between fins is to simulate the motion trajectories of all particles in the air flow at first and then to choose those particles intersecting with the water bridge surface as adhered. The validation results show that, the water bridge shape predicted by the model agrees well with the experimental image, and the predicted adhered particle mass agree with 92% of the experimental data within the deviation of ±20% and the mean deviation is 14.8%.

Dusty Nanofluid Past a Centrifugally Stretching Surface

This communication reports, the flow of Cu-water dusty nanofluid past a centrifugally stretching surface under the effect of second order slip and convective boundary conditions. The coupled nonlinear ordinary differential equations are get hold of from the partial differential equations which are derived from the conservation of momentum and energy of both nanofluid and dusty phases. Then, using apt resemblance transformation these ordinary differential equations were altered into a dimensionless form and then solved by bvp5c solver in Matlab software. The variation in velocity and temperature profiles of fluid and dusty phases for different parameters are thrash out in depth by figures and tables. The outcomes exhibit that the velocity profile of both fluid and dusty phases boot as the values of the dust particle volume fraction parameter is enlarged. Besides, the magnetic field parameter has similar effect on the velocity profile of both fluid and dusty phases. Also, the results illustrated that temperature profile of both Cu-water nanofluid and dusty particle phases are improved within an enhancement in the values of the temperature relaxation parameter, Cu-particle volume fraction, and Biot number. The results also confirm that for greater values of the magnetic field parameter the values of skin friction coefficient are enlarged for all values of the velocity ratio parameter.

Numerical model of particle deposition on wet fin surfaces of heat exchanger under dehumidifying conditions

Dusty particles may easily deposit on fin surfaces of heat exchangers under dehumidifying conditions and thus seriously deteriorate the heat transfer performance. The purpose of this study is to develop a numerical model for simulating the dusty particle deposition on wet fin surfaces in practical working processes, including the shape and mass of the deposited dusty particles in the process of particle-capturing by condensate water and that of particle adhesion on wet particulate layer. The prediction method of the dusty particle deposition in the process of particle-capturing by condensate water is to simulate the motion trajectories of all particles in the air flow at first and then to choose those particles intersecting with the water surface as deposited. The prediction method of the dusty particle deposition in the process of particle adhesion on wet particulate layer is to calculate the critical sticking velocity at first and then to choose those particles with the impact velocity being smaller than the critical sticking velocity as deposited. The validation results show that, the predicted shape of wet particulate layer agrees well with the experimental images, and the predicted mass of deposited particles agrees with 91% of the experimental data within a deviation of ±20% and the mean deviation is 11.8%. Prediction results of the quantitative influence of operation conditions with this model show that the parameters of inlet air relative humidity and particle concentration are the two most important factors on dusty particle deposition on wet fin surfaces.

Quantum effects in bi-dust plasmas

In this paper a theoretical approach has been carried out using a fluid model on a bi-dust plasma which consist of two dusts negative charged different particles in an electron–ion plasma. In such system, this fluid model describe a dense strong coupled heavy dust grain together with a weak coupled light dusty particle. The bulk is immersed in a system of electrons and ions dominated by a Thomas–Fermi density distribution, where interaction and propagation of solitary dust acoustic solitary waves will be analyzed. This investigation will be carried out for arbitrary amplitude of solitary dust acoustic waves. These are originated through the presence of both dust grains in the plasma system. Therefore, it is used a set of fluid equation which determine general expressions for the concentrations of different dust particles. The onset of the Sagdeev method is then employed in order to look for influence of the light component on the quantum system. In this way there is an increasing or decreasing in the Sagdeev potential. This is a quantum effect phenomena.

Visualization of plasma fluxes by a measurement of own rotation of a dust particle

A research of own rotation of single dust particle which is in a dust trap in the stratified glow discharge under imposed magnetic field is carried out. It is experimentally shown that in the scale of Debye length an action of azimuthal torque from the fluxes of ions and electrons is mutually compensated; an angular velocity of rotation of dusty particle remains invariable up to magnetic fields of 200 G. The found effect was given theoretical interpretation on a basis of consideration of ambipolar diffusion of positive ions and electrons to the particle surface.

Propagation characteristics of THz waves in space-time inhomogeneous and fully ionized dusty plasma sheath

When a hypersonic vehicle flies in near-space, the electron density of the plasma surrounding the aircraft is inhomogeneous and varies with time. Ablation occurs around the vehicle as the temperature rises. Therefore, investigating the propagation characteristics of electromagnetic (EM) waves in a space/time inhomogeneous and fully ionised dusty plasma sheath is important. In this article, a space/time inhomogeneous dusty plasma sheath model is first established. The expression of the dielectric coefficients of weakly collisional and fully ionised dusty plasma sheath is adopted. The shift-operator finite difference time-domain method is used to calculate the reflection and transmission coefficients of different dusty particle concentrations and radii, changes in electron density with time, electron temperatures and ion charges in the terahertz (THz) band. Finally, the propagation characteristics of THz waves with different electron density distributions at eight re-entry heights are analysed. Results show that increasing the incident wave frequency can effectively improve the effects of dusty particle concentration and radius, electron temperature and ion charge on the transmission of the EM wave. Different electron density change forms and electron density distributions significantly influence the propagation properties of THz waves.

Numerical Simulation of Dusty Air Flow and Particle Deposition Inside Permeable Alveolar Duct

There were huge inconsistencies in deposition between ducts of a particular generation and inside every alveolated duct, signifying that limited particle concentration can be much bigger than the mean acinar concentration. A large number of particles are unsuccessful to way out during expiration. Therefore, to study the effect of inhaled particles of nano size inside alveolar region of human lung we used Navier–Stokes equation by including Darcy term together with Newton equation of motion. Finite difference technique has been used to solve the governing equation, which assumed to take axial symmetry under laminar pulsatile flow condition, so that the problem efficiently becomes two dimensional. Computational work is done on MATLAB R2016 by user defined code and effect of porosity, Darcy number and Reynolds number are analysed to study the flow condition inside alveolar region. Results show that porosity is an active factor for deposition of nanoparticles and the fraction of particles trapped in the alveolus increases by decreasing the Darcy number.

Measurement of Microwave Propagation in Weakly Ionized Dusty Plasma

An experimental method of producing dusty plasma with high dusty particle density is proposed and implemented. Microdusty particles are immersed into an ac glow discharge plasma with large scale by applying electronically controlled vibratory screen mesh and continuous equidistributional dusty environment is formed. The impact of dusty particles on microwave propagation in a laboratory plasma device can be observed. The gigahertz microwave transmittance through the dusty plasma region is measured with vector network analyzer and horn antenna placed in the sides of plasma region. The results show that the dusty particles can synergize the influence on propagation of microwave in plasma.

Interactive rendering of light scattering in dust molecules using particle systems

In this paper introduces a technique for rendering effect of the volumetric lighting in dusty atmosphere using particle systems. Despite numerous techniques has been proposed for rendering these effects but still lack realism in the interactive applications. This technique is based on the sampling planes to compute radiance transport equation and use dynamic model of the dust. The scattering of light is computed by using fragment shaders and 2D texture by making use of the graphics hardware, while using ParticleEngine technique generates the dust. The technique is efficient and accurate to mimic a realistic scenes have effect such as scattering of light in dust molecules. In addition to, volumetric shadows are created resulting of density and size particles within participating media. Therefore, scattering of light is generated in presence dusty media that lead to provide visual clue closer to realistic.

Study on incoherent scatter theory of high density dusty plasma

Incoherent scatter radar is one of the most important detection instruments of the space plasma. But because of the low dust density in natural space plasma, the contribution of charged dust to incoherent scatter spectrum can be completely ignored, therefore the incoherent scattering theory has not appeared in dusty plasma. In the solid rocket plume, the propellant combustion can form a large number of nanometer- and micronmeter-sized dusty particles, and produce a high electron density from high temperature ionization, which makes considerable contributionto charged dusty particles with the high density. Therefore, we develop the incoherent scattering theory of dusty plasma in order to calculate the scattering characteristics of high density dusty plasma produced by rocket plume, for example. The theoretical model including electrons, ions and dusty particles is established by combining effects of charged dusty particles. The incoherent scatter spectral lines of ion resonance region and dust resonance regionare calculated. The effects of dusty particle radius, temperature and density on spectral line structure are discussed. With the increases of dusty particle radius and density, the amplitude of power spectrum increases. With the increase of dust temperature, the amplitude of power spectrum decreases. In the dust resonance region, the control mechanism of dust in spectrum is similar to that of the ions. With the increase of particle size (mass) and decrease of the temperature, the spectrum width narrows, and amplitude and area increase with the increase of density. But in the ion resonance region, the dust control mechanism is completely different, and the influence of the dust on ion line is in the way of attracting ions. So with the increase of dust density, ion line characteristics do not show that the area increases, and dust controls ions by adjusting the Debye radius or electrostatic shielding ball size. By comparing the ion lines with and without dust under the same parameters conditions, the amplitude of the ion line with dust is much larger than that without dust, and the resonance frequency of the ion line is greatly changed. With the dust particles of a relatively high density, one can enhance the ion line, hence the incoherent scattering phenomenon can be more easily observed in rocket plume. On the other hand, due to significant changes of frequency and amplitude in the ion line spectrum, the incoherent scattering inversion method based on the traditional theory will cause a large error in the inversion parameter, even a failure of parameter retrieval. The incoherent scattering theory and relevant physical laws of dusty plasma are presented, which are of great significance for establishing the incoherent scattering theory system and studying the rocket plume parameters.

Charging of a rodlike grain in plasma flow

In present work on the basis of numerical modeling by the dynamics of many particles, a self-consistentproblem of the formation of a charge accumulated by a dusty particle of a rodlike shape in a twotemperatureplasma flow is considered. An analytical model useful for understanding the phenomenon ofion focusing and its effect on the formation of the surface charge of a needle was considered. Pairwise radialcorrelation functions evaluated in the approximation of binary interaction for moving particles with astationary Coulomb center. Using conservation law for the momentum ion velocity component has beendetermined. It was noticed that electron shielding does not influence on the ion focusing density peak value.In that reason ion focusing parameters in the concrete doesn’t depend on the electron screening Debyeradius. A system with Coulomb particles containing moving point particles, ions and electrons, and fixedspheres have been chosen. The cases of dielectric and metallic dust grains having different orientationswith respect to the flow direction are considered.

On the interaction of microparticles with ion flux in gas discharge plasma

The charging and interaction of microparticles in the gas discharge near-electrode region, where the role of the external electric field and ion drift is significant, are considered. It is shown that the ion focusing, responsible for, as is generally accepted, the formation of vertical linear dust structures, is strongly suppressed under conditions typical of experiments with dusty plasma (i.e., the gas discharge at pressures of 10–100 Pa). The contribution of ions trapped by an ion microparticle to the dusty particle charge is estimated. It is shown that trapped ions can appreciably reduce the microparticle charge.

Three-dimensional single particle tracking in dense dust clouds by stereoscopy of fluorescent particles

In dense dust clouds of a dusty plasma single particle trajectories are impossible to follow due to occlusion of particles and ambiguities in particle correspondences. By stereoscopic imaging of fluorescent tracer particles, we were able to reconstruct 3D single particle trajectories within dense dust clouds. Several measurements are shown that justify to regard the tracer particles as suitable representatives for the whole dust system. A first analysis of dust density waves in dense clouds already shows that these waves exhibit three-dimensional dynamics at larger wave amplitudes that cannot be resolved by 2D imaging techniques: a broad velocity distribution perpendicular to the oscillation plane due to dust-dust collisions is seen, while the velocity distribution in the oscillation direction is bimodal and shifted due to the bulk wave propagation.

Simulation of interaction between dust particles and plasma sheath and its distribution

Collisionless steady plasma sheath model is taken into account to study the interaction between dusty particles and plasma sheath as well as the density distributions of electrons, ions and dusty particles. Numerical simulation results are obtained, showing that the ability of an isolated charge to absorb electrons weakens with the increase of dusty particle density and its temperature, while the collective effect strengthens with the radius of dusty particle. Simultaneously, Bohm velocity and the sheath thickness are also greatly affected. The sheath potential decreases significantly and the E-field is stronger near the electrode. In addition, the densities of electrons and ions reduce exponentially but the dusty particle has a critical value. The three particles satisfy the quasi-neutrality condition.

The reconstruction of the effective interaction potential on the base of pair correlation function measurements in dusty plasma

The effective interaction potentials between dusty particles were reconstructed by the Shommers technique (W. Schommers, Phys. Rev. A 28, 3599 (1983)) on the basis of recent measurements in dusty plasma. The potentials have both repulsive and attractive parts. The form of the potentials varies with density and also depends on the dimensions of the dusty particle structure. The Yukawa potential can fit the repulsive part of the potentials at relatively high densities.

Coulomb instability of dusty particle system in gas‐discharge plasma

AbstractAn effective anisotropic potential is proposed for the interaction between dust particles in a gas‐discharge plasma. In addition to the Coulomb repulsion this potential takes into account attraction due to the spatial positive plasma charge originating from focusing of the ionic fluxes by dusty particles. The time evolution of the dust particle kinetic and potential energies from random initial configurations have been investigated by the Brownian dynamics method. Results of our simulation showed that the attraction between dusty particles can be the main physical reason of formation and decay of classical bound dust particle pairs and many particle complexes with low potential energy, while the kinetic energy (temperature) of unbound dust particles and particle oscillating in bound complexes may increase on three order as observed in experiments. In the model without dust particle attraction the bound complexes are absent and increase of kinetic energy is much less pronounced. The influence of the high frequency and low frequency random‐charge fluctuations on the obtained results has been investigated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)