In this paper, we solve numerically the entire set of equations associated with electro-thermo-convective phenomena that take place in a planar layer dielectric liquid heated from below and subjected to unipolar injection. For first time whole coupled is solved: Navier–Stokes equations, electrohydrodynamic (EHD) energy equation. We validate numerical simulation by comparing electro-convection stability criteria ones obtained approach. The solution electro-thermo-convection problem then...

Two-dimensional numerical simulations are carried out to examine the problem of transient electroconvection stability dielectric liquids subjected unipolar injection. The entire set electrohydrodynamics equations associated with electroconvective phenomena that occur in a layer liquid between two parallel electrodes potential difference solved numerically. We first validate simulation by comparing our linear criteria those obtained other authors approach. In this paper, we restrict study...

Granular materials exhibit several regimes of behavior: plastic, inertial, fluidized, and entrained flow, but not all can pass through these states. Our concern is with the criteria that determine transition from one regime to another boundaries various flow define. Experimentally we have focused on fine, cohesive powders, where interparticle force dominates over gravitational air cause moving powder become fluidized.

The interplay of charge diffusion, a hitherto neglected phenomenon, and Coulomb repulsion in the finite-amplitude electroconvection layer insulating liquid subjected to weak unipolar injection is discussed. Analytical considerations numerical simulations show that there exists fundamental nondimensional parameter relates strength diffusion coefficient. Unless this much larger than 1, must be included. A projection two-dimensional conservation equation into one-dimensional space allows us...

The basic properties of electroconvection resulting from unipolar injection into an insulating liquid are examined. It is shown that for very weak the induced motion has only a negligible influence on total current across layer. agitation can nevertheless be intense and orders magnitude have been derived typical velocity in both viscous dominated fully turbulent regimes. This used to enhance heat transfer. experiment performed plane-parallel electrode geometry proves transfer substantially...

Melting in the presence of electrohydrodynamic (EHD) flow driven by Coulomb force dielectric phase change material is numerically studied. A model developed for EHD solid-liquid process. The fully coupled equations including mechanical equations, electrical energy and continuity interface are solved using a unified lattice Boltzmann (LBM). Firstly, numerical validated several cases hydrostatic state, all LBM results found to be highly consistent with analytical solutions. Besides, our code...

This work addresses the stability of a two-dimensional plane layer dielectric liquid enclosed in wall bounded cavities different aspect ratios and subjected to unipolar injection ions. Numerical simulations have been conducted investigate effect lateral walls, especially development electroconvective instability. It is found that an unexpected change bifurcation nature occurs for certain cavity ratios. We show above linear threshold rest state supercritical arises. takes place at given value...

We perform a theoretical and numerical study of the Coulomb-driven electroconvection flow dielectric liquid between two coaxial cylinders. The specific case, where inner to outer diameter ratio is 0.5, analyzed. A strong unipolar injection ions either from or cylinder considered introduce free charge carriers into system. finite volume method used solve all governing equations including Navier-Stokes simplified set Maxwell’s equations. characterized by subcritical bifurcation in amplitude...

Abstract We investigate the linear stability threshold of a dielectric liquid subjected to unipolar injection in two-dimensional rectangular enclosure with rigid boundaries. A finite element formulation transforms set partial differential equations that governs system into algebraic equations. The resulting poses an eigenvalue problem. calculate threshold, as well velocity field and charge density distribution, function aspect ratio domain. parameter describes paths symmetry-breaking...

Electroconvection in dielectric liquid is extended from single phase to solid-liquid interaction. Stability criteria and bifurcation are numerically predicted by the lattice Boltzmann method. Effects of interface position, permittivity mobility ratios, electric conductivity considered.

This paper describes an apparatus based on a novel use of powder bed, whereby the relationship between consolidation stress, tensile strength, and free volume fine is measured. The to be tested first initialized reproducible state. next consolidated either beyond its own weight or below by means controlled flow gas. An ultrasonic device measures height thus providing average value volume. Next bed subjected slowly increasing gas flow, so directed as put under tension. overpressure causing...

The electrohydrodynamic (EHD) flow between a line source of ions and flat plate due to an electric field acting on injected space charge is examined both theoretically experimentally. A number simplifying assumptions (e.g., laminar negligible diffusion charge) are made such that the governing equations tractable. mathematical model used taken from heat transfer analysis experimental results very close theoretical ones. With encouraging agreement it may be possible present more formal analogy...

Total cross sections for electron scattering by ${\mathrm{N}}_{2}$ molecules in the energy range 600--5000 eV have been obtained from measurements of attenuation a linear beam. The results compared with available experimental and theoretical calculations based on first Born approximation. No previous data found literature impact energies above 1600 eV.

Fine powders are the cornerstone of new energy storage solutions to assist concentrated solar power plants. Though, their ability behave like fluid can be seriously affected at high temperatures. This work investigates use nanosilica in fine limestone (calcium carbonate, CaCO3) mitigate promotion cohesion forces Experiments were conducted over powder samples with particle sizes around 45μm. The analysis was performed monitoring tensile yield strength as subjected different temperatures and...

A finite volume method solver for the electric field-enhanced boiling is developed based on OpenFoam v2012 framework. The film-boiling scenario with influence of fields numerically analyzed. By coupling Tanasawa model and leaky-dielectric model, accuracy numerical description natural physical phenomenon improved. For an overheated temperature ΔT = 5, 10, 20 K, system exhibits a classic quasi-periodicity sequence, alternate periodic-chaotic respectively. results show that bubble column leads...