Передача крутящего момента проводящей частице с использованием силы Лоренца

In the paper the concept of conductive particle rotation in DC electric field with including the Lorentz force providing generation of electric dipole moment of the particle is for the first time discussed. Some models of the torque transfer to spherical and cylindrical particles based on of the Hall effect at usual geometry and with additional electric field application and also in the case of implementation of the photoelectromagnetic effect are presented.

Porous Structure of Cylindrical Particle Compacts

The porous compacts of non-spherical particles are frequently used in energy storage devices and other advanced applications. In the present work, the microstructures of compacts of monodisperse cylindrical particles are investigated. The cylindrical particles with various aspect ratios are generated using superquadrics, and the discrete element method was adopted to simulate the compacts formed under gravity deposition of randomly oriented particles. The Voronoi tessellation is then used to quantify the porous microstructure of compacts. With one exception, the median reduced free volume of Voronoi cells increases, and the median local packing density decreases for compacts composed of cylinders with a high aspect ratio, indicating a loose packing of long cylinders due to their mechanical interlocking during compaction. The obtained data are needed for further optimization of compact porous microstructure to improve the transport properties of compacts of non-spherical particles.

DEM study of the angle of repose and porosity distribution of cylindrical particles with different lengths

Effect of the length of cylindrical particle on repose angle and porosity of a pile was numerically studied using discrete element method. The variation of repose angle and porosity with coefficient of sliding and rolling friction were also discussed. The results shown that compared with sphere particle, the bottom size of cylindrical pile is smaller, while the height of cylinder pile is larger and the heap is steeper. With the increase of the length of cylinder, the contour line of the pile becomes steep, and the angle of repose increases. The repose angle shows a positive correlation with coefficient of sliding and rolling friction. The porosity increases with the increase of the length of cylinders. The trends of porosity are basically consist with that of repose angle, and with increase of friction coefficient, the average porosity increases.

Flow and Heat Transfer Property of Oldroyd-B-Fluid-Based Nanofluids Containing Cylindrical Particles in a Pipe

Flow and heat transfer property of Oldroyd-B-fluid-based nanofluids containing cylindrical particles are studied in a pipe with circular cross-section in the range of Reynolds number (Re) from 100 to 2000, Weissenberg number (We) from 0.1 to 2, particle aspect ratio (β) from 2 to 16 and particle volume concentration (Φ) from 0.1% to 2.5%. The motion equation of Oldroyd-B fluid with particles, the equation for probability density function of particle orientation and convection-diffusion equation for particles are solved numerically. The numerical method used in the simulation is validated by comparing with the available results. The effects of Re, We, β and Φ on the friction factor (f), Nusselt number (Nu) and ratio of energy performance evaluation criterion (PECt/PECf) for Oldroyd-B-fluid-based nanofluids to that for Oldroyd-B fluids are discussed. The results showed that the values of f and Nu of Oldroyd-B-fluid-based nanofluids are larger than that of water-based nanofluids and that of pure Oldroyd-B fluids. The values of f increase with increasing Re, We and Φ, but with decreasing β. The values of Nu and PECt/PECf are enhanced with increasing Re, We, β and Φ. The increase of f is larger than that of Nu at lower Re, but is less than that of Nu at higher Re. It is more effective to use Oldroyd-B-fluid-based nanofluids with cylindrical nanoparticles to improve the heat transfer at the conditions of higher Re, We, β and Φ. Finally, the correlation formula of PECt/PECf as a function of Re, We, β and Φ is derived.