Particle Linear Velocity Research Articles

Statistical analysis of parameter effects on linear velocity of ferrous particles in an AC electric field as a new method for powder transportation

In recent years, AC electric field has been introduced as a new approach for sorting, separation, exact feeding and transportation of particles in manufacturing process. The capability of particle handling demands more studies to recognize parameters influencing linear velocity of particles. In this study, the effects of parameters including frequency, gap between electrodes, electrode width, and signal profile on particle linear velocity in a selected condition were experimentally investigated. Main effects of factors and interactions were considered in this paper and regression equation was derived. A general full factorial method was employed as experimental design.

Evaluation of tube-flow fluid-to-particle heat transfer coefficients under controlled particle oscillatory motion

A previously developed particle oscillatory motion technique, with direct temperature measurement of particles in motion under tube-flow conditions, was evaluated for studying the effect of several influencing factors associated with fluid-to-particle heat transfer coefficient ( h fp). A full factorial experimental design was employed involving spherical particles made of aluminum epoxy and Nylon of different sizes (12.7–17.5 mm), different particle linear velocities (0.06–0.21 m/s), heating medium viscosities (0 to 1% concentration of carboxymethyl cellulose solution, CMC) and fluid temperatures (60–80°C). Statistical analysis of experimental data indicated that all factors investigated had a significant ( P<0.001) effect on h fp. A t-test grouping analysis showed that mean values of h fp were different ( α=0.05) among the levels of the various factors. As expected, the fluid-to-particle heat transfer coefficient increased with particle velocity and fluid temperature, and decreased with CMC concentration. In agreement with some reports, h fp decreased with particle size. Further, the values of h fp associated with the aluminum epoxy particle were generally higher than that for the Nylon particle of the same size. The study thus demonstrates the feasibility and usefulness of the technique for gathering tube-flow h fp data under a range of conditions involving particle oscillatory motion.

EFFECT OF PRODUCT AND PROCESS VARIABLES IN THE FLOW OF SPHERICAL PARTICLES IN A CARRIER FLUID THROUGH STRAIGHT TUBES

Residence time of particles and fluid-to-particle heat transfer coefficient, two of the major unknowns in the aseptic processing of particulate fluid foods, are intimately related with the linear and rotational velocities of the solid particles. These two velocities were measured by videotaping the flow of individual spherical particles in transparent straight tubes. The effect of fluid velocity and viscosity, particle diameter and density and tube diameter and upward inclination was statistically evaluated using a replicated full factorial design at two levels. Particle linear velocities between around one third of the average fluid velocity and 15% higher were obtained. Rotational velocities were usually lower, but of the same order of magnitude. Particle density and particle diameter had a significant effect on the two particle velocities analysed. The effect of fluid velocity was