Transport phenomena of circular particles and fibers in axially rotating drum

Several processing techniques have been proposed for the fabrication of functionally graded materials (FGMs), whose composition and microstructure, i.e., the chemical and physical properties vary in the specific direction. The mechanical property of FGMs is affected by dispersed particle size, its volume fraction, and particle orientation. In order to clarify its property, it is important to disclose the particle motion during the fabrication process. In this study, circular particle and fiber motion during fabrication of Functionally Graded Materials is studied using the cold model centrifugal casting. Consideration is given to the timewise variation of the radial circular-disk and fiber motion in the axially rotating cold water drum. The velocity measurement is carried out by means of the Particle Tracking Velocimetry (PTV) method and the measured value is compared with that estimated by the theoretical prediction. It is found that (i) as the disk moves toward the rotating wall, its motion is perpendicular to the wall, (ii) the measured velocity is in good agreement with compared with the theoretical one (BBO equation), (iii) in contrast, translation and rotation of the fiber occur in the interior region and each fiber is oriented in the several directions, and (iv) these motions of the fiber are suppressed and one side of the fiber tips is attracted toward the drum wall as time progresses.