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Full-Text Articles in Physics

Qualitative Observations Of Dense Particle Motion In A Vibration-Excited Granular Bed, Timothy B. Morgan, Theodore J. Heindel Nov 2007

Qualitative Observations Of Dense Particle Motion In A Vibration-Excited Granular Bed, Timothy B. Morgan, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

The Brazil nut effect is a classic phenomenon in which larger objects typically migrate to the top of a bed of smaller granular media when exposed to vibration. An example of this phenomenon is finding Brazil nuts on the top of a can of mixed nuts. In this study, the Brazil nut problem is simulated by submerging a large particle in a bed of granular media and then subjecting the system to vibration. Stereoscopic X-ray imaging is used to visualize the large particle motion. These images are then compiled into movies where the particle motion may be tracked. Observations of ...


Stability Issues For Gas-Liquid Flows In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel Nov 2007

Stability Issues For Gas-Liquid Flows In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

In the present work, gas-liquid flow dynamics in a bubble column are simulated with CFDLib using an Eulerian-Eulerian ensemble-averaging method in a two dimensional Cartesian system. The time-averaged gas holdup simulations are compared to experimental measurements of a cylindrical bubble column performed by Rampure et al. [1]. Numerical predictions are presented for the time-averaged gas holdup at various axial heights as a function of radial position. The effects of grid resolution, bubble pressure model, and drag coefficient models on the numerical predictions are examined. The bubble pressure model is reported to account for bubble stability, thus providing physical solutions. The ...


Visualizing Fluid Flows With X-Rays, Theodore J. Heindel, Terrence C. Jensen, Joseph N. Gray Jul 2007

Visualizing Fluid Flows With X-Rays, Theodore J. Heindel, Terrence C. Jensen, Joseph N. Gray

Mechanical Engineering Conference Presentations, Papers, and Proceedings

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will ...