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Fall velocity of artificial porous particles




Unhanand, Komain, author
Colorado State University, publisher

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The objective of this research is to study the fall velocity of artificial porous particles. It is expected that this study will lead to further research concerning transport of flocules or porous particles in fluids. Two types of porous particles having two different porosities were made by cementing bearing balls together. Then another set of particles identical to the two types above were made with all pores sealed. These particles were released individually in six fluids of different viscosities and the fall velocity was found by photographic means. The drag coefficients of these particles were computed. The experimental results show that there is negligible difference in the drag coefficient of the porous and sealed particles of Type I (porosity ≈ 0.175), except at Reynolds number greater than 104. For Type II particles (porosity ≈ 0.380), the porous particles show appreciably higher values of the drag coefficient than the sealed ones, except at Reynolds number smaller than 30. The characteristics of the drag coefficient curves seem to agree satisfactorily with the theoretical analysis. This theoretical analysis included considerations of the pressure drag, shear drag, and shear resistance along the flow passage due to flow through the particle.


Includes bibliographical references.

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Dynamics of a particle
Fluid dynamics


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