Particle shape effects

A Heyd, D Dhabhar. Particle shape effect on caking of coarse granulated antacid suspensions. Drug Cosmet Ind 125 42-45. 1979. 

The validation of CFD codes using pressure drop is most reliable when actual experimental data are taken in equipment identical to the situation that is being simulated. Existing literature correlations such as the Ergun equation are known to have shortcomings with respect to wall effects, particle shape effects, application to ordered beds and validity at high Re. The applicability of literature correlations to typical CFD simulation geometries needs to be examined critically before fruitful comparisons can be made. 

In discussing particle shape effects it seems sensible to compare overall heat transfer coefficients for different shapes relative to a common base,i.e. with regard to pressure drop/extem-al surface area for non-porous supports or pressure drop/solid volume for porous supports. Thus, Fig. 4 is constructed from the heat transfer correlations in Table II, together with pressure drop data collected over the packings at NTP in a 24 an diameter tube. 

Tests carried out on pneumatically conveyed salt particles showed that Insitec data gave size distributions that were over 30% coarser than sieve data, the difference being attributable to particle shape effects. The results for both instruments showed that the particles attrited with number of passes through the system, with the Insitec being more sensitive than sieving [118]. 

C. R. Amonson and I. S. Dranoff, "Nonlinear Equilibrium and Particle Shape Effects in Inlra-... 

This chapter is an in-depth review on rheology of suspensions. The area covered includes steady shear viscosity, apparent yield stress, viscoelastic behavior, and compression yield stress. The suspensions have been classified by groups hard sphere, soft sphere, monodis-perse, poly disperse, flocculated, and stable systems. The particle shape effects are also discussed. The steady shear rheological behaviors discussed include low- and high-shear limit viscosity, shear thinning, shear thickening, and discontinuity. The steady shear rheology of ternary systems (i.e., oil-water-solid) is also discussed. 

Particle Shape Effect. To this point, we have been dealing only with spherical particle suspensions. When the particles have irregular shapes, the rheological properties are expected to be very different from those of the spherical particle suspensions. Consider, for example, a simple system of cylindrical fibre suspensions. Because the particles are expected to align in the direction of the flow or shear, the viscosity needs to be treated as a second-order tensor, that is, the values of the viscosity under the same condition are different when different directions are referred. Only at the low (zero) shear limit may the particles be randomly distributed and have an isotropic rheological behavior. 

Since a milestone paper in Science in 1996, the group of El-Sayed [238-240] has led the field of synthesis and applications of shape-specific nanoparticles. A classical example of the detailed study of metal-particle shape effects in catalysis was reported by Narayanan and El-Sayed using unsupported polyvinylpyrollidone (PVP) polymer-capped Pt shape-specific colloids (cubes, spheres, and tetrahedra) in a model electron transfer reaction between hexacyanoferrate(III) and thiosulfate... 

Wang, J, et al. 2011. Particle shape effects in discrete element modeling of cohesive angular particles. Granular Matter 13 1-12. 

AG Dixon. Correlations for wall and particle shape effects on fixed bed bulk voidage. Can J Chem Eng 66 705-708, 1988. 

PARTICLE SHAPE EFFECT ON THE DIELECTRIC PROPERTIES OF ER SUSPENSIONS AND THE ER EFFECT... 

Cheng, L., Guoding, Z., Naka, M., 2(X)1. Particle shape effect on ductihty of SiC particle reinforced LD2 matrix composite investigated by AFM-based nanoindentation. Transactions of Nonferrous Metals Society of China 4(11). 

Concentration Effect Absorption Effect Hydrodynamic Effect Multiangle Analysis - Fingerprint Particle Shape Effect Distribution Type... 

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