Fractionated voiding

Specific gravity is the most critical of the characteristics in Table 3. It is governed by ash content of the material, is the primary deterrninant of bulk density, along with particle size and shape, and is related to specific heat and other thermal properties. Specific gravity governs the porosity or fractional void volume of the waste material, ie. 

FIG. 17-2 Schematic phase diagram in the region of upward gas flow. W = mass flow solids, lh/(h fr) E = fraction voids Pp = particle density, Ih/ft Py= fluid density, Ih/ft Cd = drag coefficient Re = modified Reynolds uum-her. (Zenz and Othmei Fluidization and Fluid Particle Systems, Reinhold, New York, 1960. )... 

Fraction voids in bed of solids Dimensionless Dimensionless Dimensionless... 

Re = R nolds number, dpS UolV Sc = Schmidt number, V/D D = axial dispersion coefficient dp = Diameter of particle or empty tube = Fraction voids in packed bed Uq = Superficial velocity in the vessel. 

Relations expressing the fractional voids in a ring packed bed are useful in estimated the e values for a/e determinations [47]. The average deviation is 2.6%. 

Volume fraction voids in snow- Tensile strength of pellet in the... 

The laboratory tests as well as the industrial canister tests demonstrated excellent long-term stability of both activity and mechanical strength for the VK69 formulations selected for the tests. For the optimisation of pellet size and shape, the results for activity, fractional void, and pressure drop must be compared as shown in Table 6 for 10 mm rings, 12 mm Daisy-shape, and 9 mm Daisy-shape. 

The mixing properties in a fluidized bed are a strong function of the fraction voids. Minimum values of radial Peclet numbers udp/Djt) are observed at e = 0.7, corresponding to a transition in the type of particle circulation in the bed. 

The packing particle density and fraction voids strongly affect the radial scale of turbulence (Ab) larger scales are found for beds containing denser particles at a given fraction voids. The scale of turbulence has a maximum value at e = 0.7. 

The root-mean-square value of the radial velocity fluctuation [ C y] /C varies only slightly with fraction voids and appears to be independent of particle density. 

The scale of concentration fluctuation (A) is affected by the fraction voids in the same manner as the scale of turbulence, but it is not greatly influenced by the particle density. The scales of concentration fluctuation show that there are isoconcentration eddies several times the size of a packing particle. ... 

X/i o. Dimensionless axial variable = X/L. Dimensionless axial variable Dirac delta function, see reference (S20) Fraction voids in packed bed Eigenvalue in Eq. (67c), (68c), and (69c) Mean of tracer curve at measurement point (dimensionless) Difference in means of the tracer curves at the two measurement points Xm and Xa Kinematic viscosity of fluid... 

W. O. Smith (1933) suggested the following riiethod of interpolation for securing the number of contacts between spheres of equal diameter. Let denote the fractional voids, and assume that a linear relationship exists between the number of contacts, N, and the voids. Referring to Figure 29, if Ns denotes the number of contacts per unit volume for a... 

C = coefficient of heat conductivity measured in heat units per unit time per unit of packing volume per deg temperature difference usual units are cal per sec per deg C per cc m = a constant for limestone packings, m = 0.0073 for iron ore, 0.0105 anthracite and other coals, 0.0050 blast-furnace charge, 0.0072. The values are in metric units. q = volume of gas flow per unit-time per square unit of cross-sectional packing area, expressed as liters per sec per sq cm T = temperature, deg abs, C = fractional voids (dimensionless) d = diameter of particles, cm... 

When applied to fluidization, the empirical correlation between the drag coefficient CD and the Reynolds number Re needs to be extended to account for the automatic adjustment in particle array that results in a regular increase in the fraction void e in the interstitial spaces with increased fluid flow— that is,... 

Fig. 13.2 Structure of perfluorosulphonic acid co-polymer (Nation ). The Yeager Three Phase Model, based on a three-phase clustered system with interconnecting channels within the polymer. (a) Fluorocarbon backbone, (b) interfacial region of relatively large fractional void volume containing some pendant side chains, some water and sulphate groups, (c) clustered regions...

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