Surface-volume mean diameter

Clb liquid reactant concentration (moles/m ) ds bubble diameter (surface-volume mean) (m)... [Pg.360]

Note the mean diameter used by Geldart (1973) is actually a surface volume mean diameter dsvm, based on Eq. (3). However, comparing the fluidization curves of several materials with the Geldart (1973) diagram (e.g., fly ash, pulverized coal, coarse ash, PVC powder and screened coke), Wypych (1989b) found the following ... [Pg.720]

Substituting all the possible combinations of characteristics, i.e. values of p and q, info equation 1.10 gives rise to a number of differenf definitions of the mean size of a distribution. At minimum fluidization the drag force acting on a particle due to the flow of fluidizing gas over the particle is balanced by the net weight of fhe particle. The former is a function of surface area and the latter is proportional to particle volume. Consequently the surface-volume mean diameter, with p = 2 and = 3, is the most appropriate particle size to use in expressions for minimum fluidizing velocity. It is defined by equafion 1.11... [Pg.25]

The definition of the surface-volume mean diamefer given by equation 1.11 must be modified for use wifh dafa from a sieve analysis. By assuming that the shape and density of fhe particles are constant for all size fractions, a number distribution can be transformed fo a mass distribution (Smith, 2003) and therefore the surface-volume diameter becomes... [Pg.25]

For non-spherical particles, values of sphericity lie in the range 0 < < 1. Thus, the effective particle diameter for fluidization purposes is the product of the surface-volume mean diameter and the sphericity (Kunii and Levenspiel, 1991). The sphericity of regular-shaped particles can be deduced by geometry whilst the sphericity of irregular-shaped... [Pg.26]

Xi lower limit of size distribution Xu upper limit of size distribution X3 2 surface-volume mean diameter... [Pg.52]

Note that re-arranging the above relationship to give d/, = 6ea/a shows how a mean bubble size might be calculated from measurements of and a. A mean bubble diameter defined in this way (Volume 2, Chapter 1) is called a Sauter mean (i.e. a surface volume mean see also Section 4.3.4). [Pg.211]

The Sauter-mean diameter, a surface-volume mean, can be calculated by measuring drop sizes directly from photographs of a dispersion according to Eq. (9.21). [Pg.233]

Examples. To determine the surface-volume mean diameter from a number distribution, put t = 0,r = 2,k= 1. [Pg.127]

Light attenuation is a simple, widely used method for determining interfacial area, i.e. surface-volume mean diameter if droplet concentration is known but cannot be used for size distribution determination [206-208]. [Pg.511]

The surface volume mean diameter for a suspension of spherical particles is given by ... [Pg.533]

Another important mean diameter in the pharmaceutical industry that weighs the effects of both the total surface area and volume is the surface-volume mean diameter. This mean diameter can be very useful when the specific surface area is desired as it is inversely related to the specific surface area. [Pg.45]

Example 6. Calculate the volume, surface factor and specific surface for a perfect sphere with density of l.Og/cm and surface-volume mean diameter of 100pm. [Pg.57]

McClements and Dungan reported, based on light scattering measurements, that the Sauter or surface-volume mean diameter of drops in a dilute emulsion of n-hexadecane in water remained constant while the number of drops decreased with time during solubilization of the hydrocarbon into a 2 wt% solution of Tween 20 (sorbitan monolaurate). Weiss et al. found similar results for the same surfactant with n-tetradecane and n-octadecane. This result, which seems surprising in... [Pg.527]

Using 6-blade disc turbines in baffled tanks with pure liquids, i.e. coalescing systems, Calderbank measured interfacial area and hold-up and obtained an equation for the surface/volume mean bubble diameter (in SI units) ... [Pg.341]

Specific surface may be e q>ressed on a mass basis using the material density to modify the volume. The diameter of the here having the same equivalent ecific sur ce as the particle is sometimes termed the surface volume mean or the Sauter mean diameter. [Pg.492]

The correct mean particle diameter is therefore the surface-volume mean as defined above. (We saw in Section 1.6 that this may be calculated as the arithmetic mean of the... [Pg.21]

Determine the surface-volume mean diameter and the specific surface of the powder sample. [Pg.28]

A packed bed of solid particles of density 2500 kg/m occupies a depth of 1 m in a vessel of cross-sectional area 0.04 m. The mass of solids in the bed is 50 kg and the surface-volume mean diameter of the particles is 1mm. A liquid of density 800kg/m and viscosity 0.002Pas flows upwards through the bed, which is restrained at its upper surface. [Pg.165]

A 10 m long vertical standpipe of inside diameter 0.1 m transports solids at a flux of 100 kg/m s from an upper vessel which is held at a pressure 1.0 bar to a lower vessel held at 1.5 bar. The particle density of the solids is 2500 kg/m and the surface-volume mean particle size is 250 gm. Assuming that the voidage is constant along the standpipe and equal to 0.50, and that the effect of pressure change may be ignored, determine the direction and flow rate of gas passing between the vessels. (Properties of gas in the system density, 1 kg/m viscosity, 2 x 10 Pas.)... [Pg.242]

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