Single fiber collection efficiency

Therefore, from Eq. (8.33), the single fiber collection efficiency by inertial impaction is... 

Effect of Multiple Layers and Packing All correlations for the collection efficiency discussed so far are based on the ideal case of a single cylindrical collector. Now, let s examine a filter unit consisting of randomly oriented multiple layers. Consider an area (A) of filter at a right angle to the gas flow and with a depth dh. If the packing density a is defined as the volume of fiber per unit volume of filter bed, the velocity within the filter void space is equal to... 

Consider a clean house bag filter filled with randomly assembled fibers. The porosity of the filter is 0.97, and the fibers have an effective diameter of 10 pm. The length of the filter is 0.1 m. The viscosity of air is 1.8 x 10-5 kg/m s. For a velocity of the dust-laden air of 0.2 m/s, and a collection efficiency of a single fiber of 1.50 percent, estimate the overall efficiency of the filter. To reach a collection efficiency of 99.99 percent, what is the minimum length of this type of filter At this minimum length, what is the overall pressure drop ... 

The already fairly efficient collection efficiency of parallel n-around-1 probe has been further improved by modifications to the probe tip, four of which are shown in Figure 12.12. The single-fiber configuration has the advantage of complete overlap of excitation and collection regions and has been used successfully for fluorescence experiments. However, the background scattering... 

Fibrous deep bed fillers can be modeled as a collection of single cylindrical fibers set normal to the Row of an aerosol. The removal efficiency for the single fibers cun be e.stimated from theory if the gas velocity distribution around the fibers (cylinders) is known. 

Here, Q/. and Qg are the volumetric liquid and gas flow rates, respectively, in m /s ddr aud Udr are the diameter and velocity of the drop falling in a gas moving with a velocity Vg, so that (Vg-Udr) is the relative velocity between the drop and the gas q is the particle collection efficiency of an individual droplet, somewhat analogous to the single fiber efficiency E,s due to inertial impaction, (6.3.42a). Calvert (1984) has obtained the following expression for the overall Venturi scrubber efficiency Ep after incorporating an appropriate expression for the individual drop collection efficiency q ... 

The theoretical expression for the collection efficiency of a single isolated fiber, due solely to interception effects, can be estimated from... 

This equation is a reasonable basis for air sterilizing filter design. The single fiber efficiency, n, to use in this equation when experimental data are lacking is that based on collection due solely to interception effects estimated at an air velocity where minimal filtration efficiency is expected. 

Coalescing demister pads have been used in some single absorption plants instead of packed fiber beds to remove mist from the stack gas. For submicrometer particle collection, these devices are not as efficient as packed fiber beds. Nevertheless, they have been used in some plants to obtain nearly... 

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