Filtration and Sampling of Aerosols by Fibrous Filters - Aerosols: Measurement, Dosimetry, and Health Effects - page 446

0.6

0.4

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y

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-0.4

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-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

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FIGURE 17.4 Streamlines in the vicinity of a dumbbell cross-sectional iber. Radii of ibers joined with a
jumper b = 0.1, φ = 90°, jumper length on the symmetry axis (gap) d = 0.1, jumper thickness δ = 0.08; stream-
lines in the vicinity of an elliptic iber/streamlines correspond to the values of the low function Ψ = ± [5 × 10 −5 ,
5 × 10 −4 , 5 × 10 −3 , 2.5 × 10 −2 , 0.05, 0.1:0.1:0.5]. (From Kirsh, V.A. et al., Colloid J ., 70(5), 547, 2008.)

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15

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FIGURE 17.5 Drag force of ibers with different cross-sectional versus the midsection width: 1, dumbbell
iber; 2, a couple of parallel ibers (radius b is ixed, the gap varies); 3, elliptical iber (semi minor axis equals b );
φ = 90°, b = 0.1, dumbbell jumper thickness δ = 0.04. (From Kirsh, V.A. et al., Colloid J ., 70(5), 547, 2008.)

In particular, it was shown both theoretically and experimentally that if ibers are coupled in a
row the couple drag force equals the drag force of separate ibers. Model of a separate row was
used to study conined low in the vicinity of porous ibers [39] and ibers covered with permeable
membranes [40], and while modeling low in porous sphere particle sediments [41]. It was only the
idea of separate rows that appeared to be effective in the experimental study of preliminary air
purifying of large particles. A model ilter made of rows of parallel equidistant wires with 2 a = 8.9
and 2 h = 62 μm was used to study (1) inertia deposition of micron and submicron drops at St < 10 and
Re < 1 [42] and (2) pressure drop variation while solid [43] and liquid [44] particles accumulating.