Environmental Engineering Reference
In-Depth Information
It should be noted that the cell model which is very fruitful while solving many problems in the
iltration theory appeared to be not quite applicable to studying the inertia deposition because the
deposition eficiency is strongly affected by the prequel of the particle movement far off the iber.
So, taking this into account, model ilters consisting of separate non-affecting each other rows of
parallel equidistant ibers perpendicular the low are chosen for experimental and theoretical study
of the particles inertia deposition (Section 17.4.1).
At low air low velocity through the ilter, which conforms to the condition Re << 1, particle
deposition depends strongly on the iber system packing density and is determined by the Stokes
number and the interception parameter R . With the increase of velocity U the linear relation between
pressure drop and velocity is observed to break. Flow lines in the vicinity of ibers start being asym-
metric, which slightly affects the iber resisting force, but strongly inluences the particle capture
coeficient value. In this case the inertia particle deposition must depend on Re as well.
In the recent paper [83] the inertia particle deposition has been numerically studied for various
deposition modes. Figures 17.11 and 17.12 present examples of the capture coeficients calculation
1
2
1
4
0.1
3
-5
-6
η
0.01
0.2
1
10
St
FIGURE  17.11  Capture coeficient versus St : (1, 3) considering Re ; (2, 4) Stokes low: 2 а = 10 μm; (1, 2)
r p = 2 μm; (3, 4) r p = 1 μm; a/h = 0.1419; (5, 6) experiment (From Kirsch, A.A. and Fuchs, N.A., Ann. Occup.
Hyg ., 10, 23, 1967.): 5, R = 0.206; 6, R = 0.382. (From Kirsh, V.A. et al., Colloid J ., 72(2), 206, 2010.)
1
3
0.1
2
η
1
0.01
4
0.2
1
10
St
FIGURE 17.12  Capture coeficient versus St : curves (1, 3) considering Re ; (2, 4) the Stokes low: 2 а = 10 μm;
(1, 2) r p = 0.5 μm; (3, 4) r p = 0.25 μm; a/h = 0.1419. (From Kirsh, V.A. et al., Colloid J ., 72(2), 206, 2010.)
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