Adhesion of particles in fibrous air filters
G.P. Broom
2134/15464
https://repository.lboro.ac.uk/articles/thesis/Adhesion_of_particles_in_fibrous_air_filters/9238094
A fundamental examination of particle impact has been carried
out to determine the adhesion characteristics of particles in fibrous
filters over a range of impact parameters.
High speed films were taken of the impact of monosized glass particles
onto the edge of a slowly rotating wheel. The subsequent adhesion
probability was calculated from the films using a frame by frame digital
analyser and a digital computer. The adhesion probability and the
coefficient of restitution for particles of 4.7 µm, 8.6 µm and 11 µm
diameter were determined for two angles of impact, over a range of impact
velocities. The magnitude of the adhesion probability and the coefficient
of restitution as a function of particle diameter and impact velocity
is shown to be in agreement with theoretical reasoning. The effect of
the surface properties on the adhesion probability were investigated
by studying the impact of particles on wheels machined from differing
materials.
The adhesion characteristics were incorporated into a theoretical
model to predict the single fibre efficiency of a fibrous filter over a
range of operating conditions. The Kuwabara flow field was used in the
model to describe the gas flow through the filter.
The grade efficiency of a knitted stainless steel model filter operating
in the high inertia regime was determined for feldspar particles of
diameter between 2 µm and 22 µm. The effect of the operation conditions
on the single fibre efficiency were shown to be in accordance with the
effect predicted from theory. The influence of dust loading, test dust
size distribution and filter depth on the single fibre efficiency was
studied. The effect of these parameters is described mechanistically
2014-08-07 11:03:12
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Chemical Engineering not elsewhere classified