Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 9, pp. 1699−1704. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.G. Laptev, M.I. Farakhov, 2008, published in Khimicheskaya Promyshlennost’, 2008, Vol. 85, No. 3, pp. 156−162.
PROCESSES AND DEVICES
OF CHEMICAL MANUFACTURES
Model of an Aerosol Removal in Devices with Nozzles
A. G. Laptev and M. I. Farakhov
Engineering Implementation Center “Inzhekhim”, Russia
e-mail: email@example.com, firstname.lastname@example.org
Received May 22, 2008
Abstract—Using stochastic model and an impulse balance in a boundary layer the equations for efﬁ ciency
computation of the nozzle devices at gas scrubbing from aerosol particles were derived.
The devices for the gas scrubbing from solid and
liquid mechanic inclusions are important designing
technological devices in chemical, gas and related
branches of industry.
Dryers, furnaces, dispersers, pumps, mass and heat
exchangers and many other type of equipment can not
operate without effective gas scrubbing system. Variety
of work conditions and targets necessitates of designing
the new removal equipment and of improving their
efﬁ ciency calculation. Nowadays we have accumulated
some experience in solution of these problems. However
despite considerable achievements in a theory and a
practice of gas scrubbing a series of the problems required
new solutions remain.
Various theoretical models of a turbulent precipitation
of particles on a wall (or a liquid ﬁ lm) of a channels are
known. In dependence on the main accepted mechanism
these models are divided into ﬁ ve groups:
1) free-inertial subgroup that based on a conception
of free inertial ejection of particles from vortexes at the
2) convective inertial subgroup that associates the
precipitation with inertial effects at invasion of large
vortexes in a boundary layer;
3) rise migration subgroup that associates the
precipitation of particles with their rise migration and
4) effective diffusion subgroup proceeding from a
suggestion that a coefﬁ cient of turbulent diffusion of
the particles is higher than one of a gas in the near-wall
region due to the inertness;
5) turbulent migration subgroup that takes into account
the turbulent migration of particles to the channel wall
caused by a amplitude gradient of pulse cross component
of a gas speed.
The turbulent inertial mechanism is the most
signiﬁ cant for an experience of the gas scrubbing from
a ﬁ ne dispersion phase. It is assumed that in this case
all particles on the distance of the length of an inertial
are precipitated on the wall and their
initial velocity corresponds to quadratic mean velocity
of turbulent pulsations u
It should be noted that a movement of particles in
crosswise direction within a ﬂ ow core occurs due to the
turbulent pulsations (turbulent migration mechanism) and
near the wall due to decaying turbulent pulsations in the
boundary layer (inertial mechanism).
An intensity of the turbulent precipitation is described
by the precipitation velocity (by turbulent migration of the
particles, m/s): u
= j/n, that is, by amount of the particles
precipitated on unit surface for unit time.
It is assumed [1, 2] that for approximate estimation of
the intensity of the particle separation on the channel wall
(ﬁ lm) concentration of the dispersed phase in the distance
from the walls (out of the boundary layer) resulting
from turbulent mixing is determined exclusively by the
turbulent migration and diffusion.