MODELING OF AIR AND DUST FLOWS IN THE RANGE OF ACTION
OF A ROUND SUCTION FUNNEL ABOVE AN IMPERMEABLE PLANE.
PART 2. CHARACTERISTICS OF SEPARATION REGION
AND EFFICIENCY OF CAPTURE OF DUST PARTICLES
K. I. Logachev,
O. A. Averkova,
E. I. Tolmacheva,
A. K. Logachev,
and V. G. Dmitrienko
Translated from Novye Ogneupory, No. 2, pp. 62 – 66, February, 2016.
Original article submitted February 24, 2015.
Current near a round local ventilation suction port in the form of a funnel situated above an impermeable plane
is considered. Limiting trajectories of dust particles are constructed in the velocity field found from a new
computer program and the capture coefficient as a function of the slope and length of the funnel and distance
from the plane is determined. The geometric dimensions of the separation region at the inlet to the funnel as
functions of the distance from the plane and the length of the funnel are determined.
Keywords: local ventilation suction port, dust particles, limiting trajectories, ventilation, method of discrete
By the criterion of efficiency of a local ventilation func-
tion port — funnel for a dust particle with given geometric
and physical properties we will understand the capture coef
ficient given by
k = V
is the volume of ventilation of a suction port with a
funnel and V
the volume of ventilation of a suction port
without a funnel.
Obviously, k ³ 1. The greater is k, the more efficient is
suction. The proposed capture coefficient is a more meaning
ful efficiency criterion of a local ventilation suction port than
is the coefficient of irregularity, since it takes into account
not only the vertical component of the velocity of the air, but
also the horizontal component, which entrains polluting mat
ter closer to the axis of symmetry of the suction port, i.e.,
into the zone of more efficient capture.
The following initial data and discreteness parameters
are used in the calculations: density of a dust particle
= 2500 kg/m
; coefficient of dynamic form of particle
c = 1; free-fall acceleration g = 9.81 m/sec
; density of air
= 1.2 kg/m
; kinematic viscosity of air v=1.5 ´ 10
step of integration of system of ordinary differential
Dt = 0.00005 sec; discreteness step
= 0.0025 m; length of walls of nozzle and radius of imper
meable plane 60R; step in construction of streamline
0.00001 m; circulation of annular vortices forming the free
surface of the current g = –0.02; and average velocity in suc
tion port v
= 10 m/sec. The calculations were performed
with R = 0.1 m and the results were then reduced to
dimensionless form. The number of iterations in the process
of determining the free surface of the current was fixed and
equal to 15.
DYNAMICS OF DUST PARTICLES
Streamlines and limiting trajectories of dust particles at
suction rates of 10 m/s for funnels of length 1, 3, and 5
gauges are presented in Figs.1–3.
The limiting trajectories of dust particles with diameter
of 20, 40, 60, and 80 µm were constructed. Particles with a
diameter of 20 µm are characterized by the greatest length of
Refractories and Industrial Ceramics Vol. 57, No. 1, May, 2016
1083-4877/16/05701-0103 © 2016 Springer Science+Business Media New York
Part 1 was published in No. 12 (2015) of the present journal.
FGAOU VPO Shukhov Belgorod State Technological University,
cf. Eq. (7), Part 1.