The Effect of Solid Admixtures on the Velocity of Motion of a Free Dusty Air Jet Page: 2 of 8
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NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
TECHNICAL MEMORANDUM 1450
THE EFFECT OF SOLID ADMIXTURES ON THE VELOCITY
OF MOTION OF A FREE DUSTY AIR JET*
By A. P. Chernov
In dusty air flows occurring in industrial practice in transport
by air pressure of friable materials, in the drying, annealing, and so
forth, of a pulverized solid mass in suspension, and in other processes,
the concentration of solid particles usually has a magnitude of the order
of 1 kg per 1 kg of air. At such a concentration, the ratio of the vol-
ume of the particles to the volume of the air is small (less than one-
thousandth part). However, regardless of this, the presence of a solid
admixture manifests itself in the rules for the velocity distribution
of the air in a dusty air flow. As a result, the rules of velocity
change are different for clean and for dusty air flows. The estimation
of the influence of the admixture on the velocity of the motion of the
flow presents a definitive interest. One of the attempts to estimate
that influence on the axial velocity of a free axially symmetrical jet
with admixtures was made by Abramovich (ref. 1).
Abramovich assumed beforehand that the fine particles of the admix-
ture in the jet are subject to the motion of the air (that is, that the
velocity of the admixture is approximately equal to the local velocity
of the air); he then took as the basis of his considerations, in solving
the problem, the condition that the amount of motion of the twophase
jet must be constant.
Proceeding from these assumptions, Abramovich obtained the relation-
ship of the velocity of the air moving along the axis of the axially sym-
metrical jet in relation to the-distance to the origin of the jet in the
following form
w
uhn _ .9 +Co ~ I
- 1 + CO (1)
uoIE %% 12l
RO as 0
where um and uO are, respectively, the velocity of the air on the
axis and in the initial section of the jet; s the distance from the
origin along the axis of the jet; RO> the initial radius of the jet;
wO, the initial velocity of the admixture; CO, the initia] concentration
of the particles; and a, the coefficient of turbulence of the jet.
*"K Voprosu o Vliyanii Tverdykh Primecei na Skorost' Dvizheniya
Svobodnoi Pylevozdushnoi Strui" Zhurnal Tekhnicheskoi Fiziki, Vol XXVI,
No. 5, 1956, pp. 1060-1065. ENGINEERING DEPT. LIBRARY
CHANCE VOUGgT AICRAFT
r n~ ~"~~ INCORPORATED.IlATr An...
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Chernov, A. P. The Effect of Solid Admixtures on the Velocity of Motion of a Free Dusty Air Jet, report, April 1957; (https://digital.library.unt.edu/ark:/67531/metadc64932/m1/2/: accessed April 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.