The boundary-layer feature and the forces on the particle are analyzed in detail, and the motion parameters of the particle in the gas-solid rotary flow are divided into two parts according to the $r-z$ meridian and $r-θ$ cross section. The Lagrange method is then applied, the 3-D mathematical model of particle motion in the gas-solid rotary flow is presented, and the Gear integral method is applied to simulate the motion characteristics of the particles. The results show that the centrifugal force and Saffman lift force play important roles in the process of the particle being separated from the gas-solid rotary flow in the rotary boundary layer. The velocity gradient of radial direction is the biggest, and that of tangent direction is the smallest. For a higher density ratio of gas to solid, the deposition performance of the particle depends not only on the inlet flow velocity but also on the range of the particle diameter. Reasonable velocity gradient matching of the three directions $(r,z,θ)$ in the gas-solid rotary flow is useful to improve the separation efficiency of the rotary separators.

1.
Dietz
,
P. W.
, 1981, “
Collection Efficiency of Cyclone Separator
,”
AIChE J.
0001-1541,
27
(
6
), p.
888
.
2.
Enliang
,
L.
, 1989, “
A New Collection Theory of Cyclone Separator
,”
AIChE J.
0001-1541,
35
(
4
), p.
666
.
3.
Dirgo
,
J.
, 1985, “
Cyclone Collection Efficiency: Comparison of Experimental Results With Theoretical Predictions
,”
Aerosol Sci. Technol.
0278-6826,
4
, p.
401
.
4.
Boysan
,
F.
, 1983, “
Experimental and Theoretical Studies of Cyclone Separator
,”
Inst. Chem. Eng. Symp. Ser.
0307-0492,
69
, p.
305
.
5.
Clift
,
R.
, 1991, “
A Critique of Two Models for Cyclone Performance
,”
AIChE J.
0001-1541,
237
(
2
), p.
285
.
6.
Kim
,
W. S.
, and
Lee
,
J. W.
, 1997, “
Collection Efficiency Model Based on Boundary Layer Characteristics for Cyclones
,”
AIChE J.
0001-1541,
43
(
10
), pp.
2446
2455
.
7.
Smoot
,
L. D.
, and
Pratt
,
D. T.
, 1992,
Coal Combustion and Gasification
,
Beijing Science Press
, pp.
147
157
.
8.
Odar
,
F.
, 1966, “
Verification of Proposed Equation for Calculation of Forces on a Sphere Accelerating in a Viscous Fluid
,”
J. Fluid Mech.
0022-1120,
25
(
3
), pp.
591
592
.
9.
Basset
,
A. B.
, 1961,
A Treatise on Hydrodynamics
,
Deighton, Bell and Co.
,
Cambridge
, 1888;
Dover Publications
, New York, p.
135
.
10.
Saffman
,
P. G.
, 1968, “
The Lift on a Small Sphere in a Slow Shear Flow
,”
J. Fluid Mech.
0022-1120,
22
(
3
);
Correction appeared in
Saffman
,
P. G.
, 1968
J. Fluid Mech.
0022-1120,
31
(
3
), p.
624
.
11.
Brenner
,
H.
, 1961, “
The Slow Motion of a Sphere Through a Viscous Fluid Towards a Plane Surface
,”
Chem. Eng. Sci.
0009-2509,
16
, pp.
242
251
.
12.
Maude
,
A. D.
, 1961, “
End Effects in a Falling-sphere Viscometer
,”
Br. J. Appl. Phys.
0508-3443,
12
, pp.
293
295
.
13.
Hinze
,
J. O.
, 1975,
Turbulence
,
2nd ed.
,
McGraw-Hill
,
New York
, pp.
626
628
.
14.
Hau
,
D.
, 1988, “
Measurement of the Mean Force on the Particle Near a Boundary in Turbulent Flow
,”
J. Fluid Mech.
0022-1120,
187
, pp.
457
466
.
15.
Kallio
,
G. A.
, and
Reeks
,
M. W.
, 1989, “
A Numerical Simulation Particle Deposition in Turbulent Boundary Layers
,”
Int. J. Multiphase Flow
0301-9322,
15
, pp.
433
446
.
16.
Roahiainen
,
P. O.
, and
Stachiewicz
,
J. W.
, 1970, “
On the Deposition of Small Particles From Turbulent Streams
,”
J. Heat Transfer
0022-1481,
92
, pp.
169
177
.