The quality and efficiency of laser-aided direct metal deposition largely depends on the powder stream structure below the nozzle. Numerical modeling of the powder concentration distribution is complex due to the complex phenomena involved in the two-phase turbulence flow. In this paper, the gravity-driven powder flow is studied along with powder properties, nozzle geometries, and shielding gas settings. A 3-D numerical model is introduced to quantitatively predict the powder stream concentration variation in order to facilitate coaxial nozzle design optimizations. Effects of outer shielding gas directions, inner/outer shielding gas flow rate, powder passage directions, and opening width on the structure of the powder stream are systematically studied. An experimental setup is designed to quantitatively measure the particle concentration directly for this process. The numerical simulation results are compared with the experimental data using prototyped coaxial nozzles. The results are found to match and then validate the simulation. This study shows that the particle concentration mode is influenced significantly by nozzle geometries and gas settings.

1.
Steen
,
W. M.
,
McLean
,
M. A.
, and
Shannon
,
G. J.
, 1997, “
Shaping by Laser Cladding
,”
Laser Assisted Net Shape Engineering 2
,
Proceedings of the LANE’97
, pp.
115
127
.
2.
Vetter
,
P. A.
,
Engel
,
T.
, and
Fontaine
,
J.
, 1994, “
Laser Cladding: The Relevant Parameters for Process Control
,”
Proceedings of SPIE
, Vol.
2207
, pp.
452
462
.
3.
Lin
,
J.
, and
Steen
,
W. M.
, 1998, “
Design Characteristics and Development of a Nozzle for Coaxial Laser Cladding
,”
J. Laser Appl.
1042-346X,
10
(
2
), pp.
55
63
.
4.
Lin
,
J.
, 2000, “
Numerical Simulation of the Focused Powder Streams in Coaxial Laser Cladding
,”
J. Mater. Process. Technol.
0924-0136,
105
(
1
), pp.
17
23
.
5.
Lin
,
J.
, 2000, “
Laser Attenuation of the Focused Powder Streams in Coaxial Laser Cladding
,”
J. Laser Appl.
1042-346X,
12
(
1
), pp.
28
33
.
6.
Neto
,
O. D.
, and
Vilar
,
R.
, 2002, “
Physical-Computational Model to Describe the Interaction Between a Laser Beam and a Powder Jet in Laser Surface Processing
,”
J. Laser Appl.
1042-346X,
14
(
1
), pp.
46
51
.
7.
Pinkerton
,
A. J.
, and
Li
,
L.
, 2004, “
Modeling Powder Concentration Distribution from a Coaxial Deposition Nozzle for Laser-Based Rapid Tooling
,”
J. Manuf. Sci. Eng.
1087-1357,
126
(
1
), pp.
33
41
.
8.
Mostafa
,
A. A.
,
Mongia
,
H. C.
,
McDonell
,
V. G.
, and
Samuelsen
,
G. S.
, 1990, “
An Experimental and Numerical Study of Particle-Laden Coaxial Jet Flows
,”
Int. J. Heat Fluid Flow
0142-727X,
11
(
2
), pp.
90
97
.
9.
Fan
,
J.
,
Zhao
,
H.
, and
Cen
,
K.
, 1992, “
An Experimental Study of Two-Phase Turbulent Coaxial Jets
,”
Exp. Fluids
0723-4864,
13
(
4
), pp.
279
287
.
10.
Budilarto
,
S. G.
, and
Sinclair
,
J.
, 2000, “
Velocity Ratio Effect on Gas and Particle Motions in a Two-Phase Turbulent Coaxial Jet
,”
2000 Annual AIChE Meeting
, Los Angeles, CA.
11.
Wicker
,
R. B.
, and
Eaton
,
J. K.
, 2001, “
Structure of a Swirling, Recirculating Coaxial Free Jet and its Effect on Particle Motion
,”
Int. J. Multiphase Flow
0301-9322,
27
(
6
), pp.
949
970
.
12.
Gouesbet
,
G.
, and
Berlemont
,
A.
, 1999, “
Eulerian and Lagrangian Approaches for Predicting the Behavior of Discrete Particles in Turbulent Flows
,”
Prog. Energy Combust. Sci.
0360-1285,
25
(
2
), pp.
133
159
.
13.
Sommerfeld
,
M.
, 1992, “
Modelling of Particle-Wall Collisions in Confined Gas-Particle Flows
,”
Int. J. Multiphase Flow
0301-9322,
18
(
6
), pp.
905
926
.
14.
Huber
,
N.
, and
Sommerfeld
,
M.
, 1998, “
Modelling and Numerical Calculation of Dilute-Phase Pneumatic Conveying in Pipe Systems
,”
Powder Technol.
0032-5910,
99
(
1
), pp.
90
101
.
15.
Tsuji
,
Y.
,
Shen
,
N. Y.
, and
Morikawa
,
Y.
, 1989, “
Numerical Simulation of Gas-Solid Flows. 1: Particle-to-Wall Collision
,” Technology Reports of the Osaka Univ., Vol.
39
, No.
1975
, pp.
233
241
.
16.
Tsuji
,
Y.
,
Shen
,
N. Y.
, and
Morikawa
,
Y.
, 1991, “
Lagrangian Simulation of Dilute Gas-Solid Flows in a Horizontal Pipe
,”
Adv. Powder Technol.
0921-8831,
2
(
1
), pp.
63
81
.
17.
Launder
,
B. E.
, and
Spalding
,
D. B.
, 1972, “
Lectures in Mathematical Models of Turbulence
,” New York, Academic Press.
18.
Pan
,
H.
, and
Liou
,
F.
, 2005, “
Numerical Simulation of Metallic Powder Flow in a Coaxial Nozzle for the Laser Aided Deposition Process
,”
J. Mater. Process. Technol.
0924-0136,
168
(
2
), pp.
230
344
.
19.
Sommerfeld
,
M.
,
Kohnen
,
G.
, and
Ruger
,
M.
, 1993 “
Some Open Questions and Inconsistencies of Lagrangian Particle Dispersion Models
,”
Ninth Symposium on Turbulent Shear Flows
, Paper No. 15-1.
20.
Dunkley
,
J.
, 2002, “
Anti-Satelliting for Powders Produced by Inert Gas Atomization
,”
Mater. World
0967-8638,
10
(
7
), pp.
24
25
.
21.
Mirtich
,
B.
, 1996, “
Impulse-Based Dynamic Simulation of Rigid Body Systems
,” Ph.D. thesis, University of California, Berkeley.
22.
Nikjooy
,
M.
,
Karki
,
K. C.
,
Mongia
,
H. C.
,
McDonell
,
V. G.
, and
Samuelsen
,
G. S.
, 1989, “
A Numerical and Experimental Study of Coaxial Jets
,”
Int. J. Heat Fluid Flow
0142-727X,
10
(
3
), pp.
253
260
.
23.
Angioletti
,
M.
,
Di Tommaso
,
R. M.
,
Nino
,
E.
, and
Ruocco
,
G.
, 2003, “
Simultaneous Visualization of Flow Field and Evaluation of Local Heat Transfer by Transitional Impinging Jets
,”
Int. J. Heat Mass Transfer
0017-9310,
46
(
10
), pp.
1703
1713
.
24.
Massah
,
H.
,
Shahnam
,
M.
,
Shaffer
,
F.
, and
Sinclair
,
J.
, 1995, “
A Comparative Application of a Particle Tracking Velocimetry and Laser Doppler Velocimetry for Particle-Wall Collision Measurements
,”
FED (Am. Soc. Mech. Eng.)
0888-8116,
218
, pp.
145
150
.
25.
Lin
,
J.
, 1999, “
Concentration Mode of the Powder Stream in Coaxial Laser Cladding
,”
Opt. Laser Technol.
0030-3992,
31
(
3
), pp.
251
257
.
26.
Thakar
,
Y. D.
,
Pan
,
H.
, and
Liou
,
F.
, 2004, “
Numerical and Experimental Analysis of the Powder Flow Streams in the Laser Aided Material Deposition Process
,”
Proceeding of the 15th Conference on Solid Freeform Fabrication
,
Austin
, TX, pp.
512
522
.
27.
Pan
,
H.
,
Thakar
,
Y. D.
, and
Liou
,
F.
, 2004, “
Numerical and Experimental Study of Shielding Gas Orientation Effects on Particle Stream Concentration Mode in Coaxial Laser Aided Material Deposition Process
,”
ASME International Design Engineering Technical Conferences
, DETC2004–57049, Salt Lake City, UT.
28.
Buresi
,
G.
,
Talamelli
,
A.
, and
Petagna
,
P.
, 1994, “
Experimental Characterization of the Velocity Field of a Coaxial Jet Configuration
,”
Exp. Therm. Fluid Sci.
0894-1777,
9
(
2
), pp.
135
146
.
29.
Tsuji
,
Y.
,
Morikawa
,
Y.
,
Tanaka
,
T.
,
Nakatsukasa
,
N.
, and
Nakatani
,
M.
, 1987, “
Numerical Simulation of Gas-Solid Two-Phase Flow in a Two-Dimensional Horizontal Channel
,”
Int. J. Multiphase Flow
0301-9322,
13
, pp.
671
684
.
30.
Sommerfeld
,
M.
, and
Huber
,
N.
, 1999, “
Experimental Analysis and Modeling of Particle-Wall Collisions
,”
Int. J. Multiphase Flow
0301-9322,
25
(
6-7
), pp.
1457
1489
.
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