When gas turbine engines operate in environments where the intake air has some concentration of particles, the engine will experience degradation. Very few studies of such microparticles approaching their melting temperatures are available in open literature. The coefficient of restitution (COR), a measure of the particles' impact characteristics, was measured in this study of microparticles using a particle tracking technique. Part II of this study presents data taken using the Virginia Tech Aerothermal Rig and Arizona road dust (ARD) of 20–40 μm size range. Data were taken at temperatures up to and including 1323 K, where significant deposition of the sand particles was observed. The velocity at which the particles impact the surface was held at a constant 70 m/s for all of the temperature cases. The target on which the particles impacted was made of a nickel alloy, Hastelloy X. The particle angle of impact was also varied between 30 deg and 80 deg. Deposition of particles was observed as some particles approach their glass transition point and became molten. Other particles, which do not become molten due to different particle composition, rebounded and maintained a relatively high COR. Images were taken using a microscope to examine the particle deposition that occurs at various angles. A rebound ratio was formulated to give a measure of the number of particles which deposited on the surface. The results show an increase in deposition as the temperature approaches the melting temperature of sand.

References

References
1.
Goldsmith
,
W.
,
2002
,
Impact: The Theory and Physical Behaviour of Colliding Solids
,
Dover Publications
,
Mineola, NY
.
2.
Tabakoff
,
W.
,
Grant
,
G.
, and
Ball
,
R.
,
1974
, “
An Experimental Investigation of Certain Aerodynamic Effects on Erosion
,”
AIAA
Paper No. 74-639.10.2514/6.74-639
3.
Li
,
X.
,
Dunn
,
P. F.
, and
Brach
,
R. M.
,
2000
, “
Experimental and Numerical Studies of Microsphere Oblique Impact With Planar Surfaces
,”
Aerosol Sci. Technol.
,
31
(
5
), pp.
583
594
.10.1016/S0021-8502(99)00544-3
4.
Sommerfeld
,
M.
, and
Huber
,
N.
,
1999
, “
Experimental Analysis and Modelling of Particle-Wall Collisions
,”
Int. J. Multiphase Flow
,
25
(
6–7
), pp.
1457
1489
.10.1016/S0301-9322(99)00047-6
5.
Mok
,
C. H.
, and
Duffy
,
J.
,
1964
, “
The Behaviour of Metals at Elevated Temperatures Under Impact With a Bouncing Ball
,”
Int. J. Mech. Sci.
,
6
(2), pp.
161
175
.10.1016/0020-7403(64)90013-X
6.
Brenner
,
S. S.
,
Wriedt
,
H. A.
, and
Oriani
,
R. A.
,
1981
, “
Impact Adhesion of Iron at Elevated Temperatures
,”
Wear
,
68
(
2
), pp.
169
190
.10.1016/0043-1648(81)90086-7
7.
Tabakoff
,
W.
,
1991
, “
Measurements of Particles Rebound Characteristics on Materials Used in Gas Turbines
,”
J. Propul. Power
,
7
(
5
), pp.
805
813
.10.2514/3.23395
8.
Tabakoff
,
W.
,
Hamed
,
A.
, and
Murugan
,
D. M.
,
1996
, “
Effect of Target Materials on the Particle Restitution Characteristics for Turbomachinery Application
,”
J. Propul. Power
,
12
(
2
), pp.
260
266
.10.2514/3.24022
9.
Wakeman
,
T.
, and
Tabakoff
,
W.
,
1979
, “
Erosion Behavior in a Simulated Jet Engine Environment
,”
J. Aircr.
,
16
(
12
), pp.
828
833
.10.2514/3.58611
10.
Hamad
,
A.
, and
Tabakoff
,
W.
,
1994
, “
Experimental and Numerical Simulation of the Effects of Ingested Particles in Gas Turbine Engines
,” Erosion, Corrosion and Foreign Object Damage Effects in Gas Turbines, Propulsion and Energetics Panel (PEP) Symposium, Rotterdam, The Netherlands, Apr. 25–28, AGARD-CP-558, Paper No. 11.
11.
Reagle
,
C.
,
Delimont
,
J.
,
Ng
,
W.
,
Ekkad
,
S.
, and
Rajendran
,
V.
,
2013
, “
Measuring the Coefficient of Restitution of High Speed Microparticle Impacts Using a PTV and CFD Hybrid Technique
,”
Meas. Sci. Technol.
,
24
(
10
), p.
105303
.10.1088/0957-0233/24/10/105303
12.
Reagle
,
C. J.
,
Delimont
,
J.
,
Ng
,
W. F.
, and
Ekkad
,
S. V.
,
2013
, “
Study of Microparticle Rebound Characteristics Under High Temperature Conditions
,”
ASME J. Eng. Gas Turbines Power
,
136
(
1
), p.
011501
.10.1115/1.4025346
13.
Walsh
,
W. S.
,
Thole
,
K. A.
, and
Joe
,
C.
,
2006
, “
Effects of Sand Ingestion on the Blockage of Film-Cooling Holes
,”
ASME
Paper No. GT2014-25687.10.1115/GT2014-25687
14.
Crosby
,
J. M.
,
Lewis
,
S.
,
Bons
,
J. P.
,
Ai
,
W.
, and
Fletcher
,
T. H.
,
2008
, “
Effects of Temperature and Particle Size on Deposition in Land Based Turbines
,”
ASME J. Eng. Gas Turbines Power
,
130
(
5
), p.
051503
.10.1115/1.2903901
15.
Delimont
,
J. M.
,
Murdock
,
M. K.
,
Ng
,
W. F.
, and
Ekkad
,
S. V.
,
2014
, “
Effect of Temperature on Microparticle Rebound Characteristics at a Constant Impact Velocity
,”
ASME
Paper No. GT2014-25687.10.1115/GT2014-25687
16.
Nealy
,
D.
,
Mihelc
,
M.
,
Hylton
,
L.
, and
Gladden
,
H.
,
1984
, “
Measurements of Heat Transfer Distribution Over the Surfaces of Highly Loaded Turbine Nozzle Guide Vanes
,”
ASME J. Eng. Gas Turbines Power
,
106
(
1
), pp.
149
158
.10.1115/1.3239528
17.
Hylton
,
L.
,
Nirmalan
,
V.
,
Sultanian
,
B.
, and
Kaufman
,
R.
,
1988
, “
The Effects of Leading Edge and Downstream Film Cooling on Turbine Vane Heat Transfer
,” NASA Lewis Research Center, Cleveland, OH,
NASA
Report No. CR-182133.http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890004383.pdf
18.
Hinkley
,
D. V.
,
1969
, “
On the Ratio of Two Correlated Normal Random Variables
,”
Biometrika
,
56
(
3
), pp.
635
639
.10.1093/biomet/56.3.635
You do not currently have access to this content.