FE-14-1748

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Experimental Investigation of Solid Particle Erosion
in S-Bend
Quamrul H. Mazumder1
ASME membership: 1523811
Email: qmazumde@umflint.edu
Associate Professor, Mechanical Engineering
University of Michigan-Flint, USA
Kawshik Ahmed and Siwen Zhao
Research Assistant
ABSTRACT
Solid particle erosion is a micro-mechanical process that removes material from the surface. Erosion is a
leading cause of failure in fluid handling equipment such as pumps, pipes. An investigation was conducted
using an S-bend geometry with 12.7mm inside diameter, r/D ratio of 1.5 with three different air velocities and
two different particle sizes. This paper presents the preliminary results of an investigation to determine the
location of erosion for a wide range of conditions. The experimental results showed the location of maximum
erosion at 29-42 degrees from the inlet at 45.72 m/sec air velocity with 300 micron particle sizes.
KEYWORDS: Erosion, Multiphase Flow, S-bend, Particulated Flow
1.0 Introduction
Erosive wear damages in particulate gas-solid flows have been observed in different
industries, such as oil and gas pipe lines, aircraft, cyclone separators, boilers, fluidized
beds, gas turbines and coal gasification processes. Particle impact induced erosion was
recognized as one of the leading causes of premature and unpredicted failure modes in oil
and gas pipelines [1]. A number of factors contribute to the severity of erosion, including
_______________________________________________________________________
1
Current address: University of Michigan-Flint, 303 East Kearsley Street, Flint, MI 48502, USA
Journal of Fluids Engineering. Received December 11, 2014;
Accepted manuscript posted September 30, 2015. doi:10.1115/1.4031685
Copyright (c) 2015 by ASME
Accepted
ManuscriptNotCopyedited
Downloaded From: http://fluidsengineering.asmedigitalcollection.asme.org/ on 11/20/2015 Terms of Use: http://www.asme.org/about-asme/terms-of-use

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impact velocity, particle size and shape, and mechanical properties of both the target
material surface and the flow velocity [2]. Several investigations agreed that the erosion
rate is proportional to the exponent of the solid particle velocity or the fluid velocity
surrounding the particles [3]. This article presents the preliminary experimental results
examining the location of maximum erosion in an S-bend geometry.
2.0 Literature Review
Investigation by Wang and Shirazi showed that a long radius bend with an r/D>1.5
(where r is the elbow curvature radius and D is the diameter of pipe) has smaller
impingement angles than in a short radius bend [4]. Another important outcome of previous
investigations is the development of a mechanistic model that predicts erosion in elbows
with multiphase flow (gas-liquid-solid) by Mazumder, Siamack and Brenton [5].
When bends were less than 90°, the resulting erosion loss was smaller, but the
surface roughness increased due to vertical particle impact [6]. Several investigations
showed effective methods for erosion study, using CFD to predict erosion behavior at
different geometries, with different solid particles, and in different fluids [7] [1]. Previous
CFD analysis of U-bend geometry showed a location of maximum erosion at 182° from
inlet at 15.24 m/s air velocity and 50 micron sand [1].
The lead parameters in determining the strength of swirling flow are the Reynolds
number and the bend’s radius of curvature [8]. The flow in multiple bends is more complex
than in single bends due to the interaction of the flow dynamics within the two bends. The
great effect of a bend sweep angle and Reynolds number was studied by Niazmand and
Jaghargh. Their results showed that the Reynolds number is generally based on the
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diameter of the pipe. In S-bend or some other multiphase bend, however, the sweep angles
also have a large influence on flow [10]. The effect of the ratio of curvature on erosion in a
bend was shown in many previous research endeavors [10]. Experimental investigation of
erosion in an S-bend elbow at standard ratio (r/D =1.5) showed the location and magnitude
of maximum erosion at different velocities and particle sizes. In addition, analysis of
erosion in an S-bend elbow was compared to experimental results with good agreement
[10]. Wong, Solnordal, Swallow, Wang, Graham and Wu conducted long-term erosion of a
flat plate with 80m/sec air velocity and 150-300 micron sand at 0.030 kg/sec sand rate [11].
Chen, Brenton and Siamack performed CFD simulations and experimental validation on
elbows and plugged tees with a curvature ratio of 1.5 and relative plugged length of 1.5
[12]. Erosion predictions and experiments performed at three different air velocities
(50,100 and 150 ft/s) using an aluminum specimen showed that a plugged tee had less
erosion than a standard elbow with r/D=1.5. Mills and Mason reported the process of
erosion and location of maximum erosion in a bend for 70 and 230 micron sands [13]. No
significant difference in magnitude or location of erosion was observed for the above two
particle sizes. Fan, Yao, Zhang and Cen reported the importance of maintaining erosion test
conditions to reduce measurement uncertainties associated with mass loss measurements
when measuring erosion rates [14]. Horii, Matsumae, Cheng, Takei, Yasukawa and
Hashimoto designed a new bend by expanding the diameter fivefold in a 90 degree bend to
investigate the effect of erosion [15]. The investigation results showed 42 times less
erosion in the new bend as compared to a conventional bend for same air velocity and flow
conditions.
3.0 Present Work
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Previous investigations in the area of solid particle erosion examined the effect of
particle size on magnitude of maximum erosion. A limited number of studies reported the
location of maximum erosion for S-bend geometry. To further develop the limited research,
the current work reported in this paper focused on evaluating the location of the maximum
erosion in S-bend geometry with different air velocities and particle sizes.
3.5 Experimental Investigation
Air velocities of 15.24 m/s, 30.48 m/s and 45.72 m/s were used with 150 and 300
micron sands during the experiment. The test loop was designed to enable conducting
experiments with air-water-sand mixtures and different r/D ratios in the future. Location of
maximum erosion was measured using a paint removal process, and the angle of the
location was measured from the starting point of the bend.
3.5.1 Experimental Procedure
The S-bend geometry details are presented in Figure 1, the test loop schematic in
Figure 2 and a picture of the test section in Figure 3. The test loop was constructed using
clear plastic pipe with an inside diameter of 12.7 mm for flow visualization during the
experiments. The instrumentations included a compressor capable of delivering 18 SCFM
air flow, a pressure gage, a ST75-2AEBH00 gas flow meter, a FL-73 series water flow
meter, an air filter model F74G-4AN-QPB, and a flow regulator model R-130-15. The S-
bend test section was designed using two aluminum plates with half-pipe sections in each
plate. The two S-bend test section halves were bolted together to resemble a 12.7 mm
diameter S-bend pipe section. Before the experiment, the internal surfaces of the S-bend
test sections were painted using 3 layers of epoxy paint with approximately 1.5 mm
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thickness of each layer. The location of maximum erosion was determined by measuring
the location of paint removal in the specimen. Sand was injected from a calibrated sand
reservoir to the test section through a 1.0 cm nozzle by applying positive pressure above the
reservoir. The concentration of sand particles in the flow was approximately 2%. The gas
flow rate was controlled using a valve and flow regulator. The sand injected into a 12.7 mm
pipe was carried by the flowing gas as a gas-sand mixture to the specimen impacting the
wall of the internal S-bend pipe configurations. After flowing through the S-bend test
section, the gas-sand mixture was disposed. The distance between the sand injection point
and the S-bend test section was 67 mm and is equivalent to 5.5 times the pipe diameter.
3.5.2 Experimental Results
Each experiment was repeated to reduce measurement uncertainties and assure
repeatability of the test. After each experiment, the S-bend specimen was removed from
the test section, disassembled for observation and measured for location or locations of
paint removal. Figures 4A-4C shows the location of maximum erosion at different air
velocities with 300 micron sand. Figure 4A shows the location of maximum erosion at 20-
34 degrees from inlet in bend 1 with an air velocity of 15.24 m/sec. With an air velocity of
30.48 m/sec, erosion locations were detected at both 15-49 degrees and 110-136 degrees in
bend 1. With an air velocity of 45.72 m/sec, locations of erosion were observed at both 19-
69 degrees and 106-159 degrees in bend 1 and one additional location of erosion was
observed at 18.5-55 degrees in bend 2. Figures 4D-4F shows the location of maximum
erosion at different air velocities with 150 micron sand. Figure 4D presents the location of
maximum erosion to be 14-40 degrees in both bend 1 and 2. With a 30.48 m/sec air
velocity, the maximum erosion locations were observed at 21-64 degrees in bend 1 and 21-
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41degrees in bend 2. At 45.72 m/sec, the maximum erosion locations observed at 21-61
degrees in bend 1 and 12-41 degrees in bend 2.
3.6 Comparison with Literature Data
The experimental results from the current research were compared with previous
investigations reported in the literature and presented in Table 1. Due to limited availability
of data for erosion in S-bend geometries, erosion results for elbow, U-bend and tees were
also used in the comparison. The current investigation results showed the location of
maximum erosion at 30-40 degrees in bend 1 for most of the experimental conditions.
3.7: Summary and Conclusion
An investigation was conducted to determine the location of maximum erosion in S-
bend geometry. The experimental investigation was performed using a test section with a
12.7 mm diameter pipe and an S-bend test section with an r/D ratio of 1.5. The
experimental results were compared to available literature results. The dispersion of
literature results can be explained by the different geometries, different experimental
conditions and several other factors that were not defined in the previously published
research results.
Despite limitations associated with the current study, the present work will be able
to shed some light on the variations of locations of maximum erosion in S-bend and similar
geometries. This will enable research and design engineers to recognize that the location of
maximum erosion is equally important as the magnitude of erosion in designing fluid
handling equipment with particulate multiphase flow.
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Acknowledgement
The authors would like to acknowledge the work performed by mechanical engineering
students, Kawshik Ahmed and Siwen Zhao. The work presented in this paper was
supported by a RCAC grant, U042784 from the Office of Research, University of
Michigan-Flint, USA.
References
[1] Mazumder, Quamrul H. "Effect of liquid and gas velocities on magnitude and location
of maximum erosion in U-bend." (2012). Open Journal of Fluid Dynamics, 2, pp. 29-
34.
[2] Chen, Q., and D. Y. Li. "Computer simulation of solid particle erosion." Wear 254, no.
3 (2003): 203-210.
[3] Ionescu, Dorina. "Reduction of pipe wall erosion by creating a vortex flow in anthracite
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Development of Renewable Energies, Environment and Power Quality & International
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Compostela, Spain, 2012.
[4] Wang, Jianrong, and Siamack A. Shirazi. "A CFD based correlation for erosion factor
for long-radius elbows and bends." Journal of energy resources technology 125, no. 1
(2003): 26-34.
[5] Mazumder, Quamrul H., Siamack A. Shirazi, and Brenton S. McLaury. "Prediction of
solid particle erosive wear of elbows in multiphase annular flow-model development
and experimental validations." Journal of Energy Resources Technology 130, no. 2
(2008): 023001.
[6] Finnie, Iain. "Erosion of surfaces by solid particles." Wear 3, no. 2 (1960): 87-103.
[7] Rudolfa, P., and M. Desováa. "Flow characteristics of curved ducts." Applied and
Computational Mechanica 1 (2007): 255-264.
[8] Weske, John R. Experimental Investigation of Velocity Distributions Downstream of
Single Dust Bends. No. NACA-TN-1471. NATIONAL AERONAUTICS AND SPACE
ADMINISTRATION WASHINGTON DC, 1948.
[9] Niazmand, Hamid, and E. Rajabi Jaghargh. "Bend sweep angle and reynolds number
effects on hemodynamics of S-shaped arteries." Annals of biomedical engineering 38,
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[10] Sudo, K., M. Sumida, and H. Hibara. "Experimental investigation on turbulent flow
through a circular-sectioned 180 bend." Experiments in Fluids 28, no. 1 (2000): 51-57.
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[11] Wong, Chong Y., Christopher Solnordal, Anthony Swallow, Steven Wang, Lachlan
Graham, and Jie Wu. "Predicting the material loss around a hole due to sand erosion."
Wear 276 (2012): 1-15.
[12] Chen, Xianghui, Brenton S. McLaury, and Siamack A. Shirazi. "Application and
experimental validation of a computational fluid dynamics (CFD)-based erosion
prediction model in elbows and plugged tees." Computers & Fluids 33, no. 10 (2004):
1251-1272.
[13] Mills, D., and J. S. Mason. "Particle size effects in bend erosion." Wear 44, no. 2
(1977): 311-328.
[14] Fan, Jianren, Jun Yao, Xinyu Zhang, and Kefa Cen. "Experimental and numerical
investigation of a new method for protecting bends from erosion in gas-particle flows."
Wear 251, no. 1 (2001): 853-860.
[15] Horii, K., Y. Matsumae, X. M. Cheng, M. Takei, E. Yasukawa, and B. Hashimoto.
"An erosion resistant pipe bend." Journal of fluids engineering 113, no. 1 (1991): 149-
151.
[16] Guide, ANSYS FLUENT User’S. "Release 13.0." Canonsburg, PA (2010).
[17] Edwards, Jeremy Keith. "Development, validation, and application of a three-
dimensional, CFD-based erosion prediction procedure." PhD diss., University of Tulsa,
2000.
[18] Njobuenwu, Derrick O., and Michael Fairweather. "Modelling of pipe bend erosion
by dilute particle suspensions." Computers & Chemical Engineering 42 (2012): 235-
247.
[19] Suhane, Amit, and Vijay K. Agarwal. "Effect of bend geometry on erosion and
product degradation in pneumatic conveying pipeline systems." International Journal of
Engineering Research and Applications 2, no. 4 (2012): 129-136.
[20] Mazumder, Quamrul H., Siamack A. Shirazi, Brenton S. McLaury, John R. Shadley,
and Edmund F. Rybicki. "Development and validation of a mechanistic model to predict
solid particle erosion in multiphase flow." Wear 259, no. 1 (2005): 203-207.
Figure 1: Schematic Diagram of S-Bend Geometry
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Figure 2: Schematic of S-Bend Multiphase Test Loop
Figure 3: Picture of S-Bend Multiphase Test Loop
Figure 4: Experimental Results of Location of Maximum Erosion
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Fig 4A:300 micron sand air velocity 15.24 m/s Fig 4B:300 micron sand with air velocity 30.48 m/s
Fig 4C:300 micron sand with air velocity 45.72 m/s Fig 4D:150 micron sand with air velocity 15.24 m/s
Fig 4E:150 micron sand with air velocity 30.48 m/s Fig 4F:150 micron sand with air velocity 45.72 m/s
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Table 1: Comparison with Available Literature Data
Accepted

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