Simulation of Fluid Flow in the Deep Open Channel of the BMC Apparatus
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Asbestos toxicity has been shown to vary with fiber length. To conduct larger scale studies on this effect, a fiber separator capable of filtering large batches of fibers based on length is needed. Fibers align with local shear stress vectors, therefore fibers will be filtered when the shear stress is parallel to the wire-mesh. This study evaluates the effectiveness of the Bauer McNett Classifier (BMC) as a fiber separator. Simulation of Fluid Flow in the Deep Open Channel of the BMC Apparatus Lana Sneath and Sandra Hernandez Biomedical Engineering Class of 2015, University of Cincinnati Faculty Mentor: Dr. Urmila Ghia, Mechanical Engineering 1. Jana, C. (2011), “Numerical Study of Three-Dimensional Flow Through a Deep Open Channel-Including a Wire-Mesh Segment on One Side Wall.” M.S. Mechanical Engineering Thesis, University of Cincinnati. 2. White, F. M. (2003) “ Fluid Mechanics”, McGraw-Hill, 5 th Edition. 3. Fluent 6.3 User’s Guide. 4. Gambit 2.4 User’s Guide. 5. Tamayol, A., Wong, K. W., Bahrami, M. (2012) “Effects of microstructure on flow properties of fibrous porous media at moderate Reynolds number”, American Physical Society, Physical Review E 85. References To model a porous boundary in FLUENT, the values of the permeability (k), pressure-jump coefficient (C2), and the thickness of the porous boundary need to first be determined. For a 16 mesh, wire diameter = 0.0004572. Screen thickness is 2d, equal to 0.0009144. F and are standard coeficients for a 16 mesh [5] These values are entered into FLUENT to analyze the flow in the porous boundary model. Boundary Conditions: Calculating K and C2 Methods and Materials Results: Solid Side Walls Model • These findings indicate that the total shear stress value is greatest at the inlet, and quickly drops down as the x-position increases. • In the solid-wall model, the highest out-plane angle where the screen lies in the actual BMC channel is 8 degrees, which is primarily tangential to the wall. • The shear stress magnitude in the porous boundary model is expected to be slightly greater. The difference is expected to be determined in future work. • Flow through the screen is expected to be small, hence the contribution of the porous boundary to the off plane shear stress angle is expected to be small • Future work of this study: • Analyze the shear stress distribution of the porous boundary model • Understand the behavior of fluid flow in the porous boundary model Discussion Goal: Numerically study the fluid flow in a deep open channel Objectives: a) Learn the fundamentals of fluid dynamics. b) Learn the fundamentals of solving fluid dynamic problems numerically. c) Simulate and study the flow in the open channel of the BMC apparatus, modeling the screen as a solid wall boundary (i) d) Model the screen as a porous boundary (ii) e) Determine the orientation of shear stress vector on screen boundary for both (i) and (ii) Materials: Computational Fluid Dynamic (CFD) tools FLUENT and Gambit Steps in Methodology: a)Define channel geometry b)Set up channel geometry in Gambit and generate a computational grid c)Enter boundary conditions and obtain flow solutions i. Solid Wall Model ii.Porous Boundary Model d) Compute shear stress on flow solutions Results: Porous Boundary Model Figure 3. Channel Geometry in Gambit Figure 4. Boundary Conditions Free-Slip Wall, v=0, du/dy=0, dw/dy=0 No-Slip Wall, u = v = w = 0 Inlet, u = u(y,z), v = w =0 Outlet, p stat = 0 Total Points X Y Z ∆Y min ∆Z min 405000 50 180 45 0.0000 5 0.0007 Figure 7: Total Shear Stress Magnitude (primary y-axis) and off plane angle (secondary y-axis) along the Z-Wall; line at y= 0.1 m (mid-plane), z= 0.02 m = Deep Open Channel Figure 5: X-velocity contours in top half of channel; plane at x= 0.2 m • Velocity contours bulge towards corners • Symmetric across the center of the channel • Highest velocity is in the center of the channel Figure 6: X-vorticity contours in top half of; plane at x= 0.2m • Top corners are non- symmetrical about the angle bisector • High vorticity at the free surface • High vorticity is attributed to the free surface being modeled as a free- slip wall Figure 8: X-velocity contours in top half of channel; plane at x= 0.2 m • Velocity contours bulge towards corners • Not-symmetric across the center of the channel • Highest velocity is in the center of the channel Figure 9: X-vorticity contours in top half of channel; plane at x= 0.2 m • High vorticity at the free surface and near porous boundary • As previous case, vorticity is low at right side wall • Top corners are much more non-symmetrical about the angle bisector Solid Wall Model Porous Boundary Model Porous-Jump, K = 9.6e-10, C2=7610.7 1/m, screen thickness = 9e-4 m; Values correspond to 16 a Figure 1. Side view of BMC apparatus Figure 2. Top view of elliptical tank in the BMC Table 1. Distribution of grid points and smallest spacing near boundaries Solid wall Porous wall Porous wall Solid wall We would like to thank Dr. Ghia for being an excellent faculty mentor and taking the time to make sure we fully understood the concepts behind our research. We would also like to thanks our sponsor, the National Science Foundation , Grant ID No.: DUE-0756921 Acknowledgements 0 0.05 0.1 0.15 0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 2 4 6 8 10 12 14 Total Shear Stress Total Stress Off Plane Shear Stress Angle X-Position (m) Total Z-Wall Shear Stress Magnitude (pascals) Off Plane Angle (degrees) Introduction Pressure-Jump Coefficient (C2): = 7610.739 Permeability (K):
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Simulation of Fluid Flow in the Deep Open Channel of the BMC Apparatus. = Deep Open Channel. Lana Sneath and Sandra Hernandez Biomedical Engineering Class of 2015, University of Cincinnati Faculty Mentor: Dr. Urmila Ghia , Mechanical Engineering. Introduction. - PowerPoint PPT Presentation
Transcript of Simulation of Fluid Flow in the Deep Open Channel of the BMC Apparatus
Asbestos toxicity has been shown to vary with fiber length. To conduct larger scale studies on this effect, a fiber separator capable of filtering large batches of fibers based on length is needed. Fibers align with local shear stress vectors, therefore fibers will be filtered when the shear stress is parallel to the wire-mesh. This study evaluates the effectiveness of the Bauer McNett Classifier (BMC) as a fiber separator.
Simulation of Fluid Flow in the Deep Open Channel of the BMC ApparatusLana Sneath and Sandra Hernandez
Biomedical Engineering Class of 2015, University of CincinnatiFaculty Mentor: Dr. Urmila Ghia, Mechanical Engineering
1. Jana, C. (2011), “Numerical Study of Three-Dimensional Flow Through a Deep Open Channel-Including a Wire-Mesh Segment on One Side Wall.” M.S. Mechanical Engineering Thesis, University of Cincinnati.
2. White, F. M. (2003) “ Fluid Mechanics”, McGraw-Hill, 5th Edition. 3. Fluent 6.3 User’s Guide.4. Gambit 2.4 User’s Guide.5. Tamayol, A., Wong, K. W., Bahrami, M. (2012) “Effects of microstructure on flow properties of
fibrous porous media at moderate Reynolds number”, American Physical Society, Physical Review E 85.
References
To model a porous boundary in FLUENT, the values of the permeability (k), pressure-jump coefficient (C2), and the thickness of the porous boundary need to first be determined.
For a 16 mesh, wire diameter = 0.0004572. Screen thickness is 2d, equal to 0.0009144. F and are standard coeficients for a 16 mesh [5]These values are entered into FLUENT to analyze the flow in the porous boundary model.
Boundary Conditions: Calculating K and C2
Methods and Materials Results: Solid Side Walls Model
• These findings indicate that the total shear stress value is greatest at the inlet, and quickly drops down as the x-position increases.
• In the solid-wall model, the highest out-plane angle where the screen lies in the actual BMC channel is 8 degrees, which is primarily tangential to the wall.
• The shear stress magnitude in the porous boundary model is expected to be slightly greater. The difference is expected to be determined in future work.
• Flow through the screen is expected to be small, hence the contribution of the porous boundary to the off plane shear stress angle is expected to be small
• Future work of this study:• Analyze the shear stress distribution of the porous boundary
model• Understand the behavior of fluid flow in the porous boundary
model
Discussion
Goal: Numerically study the fluid flow in a deep open channelObjectives:a) Learn the fundamentals of fluid dynamics. b) Learn the fundamentals of solving fluid dynamic problems numerically. c) Simulate and study the flow in the open channel of the BMC apparatus, modeling the screen as a solid wall boundary (i)d) Model the screen as a porous boundary (ii)e) Determine the orientation of shear stress vector on screen boundary for both (i) and (ii)
Materials: Computational Fluid Dynamic (CFD) tools FLUENT and GambitSteps in Methodology:a) Define channel geometryb) Set up channel geometry in Gambit and generate a computational
gridc) Enter boundary conditions and obtain flow solutions
i. Solid Wall Modelii. Porous Boundary Model
d) Compute shear stress on flow solutions
Results: Porous Boundary Model
Figure 3. Channel Geometry in Gambit
Figure 4. Boundary Conditions
Free-Slip Wall, v=0, du/dy=0, dw/dy=0
No-Slip Wall, u = v = w = 0
Inlet, u = u(y,z), v = w =0
Outlet, pstat = 0Total Points
X Y Z ∆Ymin ∆Zmin
405000 50 180 45 0.00005 0.0007Figure 7: Total Shear Stress Magnitude (primary y-axis) and off plane angle (secondary y-axis) along the Z-Wall; line at y= 0.1 m (mid-plane), z= 0.02 m
= Deep Open Channel
Figure 5: X-velocity contours in top half of channel; plane at x= 0.2 m• Velocity contours bulge
towards corners• Symmetric across the
center of the channel• Highest velocity is in the
center of the channel
Figure 6: X-vorticity contours in top half of; plane at x= 0.2m• Top corners are non-
symmetrical about the angle bisector
• High vorticity at the free surface
• High vorticity is attributed to the free surface being modeled as a free-slip wall
Figure 8: X-velocity contours in top half of channel; plane at x= 0.2 m• Velocity contours bulge
towards corners• Not-symmetric across the
center of the channel• Highest velocity is in the
center of the channel
Figure 9: X-vorticity contours in top half of channel; plane at x= 0.2 m• High vorticity at the free
surface and near porous boundary
• As previous case, vorticity is low at right side wall
• Top corners are much more non-symmetrical about the angle bisector
Solid Wall Model Porous Boundary Model
Porous-Jump, K = 9.6e-10, C2=7610.7 1/m, screen thickness = 9e-4 m; Values correspond to 16 a mesh [5]
Figure 1. Side view of BMC apparatus Figure 2. Top view of elliptical tank in the BMC
Table 1. Distribution of grid points and smallest spacing near boundaries
Sol
id w
all
Por
ous
wal
l
Por
ous
wal
l
Sol
id w
all
We would like to thank Dr. Ghia for being an excellent faculty mentor and taking the time to make sure we fully understood the concepts behind our research. We would also like to thanks our sponsor, the National Science Foundation , Grant ID No.: DUE-0756921
Acknowledgements
0 0.05 0.1 0.15 0.20
0.20.40.60.8
11.21.41.61.8
2
0
2
4
6
8
10
12
14Total Shear Stress
Total Stress
Off Plane Shear Stress Angle
X-Position (m)
To
tal
Z-W
all
Sh
ea
r S
tre
ss
M
ag
nit
ud
e (
pa
sc
als
)
Off
Pla
ne
An
gle
(d
eg
ree
s)
Introduction
Pressure-Jump Coefficient (C2):
= 7610.739
Permeability (K):
