1. Goal: Numerically study the fluid flow in a deep open channel Objectives : a)Determine boundary conditions and geometry Porous plate verification case b) Simulate the open channel in FLUENT Model the screen as a porous boundary c) Determine the orientation of shear stress vectors on the screen Materials: Computational Fluid Dynamic (CFD) tools FLUENT and Gambit 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.Verification Case – Flow over porous plate ii.Porous Boundary Model d) Compute shear stress on flow solutions Figure 7: Contour plot of the X-velocity (Axial velocity) component. Figure 8: Axial variation in shear stress on solid wall at y-0.1m, z=0.02m The lower velocity in the channel at porous-jump boundary is due to the addition of the screen and increased area. The shear stress distribution on the z= 0m wall in the porous- boundary model is similar to the solid wall case. 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. 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, Department of Mechanical and Material 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 K/d^2 are standard coefficients 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 MaterialsResults: Solid Side Walls Model The results obtained are only for 0.5 seconds of the fluid flow, whereas the time period for the flow to travel across the channel is 0.87 seconds. Hence, it is expected that the results will be significantly different once the simulation is complete. Conclusions: Off plane angle of the solid-wall model is significant and shows that fibers will primarily align parallel to the screen These findings aid in understanding the chances in fluid flow behavior with the addition of the porous-jump boundary condition Future Work Further research shear stress across the porous-boundary condition Continue simulation until the fluid flow solution completes 4 to 5 cycles through the channel (at least 3 minutes) Discussion 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 XYZ∆Y min ∆Z min 40500 0 50180450.000 05 0.000 7 Figure 5: Axial variation of shear stress and off plane angle (secondary y- axis) along the Z-Wall; line at y= 0.1 m (mid-plane), z= 0.0 m = Deep Open Channel Solid Wall ModelPorous 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 apparatusFigure 2. Top view of elliptical tank in the BMC Table 1. Distribution of grid points and smallest spacing near boundaries We would like to thank Dr. Ghia for being an excellent faculty mentor Thank you to our sponsor, the National Science Foundation, Grant ID No.: DUE-0756921 Acknowledgements Introduction Figure 6: Contour plot of the X-velocity (Axial velocity) component. Boundary layer forms around porous plate Cross-over of flow across the porous plate Further understood porous-boundary condition Results: Porous Boundary Verification Case Geometry and Boundary Conditions