Flow through 90 degree diversions of rectangular cross-section
ME – 259 Introduction to Computational Fluid Dynamics
Prof. Dongmei Zhou
Presented By Pramod Krishnani
Fall 2007
Introduction CFD Model
Introduction Applications
Living Cardiovascular system
River channel Bifurcation
Fluent Settings CFD Simulation: 3ddp (3-D Double Precision)Convergence criteria:
Continuity = 1e-06 X- velocity = 1e-06 Y- velocity = 1e-06 Z- velocity = 1e-06
Discretization : Pressure : PRESTO Momentum equation setting = Second Order
UpwindSolver : Coupled
Boundary Conditions (BC)BC 1 : Main channel Velocity Inlet
BC 2 : Main channel Pressure Outlet
BC 3 : Branch Velocity outlet
Procedure For study Grid Independent Study
Creation of Different Mesh Files in GAMBIT ® Simulated in FLUENT® 3D Find Reattachment Length in Zone A Plot Truncation Error
Parameter Study Simulated
Scenario 1 : Used Cases In Benchmark Paper Scenario 2 : Change Fluid from water to Hydrogen Scenario 3 : Keeping Reynolds Number constant
changed Discharge Ratio
Grid Independent Study Simulation results of Reattachment Length in Zone A
Reattachment Length in Zone A
Analytical Resultfrom
Liepsch Paper
Mesh Size
Re-attachment
Lengthin Zone A (meters)
Error From
Analytical
% Error From
Analytical Or
Truncation error
Error From Best
Mesh Size
% Error From Best Mesh Size
Or Truncation
error
2.87704
148176 2.42857 0.44847 15.58789589 0.43507 15.19290134
453600 2.48654 0.3905 13.57297778 0.3771 13.16855471
1185408 2.64287 0.23417 8.139268137 0.22077 7.709418782
4000752 2.85714 0.0199 0.691683119 0.0065 0.226983839
4634784 2.86364 0.0134 0.465756472 0 0
Grid Independent Study Truncation Error Plots
Comparing with Liepsch Paper
Comparing with Best Mesh Size
Grid Independent Study Streamline plots of velocity of Case 1 at Z =
2.0
Grid Independent Study Comparison of velocity profiles at Z=4.0
plane
Grid Independent Study Skin Friction Plots At Outer wall Of The Main
ChannelSkin Friction Plots At Branch Left wallSkin Friction Plots At Branch Right Wall
Grid Independent Study Z-plots of Vorticity Profiles at different
positions of Y keeping X constant
Grid Independent Study Z-plots of Vorticity Profiles at different
positions of X keeping Y constant
Parameter Study Mesh Size Used : 81 x 70 x 80 Scenario Used
1. Study of Cases in Paper 2. Change of Fluid to Hydrogen 3. Keeping Re Constant Change Discharge
ratio ‘r’
Parameter Study Scenario 1 : Study of Cases in Paper
Case Reynold
Number AR
Discharge
Ratior
Main channel Velocity inlet
V1 = Ub (m/sec)
Branch Velocity Outlet
V2 (m/sec)
1 515 8 0.23 0.000258738 0.000059509
2 496 8 0.44 0.00024919 0.000109643
3 525 8 0.64 0.000026376 0.000168806
4 1062 8 0.58 0.000533548 0.000309458
5 496 1 0.44 0.00024919 0.000109643
Parameter Study Scenario 1 : Study of Cases in Paper
Velocity streamline plots of the simulation
Parameter Study Scenario 1 : Study of Cases in Paper
Velocity streamline plots of the Paper or benchmark
Parameter Study Scenario 2 : Change of Fluid to Hydrogen
Parameter Study Scenario 2 : Re-attachment Length
FluidReynolds number
Discharge Ratio ‘ r ’
Reattachment Length Xr (meters)
Water 496 0.44 2.48654
Hydrogen 496 0.44 3.2
Parameter Study Scenario 2 : Change of Fluid to Hydrogen
Parameter Study Scenario 3 : Keeping ‘Re’ Constant Change
Discharge ratio ‘r’Reynold Number
Discharge Ratio 'r' Main channel Inlet Velocity
V1 (m/sec)
Branch Velocity Outlet
V2 (m/sec)
515
0.23
0.000258738
0.000059509
0.75 0.000194053
1 0.000258738
1.5 0.000388107
2 0.000776214
Parameter Study Scenario
3 Velocity Streamline plot at r = 0.23
Parameter Study Scenario 3 Velocity Streamline plot at r = 0.75
Parameter Study Scenario 3 Velocity Streamline plot at r = 1.00
Parameter Study Scenario 3 Velocity Streamline plot at r = 1.50
Parameter Study Scenario 3 Velocity Streamline plot at r = 2.00
Conclusion Grid Independent Study
Comparing with Liepsch Paper
Comparing with Best Mesh Size
Conclusion Parameter Study Scenario 1
Conclusion Parameter Study Scenario 1
Conclusion Parameter Study Scenario 2
Conclusion Parameter Study Scenario 3
Conclusion Parameter Study Scenario 3
Conclusion Parameter Study Scenario 3
Conclusion Parameter Study Scenario 3
Conclusion Parameter Study Scenario 3
Questions
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