Simulation of Laminar Pipe Flows 57 020 Mechanics of Fluids and Transport Processes CFD PRELAB 1 By Timur Dogan Michael Conger Maysam Mousaviraad Tao Xing and Fred Stern IIHR Hydroscience Engineering The University of Iowa C Maxwell Stanley Hydraulics Laboratory Iowa City IA 52242 1585 1 Purpose The Purpose of CFD PreLab 1 is to teach students how to use the CFD educational interface ANSYS be familiar with the options in each step of CFD Process and relate simulation results to AFD concepts Students will simulate laminar pipe flow following the CFD process by an interactive step by step approach Students will have hands on experiences using ANSYS to compute axial velocity profile centerline velocity centerline pressure and wall shear stress Students will compare simulation results with AFD data analyze the differences and possible numerical errors and present results in CFD Lab 1 report Geometry Pipe ANSYS Design Modeler Laminar Turbulent Physics Mesh Solution Results General ANSYS Fluent Setup Structure ANSYS Mesh Plots ANSYS Fluent Results Model ANSYS Fluent Setup Uniform ANSYS Mesh Solution Methods ANSYS Fluent Solution Boundary Conditions ANSYS Fluent Setup ANSYS Mesh Non uniform Monitors ANSYS Fluent Solution Graphics and Animations ANSYS FluentResults Reference Values ANSYS Fluent Setup Solution Initialization ANSYS Fluent Solution Flow chart for CFD Process for pipe flow 1 2 Simulation Design In EFD Lab 2 you conducted experimental study for turbulent pipe flow The data you have measured will be used for CFD Lab 1 In CFD PreLab 1 simulation will be conducted only for laminar circular pipe flows i e the Reynolds number is less than 2300 Reynolds number based on pipe diameter and mean inlet velocity is 654 75 in the current simulation CFD predictions of friction factor and fully developed axial velocity profile will be compared with AFD data Table 1 Geometry dimensions Parameter Radius of Pipe Diameter of Pipe Length of the Pipe Unit m m m Value 0 02619 0 05238 7 62 Uniform mesh Non uniform mesh Symmetry Inlet Outlet Velocity Profile Pipe Wall Figure 1 Geometry Since the flow is axisymmetric we only need to solve the flow in a single plane from the centerline to the pipe wall Boundary conditions need to be specified include inlet outlet wall and axis as will be described in details later Uniform flow is specified at inlet the flow will reach the fully developed regions after a certain distance downstream No slip boundary condition will be used on the wall and constant pressure for the outlet Symmetric boundary condition will be applied on the pipe axis Since the flow is laminar turbulence models are not necessary Navigation Tips To zoom in and out use the magnifying glass with a plus sign in it and drag from top left to bottom right over the are you wish to zoom To look at a view plane simply click on the arrow in the coordinate system identifier in the bottom right of the screen i e if you wish to look at the XYplane click on the Z Arrow 2 3 Open ANSYS Workbench 3 1 Start All Programs ANSYS 14 5 Workbench 14 5 3 2 From the ANSYS Workbench home screen Project Schematic drag and drop the Geometry component for the Component Systems on the left side of the screen into the Project Schematic Rename the geometry by right clicking on the down arrow of the Geometry component and selecting Rename 3 3 3 Drag and drop two Mesh components and two Fluent components into the schematic as shown below Rename the components as you did the geometry previously as per the as shown below Make the connections as per below by dragging component to component 3 4 Create a Folder on the H Drive called CFD Pre Lab and Lab 1 3 5 Save the project file by clicking File Save As 3 6 Save the project onto the H Drive in the folder you just created and name it CFD Pre Lab and Lab 1 Pipe Flow This will be used for both Pre Lab 1 and Lab 1 4 Geometry Creation 4 1 Right click on Geometry and from the drop down menu select New Geometry 4 2 Select Meter for unit and click OK 4 4 3 Select the XYPlane under the Tree Outline and click New Sketch button 4 4 Right click XYPlane and select Look at 4 5 Select Sketching Rectangle Create a rectangle geometry as per below make sure to start from the origin the mouse arrow should change to a P when on the origin 5 4 6 Select Dimensions General Click on top edge then click above the geometry to place the dimension Repeat the same thing for one of the vertical edges You should have a similar figure as per below 4 7 Click on H1under Details View in the bottom left of the screen and change H1 to 7 62m Click on V2 and change it to 0 02619m 4 8 Concept Surface From Sketches select the sketch by clicking on Sketch 1 in the Tree Outline and hit Apply in the Detatils View 6 4 9 Click Generate This will create a surface 4 10 File Save Project Save project and close the Design Modeler window 5 Mesh Generation 5 1 From the Project Schematic right click on Mesh on the Fluid Flow Fluent component and select Edit 5 2 Right click on Mesh then select Insert Mapped Face Meshing 7 5 3 Select your geometry by clicking the yellow box which says No Selection the click on the geometry surface and click Apply 5 4 Click on the edge button This will allow you to select edges of your geometry 8 5 5 Right click on Mesh then select Insert Sizing 5 6 Hold Ctrl button and select the top and bottom edge of the rectangle then click Apply Specify details of sizing as per below in the Details of Edge Sizing Sizing window 5 7 Repeat step 5 5 Select the left and right edge of the rectangle and click Apply then change sizing parameters as per below 9 5 8 Click on Generate Mesh button Click Mesh under Outline The mesh should look like the mesh pictured below Uniform Mesh 5 9 Change the edge names by selecting the edge then right clicking on the edge and selecting Create Named Selection Name left right bottom and top edges as inlet outlet axis and wall respectively Your outline should look same as the figure below 10 5 10 File Save Project Save the project and close the window Update mesh on Project Schematic by right clicking on Mesh and selecting Update 11 6 Setup Physics 6 1 Right click Setup and select Edit 6 2 Check Double Precision and click OK 6 3 Solution Setup General Check Note If you get an error message you may have made a mistake while creating you mesh Review steps in mesh generation and make changes 6 4 Solution Setup General Solver Choose options shown below 12 6 5 Solution Setup Models Edit
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