ansys經(jīng)典算例：穩(wěn)態(tài)管道流體分析

1、ansys經(jīng)典算例：穩(wěn)態(tài)管道流體分析ansys經(jīng)典算例：穩(wěn)態(tài)管道流體分析Fluid #2: Velocity analysis of fluid flow in a channel USING FLOTRAN Introduction:In this example you will model fluid flow in a channelPhysical Problem:Compute and plot the velocity distribution within the elbow. Assume that the flow is uniform at both the inlet

2、and the outlet sections and that the elbow has uniform depth.Problem Description:The channel has dimensions as shown in the figureThe flow velocity as the inlet is 10 cm/sUse the continuity equation to compute the flow velocity at exitObjective:To plot the velocity profile in the channelTo plot the

3、velocity profile across the elbowYou are required to hand in print outs for the aboveFigure:IMPORTANT: Convert all dimensions and forces into SI unitsSTARTING ANSYSC lick on ANSYS 6.1in the programs menu.S elect Interactive.T he following menu comes up. Enter the working directory. All your files wi

4、ll be stored in this directory. Also under UseDefault Memory Model make sure the values 64 for Total Workspace, and 32 for Database are entered. To change these values unclick Use Default Memory ModelMODELING THE STRUCTUREG o to the ANSYS Utility Menu (the top bar)Click WorkplaneWP SettingsThe follo

5、wing window comes up:o Check the Cartesian and Grid Only buttonso Enter the values shown in the figure above?Go to the ANSYS Main Menu (on the left hand side of the screen) and click PreprocessorModelingCreateKeypointsOn Working PlaneCreate keypoints corresponding to the vertices in the figure. The

6、keypoints look like below.Now create lines joining these key points.M odelingCreateLinesLinesStraight lineT he model looks like the one below.Now create fillets between lines L4-L5 and L1-L2.C lick ModelingCreateLinesLine Fillet. A pop-up window will now appear. Select lines 4 and 5. ClickOK. The fo

7、llowing window will appear:This window assigns the fillet radius. Set this value to 0.1 m.Repeat this process of filleting for Lines 1 and 2.The model should look like this now:N ow make an area enclosed by these lines.M odelingCreateAreasArbitraryBy LinesS elect all the lines and click OK. The mode

8、l looks like the followingThe modeling of the problem is done.ELEMENT PROPERTIESSELECTING ELEMENT TYPE:?Click PreprocessorElement TypeAdd/Edit/Delete. In the Element Types window that opens click on Add. The following window opens.?Type 1 in the Element type reference number.?Click on Flotran CFD an

9、d select 2D Flotran 141. Click OK. Close the Element types window.?So now we have selected Element type 1 to be solved using Flotran, the computational fluid dynamics portion of ANSYS. This finishes the selection of element type.DEFINE THE FLUID PROPERTIES:?Go to PreprocessorFlotran Set UpFluid Prop

10、erties.?On the box, shown below, set the first two input fields as Air-SI, and then click on OK. Another box will appear. Accept the default values by clicking OK.?Now were ready to define the Material PropertiesMATERIAL PROPERTIESWe will model the fluid flow problem as a thermal conduction problem.

11、 The flow corresponds to heat flux, pressure corresponds to temperature difference and permeability corresponds to conductance.Go to the ANSYS Main MenuClick PreprocessorMaterial PropsMaterial Models. The following window will appearAs displayed, choose CFDDensity. The following window appears.Fill

12、in 1.23 to set the density of Air. Click OK.Now choose CFDViscosity. The following window appears:Now the Material 1 has the properties defined in the above table so the Material Models window may be closed. MESHING: DIVIDING THE CHANNEL INTO ELEMENTS:G o to PreprocessorMeshingSize CntrlsManualSizeL

13、inesAll Lines.I n the window that comes up type 0.01 in the field for Element edge length.Now Click OK.Now go to PreprocessorMeshingMeshAreasFree. Click the area and the OK. The mesh will look like thefollowing.BOUNDARY CONDITIONS AND CONSTRAINTSGo to PreprocessorLoadsDefine LoadsApplyFluid CFDVeloc

14、ityOn lines. Pick the left edge of the outer block and Click OK. The following window comes up.E nter 0.1 in the VX value field and click OK. The 0.1 corresponds to the velocity of 0.1 meter per second of air flowingfrom the left side.R epeat the above and set the Velocity to ZERO for the air along

15、all of the edges of the pipe. (VX=VY=0 for all sides)O nce they have been applied, the pipe will look like this:?Go to Main MenuPreprocessorLoadsDefine LoadsApplyFluid CFDPressure DOFOn Lines.?Pick the outlet line. (The horizontal line at the top of the area) Click OK.?Enter 0 for the Pressure value

16、.?Now the Modeling of the problem is done.SOLUTIONG o to ANSYS Main MenuSolutionFlotran Set UpExecution Ctrl.?The following window appears. Change the first input field value to 300, as shown. No other changes are needed. Click OK.G o to SolutionRun FLOTRAN.W ait for ANSYS to solve the problem.C lic

17、k on OK and close the Information window.POST-PROCESSINGPlotting the velocity distributionGo to General PostprocRead ResultsLast Set.Then go to General PostprocPlot ResultsContour PlotNodal Solution. The following window appears:?Select DOF Solution and Velocity VSUM and Click OK.?This is what the s

18、olution should look like:?Next, go to Main MenuGeneral PostprocPlot ResultsVector PlotPredefined.The following window will appear:?Select OK to accept the defaults. This will display the vector plot to compare to the solution of the same tutorial solved using the Heat Flux analogy. Note: This analysis is FAR more precise as shown by the followingsolution:?Go to Main MenuGeneral PostprocPath OperationsDefine PathBy Nodes?Pick points at the ends of the elbow as shown. We will graph the velocity distribution along the line joiningthese two points.?The following window co