Chapter 10: Modeling Flow Through Porous Media
This tutorial is divided into the following ctions:
10.1. Introduction
10.2. Prerequisites
10.3. Problem Description
10.4. Setup and Solution
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10.5. Summary
10.6. Further Improvements
10.1. Introduction
Many industrial applications such as filters, catalyst beds and packing, involve modeling the flow through porous media.This tutorial illustrates how to t up and solve a problem involving gas flow through porous media.
The industrial problem solved here involves gas flow through a catalytic converter. Catalytic converters are commonly ud to purify emissions from gasoline and diel engines by converting environmentally hazardous exhaust emissions to acceptable substances. Examples of such emissions include carbon monoxide (CO), nitrogen oxides (NOx), and unburned hydrocarbon fuels.The exhaust gas emissions
are forced through a substrate, which is a ceramic structure coated with a metal catalyst such as platinum or palladium.
The nature of the exhaust gas flow is a very important factor in determining the performance of the catalytic converter. Of particular importance is the pressure gradient and velocity distribution through
the substrate. Hence CFD analysis is ud to design efficient catalytic converters. By modeling the exhaust gas flow, the pressure drop and the uniformity of flow through the substrate can be determined. In
this tutorial, ANSYS FLUENT is ud to model the flow of nitrogen gas through a catalytic converter geometry, so that the flow field structure may be analyzed.
This tutorial demonstrates how to do the following:
•Set up a porous zone for the substrate with appropriate resistances.
•Calculate a solution for gas flow through the catalytic converter using the pressure-bad solver.•Plot pressure and velocity distribution on specified planes of the geometry.
恋爱问题•Determine the pressure drop through the substrate and the degree of non-uniformity of flow through cross ctions of the geometry using X-Y plots and numerical reports.
10.2. Prerequisites
This tutorial is written with the assumption that you have completed one or more of the introductory tutorials found in this manual:
•Introduction to Using ANSYS FLUENT in ANSYS Workbench: Fluid Flow and Heat Transfer in a Mixing Elbow (p.1)
•Parametric Analysis in ANSYS Workbench Using ANSYS FLUENT (p.77)
Chapter 10: Modeling Flow Through Porous Media
•Introduction to Using ANSYS FLUENT: Fluid Flow and Heat Transfer in a Mixing Elbow (p.131)
and that you are familiar with the ANSYS FLUENT navigation pane and menu structure. Some steps in the tup and solution procedure will not be shown explicitly.
10.3. Problem Description
The catalytic converter modeled here is shown in Figure 10.1 (p.448).The nitrogen flows through the inlet with a uniform velocity of 22.6 m/s, pass through a ceramic monolith substrate with square-shaped channels, and then exits through the outlet.
Figure 10.1 Catalytic Converter Geometry for Flow Modeling
While the flow in the inlet and outlet ctions is turbulent, the flow through the substrate is laminar and is characterized by inertial and viscous loss coefficients along the inlet axis.The substrate is imper-meable in other directions.This characteristic is modeled using loss coefficients that are three orders of magnitude higher than in the main flow direction.
10.4. Setup and Solution
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The following ctions describe the tup and solution steps for this tutorial:
10.4.1. Preparation
10.4.2. Step 1: Mesh
10.4.3. Step 2: General Settings
10.4.4. Step 3: Models
10.4.5. Step 4: Materials
10.4.6. Step 5: Cell Zone Conditions
10.4.7. Step 6: Boundary Conditions
10.4.8. Step 7: Solution
10.4.9. Step 8: Postprocessing
Setup and Solution 10.4.1. Preparation
1.Extract the file porous.zip from the ANSYS_Fluid_Dynamics_Tutorial_Inputs.zip archive
which is available from the Customer Portal.
Note
For detailed instructions on how to obtain the ANSYS_Fluid_Dynamics_Tutori-
al_Inputs.zip file, plea refer to Preparation (p.3) in Introduction to Using ANSYS
FLUENT in ANSYS Workbench: Fluid Flow and Heat Transfer in a Mixing Elbow (p.1).
2.Unzip porous.zip to your working folder.
The mesh file catalytic_converter.msh can be found in the porous directory created after
春节喜庆图片unzipping the file.
3.U the FLUENT Launcher to start the 3D version of ANSYS FLUENT.
For more information about FLUENT Launcher, e Starting ANSYS FLUENT Using FLUENT
Launcher in the Ur’s Guide.
4.Enable Double-Precision.
Note
The Display Options are enabled by default.Therefore, once you read in the mesh, it
will be displayed in the embedded graphics window.
10.4.2. Step 1: Mesh
1.Read the mesh file (catalytic_converter.msh).
File¡Read¡
2.Check the mesh.
General¡Check
ANSYS FLUENT will perform various checks on the mesh and report the progress in the console. Make
sure that the reported minimum volume is a positive number.
3.Scale the mesh.
General¡
a.
Select mm from the Mesh Was Created In drop-down list.b.
Click Scale .c.Select mm from the View Length Unit In drop-down list.
All dimensions will now be shown in millimeters.
d.
Clo the Scale Mesh dialog box.4.
安全教育培训内容Check the mesh.
General ¡ Check
Note
手工钱包怎么折It is a good idea to check the mesh after you manipulate it (i.e., scale, convert to poly-hedra, merge,
parate, fu, add zones, or smooth and swap.) This will ensure that the quality of the mesh has not been compromid.
5.Examine the mesh.
Rotate the view and zoom in to get the display shown in Figure 10.2 (p.451).The hex mesh on the geometry contains a total of 34,580 cells.
Chapter 10: Modeling Flow Through Porous Media
Figure 10.2 Mesh for the Catalytic Converter Geometry
我最喜爱的小动物10.4.3. Step 2: General Settings
General Setup and Solution
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