经过痛苦的一段经历;终于将局部问题真相大白;为了使保位同仁不再经过我之痛苦;现在将本人多孔介质经验公布如下;希望各位能加精：
1..Gambit中划分网格之后;定义需要做为多孔介质的区域为fluid;与缺省的fluid分别开来;再定义其名称;我习惯将名称定义为porous;
2..在fluent中定义边界条件define-boundary condition-porous刚定义的名称;将其设置边界条件为fluid;点击t按钮即弹出与fluid边界条件一样的对话框;选中porous zone与laminar复选框;再点击porous zone标签即出现一个带有滚动条的界面；
3..porous zone设置方法：
1定义矢量：二维定义一个矢量;第二个矢量方向不用定义;是与第一个矢量方向正交的；
三维定义二个矢量;第三个矢量方向不用定义;是与第一、二个矢量方向正交的；
如何知道矢量的方向：打开grid图;看看X;Y;Z的方向;如果是X向;矢量为1;0;0;同理Y向为0;1;0;Z向为0;0;1;如果所需要的方向与坐标轴正向相反;则定义矢量为负
女性梦见包子圆锥坐标与球坐标请参考fluent帮助..
2定义粘性阻力1/a与内部阻力C2：请参看本人上一篇博文“终于搞清fluent中多孔粘性阻力与内部阻力的计算方法讨论稿”;此处不赘述；
3如果了定义粘性阻力1/a与内部阻力C2;就不用定义C1与C0;因为这是两种不同的定义方法;C1与C0只在幂率模型中出现;该处保持默认就行了；
4定义孔隙率porousity;默认值1表示全开放;此值按实验测值填写即可..
完了;其他设置与普通k-e或RSM相同..总结一下;与君共享
Tutorial 7. Modeling Flow Through Porous Media
Introduction
Many industrial applications involve the modeling of flow through porous media; such as filters; catalyst beds; and packing. 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 fl新中考杰瑞鼠ow; the pressure drop and the uniformity of flow through the substrate can be determined. In this tutorial; 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.
_ 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.
Problem Description
The catalytic converter modeled here is shown in Figure 7.1. The nitrogen flows in 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.
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 in the 库房管理流程>真人性裸交视频flow X direction. The substrate is impermeable in other directions; which is modeled using loss皮皮虾怎么清洗 coefficients who values are three orders of magnitude higher than in the X direction.
Setup and Solution
Step 1: Grid
1. Read the mesh file catalytic converter.msh.
File /Read /Ca...
2. Check the grid. Grid /Check
FLUENT will perform various checks on the mesh and report the progress in the console. Make sure that the minimum volume reported is a positive number.
3. Scale the grid.
Grid
a Select mm from the Grid Was Created In drop-down list.
b Click the Change Length Units button. All dimensions will now be shown in millimeters.
c Click Scale and clo the Scale Grid panel.
4. Display the mesh. Display /
a Make sure that inlet; outlet; substrate-wall; and wall are lected in the Surfaces lection list.
b Click Display.
c Rotate the view and zoom in to get the display shown in Figure 7.2.
d Clo the Grid Display panel.
The hex mesh on the geometry contains a total of 34;580 cells.
大专实习
