fluent多孔介质简单操作
多孔介质介绍
Fluent自带了一个多孔介质的例子，catalytic_converter.cas，是一个汽车尾气催化还原装置，其中绿色部分为催化剂部分其他设置就不说了，只说说与多孔介质有关的设置。
在建立模型时，必须将多孔介质单独划分为一个区域，然后才可以在设置边界条件时将这个区域设置为多孔介质。
1、在zone中选中该区域，在type中选中fluid，点set来到设置面板。
2、在Fluid面板中，选中Porous zone选项，如果忽略多孔区域对湍流的影响，选中Laminar zone。
3、首先是速度方向的设置，在2d中，在direction-1 vector中填入速度方向，在3d中，在direction-1 vector和direction-2 vector中填入速度方向，余下的未填方向，可以根据principal axis得到。
另外也可以用Update From Plane Tool来得到这两个量。
4、填入粘性阻力系数和惯性阻力系数，这两个系数可以通过经验公式得到。
在catalytic_converter.cas中可以看到x方向的阻力系数都比其他两个方向的阻力系数小1000倍，说明x方向是主要的压力降方向，其他两个方向不流通，压力降无限大。
（经验公式可以看帮助文件，其中有详细的介绍）。
随后的Power Law Model 中两个系数是另一种描述压力降的经验模型，一般不使用，可以保留缺省值0。
5、最后是Fluid Porosity，这个值只在模型选择了Physical Velocity 时才起作用，一般对计算没有影响，这个值要小于1。
补充：这个值在计算热传导时也起作用。
下面是改变一些参数后的比较。
1、速度方向的改变：原case：1、0、0 和0、1、0 y=0截面的速度矢量图修正case：-0.7366537、0.06852359、0.6727893 和0.6694272、-0.06727878、0.7398248 y＝0速度矢量图2、修改Porosity值为0.5 原case，y＝0截面修正case，y＝0截面：修正case，且打开solver面板中的Physical Velocity选项：最后比较一下有多孔介质和无多孔介质对流场的影响。
fluent中多孔介质模型的设置
fluent中多孔介质模型的设置7.19.6 User Inputs for Porous MediaWhen you are modeling a porous region, the only additional inputs for the problem setup are as follows. Optional inputs are indicated as such.1. Define the porous zone.2. Define the porous velocity formulation. (optional)3. Identify the fluid material flowing through the porous medium.4. Enable reactions for the porous zone, if appropriate, and select the reaction mechanism.5. Enable the Relative Velocity Resistance Formulation. By default, this option is already enabled and takes the moving porous media into consideration (as described in Section 7.19.6).6. Set the viscous resistance coefficients ( in Equation7.19-1,or in Equation 7.19-2) and the inertial resistance coefficients ( in Equation 7.19-1, or in Equation 7.19-2), and define the direction vectors for which they apply. Alternatively, specify the coefficients for the power-law model.7. Specify the porosity of the porous medium.8. Select the material contained in the porous medium (required only for models that include heat transfer). Note that the specific heat capacity, , for the selected material in the porous zone can only be entered as a constant value.9. Set the volumetric heat generation rate in the solid portion of the porous medium (or any other sources, such as mass or momentum). (optional) 10. Set any fixed values for solution variables in the fluid region (optional).11. Suppress the turbulent viscosity in the porous region, if appropriate.12. Specify the rotation axis and/or zone motion, if relevant.Methods for determining the resistance coefficients and/or permeability are presented below. If you choose to use the power-law approximation of the porous-media momentum source term, you will enter thecoefficients and in Equation 7.19-3 instead of the resistance coefficients and flow direction.You will set all parameters for the porous medium inthe Fluid panel (Figure 7.19.1), which is opened from the Boundary Conditions panel (as described in Section 7.1.4).Figure 7.19.1: The Fluid Panel for a Porous Zone Defining the Porous ZoneAs mentioned in Section 7.1, a porous zone is modeled as a special type of fluid zone. To indicate that the fluid zone is a porous region, enablethe Porous Zone option in the Fluid panel. The panel will expand to show the porous media inputs (as shown in Figure7.19.1).Defining the Porous Velocity FormulationThe Solver panel contains a Porous Formulation region where you can instruct FLUENT to use either a superficial or physical velocity in the porous medium simulation. By default, the velocity is set to SuperficialVelocity. For details about using the Physical Velocity formulation, see Section 7.19.7.Defining the Fluid Passing Through the Porous MediumTo define the fluid that passes through the porous medium, select the appropriate fluid in the Material Name drop-down list in the Fluid panel. If you want to check or modify the properties of the selected material, you can click Edit... to open the Material panel; this panel contains just the properties of the selected material, not the full contents of thestandard Materials panel.If you are modeling species transport or multiphase flow,the Material Name list will not appear in the Fluid panel. Forspecies calculations, the mixture material for all fluid/porous zones will be the material you specified in the SpeciesModel panel. For multiphase flows, the materials are specified when you define the phases, as described in Section 23.10.3. Enabling Reactions in a Porous ZoneIf you are modeling species transport with reactions, you can enable reactions in a porous zone by turning on the Reaction option inthe Fluid panel and selecting a mechanism in the ReactionMechanism drop-down list.If your mechanism contains wall surface reactions, you will also need to specify a value for the Surface-to-Volume Ratio. Thisvalue is the surface area of the pore walls per unit volume ( ), and can be thought of as a measure of catalyst loading. With this value, FLUENT can calculate the total surface area on which the reaction takes place in each cell bymultiplying by the volume of the cell. See Section 14.1.4 for detailsabout defining reaction mechanisms. See Section 14.2for details about wall surface reactions.Including the Relative Velocity Resistance FormulationPrior to FLUENT 6.3, cases with moving reference frames used the absolute velocities in the source calculations for inertial and viscous resistance. This approach has been enhanced so that relative velocities are used for the porous source calculations (Section 7.19.2). Using the Relative Velocity Resistance Formulation option (turned on by default) allows you to better predict the source terms for cases involving moving meshes or moving reference frames (MRF). This option works well in cases withnon-moving and moving porous media. Note that FLUENT will use the appropriate velocities (relative or absolute), depending on your case setup. Defining the Viscous and Inertial Resistance CoefficientsThe viscous and inertial resistance coefficients are both defined in the same manner. The basic approach for defining the coefficients using a Cartesian coordinate system is to define one direction vector in 2D or two direction vectors in 3D, and then specify the viscous and/or inertial resistance coefficients in each direction. In 2D, the second direction, which is not explicitly defined, is normal to the plane defined by the specified direction vector and the direction vector. In 3D, the third direction is normal to the plane defined by the two specified direction vectors. For a 3D problem, the second direction must be normal to the first. If you fail to specify two normal directions, the solver will ensure that they are normal by ignoring any component of the second direction that is in the first direction. You should therefore be certain that the first direction is correctly specified. You can also define the viscous and/or inertial resistance coefficients in each direction using a user-defined function (UDF). The user-defined options become available in the corresponding drop-down list when the UDF has been created and loaded into FLUENT. Note that the coefficients defined in the UDF must utilize the DEFINE_PROFILE macro. For moreinformation on creating and using user-defined function, see the separate UDF Manual.If you are modeling axisymmetric swirling flows, you can specify an additional direction component for the viscous and/or inertial resistance coefficients. This direction component is always tangential to the other two specified directions. This option is available for both density-based and pressure-based solvers.In 3D, it is also possible to define the coefficients using a conical (or cylindrical) coordinate system, as described below.Note that the viscous and inertial resistance coefficients aregenerally based on the superficial velocity of the fluid in the porous media.The procedure for defining resistance coefficients is as follows:1. Define the direction vectors.To use a Cartesian coordinate system, simply specify the Direction-1 Vector and, for 3D, the Direction-2 Vector. The unspecifieddirection will be determined as described above. These directionvectors correspond to the principle axes of the porous media.For some problems in which the principal axes of the porous mediumare not aligned with the coordinate axes of the domain, you may notknow a priori the direction vectors of the porous medium. In suchcases, the plane tool in 3D (or the line tool in 2D) can help you todetermine these direction vectors.(a) "Snap'' the plane tool (or the line tool) onto the boundary of theporous region. (Follow the instructions inSection 27.6.1 or 27.5.1 for initializing the tool to a position on anexisting surface.)(b) Rotate the axes of the tool appropriately until they are alignedwith the porous medium.(c) Once the axes are aligned, click on the Update From PlaneTool or Update From Line Tool button inthe Fluid panel. FLUENT will automatically set the Direction-1Vector to the direction of the red arrow of the tool, and (in 3D)the Direction-2 Vector to the direction of the green arrow.To use a conical coordinate system (e.g., for an annular, conical filter element), follow the steps below. This option is available only in 3D cases.(a) Turn on the Conical option.(b) Specify the Cone Axis Vector and Point on Cone Axis. Thecone axis is specified as being in the direction of the Cone AxisVector (unit vector), and passing through the Point on Cone Axis.The cone axis may or may not pass through the origin of thecoordinate system.(c) Set the Cone Half Angle (the angle between the cone's axis andits surface, shown in Figure 7.19.2). To use a cylindrical coordinate system, set the Cone Half Angle to 0.Figure 7.19.2: Cone Half AngleFor some problems in which the axis of the conical filter element is not aligned with the coordinate axes of the domain, you may notknow a priori the direction vector of the cone axis and coordinates ofa point on the cone axis. In such cases, the plane tool can help you todetermine the cone axis vector and point coordinates. One method is as follows:(a) Select a boundary zone of the conical filter element that isnormal to the cone axis vector in the drop-down list next to the Snap to Zone button.(b) Click on the Snap to Zone button. FLUENT will automatically"snap'' the plane tool onto the boundary. It will also set the Cone Axis Vector and the Point on Cone Axis. (Note that you will still have to set the Cone Half Angle yourself.)An alternate method is as follows:(a) "Snap'' the plane tool onto the boundary of the porous region.(Follow the instructions in Section 27.6.1 for initializing the tool to a position on an existing surface.)(b) Rotate and translate the axes of the tool appropriately until thered arrow of the tool is pointing in the direction of the cone axisvector and the origin of the tool is on the cone axis.(c) Once the axes and origin of the tool are aligned, click onthe Update From Plane Tool button inthe Fluid panel. FLUENT will automatically set the Cone AxisVector and the Point on Cone Axis. (Note that you will still have toset the Cone Half Angle yourself.)2. Under Viscous Resistance, specify the viscous resistancecoefficient in each direction.Under Inertial Resistance, specify the inertial resistance coefficient in each direction. (You will need to scroll down with the scroll bar to view these inputs.)For porous media cases containing highly anisotropic inertial resistances, enable Alternative Formulation under Inertial Resistance.The Alternative Formulation option provides better stability to the calculation when your porous medium is anisotropic. The pressure loss through the medium depends on the magnitude of the velocity vector ofthe i th component in the medium. Using the formulation ofEquation 7.19-6 yields the expression below:(7.19-10) Whether or not you use the Alternative Formulation option depends on how well you can fit your experimentally determined pressure drop data to the FLUENT model. For example, if the flow through the medium is aligned with the grid in your FLUENT model, then it will not make a difference whether or not you use the formulation.For more infomation about simulations involving highly anisotropic porous media, see Section 7.19.8.Note that the alternative formulation is compatible only with the pressure-based solver.If you are using the Conical specification method, Direction-1 is the cone axis direction, Direction-2 is the normal to the cone surface (radial ( )direction for a cylinder), and Direction-3 is the circumferential ( ) direction.In 3D there are three possible categories of coefficients, and in 2D there are two:In the isotropic case, the resistance coefficients in all directions are the same (e.g., a sponge). For an isotropic case, you must explicitlyset the resistance coefficients in each direction to the same value.When (in 3D) the coefficients in two directions are the same and those in the third direction are different or (in 2D) the coefficients inthe two directions are different, you must be careful to specify thecoefficients properly for each direction. For example, if you had aporous region consisting of cylindrical straws with small holes inthem positioned parallel to the flow direction, the flow would passeasily through the straws, but the flow in the other two directions(through the small holes) would be very little. If you had a plane offlat plates perpendicular to the flow direction, the flow would notpass through them at all; it would instead move in the other twodirections.In 3D the third possible case is one in which all three coefficients are different. For example, if the porous region consisted of a plane ofirregularly-spaced objects (e.g., pins), the movement of flow between the blockages would be different in each direction. You wouldtherefore need to specify different coefficients in each direction. Methods for deriving viscous and inertial loss coefficients are described in the sections that follow.Deriving Porous Media Inputs Based on Superficial Velocity, Using a Known Pressure LossWhen you use the porous media model, you must keep in mind that the porous cells in FLUENT are 100% open, and that the values that you specify for and/or must be based on this assumption. Suppose, however, that you know how the pressure drop varies with the velocity through the actual device, which is only partially open to flow. The following exercise is designed to show you how to compute a valuefor which is appropriate for the FLUENT model.Consider a perforated plate which has 25% area open to flow. The pressure drop through the plate is known to be 0.5 times the dynamic head in the plate. The loss factor, , defined as(7.19-11)is therefore 0.5, based on the actual fluid velocity in the plate, i.e., the velocity through the 25% open area. To compute an appropriate valuefor , note that in the FLUENT model:1. The velocity through the perforated plate assumes that the plate is 100% open.2. The loss coefficient must be converted into dynamic head loss per unit length of the porous region.Noting item 1, the first step is to compute an adjusted loss factor, , which would be based on the velocity of a 100% open area:(7.19-12) or, noting that for the same flow rate, ,(7.19-13)The adjusted loss factor has a value of 8. Noting item 2, you must now convert this into a loss coefficient per unit thickness of the perforated plate. Assume that the plate has a thickness of 1.0 mm (10 m). The inertial loss factor would then be(7.19-14)Note that, for anisotropic media, this information must be computed for each of the 2 (or 3) coordinate directions.Using the Ergun Equation to Derive Porous Media Inputs for a Packed BedAs a second example, consider the modeling of a packed bed. In turbulent flows, packed beds are modeled using both a permeability and an inertial loss coefficient. One technique for deriving the appropriate constants involves the use of the Ergun equation [ 98], a semi-empirical correlation applicable over a wide range of Reynolds numbers and for many types of packing:(7.19-15)When modeling laminar flow through a packed bed, the second term in the above equation may be dropped, resulting in the Blake-Kozenyequation [ 98]:(7.19-16) In these equations, is the viscosity, is the mean particlediameter, is the bed depth, and is the void fraction, defined as the volume of voids divided by the volume of the packed bed region. Comparing Equations 7.19-4 and 7.19-6 with 7.19-15, the permeability and inertial loss coefficient in each component direction may be identified as(7.19-17) and(7.19-18) Using an Empirical Equation to Derive Porous Media Inputs for Turbulent Flow Through a Perforated PlateAs a third example we will take the equation of Van Winkle et al. [ 279, 339] and show how porous media inputs can be calculated for pressure loss through a perforated plate with square-edged holes.The expression, which is claimed by the authors to apply for turbulent flow through square-edged holes on an equilateral triangular spacing, is(7.19-19) where= mass flow rate through the plate= the free area or total area of the holes= the area of the plate (solid and holes)= a coefficient that has been tabulated for various Reynolds-numberrangesand for various= the ratio of hole diameter to plate thicknessfor and for the coefficient takes a value of approximately 0.98, where the Reynolds number is based on hole diameter and velocity in the holes.Rearranging Equation 7.19-19, making use of the relationship(7.19-20)and dividing by the plate thickness, , we obtain(7.19-21)where is the superficial velocity (not the velocity in the holes). Comparing with Equation 7.19-6 it is seen that, for the direction normal to the plate, the constant can be calculated from(7.19-22)Using Tabulated Data to Derive Porous Media Inputs for Laminar Flow Through a Fibrous MatConsider the problem of laminar flow through a mat or filter pad which is made up of randomly-oriented fibers of glass wool. As an alternative to the Blake-Kozeny equation (Equation 7.19-16) we might choose to employ tabulated experimental data. Such data is available for many types offiber [ 158].fraction of dimensionless permeability of glass woolwhere and is the fiber diameter. , for use inEquation 7.19-4, is easily computed for a given fiber diameter and volume fraction.Deriving the Porous Coefficients Based on Experimental Pressure and Velocity DataExperimental data that is available in the form of pressure drop against velocity through the porous component, can be extrapolated to determine the coefficients for the porous media. To effect a pressure drop across a porous medium of thickness, , the coefficients of the porous media are determined in the manner described below.If the experimental data is:then an curve can be plotted to create a trendline through these points yielding the following equationwhere is the pressure drop and is the velocity.Note that a simplified version of the momentum equation, relating the pressure drop to the source term, can be expressed as (7.19-24)or(7.19-25)Hence, comparing Equation 7.19-23 to Equation 7.19-2, yields the following curve coefficients:(7.19-26)with kg/m , and a porous media thickness, , assumed to be 1m in this example, the inertial resistance factor, .Likewise,with , the viscous inertial resistancefactor,. Note that this same technique can be applied to the porous jump boundary condition. Similar to the case of the porous media, you have to take into account the thickness of the medium . Yourexperimental data can be plotted in ancurve, yielding an equation that is equivalent to Equation 7.22-1. From there, you can determine the permeability and the pressure jumpcoefficient .Using the Power-Law ModelIf you choose to use the power-law approximation of the porous-media momentum source term (Equation 7.19-3), the only inputs required are the coefficients and . Under Power Law Model in the Fluid panel, enter the values for C0 and C1. Note that the power-law model can be used in conjunction with the Darcy and inertia models.C0 must be in SI units, consistent with the value of C1.Defining PorosityTo define the porosity, scroll down below the resistance inputs inthe Fluid panel, and set the Porosity under Fluid Porosity .You can also define the porosity using a user-defined function (UDF). The user-defined option becomes available in the corresponding drop-down list when the UDF has been created and loaded into FLUENT. Note that the porosity defined in the UDF must utilize the DEFINE_PROFILE macro. For more information on creating and using user-defined function, see the separate UDF Manual.The porosity, , is the volume fraction of fluid within the porous region (i.e., the open volume fraction of the medium). The porosity is used in the prediction of heat transfer in the medium, as described in Section 7.19.3, and in the time-derivative term in the scalar transport equations for unsteady flow, as described in Section 7.19.5. It also impacts the calculation of reaction source terms and body forces in the medium. These sources will be proportional to the fluid volume in the medium. If you want to represent the medium as completely open (no effect of the solid medium), you should set the porosity equal to 1.0 (the default). When the porosity is equal to 1.0, the solid portion of the medium will have no impact on heat transfer or thermal/reaction source terms in the medium.Defining the Porous MaterialIf you choose to model heat transfer in the porous medium, you must specify the material contained in the porous medium.To define the material contained in the porous medium, scroll down below the resistance inputs in the Fluid panel, and select the appropriate solid in the Solid Material Name drop-down list under Fluid Porosity. If you want to check or modify the properties of the selected material, you canclick Edit... to open the Material panel; this panel contains just the properties of the selected material, not the full contents of thestandard Materials panel. In the Material panel, you can define thenon-isotropic thermal conductivity of the porous material using auser-defined function (UDF). The user-defined option becomes available in the corresponding drop-down list when the UDF has been created and loaded into FLUENT. Note that the non-isotropic thermal conductivity defined in the UDF must utilize the DEFINE_PROPERTY macro. For more information on creating and using user-defined function, see the separate UDF Manual.Defining SourcesIf you want to include effects of the heat generated by the porous medium in the energy equation, enable the Source Terms option and set anon-zero Energy source. The solver will compute the heat generated by the porous region by multiplying this value by the total volume of the cells comprising the porous zone. You may also define sources of mass, momentum, turbulence, species, or other scalar quantities, as described in Section 7.28.Defining Fixed ValuesIf you want to fix the value of one or more variables in the fluid region of the zone, rather than computing them during the calculation, you can do so by enabling the Fixed Values option. See Section 7.27 for details. Suppressing the Turbulent Viscosity in the Porous RegionAs discussed in Section 7.19.4, turbulence will be computed in the porous region just as in the bulk fluid flow. If you are using one of the turbulence models (with the exception of the Large Eddy Simulation (LES) Model), and you want the turbulence generation to be zero in the porous zone, turn on the Laminar Zone option in the Fluid panel. Refer to Section 7.17.1 for more information about suppressing turbulence generation.Specifying the Rotation Axis and Defining Zone MotionInputs for the rotation axis and zone motion are the same as for a standard fluid zone. See Section 7.17.1 for details.。
【2019年整理】多孔介质-Fluent模拟
7.19多孔介质边界条件多孔介质模型适用的范围非常广泛，包括填充床，过滤纸，多孔板，流量分配器，还有管群，管束系统。
当使用这个模型的时候，多孔介质将运用于网格区域，流场中的压降将由输入的条件有关，见Section 7.19.2.同样也可以计算热传导，基于介质和流场热量守恒的假设，见Section 7.19.3.通过一个薄膜后的已知速度/压力降低特性可以简化为一维多孔介质模型，简称为“多孔跳跃”。
多孔跳跃模型被运用于一个面区域而不是网格区域，而且也可以代替完全多孔介质模型在任何可能的时候，因为它更加稳定而且能够很好地收敛。
见Section 7.22.7.19.1 多孔介质模型的限制和假设多孔介质模型就是在定义为多孔介质的区域结合了一个根据经验假设为主的流动阻力。
本质上，多孔介质模型仅仅是在动量方程上叠加了一个动量源项。
这种情况下，以下模型方面的假设和限制就可以很容易得到：•因为没有表示多孔介质区域的实际存在的体，所以fluent默认是计算基于连续性方程的虚假速度。
做为一个做精确的选项，你可以适用fluent中的真是速度，见section7.19.7。
•多孔介质对湍流流场的影响，是近似的，见7.19.4。
•当在移动坐标系中使用多孔介质模型的时候，fluent既有相对坐标系也可以使用绝对坐标系，当激活相对速度阻力方程。
这将得到更精确的源项。
相关信息见section7.19.5和7.19.6。
•当需要定义比热容的时候，必须是常数。
7.19.2 多孔介质模型动量方程多孔介质模型的动量方程是在标准动量方程的后面加上动量方程源项。
源项包含两个部分：粘性损失项（达西公式项，方程7.19-1右边第一项），和惯性损失项（方程7.19-1右边第二项）(7.19-1)式中，si是i（x，y，z）动量方程的源项，是速度大小，D和C是矩阵。
动量源项对多孔介质区域的压力梯度有影响，生成一个与速度大小（速度平方）成正比的压降。
多孔介质-Fluent模拟
多孔介质-Fluent模拟7.19多孔介质边界条件多孔介质模型适用的范围非常广泛，包括填充床，过滤纸，多孔板，流量分配器，还有管群，管束系统。
当使用这个模型的时候，多孔介质将运用于网格区域，流场中的压降将由输入的条件有关，见Section 7.19.2.同样也可以计算热传导，基于介质和流场热量守恒的假设，见Section 7.19.3.通过一个薄膜后的已知速度/压力降低特性可以简化为一维多孔介质模型，简称为“多孔跳跃”。
多孔跳跃模型被运用于一个面区域而不是网格区域，而且也可以代替完全多孔介质模型在任何可能的时候，因为它更加稳定而且能够很好地收敛。
见Section 7.22.7.19.1 多孔介质模型的限制和假设多孔介质模型就是在定义为多孔介质的区域结合了一个根据经验假设为主的流动阻力。
本质上，多孔介质模型仅仅是在动量方程上叠加了一个动量源项。
这种情况下，以下模型方面的假设和限制就可以很容易得到:, 因为没有表示多孔介质区域的实际存在的体，所以fluent默认是计算基于连续性方程的虚假速度。
做为一个做精确的选项，你可以适用fluent中的真是速度，见section7.19.7。
, 多孔介质对湍流流场的影响，是近似的，见7.19.4。
, 当在移动坐标系中使用多孔介质模型的时候，fluent既有相对坐标系也可以使用绝对坐标系，当激活相对速度阻力方程。
这将得到更精确的源项。
相关信息见section7.19.5和7.19.6。
, 当需要定义比热容的时候，必须是常数。
7.19.2 多孔介质模型动量方程多孔介质模型的动量方程是在标准动量方程的后面加上动量方程源项。
源项包含两个部分:粘性损失项(达西公式项，方程7.19-1右边第一项)，和惯性损失项(方程7.19-1右边第二项)(7.19-1)式中，si是i(x，y，z)动量方程的源项，是速度大小，D和C是矩阵。
动量源项对多孔介质区域的压力梯度有影响，生成一个与速度大小(速度平方)成正比的压降。
FLUENT多孔介质中平面面板(plane surface)工具的使用
1、输出grid图形2、选择surface---plane,打开plane surface面板3、通过确定三个点来确定平面位置。
单击slect point，出现提示，不点选cancel.在grid 图形的多孔介质区域任意位置右键点选3个点。
4、回到plane surface面板，勾选plane tool，则在grid图形的多孔介质区域出现一个平面。
若出现的平面与我们的预期相差比较大的话，可以单击reset points,可以获得一个特殊位置的平面。
5、打开多孔介质的控制面板，选择porou zone标签，点击update from plane tool按钮，获得方向矢量1，和方向矢量2的原始值，并与左下角的坐标系统比较，确定我们大概的旋转方向。
6、对比grid图形左下角的坐标系统，红线和红色箭头代表的是方向矢量1，绿线和绿色箭头代表的是方向矢量2应该使红线和X正方向平行，绿线和Y正方向平行。
具体的操作应该是：一：先单击白线的蓝色箭头，固定了该方向在旋转过程中不变，可以保证在旋转的过程比较有规律，然后右键点选白线的红色箭头旋转红线的红色箭头到X的正轴；二: 接下来应该是单击白线的红色箭头，固定该方向不变，单击白线的蓝色箭头，旋转绿线的绿色箭头指向Y的正轴。
（所以多孔介质区域我们一般是设置在坐标系统里面，轴线等与坐标系统无非直角角度关系）。
把平面移动到图形外有利于旋转，比较清楚。
平面法线方向的移动是用鼠标右键单击平面阴影部分并拖动，横向移动则需按下shift并进行如上操作。
7、旋转到适当的位置后（鼠标右键拖动箭头），再次点击update from plane tool按钮，获得方向矢量1，和方向矢量2。
得到的数值很可能不是整数，这个时候我们可以把他简化为整数。
例如：0.9123可以简化为1，0.01245可以简化为0，以此类推。
FLUENT多孔介质数值模拟设置
FLUENT多孔介质数值模拟设置C=对于不同D/t的不同雷诺数范围被列成不同的表的系数A_p=圆盘的面积（固体和洞)如果你选择在多孔介质中模拟热传导，你必须指定多孔介质中的材料以及多孔性。
要定义多孔介质的材料，向下拉流体面板中阻力输入底下的滚动条，然后在多孔热传导的固体材料下拉列表中选中适当的固体。
另一个处理收敛性差的要领是临时取消多孔介质模型（在流体面板中关闭多孔区域）然后获取一个不受多孔区域影响的初始流场。
取消多孔区域后，FLUE ＮT会将多孔区域处理为流体区域并按响应的流体区域来计算。
一旦获取了初始解，或者计算很容易收敛，你就可以激活多孔模型继续计算包罗多孔区域的流场（对于大阻力多孔介质不保举使用该要领）。
这些变量会在后处理面板的变量选择下拉菜谱制定类别中出现。
然后在多孔热传导下设定多孔性。
多孔性f是多孔介质中流体的体积分数（即介质的开放体积分数）。
多孔性用于介质中的热传导预测，处理要领请参阅多孔介质能量方程的处理一节。
它还对介质中的反应源项和体力的计算有影响。
这个源项和介质中流体的体积成比例。
如果你想要模拟完全开放的介质（固体介质没有影响），你应该设定多孔性为1.0。
当多孔性为1.0时，介质的固体部门对于热传导和（或）热源项/反应源项没有影响。
注意：多孔性永远不会影响介质中的流体速率，这已经在多孔介质的动量方程一节中介绍了。
不管你将多孔性设定为何值，，FLUEＮT所预测的速率都是介质中的外貌速率。
对于多孔介质动量源项（多孔介质动量方程中的方程5），如果你使用幂律模型近似，你只要在流体面板的幂律模型中输入系数C_0和C_1就可以了。
如果C_0或C_1为非零值，解算器会忽略面板中除了多孔介质幂律模型之外的所有输入。
定义源项一般说来，在模拟多孔介质时，你可以使用标准的解算步骤以及解参数的设置。
然而你会发现如果多孔区域在流动方向上压降至关大（比如：渗透性a很低或者内部因数C_2很大）的话，解的收敛速率就会变慢。
fluent多孔板处理方法
fluent多孔板处理方法
Fluent多孔板处理方法是指在Fluent软件中使用多孔板模型进行流体处理的技术。
多孔板是一种被广泛应用于过滤、分离和增加传质过程的设备，它具有各种孔隙形状和尺寸。
在使用Fluent进行多孔板处理时，首先需要建立一个合适的几何模型，包括多孔板的尺寸和流体领域的设置。
然后，根据实际情况选择适当的物理模型和边界条件。
在多孔板模型中，主要涉及两个关键参数：流体流动速度和多孔介质的阻力系数。
流体流动速度可以通过设置入口边界条件来实现，常用的边界条件有速度入口和压力出口。
多孔介质的阻力系数可以通过实验或经验公式获得，并在模型中进行设置。
在处理过程中，还需要考虑多孔板的材料特性，如孔隙率、孔隙形状和孔隙分布。
这些参数将直接影响到流体在多孔介质中的传递和分布过程。
Fluent提供了多种求解器来模拟多孔板处理过程，其中包括具有多孔效应的流体流动模型。
通过使用这些求解器，可以获得多孔板内部的流体速度分布、压力分布和质量传递情况。
总之，Fluent多孔板处理方法是利用Fluent软件模拟多孔板内部流体流动和传质过程的一种技术。
通过合理设置模型参数、边界条件和材料特性，可以准确地模拟和分析多孔板系统中的流体行为，为工程设计和优化提供有效的参考依据。
FLUENT多孔介质数值模拟设置
FLUENT多孔介质数值模拟设置多孔介质条件多孔介质模型可以应用于很多问题，如通过充满介质的流动、通过过滤纸、穿孔圆盘、流量分配器以及管道堆的流动。
当你使用这一模型时，你就定义了一个具有多孔介质的单元区域，而且流动的压力损失由多孔介质的动量方程中所输入的内容来决定。
通过介质的热传导问题也可以得到描述，它服从介质和流体流动之间的热平衡假设，具体内容可以参考多孔介质中能量方程的处理一节。
多孔介质的一维化简模型，被称为多孔跳跃，可用于模拟具有已知速度/压降特征的薄膜。
多孔跳跃模型应用于表面区域而不是单元区域，并且在尽可能的情况下被使用（而不是完全的多孔介质模型），这是因为它具有更好的鲁棒性，并具有更好的收敛性。
详细内容请参阅多孔跳跃边界条件。
多孔介质模型的限制如下面各节所述，多孔介质模型结合模型区域所具有的阻力的经验公式被定义为“多孔”。
事实上多孔介质不过是在动量方程中具有了附加的动量损失而已。
因此，下面模型的限制就可以很容易的理解了。
流体通过介质时不会加速，因为事实上出现的体积的阻塞并没有在模型中出现。
这对于过渡流是有很大的影响的，因为它意味着FLUENT不会正确的描述通过介质的过渡时间。
多孔介质对于湍流的影响只是近似的。
详细内容可以参阅湍流多孔介质的处理一节。
多孔介质的动量方程多孔介质的动量方程具有附加的动量源项。
源项由两部分组成，一部分是粘性损失项 (Darcy)，另一个是内部损失项：其中S_i是i向(x, y, or z)动量源项，D和C是规定的矩阵。
在多孔介质单元中，动量损失对于压力梯度有贡献，压降和流体速度（或速度方阵）成比例。
对于简单的均匀多孔介质：其中a是渗透性，C_2时内部阻力因子，简单的指定D和C分别为对角阵1/a 和C_2其它项为零。
FLUENT还允许模拟的源项为速度的幂率：其中C_0和C_1为自定义经验系数。
注意：在幂律模型中，压降是各向同性的，C_0的单位为国际标准单位。
多孔介质的Darcy定律通过多孔介质的层流流动中，压降和速度成比例，常数C_2可以考虑为零。
多孔介质在fluent中的操作方法 网络上传版本
如何在Fluent中实现多孔介质双能量方程(LNTE)How to use Non-equilibrium Thermal equation (LNTE) model forPorous media in Fluent Software●请参照本人发表的文章：●Please refer to the following papers：1)Wang Fu–Qiang*，Shuai Yong*，Wang Zhi–Q iang，Leng Yu，Tan He–Ping.Thermal and chemical reaction performance analyses of steam methane reforming in porous media solar thermochemical reactor，International Journal of Hydrogen Energy，39(2)：718-730，2014关键词：Porous, Solar, Hydrogen, Methane, Reforming, P1 approximation, radiative heat transfer2)Wang Fu–Qiang*，Shuai Yong*，Tan He–Ping，Zhang Xiao-Feng，MaoQian-Jun，Heat transfer analyses of porous media receiver with multi–dish collector by coupling MCRT and FVM method，Solar Energy，93：158–168，2013关键词：Solar, Porous, dish concentrator, Receiver, Monte Carlo3)Wang Fu–Qiang*，Shuai Yong*，Tan He–Ping，Yu Chun–Liang，ThermalPerformance Analysis of Porous Media Receiver with Concentrated Solar Irradiation，International Journal of Heat and Mass Transfer，62：247–254，2013关键词：Solar, Porous, dish concentrator, Receiver, Monte Carlo一、说明1、模型此例基于稳态、层流、对称模型。
fluent中多孔介质设置问题和算例
fluent中多孔介质设置问题和算例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set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）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”，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 MediaIntroductionMany industrial applications involve the modeling of flow through porous media, such as filters, catalyst beds, and packing. This tutorial illustrates how to set 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 used to purify emissions from gasoline and diesel 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. These 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 used 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, FLUENT is used 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 based 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 sections of the geometry using X-Y plots and numerical reports.Problem DescriptionThe 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, passes through a ceramic monolith substrate with square shaped channels, and then exits through the outlet.While the flow in the inlet and outlet sections is turbulent, the flow through the substrate is laminar and is characterized by inertial and viscous loss coefficients in the flow (X) direction. The substrate is impermeable in other directions, which is modeled using loss coefficients whose values are three orders of magnitude higher than in the X direction.Setup and SolutionStep 1: Grid1. Read the mesh file (catalytic converter.msh).File /Read /Case...2. Check the grid. Grid /CheckFLUENT 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! Scale...(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 close the Scale Grid panel.4. Display the mesh. Display /Grid...(a) Make sure that inlet, outlet, substrate-wall, and wall are selected in the Surfaces selection list.(b) Click Display.(c) Rotate the view and zoom in to get the display shown in Figure 7.2.(d) Close the Grid Display panel.The hex mesh on the geometry contains a total of 34,580 cells.Step 2: Models1. Retain the default solver settings. Define /Models /Solver...2. Select the standard k-ε turbulence model. Define/ Models /Viscous...Step 3: Materials1. Add nitrogen to the list of fluid materials by copying it from the Fluent Database for materials. Define /Materials...(a) Click the Fluent Database... button to open the Fluent Database Materials panel.i. Select nitrogen (n2) from the list of Fluent Fluid Materials.ii. Click Copy to copy the information for nitrogen to your list of fluid materials. iii. Close the Fluent Database Materials panel.(b) Close the Materials panel.Step 4: Boundary Conditions. Define /Boundary Conditions...1. Set the boundary conditions for the fluid (fluid).(a) Select nitrogen from the Material Name drop-down list.(b) Click OK to close the Fluid panel.2. Set the boundary conditions for the substrate (substrate).(a) Select nitrogen from the Material Name drop-down list.(b) Enable the Porous Zone option to activate the porous zone model.(c) Enable the Laminar Zone option to solve the flow in the porous zone without turbulence.(d) Click the Porous Zone tab.i. Make sure that the principal direction vectors are set as shown in Table7.1. Use the scroll bar to access the fields that are not initially visible in the panel.ii. Enter the values in Table 7.2 for the Viscous Resistance and Inertial Resistance. Scroll down to access the fields that are not initially visible in the panel.(e) Click OK to close the Fluid panel.3. Set the velocity and turbulence boundary conditions at the inlet (inlet).(a) Enter 22.6 m/s for the Velocity Magnitude.(b) Select Intensity and Hydraulic Diameter from the Specification Method dropdown list in the Turbulence group box.(c) Retain the default value of 10% for the Turbulent Intensity.(d) Enter 42 mm for the Hydraulic Diameter.(e) Click OK to close the Velocity Inlet panel.4. Set the boundary conditions at the outlet (outlet).(a) Retain the default setting of 0 for Gauge Pressure.(b) Select Intensity and Hydraulic Diameter from the Specification Method dropdown list in the Turbulence group box.(c) Enter 5% for the Backflow Turbulent Intensity.(d) Enter 42 mm for the Backflow Hydraulic Diameter.(e) Click OK to close the Pressure Outlet panel.5. Retain the default boundary conditions for the walls (substrate-wall and wall) and close the Boundary Conditions panel. Step 5: Solution1. Set the solution parameters. Solve /Controls /Solution...(a) Retain the default settings for Under-Relaxation Factors.(b) Select Second Order Upwind from the Momentum drop-down list in the Discretization group box.(c) Click OK to close the Solution Controls panel.2. Enable the plotting of residuals during the calculation. Solve/Monitors /Residual...(a) Enable Plot in the Options group box.(b) Click OK to close the Residual Monitors panel.3. Enable the plotting of the mass flow rate at the outlet.Solve / Monitors /Surface...(a) Set the Surface Monitors to 1.(b) Enable the Plot and Write options for monitor-1, and click the Define... button to open the Define Surface Monitor panel.i. Select Mass Flow Rate from the Report Type drop-down list.ii. Select outlet from the Surfaces selection list.iii. Click OK to close the Define Surface Monitors panel.(c) Click OK to close the Surface Monitors panel.4. Initialize the solution from the inlet. Solve /Initialize /Initialize...(a) Select inlet from the Compute From drop-down list.(b) Click Init and close the Solution Initialization panel.5. Save the case file (catalytic converter.cas). File /Write /Case...6. Run the calculation by requesting 100 iterations. Solve /Iterate...(a) Enter 100 for the Number of Iterations.(b) Click Iterate.The FLUENT calculation will converge in approximately 70 iterations. By this point the mass flow rate monitor has attended out, as seen in Figure 7.3.(c) Close the Iterate panel.7. Save the case and data files (catalytic converter.cas and catalytic converter.dat).File /Write /Case & Data...Note: If you choose a file name that already exists in the current folder, FLUENTwill prompt you for confirmation to overwrite the file.Step 6: Post-processing1. Create a surface passing through the centerline for post-processing purposes.Surface/Iso-Surface...(a) Select Grid... and Y-Coordinate from the Surface of Constant drop-down lists.(b) Click Compute to calculate the Min and Max values.(c) Retain the default value of 0 for the Iso-Values.(d) Enter y=0 for the New Surface Name.(e) Click Create.2. Create cross-sectional surfaces at locations on either side of the substrate, as well as at its center. Surface /Iso-Surface...(a) Select Grid... and X-Coordinate from the Surface of Constant drop-down lists.(b) Click Compute to calculate the Min and Max values.(c) Enter 95 for Iso-Values.(d) Enter x=95 for the New Surface Name.(e) Click Create.(f) In a similar manner, create surfaces named x=130 and x=165 with Iso-Values of 130 and 165, respectively. Close the Iso-Surface panel after all the surfaces have been created.3. Create a line surface for the centerline of the porous media.Surface /Line/Rake...(a) Enter the coordinates of the line under End Points, using the starting coordinate of (95, 0, 0) and an ending coordinate of (165, 0, 0), as shown.(b) Enter porous-cl for the New Surface Name.(c) Click Create to create the surface.(d) Close the Line/Rake Surface panel.4. Display the two wall zones (substrate-wall and wall). Display /Grid...(a) Disable the Edges option.(b) Enable the Faces option.(c) Deselect inlet and outlet in the list under Surfaces, and make sure that only substrate-wall and wall are selected.(d) Click Display and close the Grid Display panel.(e) Rotate the view and zoom so that the display is similar to Figure 7.2.5. Set the lighting for the display. Display /Options...(a) Enable the Lights On option in the Lighting Attributes group box.(b) Retain the default selection of Gourand in the Lighting drop-down list.(c) Click Apply and close the Display Options panel.6. Set the transparency parameter for the wall zones (substrate-wall and wall).Display/Scene...(a) Select substrate-wall and wall in the Names selection list.(b) Click the Display... button under Geometry Attributes to open the Display Properties panel.i. Set the Transparency slider to 70.ii. Click Apply and close the Display Properties panel.(c) Click Apply and then close the Scene Description panel.7. Display velocity vectors on the y=0 surface.Display /Vectors...(a) Enable the Draw Grid option. The Grid Display panel will open.i. Make sure that substrate-wall and wall are selected in the list under Surfaces.ii. Click Display and close the Display Grid panel.(b) Enter 5 for the Scale.(c) Set Skip to 1.(d) Select y=0 from the Surfaces selection list.(e) Click Display and close the Vectors panel.The flow pattern shows that the flow enters the catalytic converter as a jet, with recirculation on either side of the jet. As it passes through the porous substrate, it decelerates and straightens out, and exhibits a more uniform velocity distribution. This allows the metal catalyst present in the substrate to be more effective.Figure 7.4: Velocity Vectors on the y=0 Plane8. Display filled contours of static pressure on the y=0 plane.Display /Contours...(a) Enable the Filled option.(b) Enable the Draw Grid option to open the Display Grid panel.i. Make sure that substrate-wall and wall are selected in the list under Surfaces.ii. Click Display and close the Display Grid panel.(c) Make sure that Pressure... and Static Pressure are selected from the Contours of drop-down lists.(d) Select y=0 from the Surfaces selection list.(e) Click Display and close the Contours panel.Figure 7.5: Contours of the Static Pressure on the y=0 planeThe pressure changes rapidly in the middle section, where the fluid velocity changes as it passes through the porous substrate. The pressure drop can be high, due to the inertial and viscous resistance of the porous media. Determining this pressure drop is a goal of CFD analysis. In the next step, you will learn how to plot the pressure drop along the centerline of the substrate.9. Plot the static pressure across the line surface porous-cl.Plot /XY Plot...(a) Make sure that the Pressure... and Static Pressure are selected from the Y Axis Function drop-down lists.(b) Select porous-cl from the Surfaces selection list.(c) Click Plot and close the Solution XY Plot panel.Figure 7.6: Plot of the Static Pressure on the porous-cl Line SurfaceIn Figure 7.6, the pressure drop across the porous substrate can be seen to be roughly 300 Pa. 10. Display filled contours of the velocity in the X direction on the x=95, x=130 and x=165 surfaces. Display /Contours...。
FLUENT帮助里自带的多孔介质算例-经典资料
Tutorial 7. Modeling Flow Through Porous Media IntroductionMany industrial applications involve the modeling of ow through porous media, such as _lters, catalyst beds, and packing. This tutorial illustrates how to set up and solve a problem involving gas ow through porous media.The industrial problem solved here involves gas ow through a catalytic converter. Catalytic converters are commonly used to purify emissions from gasoline and diesel 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. These 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 ow 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 used to designe_cient catalytic converters: by modeling the exhaust gas ow, the pressure drop andthe uniformity of ow through the substrate can be determined. In this tutorial, FLUENTis used to model the ow of nitrogen gas through a catalytic converter geometry, so that the ow _eld structure maybe 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 ow through the catalytic converter using the pressurebased solver._ Plot pressure and velocity distribution on speci_ed planes of the geometry._ Determine the pressure drop through the substrate and the degree of non-uniformityof ow through cross sections of the geometry using X-Y plots and numerical reports.许多工业应用都涉及通过多孔介质（如过滤器，催化剂床和填料）的流动模型。
FLUENT中定义多孔介质的方法
FLUENT中定义多孔介质的方法多孔介质计算中需要输入的项目如下：（1）定义多孔介质区域。
（2）定义多孔介质速度函数形式。
（3）定义流过多孔介质区的流体属性。
（4）设定多孔区的化学反应。
（5）设定粘性阻力系数。
（6）设定多孔介质的多孔率。
（7）在计算热交换的过程中选择多孔介质的材料。
（8）设定多孔介质固体部分的体热生成率。
（9）设定流动区域上的任意固定值的流动参数。
（10）需要的话，将多孔区流动设为层流，或取消湍流计算。
（11）定义旋转轴或区域的运动。
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set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）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：见附fluent中多孔粘性阻力系数与惯性阻力系数的方法：对比Darcy 定律v K J =⋅J 为水力坡度，即流经路径长度为L 的水头损失，m/m ；K 为比例系数，也称渗流系数，m/sg p v Kρ∆=- p μνα∆=- 这样可以得到，g K ρμα=，所以1g K ραμ= 其中： 1α为粘性阻力系数，1/m 2； K 为比例系数，也称渗流系数，m/s ；μ为动力粘度，Pa.s ；ρ为流体密度，kg/m 3；g 为重力加速度，m/s 2；采用20℃饱和水的物性参数：密度为998.2kg/m 3 ，运动粘度1.004×10-3Pa.s ；渗流速度取1.0×10-6m/s ，K 取1.0×10-4m/s ，水力坡度约为0.01m/m ； 10461998.29.89.74101.010100410g K ραμ--⨯===⨯⨯⨯⨯ 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。
多孔介质-Fluent模拟
7.19多孔介质边界条件多孔介质模型适用的范围非常广泛，包括填充床，过滤纸，多孔板，流量分配器，还有管群，管束系统。
当使用这个模型的时候，多孔介质将运用于网格区域，流场中的压降将由输入的条件有关，见Section 7.19.2.同样也可以计算热传导，基于介质和流场热量守恒的假设，见Section 7.19.3.通过一个薄膜后的已知速度/压力降低特性可以简化为一维多孔介质模型，简称为“多孔跳跃”。
多孔跳跃模型被运用于一个面区域而不是网格区域，而且也可以代替完全多孔介质模型在任何可能的时候，因为它更加稳定而且能够很好地收敛。
见Section 7.22.7.19.1 多孔介质模型的限制和假设多孔介质模型就是在定义为多孔介质的区域结合了一个根据经验假设为主的流动阻力。
本质上，多孔介质模型仅仅是在动量方程上叠加了一个动量源项。
这种情况下，以下模型方面的假设和限制就可以很容易得到：•因为没有表示多孔介质区域的实际存在的体，所以fluent默认是计算基于连续性方程的虚假速度。
做为一个做精确的选项，你可以适用fluent中的真是速度，见section7.19.7。
•多孔介质对湍流流场的影响，是近似的，见7.19.4。
•当在移动坐标系中使用多孔介质模型的时候，fluent既有相对坐标系也可以使用绝对坐标系，当激活相对速度阻力方程。
这将得到更精确的源项。
相关信息见section7.19.5和7.19.6。
•当需要定义比热容的时候，必须是常数。
7.19.2 多孔介质模型动量方程多孔介质模型的动量方程是在标准动量方程的后面加上动量方程源项。
源项包含两个部分：粘性损失项（达西公式项，方程7.19-1右边第一项），和惯性损失项（方程7.19-1右边第二项）(7.19-1)式中，si是i（x，y，z）动量方程的源项，是速度大小，D和C是矩阵。
动量源项对多孔介质区域的压力梯度有影响，生成一个与速度大小（速度平方）成正比的压降。
fluent多孔跳跃模型参数设置
fluent多孔跳跃模型参数设置摘要：1.Fluent 软件简介2.多孔跳跃模型的设置方法3.多孔介质模型的参数设置4.模型应用实例正文：一、Fluent 软件简介Fluent 是一款国际上流行的商用计算流体动力学（CFD）软件包，广泛应用于航空航天、汽车设计、石油天然气和涡轮机设计等领域。
它具有丰富的物理模型、先进的数值方法和强大的前后处理功能，在美国的市场占有率达到60%。
二、多孔跳跃模型的设置方法在Fluent 中，多孔跳跃模型的设置主要分为以下几个步骤：1.定义多孔介质包含的材料属性和多孔性。
2.设定多孔区域的固体部分的体积热生成速度（或任何其它源项，如质量、动量）（此项可选）。
3.如果合适的话，限制多孔区域的湍流粘性。
4.如果相关的话，指定旋转轴和/或区域运动。
三、多孔介质模型的参数设置在Fluent 中设置多孔介质模型时，需要考虑以下几个参数：1.空隙率：多孔介质中的空隙体积与总体积之比。
2.热导率：多孔介质中的热传导性能，单位为瓦特/(米·开尔文)。
3.密度：多孔介质中的质量密度，单位为千克/立方米。
4.比热容：多孔介质中的比热容，单位为焦耳/(千克·开尔文)。
5.粘性阻力：多孔介质中的流体阻力，单位为帕斯卡。
6.内部阻力：多孔介质中的内部阻力，单位为帕斯卡。
四、模型应用实例Fluent 中的多孔跳跃模型在许多实际应用中都取得了良好的效果，例如在航空航天、汽车设计、石油天然气和涡轮机设计等领域。
通过设置合适的多孔介质模型参数，可以更准确地模拟流体在多孔介质中的流动过程，从而为工程设计提供有力的支持。
综上所述，Fluent 中的多孔跳跃模型参数设置涉及多个方面，需要综合考虑多孔介质的材料属性、热生成速度、湍流粘性等因素。
fluent多孔介质参数设定
Chapter 10: Modeling Flow Through Porous MediaThis tutorial is divided into the following sections:10.1. Introduction10.2. Prerequisites10.3. Problem Description10.4. Setup and Solution10.5. Summary10.6. Further Improvements10.1. IntroductionMany industrial applications such as filters, catalyst beds and packing, involve modeling the flow through porous media.This tutorial illustrates how to set 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 used to purify emissions from gasoline and diesel 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.These exhaust gas emissionsare 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 throughthe substrate. Hence CFD analysis is used 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. Inthis tutorial, ANSYS FLUENT is used 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-based 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 sections of the geometry using X-Y plots and numerical reports.10.2. PrerequisitesThis 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 setup and solution procedure will not be shown explicitly.10.3. Problem DescriptionThe 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, passes through a ceramic monolith substrate with square-shaped channels, and then exits through the outlet.Figure 10.1 Catalytic Converter Geometry for Flow ModelingWhile the flow in the inlet and outlet sections 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 SolutionThe following sections describe the setup and solution steps for this tutorial:10.4.1. Preparation10.4.2. Step 1: Mesh10.4.3. Step 2: General Settings10.4.4. Step 3: Models10.4.5. Step 4: Materials10.4.6. Step 5: Cell Zone Conditions10.4.7. Step 6: Boundary Conditions10.4.8. Step 7: Solution10.4.9. Step 8: PostprocessingSetup and Solution 10.4.1. Preparation1.Extract the file porous.zip from the ANSYS_Fluid_Dynamics_Tutorial_Inputs.zip archivewhich is available from the Customer Portal.NoteFor detailed instructions on how to obtain the ANSYS_Fluid_Dynamics_Tutori-al_Inputs.zip file, please refer to Preparation (p.3) in Introduction to Using ANSYSFLUENT 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 afterunzipping the file.e the FLUENT Launcher to start the 3D version of ANSYS FLUENT.For more information about FLUENT Launcher, see Starting ANSYS FLUENT Using FLUENTLauncher in the User’s Guide.4.Enable Double-Precision.NoteThe Display Options are enabled by default.Therefore, once you read in the mesh, itwill be displayed in the embedded graphics window.10.4.2. Step 1: Mesh1.Read the mesh file (catalytic_converter.msh).File¡Read¡Mesh...2.Check the mesh.General¡CheckANSYS FLUENT will perform various checks on the mesh and report the progress in the console. Makesure that the reported minimum volume is a positive number.3.Scale the mesh.General¡Scale...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.Close the Scale Mesh dialog box.4.Check the mesh.General ¡ CheckNoteIt is a good idea to check the mesh after you manipulate it (i.e., scale, convert to poly-hedra, merge, separate, fuse, add zones, or smooth and swap.) This will ensure thatthe quality of the mesh has not been compromised.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 MediaFigure 10.2 Mesh for the Catalytic Converter Geometry10.4.3. Step 2: General SettingsGeneral Setup and SolutionChapter 10: Modeling Flow Through Porous Media1.Retain the default solver settings.10.4.4. Step 3: ModelsModels1.Select the standard - turbulence model.Models¡Viscous¡Edit...Setup and Solutiona.Select k-epsilon (2eqn) in the Model list.The original Viscous Model dialog box will now expand.b.Retain the default settings for k-epsilon Model and Near-Wall Treatment and click OK to closethe Viscous Model dialog box.10.4.5. Step 4: MaterialsMaterials1.Add nitrogen to the list of fluid materials by copying it from the FLUENT Database of materials.Materials¡air¡Create/Edit...Chapter 10: Modeling Flow Through Porous Mediaa.Click the FLUENT Database... button to open the FLUENT Database Materials dialog box.Setup and Solutioni.Select nitrogen (n2) in the FLUENT Fluid Materials selection list.ii.Click Copy to copy the information for nitrogen to your list of fluid materials.iii.Close the FLUENT Database Materials dialog box.b.Click Change/Create and close the Create/Edit Materials dialog box.10.4.6. Step 5: Cell Zone ConditionsCell Zone ConditionsChapter 10: Modeling Flow Through Porous Media1.Set the cell zone conditions for the fluid (fluid ).Cell Zone Conditions¡fluid¡Edit...a.Select nitrogen from the Material Name drop-down list.b.Click OK to close the Fluid dialog box.2.Set the cell zone conditions for the substrate (substrate).Cell Zone Conditions¡substrate¡Edit...a.Select nitrogen from the Material Name drop-down list.b.Enable Porous Zone to activate the porous zone model.c.Enable Laminar Zone to solve the flow in the porous zone without turbulence.d.Click the Porous Zone tab.i.Make sure that the principal direction vectors are set as shown in Table 10.1:Values for thePrinciple Direction Vectors (p.459).ANSYS FLUENT automatically calculates the third (z-direction) vector based on your inputsfor the first two vectors.The direction vectors determine which axis the viscous and inertialresistance coefficients act upon.Table 10.1 Values for the Principle Direction VectorsAxisDirection-1 VectorDirection-2 Vector1XY1ZUse the scroll bar to access the fields that are not initially visible in the dialog box.ii.Enter the values in Table 10.2:Values for the Viscous and Inertial Resistance (p.459)Viscous Resistance and Inertial Resistance.Direction-2 and Direction-3 are set to arbitrary large numbers.These values are severalorders of magnitude greater than that of the Direction-1 flow and will make any radial flowinsignificant.Scroll down to access the fields that are not initially visible in the panel.Table 10.2 Values for the Viscous and Inertial ResistanceDirectionViscous Resistance (1/m2)Inertial Resistance (1/m)3.846e+07Direction-120.414Direction-23.846e+1020414Direction-33.846e+1020414e.Click OK to close the Fluid dialog box.10.4.7. Step 6: Boundary ConditionsBoundary Conditions1.Set the velocity and turbulence boundary conditions at the inlet (inlet).Boundary Conditions¡inlet¡Edit...a.Enter 22.6 m/s for Velocity Magnitude.b.Select Intensity and Hydraulic Diameter from the Specification Method drop-down list in theTurbulence group box.c.Retain the default value of 10% for the Turbulent Intensity.d.Enter 42 mm for the Hydraulic Diameter.e.Click OK to close the Velocity Inlet dialog box.2.Set the boundary conditions at the outlet (outlet).Boundary Conditions¡outlet¡Edit...a.Retain the default setting of 0 for Gauge Pressure.b.Select Intensity and Hydraulic Diameter from the Specification Method drop-down list in theTurbulence group box.c.Enter 5% for the Backflow Turbulent Intensity.d.Enter 42 mm for the Backflow Hydraulic Diameter.e.Click OK to close the Pressure Outlet dialog box.3.Retain the default boundary conditions for the walls (substrate-wall and wall).10.4.8. Step 7: Solution1.Set the solution parameters.Solution Methodsa.Select Coupled from the Scheme drop-down list.b.Retain the default selection of Least Squares Cell Based from the Gradient drop-down list inthe Spatial Discretization group box.c.Retain the default selection of Second Order Upwind from the Momentum drop-down list.d.Enable Pseudo Transient.2.Enable the plotting of residuals during the calculation.Monitors¡Residuals¡Edit...a.Retain the default settings.b.Click OK to close the Residual Monitors dialog box.3.Enable the plotting of the mass flow rate at the outlet.Monitors(Surface Monitors)¡Create...a.Enable Plot and Write.b.Select Mass Flow Rate from the Report Type drop-down list.c.Select outlet in the Surfaces selection list.d.Click OK to close the Surface Monitor dialog box.4.Initialize the solution from the inlet.Solution Initializationa.Retain the default selection of Hybrid Initialization from the Initialization Methods group box.b.Click Initialize.NoteA warning is displayed in the console stating that the convergence tolerance of1.000000e-06 not reached during Hybrid Initialization.This means that the defaultnumber of iterations is not enough.You will increase the number of iterations andre-initialize the flow. For more information refer to Hybrid Initialization in the User'sGuide.c.Click More Settings....i.Increase the Number of Iterations to 15.ii.Click OK to close the Hybrid Initialization dialog box.d.Click Initialize once more.NoteClick OK in the Question dialog box, where it asks to discard the current data.Theconsole displays that hybrid initialization is done.NoteFor flows in complex topologies, hybrid initialization will provide better initial velocityand pressure fields than standard initialization.This will improve the convergence be-havior of the solver.5.Save the case file (catalytic_converter.cas.gz).File¡Write¡Case...6.Run the calculation by requesting 100 iterations.Run Calculationa.Enter 100 for Number of Iterations.b.Click Calculate to begin the iterations.The ANSYS FLUENT calculation will converge in approximately 95 iterations.The mass flow rate monitor flattens out, as seen in Figure 10.3 (p.468).Figure 10.3 Surface Monitor Plot of Mass Flow Rate with Number of Iterations7.Save the case and data files (catalytic_converter.cas and catalytic_converter.dat).File¡Write¡Case & Data...NoteIf you choose a file name that already exists in the current folder, ANSYS FLUENT willprompt you for confirmation to overwrite the file.10.4.9. Step 8: Postprocessing1.Create a surface passing through the centerline for postprocessing purposes.Surface¡Iso-Surface...a.Select Mesh... and Y-Coordinate from the Surface of Constant drop-down lists.b.Click Compute to calculate the Min and Max values.c.Retain the default value of 0 for Iso-Values.d.Enter y=0 for New Surface Name.e.Click Create.NoteTo interactively place the surface on your mesh, use the slider bar in the Iso-Surfacedialog box.2.Create cross-sectional surfaces at locations on either side of the substrate, as well as at its center.Surface¡Iso-Surface...a.Select Mesh... and X-Coordinate from the Surface of Constant drop-down lists.b.Click Compute to calculate the Min and Max values.c.Enter 95 for Iso-Values.d.Enter x=95 for the New Surface Name.e.Click Create.f.In a similar manner, create surfaces named x=130 and x=165 with Iso-Values of 130 and 165,respectively.g.Close the Iso-Surface dialog box after all the surfaces have been created.3.Create a line surface for the centerline of the porous media.Surface¡Line/Rake...a.Enter the coordinates of the end points of the line in the End Points group box as shown.b.Enter porous-cl for the New Surface Name.c.Click Create to create the surface.d.Close the Line/Rake Surface dialog box.4.Display the two wall zones (substrate-wall and wall).Graphics and Animations¡Mesh¡Set Up...a.Disable Edges and enable Faces in the Options group box.b.Deselect inlet and outlet in the Surfaces selection list, and make sure that only substrate-walland wall are selected.c.Click Display and close the Mesh Display dialog box.d.Rotate the view and zoom so that the display is similar to Figure 10.2 (p.451).5.Set the lighting for the display.Graphics and Animations¡Options...a.Enable Lights On in the Lighting Attributes group box.b.Select Gouraud from the Lighting drop-down list.c.Click Apply and close the Display Options dialog box.6.Set the transparency parameter for the wall zones (substrate-wall and wall).Graphics and Animations¡Scene...a.Select substrate-wall and wall in the Names selection list.b.Click the Display... button in the Geometry Attributes group box to open the Display Propertiesdialog box.i.Make sure that Red,Green, and Blue sliders are set to the maximum position (i.e. 255).ii.Set the Transparency slider to 70.iii.Click Apply and close the Display Properties dialog box.c.Click Apply and close the Scene Description dialog box.7.Display velocity vectors on the y=0 surface (Figure 10.4 (p.475)).Graphics and Animations¡Vectors¡Set Up...a.Enable Draw Mesh in the Options group box to open the Mesh Display dialog box.i.Make sure that substrate-wall and wall are selected in the Surfaces selection list.ii.Click Display and close the Mesh Display dialog box.b.Enter 5 for Scale.c.Set Skip to 1.d.Select y=0 in the Surfaces selection list.e.Click Display and close the Vectors dialog box.Figure 10.4 Velocity Vectors on the y=0 PlaneThe flow pattern shows that the flow enters the catalytic converter as a jet, with recirculation on either side of the jet. As it passes through the porous substrate, it decelerates and straightens out, and exhibitsa more uniform velocity distribution.This allows the metal catalyst present in the substrate to be moreeffective.8.Display filled contours of static pressure on the y=0 plane (Figure 10.5 (p.477)).Graphics and Animations¡Contours¡Set Up...a.Enable Filled in the Options group box.b.Enable Draw Mesh to open the Mesh Display dialog box.i.Make sure that substrate-wall and wall are selected in the Surfaces selection list.ii.Click Display and close the Mesh Display dialog box.c.Make sure that Pressure... and Static Pressure are selected from the Contours of drop-downlists.d.Select y=0 in the Surfaces selection list.e.Click Display and close the Contours dialog box.The pressure changes rapidly in the middle section, where the fluid velocity changes as it passes through the porous substrate.The pressure drop can be high, due to the inertial and viscous resistance of the porous media. Determining this pressure drop is one of the goals of the CFD analysis. In the next step, you will learn how to plot the pressure drop along the centerline of the substrate.Figure 10.5 Contours of Static Pressure on the y=0 plane9.Plot the static pressure across the line surface porous-cl (Figure 10.6 (p.478)).Plots¡XY Plot¡Set Up...a.Make sure that Pressure... and Static Pressure are selected from the Y Axis Function drop-downlists.b.Select porous-cl in the Surfaces selection list.c.Click Plot and close the Solution XY Plot dialog box.Figure 10.6 Plot of Static Pressure on the porous-cl Line SurfaceAs seen in Figure 10.6 (p.478), the pressure drop across the porous substrate is approximately 300 Pa.10.Display filled contours of the velocity in the X direction on the x=95,x=130, and x=165 surfaces(Figure 10.7 (p.480)).Graphics and Animations¡Contours¡Set Up...a.Enable Filled in the Options group box.b.Enable Draw Mesh to open the Mesh Display dialog box.i.Make sure that substrate-wall and wall are selected in the Surfaces selection list.ii.Click Display and close the Mesh Display dialog box.c.Disable Global Range in the Options group box.d.Select Velocity... and X Velocity from the Contours of drop-down lists.e.Select x=130,x=165, and x=95 in the Surfaces selection list.f.Click Display and close the Contours dialog box.Figure 10.7 Contours of the X Velocity on the x=95, x=130, and x=165 SurfacesThe velocity profile becomes more uniform as the fluid passes through the porous media.The velocity is very high at the center (the area in red) just before the nitrogen enters the substrate and then de-creases as it passes through and exits the substrate.The area in green, which corresponds to a moderate velocity, increases in extent.e numerical reports to determine the average, minimum, and maximum of the velocity distributionbefore and after the porous substrate.Reports¡Surface Integrals¡Set Up...a.Select Mass-Weighted Average from the Report Type drop-down list.b.Select Velocity and X Velocity from the Field Variable drop-down lists.c.Select x=165 and x=95 in the Surfaces selection list.d.Click Compute.e.Select Facet Minimum from the Report Type drop-down list and click Compute.f.Select Facet Maximum from the Report Type drop-down list and click Compute.The numerical report of average, maximum and minimum velocity can be seen in the main ANSYS FLUENT console.g.Close the Surface Integrals dialog box.The spread between the average, maximum, and minimum values for X velocity gives the degree to which the velocity distribution is non-uniform.You can also use these numbers to calculate the velocity ratio (i.e., the maximum velocity divided by the mean velocity) and the space velocity (i.e., the product of the mean velocity and the substrate length).Custom field functions and UDFs can be also used to calculate more complex measures of non-uniformity, such as the standard deviation and the gamma uniformity index.Mass-Weighted AverageX Velocity (m/s)-------------------------------- --------------------x=165 4.0085778x=95 5.2300396---------------- --------------------Net 4.6152096Minimum of Facet ValuesX Velocity (m/s)-------------------------------- --------------------x=165 2.4166288x=95 0.32106033---------------- --------------------Net 0.32106033Maximum of Facet ValuesX Velocity (m/s)-------------------------------- --------------------x=165 6.1929517x=95 7.7427068---------------- --------------------Net 7.742706810.5. SummaryIn this tutorial, you learned how to set up and solve a problem involving gas flow through porous media in ANSYS FLUENT.You also learned how to perform appropriate postprocessing. Flow non-uniformities were rapidly discovered through images of velocity vectors and pressure contours. Surface integralsand xy-plots provided purely numeric data.For additional details about modeling flow through porous media (including heat transfer and reaction modeling), see Porous Media Conditions in the User's Guide.10.6. Further ImprovementsThis tutorial guides you through the steps to reach an initial solution.You may be able to obtain a more accurate solution by using an appropriate higher-order discretization scheme and by adapting the mesh. Mesh adaption can also ensure that the solution is independent of the mesh.These steps are demon-strated in Introduction to Using ANSYS FLUENT: Fluid Flow and Heat Transfer in a Mixing Elbow (p.131).。
fluent多孔介质简单操作
[转]fluent中多孔介质porous media设置问题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f luid,与缺省的f luid分别开来，再定义其名称，我习惯将名称定义为porous;2。
在f luent中定义边界条件def ine-boundary condition-porous(刚定义的名称)，将其设置边界条件为f luid,点击set按钮即弹出与f luid 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）圆锥坐标与球坐标请参考f luent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”，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!。
FLUENT多孔介质中平面面板(plane surface)工具的使用
1、输出grid图形2、选择surface---plane,打开plane surface面板3、通过确定三个点来确定平面位置。
单击slect point，出现提示，不点选cancel.在grid 图形的多孔介质区域任意位置右键点选3个点。
4、回到plane surface面板，勾选plane tool，则在grid图形的多孔介质区域出现一个平面。
若出现的平面与我们的预期相差比较大的话，可以单击reset points,可以获得一个特殊位置的平面。
5、打开多孔介质的控制面板，选择porous zone标签，点击update from plane tool按钮，获得方向矢量1，和方向矢量2的原始值，并与左下角的坐标系统比较，确定我们大概的旋转方向。
6、对比grid图形左下角的坐标系统，红线和红色箭头代表的是方向矢量1，绿线和绿色箭头代表的是方向矢量2应该使红线和X正方向平行，绿线和Y正方向平行。
具体的操作应该是：一：先单击白线的蓝色箭头，固定了该方向在旋转过程中不变，可以保证在旋转的过程比较有规律，然后右键点选白线的红色箭头旋转红线的红色箭头到X的正轴；二: 接下来应该是单击白线的红色箭头，固定该方向不变，单击白线的蓝色箭头，旋转绿线的绿色箭头指向Y的正轴。
（所以多孔介质区域我们一般是设置在坐标系统里面，轴线等与坐标系统无非直角角度关系）。
把平面移动到图形外有利于旋转，比较清楚。
平面法线方向的移动是用鼠标右键单击平面阴影部分并拖动，横向移动则需按下shift并进行如上操作。
7、旋转到适当的位置后（鼠标右键拖动箭头），再次点击update from plane tool按钮，获得方向矢量1，和方向矢量2。
得到的数值很可能不是整数，这个时候我们可以把他简化为整数。
例如：0.9123可以简化为1，0.01245可以简化为0，以此类推。
FLUENT多孔介质数值模拟设置
FLUENT多孔介质数值模拟设置多孔介质条件多孔介质模型可以应用于很多问题，如通过充满介质的流动、通过过滤纸、穿孔圆盘、流量分配器以及管道堆的流动。
当你使用这一模型时，你就定义了一个具有多孔介质的单元区域，而且流动的压力损失由多孔介质的动量方程中所输入的内容来决定。
通过介质的热传导问题也可以得到描述，它服从介质和流体流动之间的热平衡假设，具体内容可以参考多孔介质中能量方程的处理一节。
多孔介质的一维化简模型，被称为多孔跳跃，可用于模拟具有已知速度/压降特征的薄膜。
多孔跳跃模型应用于表面区域而不是单元区域，并且在尽可能的情况下被使用（而不是完全的多孔介质模型），这是因为它具有更好的鲁棒性，并具有更好的收敛性。
详细内容请参阅多孔跳跃边界条件。
多孔介质模型的限制如下面各节所述，多孔介质模型结合模型区域所具有的阻力的经验公式被定义为“多孔”。
事实上多孔介质不过是在动量方程中具有了附加的动量损失而已。
因此，下面模型的限制就可以很容易的理解了。
流体通过介质时不会加速，因为事实上出现的体积的阻塞并没有在模型中出现。
这对于过渡流是有很大的影响的，因为它意味着FLUENT不会正确的描述通过介质的过渡时间。
多孔介质对于湍流的影响只是近似的。
详细内容可以参阅湍流多孔介质的处理一节。
多孔介质的动量方程多孔介质的动量方程具有附加的动量源项。
源项由两部分组成，一部分是粘性损失项 (Darcy)，另一个是内部损失项：其中S_i是i向(x, y, or z)动量源项，D和C是规定的矩阵。
在多孔介质单元中，动量损失对于压力梯度有贡献，压降和流体速度（或速度方阵）成比例。
对于简单的均匀多孔介质：其中a是渗透性，C_2时内部阻力因子，简单的指定D和C分别为对角阵1/a 和C_2其它项为零。
FLUENT还允许模拟的源项为速度的幂率：其中C_0和C_1为自定义经验系数。
注意：在幂律模型中，压降是各向同性的，C_0的单位为国际标准单位。
多孔介质的Darcy定律通过多孔介质的层流流动中，压降和速度成比例，常数C_2可以考虑为零。
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[转]fluent中多孔介质porous media设置问题
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。
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。
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）
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”，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!。