60 - CFX总结 - 图文

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The CFX solver supports orthotropic thermal conductivity. It is a hidden beta feature which means that you need to set it up by editing the CCL outside of CFX-Pre.

To do this, set up your simulation and write out a definition file with the thermal conductivity for the material of interest set to a constant value.

1. You will then extract the ccl content from the definition file to a text file using the folloiwng command which you can

execute from the CFX command prompt (CFX Launcher/Tools/Command Line). Suppose that your definition file is named test.def. You would type the following command :

cfx5cmds -read -def test.def -text test.ccl

You will then have a text file called test.ccl with the problem setup information.

2. You then edit the test.ccl file and replace, for the material of interest.

THERMAL CONDUCTIVITY:

Option = Value

Thermal Conductivity = 12.0 [W m^-1 K^-1]

END

with:

THERMAL CONDUCTIVITY:

Option = Orthotropic Cartesian Components

Thermal Conductivity X Component = 1 [W m^-1 K^-1]

Thermal Conductivity Y Component = 2 [W m^-1 K^-1]

Thermal Conductivity Z Component = 3 [W m^-1 K^-1]

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END

I used 1,2,3 for convenience.

This is for the Cartesian Components, if you prefer to use Cylindrical Components, use the following text to replace the old one:

THERMAL CONDUCTIVITY:

Option = Orthotropic Cylindrical Components

Thermal Conductivity Axial Component = 1 [W m^-1 K^-1]

Thermal Conductivity Theta Component = 2 [W m^-1 K^-1]

Thermal Conductivity r Component = 3 [W m^-1 K^-1]

AXIS DEFINITION:

Option = Coordinate Axis

Rotation Axis = Coord 0.1

END

END

Where Coord 0.1 is the global X axis, so global Y and Z axis will be Coord 0.2 and Coord 0.3, respectively.

3. You then write the modified test.ccl back to the definition file using the following command:

cfx5cmds -write -def test.def -txt test.ccl

4. You will see in your subsequent output file (when running the case)

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that the orthotropic values are there. --

C. Kurt Svihla, Ph.D.

Senior Technical Services Engineer ANSYS, Inc. Southpointe

275 Technology Drive Canonsburg PA 15317 Tel: (724)514-3600 Fax: (724)514-5096 www.ansys.com

8. CFX提交求解出错？

在windows64位下提交任务，用了标准算例的各个*.def文件都不行，出错（见上图）。提交过程没有选择并行，即只是单CPU就出错。为什么？

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CFX后处理

1. 如何在CFX-Post中求温度或密度等Scalar的梯度？

2. CFX如何求得换热系数的？

答：h=q/(T-Tbulk)；Tbulk一般选取主流温度或来流温度或全场平均温度。为了让数值求解的h和实验数据一致，需要数值求解的所使用的Tbulk和实验所选择的Tbulk相同。

3. 在CFD-Post中如何显示周向速度和径向速度分量？

答：在www.cfd-online.com上获得答案如下，事实证明是可行的。

In cfx post go to turbo mode then define your rotation axis next click calculate velocity components.now you can plot the variables you need.

4. 如何创建任意形状的切面（平面或曲面）

答：把想创建的切面（任意复杂度的平面或曲面）通过CAD软件创建出来，给此切面划分网格，把此网格读入到CFX-Post中（也可以先生成*.def文件在读入CFX_Post），通过“File-Export...”把此边界保存成*.csv格式的文本文件。应用“User Surface”方法创建，选择“From File”方法！把此*.csv文件读入即可。

CFX并行

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