稳态热分析报告案例(ANSYS15.0版)

本例题的主要部分为一个圆筒形罐，其上沿径向有一材料一样的接管（如图？？？？所所示），罐内流动着450°F（232°C）的高温流体，接管内流动着100°F（38 °C）的低温流体，两个流体区域由薄壁管隔离。罐的对流换热系数为250Btu/hr-ft2-o F（1420watts/m2-°K），接管的对流换热系数随管壁温度而变，它的热物理性能如表？？？所示。要求计算罐与接管的温度分布。

表？？？？

6.5.1 预处理

Step 1: 确定分析标题

起动ANSYS后，开始一个分析，需要输入一个标题，按下面方法进行操作：

1.选择Utility Menu> File> Change Title，弹出相应对话框

2.输入Steady-state thermal analysis of pipe junction。

3.点击OK。

Step 2: 设置分析单位系统

You need to specify units of measurement for the analysis. For this pipe junction example, measurements use the U. S. Customary system of units

(based on inches). To specify this, type the command /UNITS,BIN in the ANSYS Input window and press ENTER.在分析之前，需要为分析系统设定单位系统，

Step 3: Define the Element Type

The example analysis uses a thermal solid element. To define it, do the following:

1.Choose Main Menu> Preprocessor> Element Type> Add/Edit/Delete.

The Element Types dialog box appears.

2.Click on Add. The Library of Element Types dialog box appears.

3.In the list on the left, scroll down and pick (highlight) "Thermal

Solid." In the list on the right, pick "Brick20node 90."

4.Click on OK.

5.Click on Close to close the Element Types dialog box.

Step 4: Define Material Properties

To define material properties for the analysis, perform these steps:

1.Choose Main Menu> Preprocessor> Material Props> Material Models.

The Define Material Model Behavior dialog box appears.

2.In the Material Models Available window, double-click on the

following options: Thermal, Density. A dialog box appears.

3.Enter .285 for DENS (Density), and click on OK. Material Model

Number 1 appears in the Material Models Defined window on the left.

4.In the Material Models Available window, double-click on the

following options: Conductivity, Isotropic. A dialog box appears.

5.Click on the Add Temperature button four times. Four columns are

added.

6.In the T1 through T5 fields, enter the following temperature values:

70, 200, 300, 400, and 500. Select the row of temperatures by

dragging the cursor across the text fields. Then copy the

temperatures by pressing Ctrl-c.

7.In the KXX (Thermal Conductivity) fields, enter the following

values, in order, for each of the temperatures, then click on OK.

Note that to keep the units consistent, each of the given values of KXX must be divided by 12. You can just input the fractions and have ANSYS perform the calculations.

8.35/12

8.90/12

9.35/12

9.80/12