利用ANSYS CFX计算NACA0012翼型外流场的基本流程
本文摘要(由AI生成):
本文介绍了利用ANSYS CFX计算NACA0012翼型外流场的基本流程。首先,介绍了问题描述,包括来流速度、攻角、压力与温度等参数。接着,详细介绍了CFX设置,包括启动CFX、导入计算网格、计算区域设置、创建坐标系、边界条件设置、指定求解监控、设置求解控制参数和解算计算等步骤。最后,展示了计算结果,包括Y+分析、速度云图分布和压力云图分布等。
本案例演示利用ANSYS CFX计算NACA0012翼型外流场的基本流程。
1 问题描述
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919654_68o2c4.jpg?imageView2/0)
来流速度为0.7 Ma,攻角1.55°。可根据等熵条件计算压力与温度。![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911719_plcp09.jpg?imageView2/0)
式中,p0为总压,101325 Pa;P为静压;γ为比容比,对于空气γ=1.4;M为马赫数,0.7;带入公式可得到:![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911607_0l81ew.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920751_yniw79.jpg?imageView2/0)
式中,T0为总温,311 K;T为静温;γ=1.4;M为马赫数,0.7;带入公式可得到:![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917988_gpsb8z.jpg?imageView2/0)
2 CFX设置
2.1 启动CFX
- 启动CFX,如下图所示设置Work Directory,点击按钮CFX-Pre启动CFX
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488912141_c0198e.jpg?imageView2/0)
- 点击工具栏按钮New Case打开设置对话框,选择General项,点击按钮OK新建Case
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920875_d70uno.jpg?imageView2/0)
2.2 导入计算网格
- 选择菜单File → Import → Mesh…打开文件选择对话框
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919770_qjydcw.jpg?imageView2/0)
- 如下图所示选择网格文件naca0012.cfx,点击OK按钮导入网格文件
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917745_kf8gem.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919654_68o2c4.jpg?imageView2/0)
2.3 计算区域设置
- 鼠标双击模型树节点Default Domain打开区域设置面板
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488914888_3gp42i.jpg?imageView2/0)
- 进入Basic Settings标签页,如下图所示设置Material为Air Ideal Gas,设置Reference Pressure为73048 Pa
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917344_x0dzb9.jpg?imageView2/0)
注:这里考虑的流体是可压缩的,其密度取决于绝对压力。选择的参考压力以确保求解导到的静压值与压力变化量相比不太大,以减少舍入错误。
- 进入Fluid Models标签页,设置Heat Transfer Option为Total Energy,指定湍流模型为Shear Stress Transport,点击OK按钮关闭面板
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917016_8oyfpo.jpg?imageView2/0)
注:Total Energy可以考虑高速流体产生的气动热。
2.4 创建坐标系
- 选择菜单Insert → Coordinate Frame插入坐标系
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920344_lttrqs.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488921052_y6910g.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920176_wsx0ds.jpg?imageView2/0)
注:这里其实也可以不用定义,在后面输入边界值的时候直接按分量给也行。
2.5 边界条件设置
- 右键选择节点Default Domain,选择弹出对话框Insert → Boundary插入边界
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911302_5ubfzz.jpg?imageView2/0)
- 如下图所示指定边界名称为inlet,点击OK按钮打开设置面板
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488912809_7i1jou.jpg?imageView2/0)
- 进入面板Basic Settings标签页,设置Boundary Type为Inlet,指定Location为inlet,激活选项Coordinate Frame,选择坐标系为Coord 1,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488918096_abukuq.jpg?imageView2/0)
- 进入Boundary Details标签页,如下图所示指定速度分量及Static Temperature为283.34 K,点击OK按钮关闭对话框
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488915280_m20bi1.jpg?imageView2/0)
2、插入出口边界outlet
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911302_5ubfzz.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919274_k19q3u.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920464_z5xadh.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917232_wgovwp.jpg?imageView2/0)
3、壁面边界
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916855_hklz4i.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488921247_kvwcwn.jpg?imageView2/0)
4、定义对称边界
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488914279_ou5mfb.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911826_hal2eg.jpg?imageView2/0)
2.6 指定求解监控
- 点击按钮Output Control弹出设置对话框
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488918221_ea31wx.jpg?imageView2/0)
- 如下图所示定义监测变量Lift Coef,
force_x_Coord 1()@airfoil * 2 / (massFlowAve(Density)@inlet*(massFlowAve(Velocity)@inlet)^2*0.6 [m]* 1[m])
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911416_wcvp6p.jpg?imageView2/0)
- 如下图所示定义监测变量Drag Coef,
force_z_Coord 1()@airfoil * 2 / (massFlowAve(Density)@inlet *
(massFlowAve(Velocity)@inlet)^2*0.6 [m]* 1[m])
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916501_8blo1f.jpg?imageView2/0)
2.5 设置求解控制参数
- 鼠标双击模型树节点Solver Control弹出参数设置面板
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488921423_k9kqu6.jpg?imageView2/0)
- 指定最小迭代次数100,最大迭代次数为200,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488918778_rr8cw1.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916745_jx9vpc.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488915159_ow30u8.jpg?imageView2/0)
2.6 求解计算
- 如下图所示设置并行计算参数,指定CPU数量,点击按钮Start Run开始求解计算
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916017_y8c5br.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916243_8cyuv2.jpg?imageView2/0)
- 计算完毕后如下图所示,选中选项Post-Process Results,点击OK按钮打开CFD-Post进行后处理
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488914690_pfalip.jpg?imageView2/0)
3 计算结果
3.1 Y+分析
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916380_ttonvu.jpg?imageView2/0)
注:CFX中,SST模型要求将第一层网格节点放置于粘性子层内,y+<2
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488920625_h7h7z4.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919049_eg6k4o.jpg?imageView2/0)
- 定义表达式
p/(0.5*massFlowAve(Density)@inlet*(massFlowAve(Velocity)@inlet)^2)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488911936_k43gam.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488916131_ikfc7l.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919963_09zfkv.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488918403_ea548q.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488919442_j0xvtb.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1576488917538_xr1iou.jpg?imageView2/0)
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