利用CFX中的多相流模型计算搅拌容器中空气与水的混合情况
本文摘要(由AI生成):
本文介绍了使用CFX中的多相流模型计算搅拌容器中空气与水的混合情况的案例。首先,导入计算网格,包括两个区域,一个是混合容器,另一个是空气注入管。然后,创建计算区域,包括空气入口、液体表面、挡板、旋转叶轮和旋转轴。接着,指定初始值,包括空气和水的体积分数和速度。最后,进行求解控制和创建监控,开始计算,得到计算结果,包括速度分布、空气体积分数分布和计算叶片上力矩等。
本案例演示利用CFX中的多相流模型计算搅拌容器中空气与水的混合情况。
1 问题描述
本案例计算的模型如图所示。计算区域中包含1个混合容器、1个空气注入管、4个挡板、1个旋转叶轮以及1个旋转轴。叶轮旋转速度为84 rpm,空气从叶轮底部的通道以5 m/s速度进入计算区域,空气 进口管道直径2.48 cm。计算假设水与空气保持恒定温度25°C,且空气为不可压缩,假设气泡直径为3 mm。
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240795_4lnoqk.jpg?imageView2/0)
2 CFX设置
2.1 导入计算网格
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242807_czl61d.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071233639_sex1no.jpg?imageView2/0)
- 导入计算网格MixerImpellerMesh.gtm,如图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236944_bke4pw.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235382_7jd3jv.jpg?imageView2/0)
- 右键选择节点MixerImpellerMesh.gtm,选择菜单项Transform Mesh打开设置对话框
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240962_6vt5a3.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240381_vt5zyl.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234659_c1loxc.jpg?imageView2/0)
3.2 创建计算区域
- 修改默认计算区域Default Domain的名称为impeller
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242683_q8bn27.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239860_4whllk.jpg?imageView2/0)
注:1、空气为分散相,指定其粒径为3 mm,水为连续相。2、指定计算区域沿X轴旋转速度为84 rpm。
- 如下图所示指定Turbulence为Fluid Dependent
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241691_m6p6pe.jpg?imageView2/0)
- 进入Fluid Pair Models标签页,如下图所示指定相间作用参数
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235253_s7272l.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241275_tabiv0.jpg?imageView2/0)
- 选择Location为Primitive 3D,其他参数保持默认设置
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235528_he4f4c.jpg?imageView2/0)
3.3 创建边界条件
- 在tank区域中插入边界,如下图所示,命名为Airin
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239724_012z1h.jpg?imageView2/0)
- 指定边界类型为Inlet,选择Location为INLET_DIPTUBE,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234107_mkv108.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071237285_7pcw2h.jpg?imageView2/0)
- 进入Fluid Values标签页, 如下图所示指定Air的速度为5 m/s,指定Volume Fraction为1
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242128_devybt.jpg?imageView2/0)
- 指定water的Volume Fraction为0
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236764_dqisud.jpg?imageView2/0)
- 在tank区域中插入边界,命名为LiquidSurface
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239724_012z1h.jpg?imageView2/0)
- 设置边界类型为Outlet,指定Location为WALL_LIQUID_SURFACE
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238618_hi26t9.jpg?imageView2/0)
- 进入Boundary Details标签页,指定Mass And Momentum为Degassing Condition,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238447_sfwkz9.jpg?imageView2/0)
注:Degassing边界允许颗粒相离开,不允许连续相离开。
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239724_012z1h.jpg?imageView2/0)
- 设置区域类型为Wall,选择Location为WALL_BAFFLES
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235672_u56084.jpg?imageView2/0)
- 在Boundary Details标签页中指定Mass And Momentum为Fluid Dependent
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235836_5iv7qb.jpg?imageView2/0)
- 进入Fluid Values标签页,指定Air为Free Slip Wall
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242316_hmzis0.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239724_012z1h.jpg?imageView2/0)
- 指定区域类型为Wall,设置Location为WALL_SHAFT、WALL_SHAFT_CENTER
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071237122_3t3hs5.jpg?imageView2/0)
- 在Boundary Details标签页中指定Mass And Momentum为Fluid Dependent
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234228_1u0j9d.jpg?imageView2/0)
- 进入Fluid Values标签页,激活选项Wall Velocity,如下图所示指定旋转速度为X轴84 rpm
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238024_6q5cjl.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240657_a2ur6i.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071237656_5ylslq.jpg?imageView2/0)
- 指定边界类型为Wall,设置Location为Hub、Shaft,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239168_038ybo.jpg?imageView2/0)
- 在Boundary Details标签页中指定Mass And Momentum为Fluid Dependent
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241557_gszkkc.jpg?imageView2/0)
- 进入Fluid Values标签页,指定Air为Free Slip Wall
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071233931_64guv9.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236382_2xskes.jpg?imageView2/0)
- 进入tank Default边界设置面板的Boundary Details标签页,指定Mass And Momentum为Fluid Dependent
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234947_dazlg3.jpg?imageView2/0)
- 进入Fluid Values标签页,指定Air为Free Slip Wall
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242974_omv4ix.jpg?imageView2/0)
3.4 创建交界面
- 创建交界面Blade Thin Surface,如下图所示进行设置参数,软件会自动创建两个边界Blade Thin Surface Side 1、Blade Thin Surface Side 2
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071237455_df3m6e.jpg?imageView2/0)
- 双击节点Blade Thin Surface Side 1打开编辑对话框,如下图所示进行设置
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241098_29bh2j.jpg?imageView2/0)
- 进入Fluid Values标签页,指定Air为Free Slip Wall
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238789_vpytk5.jpg?imageView2/0)
- 双击节点Blade Thin Surface Side 2打开编辑对话框,进入Fluid Values标签页,指定Air为Free Slip Wall
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071242490_u0nrk8.jpg?imageView2/0)
- 创建交界面ImpellerPeriodic,如下图所示设置参数
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236559_jo7l2t.jpg?imageView2/0)
- 创建交界面TankPeriodic,如下图设置参数
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236154_03mlu7.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239336_95d1kq.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240150_pocls6.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238217_gdx2hq.jpg?imageView2/0)
3.5 指定初始值
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071238984_drp7rg.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071239538_hjqdl2.jpg?imageView2/0)
3.6 求解控制
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241411_acpul0.jpg?imageView2/0)
- 进入Advanced Options标签页,指定高级控制参数,如下图所示
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234363_fgeegk.jpg?imageView2/0)
3.7 创建监控
TankAirHoldUp = volumeAve(Air.vf)@tank
ImpellerAirHoldUp = volumeAve(Air.vf)@impeller
TotalAirHoldUp = (volume()@tank * TankAirHoldUp +
volume()@impeller * ImpellerAirHoldUp) /
(volume()@tank + volume()@impeller)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071237881_5stmzc.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071236015_kdp09m.jpg?imageView2/0)
3.8 开始计算
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234808_o2j50i.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071234506_3ra3n0.jpg?imageView2/0)
4 计算结果
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241819_v9nes7.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071241954_i9fla2.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071233787_fcg1ss.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240516_74m7zc.jpg?imageView2/0)
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071235125_1wuntk.jpg?imageView2/0)
两者之和约为-72 [N m],4个叶片则总力矩为288 [N m]
![](https://public.fangzhenxiu.com/fixComment/commentContent/imgs/1577071240016_apjj13.jpg?imageView2/0)
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