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摘要搅拌桨广泛应用于化工生产领域，搅拌槽内的流动是一个复杂的、非稳态的过程。本文采用基于标准 模型的分离涡模型对搅拌槽内的流场进行了模拟。通过对带挡板的优尔直叶圆盘涡轮和四斜叶涡轮桨搅拌槽内的流场进行模拟，并将径向速度、轴向速度、切向速度和湍动动能的模拟值与文献值进行比较，证明相比较标准 模型而言，分离涡模型能更加精确地预测搅拌槽内的流场。同时使用分离涡模型对两种多层组合搅拌桨（前者的底桨为优尔叶半椭圆管涡轮，中桨和上桨都为上提式四宽叶翼涡轮，后者的底桨为优尔叶半椭圆管涡轮，中桨为上提式优尔斜叶圆盘涡轮，上桨为优尔叶下压开启式涡轮）的流场进行模拟，通过对不同位置的径向、轴向、切向速度以及湍动动能的比较，对速度分布和湍动动能进行相位解析，发现前者能形成更高的湍动动能。10103
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关键词 多层搅拌桨 流场 分离涡 模拟毕业设计说明书（论文）外文摘要
Title Detached Eddy Simulation of the flow field in multiple impellers stirred tanks
Abstract
Stirred tanks are widely used in many chemical industry fields. The flow in the stirred tank is highly complex and unsteady. The detached eddy simulation (DES) based on the standard model was uesd to predict the flow field in the stirred tank. The flow field produced by radial and axial impellers in a baffled stirred tank was simulated by standard model and DES model,the three dimensional velocity and turbulent kinetic energy was compared with literature data. It is demonstrated that DES model can predict more accurately than standard model. Two triple impellers,one of them,a deep hollow blade (semi-ellipse) disk turbine (HEDT) was used as bottom impeller and two upward-pumping four-wide-blade hydrofoil impellers (WHu) were used as middle and upper impellers,and another, a HEDT was used as bottom impeller,a upward-pumping six helical blade disc turbine used as middle impeller and a downward-pumping six oblique leaf open type turbine was used as upper impeller. The flow field produced by these two impellers in a baffled stirred tank was simulated by DES model. The three dimensional velocitys and turbulent kinetic energys were compared with each other. The velocity distribution and turbulent kinetic energy has been phase resolved. It is indentifed that the former impeller can produce higher kinetic energy than latter.
Keywords multiple impellers flow field DES simulation
目录
1 引言 1
1.1 研究背景及意义 1
1.2 搅拌桨 2
1.2.1 径流桨 2
1.2.2 轴流桨 3
1.2.3 多层组合桨 3
1.3 搅拌槽内流场的实验测量方法 5
1.3.1 毕托管 5
1.3.2 热线/热膜风速测量 5
1.3.3 激光多普勒测速 6
1.3.4 粒子图像测速 6
1.4 搅拌槽流场的数值模拟 6
1.4.1 模拟方法 7
1.4.2 桨区的处理方法 11
1.5主要研究内容 13
2 实验部分 14
2.1 径向桨的模拟 14
2.1.1 建立模型 14
2.1.2 模拟方法 14
2.1.3 模拟结果 15
2.2 轴向桨的模拟 21
2.2.1 建立模型 21
2.2.2 模拟方法 22
2.2.3 模拟结果 22
2.3 多层组合桨的模拟 28
2.3.1 建立模型 30