桨叶层数不同对搅拌槽内流动场的影响 本科毕业论文

分类号 单位代码

密 级 学 号

学生毕业设计

题 目 桨叶层数不同

对搅拌槽内流动场的影响

作 者

院 (系)

专 业

指导教师

答辩日期 年 月 日

榆 林 学 院

毕业设计诚信责任书

本人郑重声明：所呈交的毕业设计，是本人在导师的指导下独立进行研究所取得的成果。毕业设计中凡引用他人已经发表或未发表的成果、数据、观点等，均已明确注明出处。尽我所知，除文中已经注明引用的内容外，本论文不包含任何其他个人或集体已经公开发表或撰写过的研究成果。对本文的研究做出重要贡献的个人和集体，均已在文中以明确方式标明。

本人毕业设计与资料若有不实，愿意承担一切相关的法律责任。

论文作者签名:

年 月 日

榆林学院本科毕业论文

I

摘 要

搅拌设备广泛应用于工业生产中，如石油、化工、制药、食品、采矿、冶金、废水处理等领域。搅拌操作是工业反应过程中的重要环节，在促进槽内物料流动，使得搅拌槽内物料均匀分布的同时，能够增大传热和传质系数，加速反应的进行。因此，研究搅拌槽的流动性能在工业生产中具有重要意义。

本文采用计算流体力学（CFD）对搅拌槽内的三维流动场进行了数值模拟，考察了六直叶圆盘桨（6DT）、六叶上斜叶桨（6PDTU）、六叶下斜叶桨（6PDTD）在桨叶层数不同时，搅拌槽内的流动场及搅拌功率。结果表明：相同类型的桨叶，在桨叶层数不同时，槽内的流场不同，双层桨时流体的速度分布比单层桨时更加均匀，功率消耗更大。（1）6DT桨在单层时，在整个搅拌槽内形成四个对称的漩涡，功率消耗比较大；6DT+6DT桨由于上下桨间的干涉作用，两层桨之间漩涡不明显，功率消耗更大。（2）6PDTU在单层时，其上扬作用使搅拌槽内形成四个大小不等的漩涡，功率消耗最小；6PDTU+6PDTU桨由于两层桨的相互作用，槽内流体混合均匀。（3）6PDTD桨在单层时，由于其下压作用使槽内流体在搅拌槽内仍然形成四个漩涡，且下部漩涡较小，上部漩涡较大；6PDTD+6PDTD桨由于两层桨相互干涉，在整个搅拌槽出现六个循环流动。研究结果对搅拌反应器的优化设计具有一定的参考价值。

关 键 词：搅拌槽，桨叶层数，计算流体动力学（CFD），数值模拟

桨叶层数不同对搅拌槽内流动场的影响

II

Numerical Analysis of the Flow Field of Stirred Tank

with Different Impeller Layers

ABSTRACT

Mixing equipments are widely used in industrial production, such as petroleum,

chemical industry, pharmaceutical industry, foodstuff, mining, metallurgy, waste-water

treatment, etc. Stirring operation is an important part of the industry reaction process, it

can promote the flowing of materials and make materials distributing evenly in the

stirred tank. At the same time, it can increase the coefficient of heat and mass transfer

and accelerate the reaction.Therefore, it has an important significance in industrial

production to study the flow characteristics of stirred tank.

Three-dimensional flow fields in stirred tank has been simulated numerically by

utlizing Computational Fluid Dynamics (CFD), when the impeller layers are different,

the flow characteristics and the mixing power demand of 6DT, 6PDTU and 6PDTD is

researched. The results indicate that: With the same type of impeller, the flow field can

be changed due to the different impeller layers. The liquid with dual impellers is mixed

evenly than single impeller and it costs maximum power demand. (1) As for the 6DT

with single impeller, four symmetrical vortexes are formed in the stirred tank and the

power demand is larger. When the impeller is 6DT+6DT, because of the interference

function,the vortexes between the upper and the lower impeller is not obvious, it costs

maximum power demand.(2)As for the 6PDTU with single impeller, its upward

function results in four vortexes with different size in the stirred tank; When the

impeller is 6PDTU+6PDTU, because of the mutual interference function between the

upper and the lower impeller, The liquid is mixed evenly and the power demand is the

least in the stirred tank. (3)As for the 6PDTD with single impeller, its downward

function also result in four vortexes in the stirred tank, and the range of the upper

vortexes is smaller, while the range of the lower vortexes is larger; When the impeller

is 6PDTD+6PDTD,there are six vortexes in the stirred tank because of the interference

function between the upper and the lower impeller. The results are of importance to the

design and optimization of the stirred reactor.

榆林学院本科毕业论文

III

Key words: Stirred tank, Impeller layers, Computational fluid dynamics(CFD),

Numerical simulation

桨叶层数不同对搅拌槽内流动场的影响

IV

目 录

1绪论 ........................................................................................................................ 1

1.1搅拌槽简介 ................................................................................................. 1

1.2 搅拌槽内流动特性研究现状 .................................................................... 1

1.2.1 宏观流动场 ..................................................................................... 1

1.2.2微观特性研究 .................................................................................. 2

1.2.3 搅拌槽内流动特性的发展 ..................................................................... 2

2计算流体动力学 .................................................................................................... 4

2.1 CFD技术原理介绍 .................................................................................... 4

2.1.1 CFD简介 ......................................................................................... 4

2.2 CFD技术在搅拌槽中应用 ........................................................................ 4

3研究目的、研究内容及研究方法 ........................................................................ 7