机械搅拌槽混合数值模拟及实验研究

发布时间：2018-05-17 06:32

本文选题：机械搅拌槽 + 数值模拟　；参考：《广西大学》2017年硕士论文

【摘要】：随着工业的不断发展和进步,机械搅拌槽在工业的诸多领域得到了广泛应用,特别是在化工、食品、冶金、造纸、和污水处理等领域,是应用最广泛的化工设备之一。机械搅拌槽按不同工业要求常用于介质混合溶解、制备悬浮液、促进传质、强化传热等操作,具有制作方便、操作简单、适应性强等优点。但目前机械搅拌槽设计与制作大多依靠于经验,对搅拌槽设计参数、搅拌规律等认识不足,缺乏对搅拌过程的直观了解,无法保证和满足不同的工业要求。随着计算机流体力学(CFD)相关软件的发展,对搅拌过程进行数值模拟成为了现实,利用CFD软件对搅拌槽的搅拌过程进行模拟,可直观认识搅拌过程中搅拌效果,可大大缩短搅拌槽的设计成本,对搅拌槽参数的设计具有一定促进作用。本文利用CFD软件对方形搅拌槽、圆形搅拌槽进行数值模拟,利用RNG k-ε湍流模型、组分输运模型、滑移网格模型对搅拌槽进行瞬态数值模拟。对搅拌槽的桨叶角度、桨叶离底高度、桨叶宽度、桨叶直径、加药点等参数分别进行单因素模拟,并根据单因素分析结果进行5因素4水平正交数值模拟分析,根据混合时间、搅拌功率以及单位体积混合能综合评判搅拌槽混合效果,并对不同搅拌槽的结构参数提出合理化建议。对搅拌槽的最优参数组合进行单向耦合静力学分析,结果显示桨叶受到的最大应力远小于材料的许用应力值,可确保最优组合桨叶的正常运转。分别对圆形搅拌槽、方形搅拌槽中的桨叶角度、桨叶离底高度、转速因素进行实验分析,获取监测点的示踪剂浓度,并与仿真实验中同一位置监测点的浓度数据进行对比。实验是利用电导率传感器测量电导率值,经公式转换为溶液浓度值,通过曲线相关系数、混合时间、溶液最终浓度等参数与仿真实验获取的数据综合比较。结果显示:实验数据与仿真数据的曲线相关系数较高,整体趋势基本吻合;混合时间、溶液最终浓度均相差不大。
[Abstract]:With the continuous development and progress of industry, mechanical agitator has been widely used in many fields of industry, especially in chemical, food, metallurgy, papermaking, sewage treatment and other fields, is one of the most widely used chemical equipment. Mechanical agitator is often used in medium mixing dissolution, preparation of suspension, mass transfer, heat transfer and other operations according to different industrial requirements. It has the advantages of convenient manufacture, simple operation, strong adaptability and so on. However, at present, the design and manufacture of mechanical agitator mostly depend on experience, lack of understanding of the design parameters and rules of mixing tank, lack of intuitive understanding of the mixing process, and can not guarantee and meet different industrial requirements. With the development of computer fluid dynamics (CFD) software, the numerical simulation of mixing process has become a reality. Using CFD software to simulate the mixing process of stirred tank, can intuitively understand the mixing effect in mixing process. It can greatly shorten the design cost of agitator and promote the design of agitator parameters. In this paper, CFD software is used to simulate the square and circular stirred cells, and RNG k- 蔚 turbulence model, component transport model and sliding grid model are used to simulate the transient numerical simulation of the stirred tank. The parameters such as blade angle, blade height, blade width, blade diameter and charge point were simulated by single factor simulation, and 5 factors and 4 horizontal orthogonal numerical simulation were carried out according to the results of single factor analysis, according to mixing time, Mixing power and unit volume mixing can comprehensively evaluate the mixing effect of mixing tank and give some reasonable suggestions on the structural parameters of different mixing tanks. The unidirectional coupling statics analysis of the optimal parameter combination of the stirred tank shows that the maximum stress of the blade is much less than the allowable stress of the material, which can ensure the normal operation of the optimal combination blade. The factors of blade angle, blade height and rotational speed in circular stirred tank and square stirred tank are analyzed experimentally, the tracer concentration of monitoring point is obtained, and the concentration data of monitoring point at the same position in simulation experiment are compared. The experiment uses the conductivity sensor to measure the conductivity value, which is converted into the solution concentration value by the formula. The parameters such as curve correlation coefficient, mixing time, solution final concentration and so on are compared with the data obtained from the simulation experiment. The results show that the curve correlation coefficient between the experimental data and the simulation data is high, and the overall trend is basically consistent, and the mixing time and the final concentration of the solution are not different.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.72

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