双层交错桨搅拌槽层流流场的数值模拟与实验研究
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摘要
搅拌设备在化学工业、生物工程、制药工程、材料加工及食品加工等领域有着广泛的应用。当流体粘度很大或者对剪切敏感时,就要求搅拌处于低雷诺数的层流状态。已有的研究大多集中在标准搅拌桨,本文将集中于交错搅拌桨,对径向桨、轴向桨和组合桨的流动特性进行了数值模拟,找出叶片不同布置方式对流场的影响。本文还采用PIV技术对槽径为Φ200 mm的搅拌槽进行了实验研究。
用FLUENT软件对径向桨搅拌过程进行数值模拟,采用桨叶交错的布置方式,来增加对搅拌槽中层流流体的搅动,与标准径向桨相比,交错桨拥有更大的高速区域面积,提高了混合效率。
比较斜45°桨,四叶CBY桨和交错45°桨三种轴向桨的流场情况,分析不同桨叶布置方式对轴向桨流场的影响。对比三种轴向桨的速度变化情况发现叶片交错布置对斜叶桨的流场有所改善。叶片的空间布置方式和叶片的数量对流场影响较大。
对组合桨在桨和槽同轴布置与桨和槽偏轴布置情况下进行模拟,研究偏轴布置对流场的影响。偏轴布置的情况打破了流场的对称性,但远离搅拌轴的一边搅拌强度明显减弱,降低了整体搅拌的效率。组合桨在上层桨叶和下层桨叶相对偏移后,流场的对称性被打破,流场情况更加复杂。采用交错方式布置桨叶时,搅拌效果更好。
运用PIV技术对标准偏心组合桨和交错偏心组合桨的搅拌过程进行了实验研究。得到了搅拌槽内的实际流场情况。对比分析实验结果和模拟结果,发现实验结果和模拟结果较为吻合,验证了数值模拟的正确性。
In the field of chemical industry, biotechnology, pharmaceutical engineering, materials processing and food processing, stirring equipment has been widely used. When the fluid viscosity is large or when the media is shear-sensitive, mixing is required in a laminar flow with low Reynolds number. There have many researches that concentrate on the aspect of standard impeller. This paper will simulate the flow characteristics of the standard impeller and the staggered impeller, and find impeller of different layout of the flow field. This thesis also uses PIV technology as the research onΦ200 mm diameter tank of agitation.
The flow of radial impeller is simulated with FLUENT software. Compared with the standard radial impeller, staggered impeller has greater high-speed area and enhanced the efficiency of the flow field.
Analyzing the flow of different axial impeller which include of 45°oblique impeller, 4-blade CBY and staggered 45°oblique impeller. Comparison of three axial impeller speed changes, find that staggered impeller improved the flow field of the oblique impeller. Arrangement of impeller and the number of impeller have a great effect on the impact of mixing.
Combination impeller of the tank and propeller shaft in the concentric and eccentric are simulated. The situation of oars and the eccentric groove break the symmetry of the flow field and the dead space of the stirred tank is decreased. However, the side away from the stirring shaf stirring is weakened, reducing the overall mixing effect. When the upper blade and lower blade relative shift, the flow field symmetry is broken. The superposition between two blades is strengthened. Staggered agitators increase the mixing efficiency.
Using PIV technique to study combination of impeller, analyzing the experimental results and simulation results to receive that the simulation results agreed well with experimental results.
用FLUENT软件对径向桨搅拌过程进行数值模拟,采用桨叶交错的布置方式,来增加对搅拌槽中层流流体的搅动,与标准径向桨相比,交错桨拥有更大的高速区域面积,提高了混合效率。
比较斜45°桨,四叶CBY桨和交错45°桨三种轴向桨的流场情况,分析不同桨叶布置方式对轴向桨流场的影响。对比三种轴向桨的速度变化情况发现叶片交错布置对斜叶桨的流场有所改善。叶片的空间布置方式和叶片的数量对流场影响较大。
对组合桨在桨和槽同轴布置与桨和槽偏轴布置情况下进行模拟,研究偏轴布置对流场的影响。偏轴布置的情况打破了流场的对称性,但远离搅拌轴的一边搅拌强度明显减弱,降低了整体搅拌的效率。组合桨在上层桨叶和下层桨叶相对偏移后,流场的对称性被打破,流场情况更加复杂。采用交错方式布置桨叶时,搅拌效果更好。
运用PIV技术对标准偏心组合桨和交错偏心组合桨的搅拌过程进行了实验研究。得到了搅拌槽内的实际流场情况。对比分析实验结果和模拟结果,发现实验结果和模拟结果较为吻合,验证了数值模拟的正确性。
In the field of chemical industry, biotechnology, pharmaceutical engineering, materials processing and food processing, stirring equipment has been widely used. When the fluid viscosity is large or when the media is shear-sensitive, mixing is required in a laminar flow with low Reynolds number. There have many researches that concentrate on the aspect of standard impeller. This paper will simulate the flow characteristics of the standard impeller and the staggered impeller, and find impeller of different layout of the flow field. This thesis also uses PIV technology as the research onΦ200 mm diameter tank of agitation.
The flow of radial impeller is simulated with FLUENT software. Compared with the standard radial impeller, staggered impeller has greater high-speed area and enhanced the efficiency of the flow field.
Analyzing the flow of different axial impeller which include of 45°oblique impeller, 4-blade CBY and staggered 45°oblique impeller. Comparison of three axial impeller speed changes, find that staggered impeller improved the flow field of the oblique impeller. Arrangement of impeller and the number of impeller have a great effect on the impact of mixing.
Combination impeller of the tank and propeller shaft in the concentric and eccentric are simulated. The situation of oars and the eccentric groove break the symmetry of the flow field and the dead space of the stirred tank is decreased. However, the side away from the stirring shaf stirring is weakened, reducing the overall mixing effect. When the upper blade and lower blade relative shift, the flow field symmetry is broken. The superposition between two blades is strengthened. Staggered agitators increase the mixing efficiency.
Using PIV technique to study combination of impeller, analyzing the experimental results and simulation results to receive that the simulation results agreed well with experimental results.
引文
1李志鹏.CBY搅拌桨叶的数值分析.[北京化工大学硕士学位论文].2004:50-51
2蒋勇.搅拌槽内微观混合的研究.[北京化工大学硕士学位论文].2004:52
3聂毅强.搅拌槽内三维流动场的实验测量与数值模拟.[北京化工大学硕士学位论文].2001:64-65
4周国忠.搅拌槽内流动与混合过程的实验研究及数值模拟.[北京化工大学博士学位论文].2002:113-115
5张国娟.搅拌槽内混合过程的数值模拟.[北京化工大学硕士学位论文].2004:73
6孙海燕.搅拌槽内流场数值模拟和表面曝气的研究.[中国科学院过程工程研究所博士学位论文].2003:140-141
7肖建军.带导流通搅拌槽内流场的研究.[北京化工大学硕士学位论文].2002:67-68
8王卫京.气液两相搅拌槽的数值模拟与实验研究.[中国科学院过程工程研究所博士学位论文].2002:99-100
9李岩.层流搅拌槽内三维混沌混合流场数值模拟及可视化研究.[燕山大学硕士学位论文].2007:12
10梁瑛娜.直-斜叶组合搅拌桨搅拌槽内三维流场的数值模拟与实验研究.[燕山大学硕士学位论文].2008:10
11刘敏珊,张丽娜,董其伍.涡轮桨搅拌槽内混合特性模拟研究.工程热物理学报,2009,30(10):1700-1702
12苗一,潘家祯,张国娟,等.双层涡轮搅拌槽内混合过程的数值模拟[J].华东理工大学学报(自然科学版),2006,32(3):352-356
13苗一,潘家祯,牛国瑞,等.多层桨搅拌槽内的宏观混合特性[J].华东理工大学学报(自然科学版),2006,32(3):357-360
14 Kaminoyamag M,Watanabe M,Nishi K.Numerical Simulation of Local Heat Transfer Coefficients in Stirred Vessel with Impeller for Highly Viscous Fluids[J].J.Chem.Eng.Jpn,1999,32(1):23-30
15张庆华,毛在砂.一种计算搅拌槽混合时间的新方法.化工学报,2007,58(8):1891-1896
57江涵,刘心洪,黄雄斌.用2D-PIV方法研究固-液方形搅拌槽内液相湍流.过程工程学报,2010,10(1)1-9
58宁涛,郭富德,陈斌,粘弹性流体泡状流混合层流动的PIV实验研究.工程热物理学报,2010,30(1)58-60
59史志伟,张海涛.合成射流控制翼型分离的流动显示与PIV测量.实验流体力学,2008,22(3)50-53
60李福宝,徐成海,伍沅,等.液体连续相撞击流PIV测量系统中坐标转换方法研究.仪器仪表学报,2008,29(9)1827-1830
61邓丽颖,刘春嵘.DPTV算法的精度分析.液压与气动,2008,(120,20-22
62邵春雷,顾伯勤,陈桦.PIV测量用模型泵的设计及测量中的误差分析.流体机械,2007,35(12)39-42
63罗万银,董治宝,钱广强.PIV技术及其在风沙边界层研究中的应用.中国沙漠,2007,27(5)734-736
64徐玉明,迟卫,莫立新.PIV测试技术及其应用.船舶科学技术,2007,29(3),102-105
65陈钊,郭永彩,高潮.三维PIV原理及其实现方法.实验流体力学,2006.20(4)78-82
66陈次昌,李丹,季全凯.混流式水轮机尾水管内部流场的PIV测试.机械工程学报,2006,42(12)84-88
2蒋勇.搅拌槽内微观混合的研究.[北京化工大学硕士学位论文].2004:52
3聂毅强.搅拌槽内三维流动场的实验测量与数值模拟.[北京化工大学硕士学位论文].2001:64-65
4周国忠.搅拌槽内流动与混合过程的实验研究及数值模拟.[北京化工大学博士学位论文].2002:113-115
5张国娟.搅拌槽内混合过程的数值模拟.[北京化工大学硕士学位论文].2004:73
6孙海燕.搅拌槽内流场数值模拟和表面曝气的研究.[中国科学院过程工程研究所博士学位论文].2003:140-141
7肖建军.带导流通搅拌槽内流场的研究.[北京化工大学硕士学位论文].2002:67-68
8王卫京.气液两相搅拌槽的数值模拟与实验研究.[中国科学院过程工程研究所博士学位论文].2002:99-100
9李岩.层流搅拌槽内三维混沌混合流场数值模拟及可视化研究.[燕山大学硕士学位论文].2007:12
10梁瑛娜.直-斜叶组合搅拌桨搅拌槽内三维流场的数值模拟与实验研究.[燕山大学硕士学位论文].2008:10
11刘敏珊,张丽娜,董其伍.涡轮桨搅拌槽内混合特性模拟研究.工程热物理学报,2009,30(10):1700-1702
12苗一,潘家祯,张国娟,等.双层涡轮搅拌槽内混合过程的数值模拟[J].华东理工大学学报(自然科学版),2006,32(3):352-356
13苗一,潘家祯,牛国瑞,等.多层桨搅拌槽内的宏观混合特性[J].华东理工大学学报(自然科学版),2006,32(3):357-360
14 Kaminoyamag M,Watanabe M,Nishi K.Numerical Simulation of Local Heat Transfer Coefficients in Stirred Vessel with Impeller for Highly Viscous Fluids[J].J.Chem.Eng.Jpn,1999,32(1):23-30
15张庆华,毛在砂.一种计算搅拌槽混合时间的新方法.化工学报,2007,58(8):1891-1896
57江涵,刘心洪,黄雄斌.用2D-PIV方法研究固-液方形搅拌槽内液相湍流.过程工程学报,2010,10(1)1-9
58宁涛,郭富德,陈斌,粘弹性流体泡状流混合层流动的PIV实验研究.工程热物理学报,2010,30(1)58-60
59史志伟,张海涛.合成射流控制翼型分离的流动显示与PIV测量.实验流体力学,2008,22(3)50-53
60李福宝,徐成海,伍沅,等.液体连续相撞击流PIV测量系统中坐标转换方法研究.仪器仪表学报,2008,29(9)1827-1830
61邓丽颖,刘春嵘.DPTV算法的精度分析.液压与气动,2008,(120,20-22
62邵春雷,顾伯勤,陈桦.PIV测量用模型泵的设计及测量中的误差分析.流体机械,2007,35(12)39-42
63罗万银,董治宝,钱广强.PIV技术及其在风沙边界层研究中的应用.中国沙漠,2007,27(5)734-736
64徐玉明,迟卫,莫立新.PIV测试技术及其应用.船舶科学技术,2007,29(3),102-105
65陈钊,郭永彩,高潮.三维PIV原理及其实现方法.实验流体力学,2006.20(4)78-82
66陈次昌,李丹,季全凯.混流式水轮机尾水管内部流场的PIV测试.机械工程学报,2006,42(12)84-88