Acceleration of Coagulation of Particles in Liquid Utilizing an A.C. Electric Field

利用交流电场加速液体中颗粒的凝结

• 批准号: 12650163
• 负责人: YANADA Hideki
• 金额: $ 1.86万
• 依托单位: Toyohashi University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650163/
• 关键词: Electrostatic filtration; Contaminant particle; A. C. electric field; Coagulation; Electric double layer; Velocity gradient; Zeta potential; 静電気応用; 静電フィルタ; 粒子

The effect of the velocity gradient on the coagulation of particles in oil under an A.C. electric field was investigated using a Couette flow system consisting of coaxial double cylinders with a small radial gap. The relation between the mean oscillation amplitude of particles and the degree of coagulation was examined under different zeta potentials of silica particles and different electric field strengths. The results obtained are as follows:1. The value of the velocity gradient that most accelerates the coagulation is a few to 10 s^<-1>.2. The application of a high electric field is not always advantageous to the coagulation. A certain electric field strength that maximizes the degree of coagulation exists for most test oils.3. The particles are relatively easily coagulated in oil with a low electric conductivity but are not easily coagulated in oil with a relatively high electric conductivity.4. The degree of coagulation is not dominated by the oscillation amplitude itself but is dominated by the relative oscillation amplitude to the electric double layer thickness.5. Considering the results 2 to 4, the following estimation can be made regarding the coagulation mechanism:(1) The coagulation is most accelerated when particles are moderately polarized in their surrounding double layers.(2) The double layer thickness in a (relatively) high conductivity liquid is thin and the electric charges in the double layer can follow the particle motion when it oscillates. This leads to a week polarization and hence to a lower degree of coagulation.6. The mechanical conditions that most accelerate the coagulation are as follows: the velocity gradient is a few to 10 s^<-1>: the electric field strength is 1 to 2 kV/mm: the oscillation amplitude of particles is approximately equal to the double layer thickness.

利用具有小径向间隙的同轴双柱Couette流动系统，研究了交流电场作用下速度梯度对油中颗粒凝聚的影响。考察了二氧化硅颗粒在不同Zeta电位和不同电场强度下颗粒的平均振荡幅度与凝聚度的关系。得到的结果如下：1.加速混凝作用最大的速度梯度在S~(-1)~(-1)之间。施加高电场并不总是有利于混凝。大多数试验油都存在使凝聚度最大化的某一电场强度。微粒在电导率较低的油中较易凝聚，在电导率较高的油中不易凝结。凝聚程度不是由振荡幅度本身决定的，而是由相对双电层厚度的振荡幅度决定的。考虑到结果2~4，可以对混凝机理作出如下估计：(1)当颗粒在其周围的双层中适度极化时，凝聚最快。(2)在(相对)高电导率的液体中，双层厚度较薄，双层中的电荷在振荡时可以跟随颗粒的运动。这会导致一周的极化，从而导致较低的凝结程度。最能促进混凝的力学条件是：速度梯度在几到10 S之间；电场强度在1~2kV/mm之间；颗粒的振荡幅度大致等于双层厚度。

项目成果

Hideki YANADA: "Coagulation of Particles in Oil under an A.C. Electric Field (Examination of Coagulation Mechanism)"Proceedings of Gifu Area Meeting of Tokai Branch, Japan Society of Mechanical Engineers. No. 013-2. 66-67 (2001)

柳田秀树：“交流电场下油中颗粒的凝结（凝结机制的检验）”日本机械工程学会东海分会岐阜地区会议论文集。

Tomoaki IMAGAWA: "Coagulation of Particles in Oil under an A.C. Electric Field (Effect of Velocity Gradient)"Proceedings of 76th Annual Meeting of Kansai Branch, Japan Society of Mechanical Engineers. No. 014-1. 8-11-8-12 (2001)

Tomoaki IMAGAWA：“交流电场下油中颗粒的凝结（速度梯度的影响）”日本机械工程师学会关西分会第 76 届年会论文集。

柳田秀記: "交流電界を利用した油中粒子の凝集促進に関する研究"日本機械学会講演論文集. No.027-1. 23-24 (2002)

Hideki Yanagida：“利用交流电场促进油中颗粒聚集的研究”日本机械工程师学会会议记录第 027-1 号（2002 年）。

Hideki YANADA: "Acceleration of Coagulation of Particles in Oil Utilizing an A.C. Electric Field"Proceedings of 39th Annual Meeting of Hokuriku-Shinetsu Branch, Japan Society of Mechanical Engineers. No. 027-1. 23-24 (2002)

Hideki YANADA：“利用交流电场加速油中颗粒的凝结”日本机械工程师学会北陆信越分会第 39 届年会论文集。

今川智哲: "交流電界の作用による油中粒子の凝集(速度勾配の影響)"日本機械学会講演論文集. No.041-1. 8-11-8-12 (2001)

Chitetsu Imakawa：“由于交流电场的作用（速度梯度的影响）而导致油中颗粒的聚集”，日本机械工程学会论文集第 041-1 号（2001 年）。