Application of functional property generated with the anisotropic shear induced structure of suspension and colloidal systems

悬浮液和胶体系统各向异性剪切诱导结构产生的功能特性的应用

• 批准号: 12650159
• 负责人: NARUMI Takatsune
• 金额: $ 2.37万
• 依托单位: Niigata University
• 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-12650159/
• 关键词: Suspension; Colloidal Dispersion; Shear Induced Structure; Memory Effect; Functional Fluid

We have investigated the flow-induced structures of suspension and colloidal systems and those influence on the flow characteristics, relating to the application as the functional fluids.In the first test with concentrated suspensions, we had concerned with the rearrangement process of the particle structure after a shear reversal in oscillatory flow with large strain. Regardless of the shear rate applied, the process was a solid like behavior because it was only depended on the strain. The apparent viscosity estimated in the quasi-steady oscillatory flow after the transient period was affected with the unsteadiness. That is, the apparent fluidity was increased in high frequency conditions and this tendency was conspicuously observed in the mono-dispersed systems. Moreover, the dependency of the viscosity evaluated in the oscillatory flow on the rate of the volume fraction in bi-disperse systems was remarkably different with that obtained in steady flow.In the squeezing test of the concentrated suspensions, we had found that the apparent yield stress, that is solid like property, was increased with the reciprocated squeezing motion. The results obtained with the different conditions in squeezing velocity, particle shape and so on show that the concentration and the stronger cohesive structure was generated at the center region of squeezing flow due to the filtration effectsIn the test of colloidal systems, we have experimentally studied the dilute colloidal dispersion of the fine polystystyrene spheres passing through a small orifice, where it was obtained that the colloidal particles gave a stability or an instability effect on the orifice flow depending on the electrolyte density. This measured flow rates fluctuated with strong electrostatic repulsion. The increase in the electrolyte density stabilized the orifice flow, whereas excessively high electrolyte density caused instability in the flow rates.

我们研究了悬浮液和胶体体系的流动诱导结构及其对流动特性的影响，这与作为功能流体的应用有关。在第一次浓悬浮液试验中，我们关注的是大应变振荡流中剪切反转后颗粒结构的重排过程。无论施加的剪切速率如何，该过程都是类似固体的行为，因为它仅取决于应变。在准定常振荡流中，过渡期后的表观粘度估计值受非定常性的影响。也就是说，表观流动性在高频条件下增加，并且在单分散体系中显著观察到这种趋势。此外，在振荡流中得到的双分散体系的粘度对体积分数的依赖性与稳态流中得到的结果有很大的不同，在浓悬浮液的挤压实验中，我们发现，随着往复挤压运动的进行，表观屈服应力（即固体性质）增大。在不同的挤压速度、颗粒形状等条件下的实验结果表明，由于过滤作用，在挤压流的中心区域产生了浓度和较强的内聚结构。在胶体体系的实验中，我们对聚苯乙烯微球通过小孔的稀胶体分散进行了实验研究，其中得到胶体颗粒根据电解质密度对孔口流动产生稳定性或不稳定性影响。该测量的流量波动具有强静电排斥。电解质密度的增加稳定了孔流，而过高的电解质密度导致流速不稳定。

项目成果

栂 伸司, 長谷川富市, 鳴海敬倫: "コロイドのオリフィス流れにおける塩濃度の影響"第50回レオロジー討論会講演要旨集. 13-14 (2002)

Shinji Tsuga、Tomiichi Hasekawa、Takahiro Narumi：“盐浓度对胶体孔板流动的影响”第 50 届流变学研讨会论文集 13-14（2002 年）。

T.Narumi, T.Hasegawa(他4名): "Transient response of concentrated suspensions after shear reversal"Journal of Rheology. Vol.46, No.1. 295-305 (2002)

T.Narumi、T.Hasekawa（其他 4 人）：“剪切反转后浓缩悬浮液的瞬态响应”流变学杂志第 46 卷，第 1 期（2002 年）。

Y. Ohmi, T. Narumi, T. Hasegawa and H. See: "Investigation of Bingham like behavior of concentrated suspensions in a squeezing flow"Proc. SRJ 50th Rheology Conference. 243-244 (2002)

Y. Ohmi、T. Narumi、T. Hasekawa 和 H. 请参阅：“挤压流中浓缩悬浮液的宾汉姆样行为的研究”Proc。

S.Toga,T.Hasegawa and T.Narumi: "Anomaly in Excess Pressure Drops of Deionized Colloidal Dispersions Flowing through Orifice"Proc.13th Int.Congr.on Rheology. Vol.4. 199-201 (2000)

S.Toga、T.Hasekawa 和 T.Narumi：“流经孔口的去离子胶体分散体的过度压降异常”Proc.13th Int.Congr.on 流变学。

T.Narumi, T.Hasegawa(他4名): "Transient response of concentrated suspensions after shear reversal"Journal of Rheology. Vol.46,No.1. 295-305 (2002)

T.Narumi、T.Hasekawa（其他 4 人）：“剪切反转后浓缩悬浮液的瞬态响应”流变学杂志第 46 卷，第 295-305 期（2002 年）。