Development of Micro Flow Systems utilizing Functional Fluids of non-Suspension Type

点击翻译按钮获取中文摘要

We have been trying the development of micro flow systems utilizing the molecular alignment or the electroconvection of the liquid crystal in electric fields for an application to the micro machine. Relating to a micro damper or a micro lubrication system, we have investigated the influence of the electric field strength and the frequency of AC electric fields on the electrorheological (ER) effects in the narrow gaps. The following results are obtained : (1) In the DC electric field, a larger ER effect is obtained in the case of a molecular alignment than of the electroconvection. In the AC electric field, the ER effect is caused with the molecular alignment and nearly the same ER effect as in the DC electric field is obtained. In the view point of the industrial application, it is considered that the flow under the AC electric field has an advantage in the stability of the ER effect for the micro damper and micro lubrication system. (2) A transient response in the ER effect is nearly the same as the optical response. (3) In the case of very narrow gap (<10 mum), ER effect is decreased with the wall effect. (4) Liquid crystal with a positive dielectric anisotropy is useful in this purpose.We have also examined a micro flow generator (micro pump) by controlling the electroconvection. The electric field is yielded from up-stream to down-stream between two electrode combs faced each other. We couldn't control the electronconvection enough but a weak flow is generated in this apparatus. So, it may be said that these results will be applied to a micro pump and a micro actuator development.It is shown the high applicability of the liquid crystal to the micro flow systems from above results. Now we are developing the another type flow systems utilizing the electroconvection of liquid crystal.