电流变活性的若干判据

Some Criteria for Electrorheological Activity

给出了一个简化模型描述载流子在电流变液中的输运 .颗粒极化可分为两部分 ,慢极化分量由载流子的受阻输运所致 ;快极化分量是载流子所在介电背景的极化 .在切变场中 ,一个强的电流变强度要求强而相对稳定的颗粒相互作用 .大的极化强度确保相互作用强度 ,合适的极化速率和介电损耗以保证颗粒相互作用的相对稳定性 .根据计算结果并考虑到切变场对介电响应的影响 ,这里给出一个半经验电流变活性判据 :对于ω <10 3s-1,ωτ >10 -4 ,存在 1<d/λ <10 0和ωτd/λ<1.该判据半定量或定性地得到实验检验 .

A simplified model is developed for the transport of charge carriers in electrorheological (ER) fluids. The polarization of particles consists of two components. One results from the resistive transport of charge carriers; the other corresponds to the polarization of dielectric background in which the charge carriers transport. A strong and relatively stable interaction between particles in required for a large electrorheological strength in shearing field. A large polarization magnitude is responsible for the strength of interaction while proper polarization rate and dielectric loss are necessary for the stability of interactions among particles. From calculated results and taking the effect of shearing field on the dielectric response of particles into account, the criteria for electrorheological activity are presented as ωτ>10 -4, 1<d/λ<100 and ωτd/λ<1 for ω<103 s -1, which are qualitatively testified by our experiments.