分散相颗粒几何因素对电流变液体反应时间的影响

THE EFFECT OF GEOMETRICAL FACTOR OF DISPERSED PHASE PARTICLES ON THE RESPONSE TIME OF ELECTRORHEOLOGICAL FLUID

瞬变的反应时间是电流变液体的一个重要参数．本文通过实验和理论分析，建立了考虑分散相颗粒几何因素的电流变反应时间模型根据此模型，长椭球状颗粒的电流变液体反应时间比等效球状颗粒的短，扁椭球状和片状颗粒的电流变液体反应时间比等效球状颗粒的长，而棒状颗粒的电流变液体反应时间则视－ε＿ｐ／ε＿ｆ比值大小或快于或慢于等效球状颗粒的反应时间．且反应时间与分散相尺寸的关系是（１）随体积增大，各种形状颗粒的电流变液体反应时间均变短；（２）同体积下，随长径比增大，长椭球状颗粒的电流变液体反应时间变短，而扁椭球状颗粒和片状颗粒的电流变液体反应时间变长，棒状颗粒的电流变液体反应时间则视。ε＿ｐ／ε＿ｆ比值大小或增快或减慢．因此，要获得反应快的电流变液体，颗粒形状除选择球状外，还可在使雷诺数较小范围内，选择一定尺寸的长椭球状或棒状颗粒。

Instantaneous response time is an important parameter of electrorheological (ER) fluids.Based on the expetiment and theoretical analyses, a model of response time of ER fluid re garding the geometrical factor of dispersed phase particles is established. According to themodel, for the same particle volume of the dispersed phase particles the response time of theER fluid which consists of prolate ellipsoid particles is shorter than that of the ER fluid whichconsists of sphere-like particles, while the response time of the ER fluid which consists ofoblate ellipsoid or laminar-like particles is longer than that of the ER fluid which consists ofsphere-like particles, and the response time of the ER fluid which contains rod-like particlesis shorter or longer than that of the ER fluid which contains sphere-like particles dependingon the value of εp/εf. The relationship between the response time and the size of particles isthat (1) with the increase of the particle volume, the resPOnse time of ER fluids containingdifferent shape particles decrease; (2 ) under the same volume, with the increase of the prolateradius ratio, the resPOnse time of ER fluid containing prolate ellipsoid particles decreases,while the response time of ER fluid containing oblate ellipsoid or larninar-like particles in creases, and the response time of ER fluid containing rod-like particles increases or decreasesin accordance with the value of εp/εf. In order to get ER fluid with short response time, be sides sphere-like particles other shapes such as prolate ellipsoid and rod-like particles with agiven size can be choosed at a low Reynold number.