摘要
目的研究假塑性流体和胀流型流体在显微镜载玻片及云母表面上的铺展动力学.方法采用液滴铺展法测试两种流体在毛细区铺展半径随铺展时间的变化关系.结果对于完全浸润系统,铺展半径随时间的演化可用幂指关系表示,其中假塑性流体铺展指数m小于0.1,胀流型流体铺展指数m大于0.1.m小于0.1时铺展速率低于牛顿流体,m大于0.1时铺展速率高于牛顿流体,同时流体非牛顿效应越强,铺展指数偏离牛顿流体理论值0.1越大.部分浸润系统,铺展半径与时间呈非单一幂指函数关系.结论笔者提出的指数关系R描述其铺展的规律,可很好描述整个铺展过程液滴半径随时间的演化.假塑性流体和胀流型流体铺展定律与牛顿流体显著不同,幂指数n是影响铺展定律的关键参数.
An experimental investigation was conducted to understand the drop spreading dynamics of the pseudo-plastic and dilatant fluids, which showed that the spreading law of both fluids was related to the rheological characteristics or power exponent n. For the completely wetting system, the evolution of the wetting radius with time can be expressed by a power law R, where the spreading exponent m of the dilatant fluids is greater than 0.1, but the spreading exponent rn of pseudo-plastic fluids is less than 0.1, indicating that the spreading rate of the dilatant fluids is higher than Newtonian one, but the spreading rate of the pseudo-plastic fluids is lower than Newtonian one. The stronger the non-Newtonian effects, the more deviation from the theoretical value 0.1 of Newtonian fluids the spreading exponent. For the partially wetting system, the power law on the time dependence of wetting radius no longer holds, therefore, an exponential power law, R was proposed, where Reg denotes the equilibrium radius of drop, a is a coefficient. The comparison of experimental data with the exponential power law showed that both are in good consistence. Furthermore, it was found that the spreading exponent rn is dependent on not only the power exponent n, but also the static contact angle θ0.
出处
《沈阳建筑大学学报（自然科学版）》
EI
CAS
2008年第6期1060-1065,共6页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家自然科学基金项目(50876009)
