带凹槽的微通道中液滴运动数值模拟

运用改进的耗散粒子动力学方法模拟了液滴在由凹槽所构成的粗糙表面微通道内的运动行为.改进的耗散粒子动力学方法采用新近提出的一种短程排斥、长程吸引相互作用势能函数,从而可以模拟带有自由面的流体,如液滴等.模拟了新势能函数下液滴与固体壁面的静态接触角,并用2次多项式拟合了"接触角-a_wf/a_f"变化曲线.研究了液滴在带凹槽的微通道中运动时,微通道壁面浸润性、外场力、液滴温度对液滴流动特性的影响.研究表明壁面浸润性和外场力对液滴流动特性的影响较大,液滴温度对液滴流动特性的影响较小.研究结果对运用耗散粒子动力学方法模拟并分析微流体在复杂微通道的流动有一定的参考价值.

Numerical simulation of a droplet motion in a grooved microchannel

In this paper,an improved dissipative particle dynamics（DPD） method is used to simulate droplet motion in a grooved microchannel. In the improved DPD method,a recently proposed combination of short-range repulsive and long-range attractive interaction is adopted can simulate fluid flows with free surfaces,such as droplet motions.Firstly the static contact angle between the droplet and the solid wall is simulated with a new potential function,and "static contact angle～a_wf/a_f" curve is obtained by the 2nd order polynomial fit.Then the influences of wall wettability,flow field force,and droplet temperature on the flow pattern of droplet in the grooved microchannel are investigated.The results show that wall wettability and flow field force have large affects on the flow pattern of the droplet,while droplet temperature has little effects on it.The results in this paper are helpful for understanding the fluid flow behavior with free surfaces on rough surface.