共轴微通道内液滴生成的二维数值模拟分析

为探究材料参数和操作参数对共轴微流控装置内液滴生成特性的影响,建立适用于液液两相流模拟的计算模型,并采用VOF法进行数值求解。模拟过程中通过改变两相不同流率、两相梯度黏性和表面张力对液滴尺寸及伴随液滴生成的机制进行分析。通过分析发现:在外流场中,随着连续相流速的增大,生成液滴的直径会相应的减小;离散相流率变化会引起毛细管后液线长度发生变化,进而引起流态之间的转化,更重要的是会直接导致液滴尺寸发生改变,但离散相黏度对液滴直径的影响甚微;在相同流场变量下,换用表面张力更小的离散相后,发现生成的液滴直径也变小;最后,调整毛细管和外部通道的尺寸,发现液滴生成率和液滴直径的变化规律与调整前是一致的。

Effect of Acoustic Resonance Phenomenon on Fluid Flow with Light Dust

In the present paper,the attention is focused on the characteristics of lightweight materials collection in the duct using acoustic resonance phenomena.The acoustic resonance was excited by using a controlled speaker at the middle of a test duct.We measured the sound pressure level,frequency response characteristics,acoustic damping ratio,mode shape,and lightweight materials response to acoustic resonance excited by a speaker.As a result,the acoustic damping ratio decreased as the mode number of acoustic resonance increased.The tissue strips and the lightweight materials were collected at the node of acoustic pressure when the acoustic resonance was excited.It was made clear that it is possible to control lightweight materials using acoustic resonance excited by a speaker.