Zhang Meng, Zhang Wu, Wu Zhengwei, Shen Yinan, Chen Yicheng, Lan Chaofeng, Li Fengchen, Cai Weihua
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
Micromachines (Basel). 2019 Apr 18;10(4):262. doi: 10.3390/mi10040262.
Fluid mixing plays an essential role in many microfluidic applications. Here, we compare the mixing in time pulsing flows for both a Newtonian fluid and a viscoelastic fluid at different pulsing frequencies. In general, the mixing degree in the viscoelastic fluid is higher than that in the Newtonian fluid. Particularly, the mixing in Newtonian fluid with time pulsing is decreased when the Reynolds number is between 0.002 and 0.01, while it is enhanced when is between 0.1 and 0.2 compared with that at a constant flow rate. In the viscoelastic fluid, on the other hand, the time pulsing does not change the mixing degree when the Weissenberg number ≤ 20, while a larger mixing degree is realized at a higher pulsing frequency when = 50.
流体混合在许多微流体应用中起着至关重要的作用。在此，我们比较了牛顿流体和粘弹性流体在不同脉冲频率下的时间脉冲流中的混合情况。一般来说，粘弹性流体中的混合程度高于牛顿流体中的混合程度。特别地，当雷诺数在0.002至0.01之间时，牛顿流体中随时间脉冲的混合会降低，而与恒定流速相比，当雷诺数在0.1至0.2之间时，混合会增强。另一方面，在粘弹性流体中，当魏森贝格数≤20时，时间脉冲不会改变混合程度，而当魏森贝格数 = 50时，在较高的脉冲频率下会实现更大的混合程度。
