Experimental Studies of Microchannel Tapering on Droplet Forming Acceleration in Liquid Paraffin/Ethanol Coaxial Flows
Abstract
:1. Introduction
2. Materials and Experimental Set-Ups
3. Liquid Paraffin–Ethanol Coaxial Flow at the Convergence Angle
3.1. State Diagram about the Dripping-to-Jetting Transitions
3.2. Droplet Diameter in Dripping Mode
3.3. Droplet Diameter in the Jetting Mode
4. The Role of Convergence Angle, and
4.1. The Influence of Microchannel Tapering on the State Diagram
4.2. The Influence of Microchannel Tapering on Droplet Generation Characteristics in the Dripping and Jetting Modes
4.2.1. Dripping Mode
4.2.2. Jetting Mode
5. Conclusions
- (1)
- In the straight-tube () coaxial stream, the experimental results of the Dripping-to-Jetting transition, flow patterns, and droplet characteristics are consistent with the data and fitting laws in the related literature.
- (2)
- The tapered microchannel () changes the state diagram of the liquid paraffin/ethanol coaxial in the – space. The Dripping mode is not affected, and the Jetting regime is the most compressed by the emerging Threading mode at a large .
- (3)
- The tapered microchannel () causes little change about the droplet forming processes in the Dripping mode, which is different from that of the Jetting mode. In the Jetting mode, the size of the droplet decreases as the tube diameter reduces by tapering, which is exactly the opposite for the droplet forming frequency. The droplet forming frequency grows quickly as the tube diameter reduces, .
Author Contributions
Funding
Conflicts of Interest
References
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Phase | Material | (mPa·s) | (g/cm ) | (mN/m) |
---|---|---|---|---|
Continuous phase | Ethanol (95 vol.%) | 1.3 | 0.817 | 4.5 |
Dispersed phase | Liquid paraffin | 15.8 | 0.836 |
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Zhang, J.; Wang, C.; Liu, X.; Yi, C.; Wang, Z.L. Experimental Studies of Microchannel Tapering on Droplet Forming Acceleration in Liquid Paraffin/Ethanol Coaxial Flows. Materials 2020, 13, 944. https://doi.org/10.3390/ma13040944
Zhang J, Wang C, Liu X, Yi C, Wang ZL. Experimental Studies of Microchannel Tapering on Droplet Forming Acceleration in Liquid Paraffin/Ethanol Coaxial Flows. Materials. 2020; 13(4):944. https://doi.org/10.3390/ma13040944
Chicago/Turabian StyleZhang, Jinsong, Chao Wang, Xianfeng Liu, Chunming Yi, and Z. L. Wang. 2020. "Experimental Studies of Microchannel Tapering on Droplet Forming Acceleration in Liquid Paraffin/Ethanol Coaxial Flows" Materials 13, no. 4: 944. https://doi.org/10.3390/ma13040944