Study on the flow of highly concentrated emulsions

ABSTRACT

An investigation was performed into the flow of highly concentrated water-in-oil emulsions. The viscosity of the low shear rate region in the downward curve was much higher than the viscosity of the upward curve due to the refining effect of the intensive shear. However, this refining effect lasted for just a short time. After that, the structure of highly concentrated emulsion (HCE) can return to its original state. The flow of HCE depends on the shear rate and droplet size of the dispersed phase. The viscosity curve of HCE, which is measured in the initial upward shearing sweep, had two platforms, whereas the region of shear rate was 10⁻⁴ s⁻¹ ∼ 10³ s⁻¹. The water-in-oil structure was destroyed by intensive shear and much solid ammonium nitrate (AN) was observed in the image of HCE. The small droplets can enhance the capacity of HCE to prevent the breakage of structure under shearing. The microstructure of HCE was closer to its original situation when the droplet size was small.

GRAPHICAL ABSTRACT

KEYWORDS:

• Flow
• highly concentrated emulsions
• microstructure
• viscosity

Additional information

Funding

The authors thank the National Natural Science Foundation of China (Grant No. 51604155, 21603101) and Natural Science Foundation of Jiangsu (Grant No. BK20160774) for financial support.