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Abstract：
Nano-fluid flooding is a new method capable of improving oil recovery; however, nanoparticles (NPs) significantly affect electric dehydration, which has rarely been investigated. The effect of silica (SiO2) NPs on the droplet-interface coalescence was investigated using a high-speed digital camera under an electric field. The droplet experienced a fall, coalescence, and secondary droplet formation. The results revealed that the oil-water interfacial tension and water conductivity changed because of the SiO2 NPs. The decrease of interfacial tension facilitated droplet deformation during the falling process. However, with the increase of particle concentration, the formed particle film inhibited the droplet deformation degree. Droplet and interface are connected by a liquid bridge during coalescence, and the NP concentration also resulted in the shape of this liquid bridge changing. The increase of NP concentration inhibited the horizontal contraction of the liquid bridge while promoting vertical collapse. As a result, it did not facilitate secondary droplet formation. Moreover, the droplet falling velocity decreased, while the rising velocity of the secondary droplet increased. Additionally, the inverse calculation of the force balance equation showed that the charge of the secondary droplet also increased. This is attributed to nanoparticle accumulation, which resulted in charge accumulation on the top of the droplet.
摘要：
纳米流体驱是一种能够提高采收率的新方法,纳米粒子（NPs）显着影响电脱水，很少被调查。使用高速数码相机在电场下研究了二氧化硅（SiO2）NP对液滴界面聚结的影响。水滴经历了一次坠落，聚结,和二次液滴形成。结果表明，由于SiO2NPs的存在，油水界面张力和水电导率发生了变化。界面张力的降低促进了液滴在下落过程中的变形。然而,随着颗粒浓度的增加，形成的颗粒膜抑制了液滴变形程度。液滴和界面在聚结过程中通过液桥连接，NP浓度也导致该液桥的形状发生变化。NP浓度的增加抑制了液桥的水平收缩，同时促进了垂直塌陷。因此,它没有促进二次液滴形成。此外，液滴下落速度降低，而二次液滴的上升速度增加。此外,力平衡方程的反计算表明，二次液滴的电荷也增加了。这归因于纳米粒子的积累，这导致电荷积聚在液滴的顶部。
