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671.
Haihua Pei Jijiang Ge Mingchao Ma Lei Zhang Yueliang Liu 《Journal of Dispersion Science and Technology》2013,34(11):1548-1556
Severe viscous fingering during water flooding of heavy oil leaves a large amount of oil untouched in the reservoir. Improving sweep efficiency is vital for enhancing heavy oil recovery. This study presented a laboratory study for improving sweep efficiency by alkaline flooding in heavy oil Reservoirs. This included glass-etched micromodel flooding tests, one-dimensional flooding experiments and three-dimensional physical model study. The micromodel tests show that W/O droplet flow plays a prominent role in the alkaline flooding to improve sweep efficiency. There is a minimum alkaline concentration that generates the W/O droplet flow, and the W/O droplet flow is more obvious with the alkaline concentration increasing. A series of flood tests were conducted using 325 mPa · s, 2000 mPa · s, and 3950 mPa · s heavy oils to assess the effectiveness of W/O droplet flow in alkaline flooding for enhanced heavy oil recovery. The flood tests results demonstrate the considerable potential for improved heavy oil recovery by alkaline flooding, and moreover, the incremental oil recovery has been found to increase as the alkaline concentration increases. The result obtained in three-dimensional physical model study indicates that the sweep area can be greatly improved by the formation of W/O droplet flow in alkaline flooding. 相似文献
672.
Maria‐Teresa Celis 《Journal of Dispersion Science and Technology》2013,34(1):20-26
Emulsification processes results in the generation of droplets populations produced from the dynamic equilibrium between the breakup and coalescence phenomena determined primarily by the formulation and composition variables, mixing characteristics and emulsion preparation. The information contained in the UV‐vis spectrum on the absorption and scattering properties of the emulsions lead to the interpretation of the spectra in terms of the particle size distribution, the particle shape, and the chemical composition of the oil and emulsifier. This article reports analysis of emulsions on transmission spectrum as function of the oil concentration and physicochemical variables. The quantitative interpretation of the transmission spectrum is performed in the portion where no absorption is present (300–820 nm) leading to reliable estimated of droplet size populations in the range of 1 to 20 µm. The possibility of obtaining information from a single multiwavelength measurement makes UV‐vis spectroscopy a powerful tool for characterization of dispersed systems. 相似文献
673.
In this work a set of experimental data points is used to study some scaling properties of Miesowicz coefficients. Using the fact that all the compounds studied present two critical points—the crystal–nematic and the nematic–isotropic phase transitions—a common temperature scale was defined. With the use of this unique temperature scale two relevant aspects that distinguish the viscosity of these materials can be simultaneously extracted and studied: (1) the molecular shape anisotropy and (2) the different strengths of molecular interaction of the different compounds. Through the study of the scaling properties associated with these properties, the existence of a common law connecting the Miesowicz coefficients with the associated decay time is proposed. 相似文献
674.
Chen Luo Yuan Ma Haifang Li Fengming Chen Katsumi Uchiyama Jin‐Ming Lin 《Journal of mass spectrometry : JMS》2013,48(3):321-328
We report the association of inkjet and electrospray ionization MS to detect picoliter droplet, where the liquid volume and its position onto the tip can be precisely controlled to form ultrafine droplets for successive ionization of the analyte. Single rectangle pulse was applied to piezoelectric device on inkjet microchip for the ejection of each picoliter droplet, and it was controlled by a computer. The voltage and width of driving pulse for the inkjet were optimized to make reproducible ejection of the solvent with low viscosity. The volume of each droplet was about 600 pl, and a trigger of 10 droplets was selected as the best inlet mode taking relative standard derivation of the droplets into consideration. The target substrate used with high voltage to form ionization was graphite, after several attempts with some materials. High‐speed camera was used to capture the breaking‐up process of a droplet. The distance between the inkjet nozzle and the tip was set at 2 cm to avoid short circuit. The influences on the mass intensity of the diameter of the tip, the volume and the concentration of the sample were examined. The tip with a small diameter performed greater intensity, and the limit of detection decreased, whereas the small volume of liquid played high ionization efficiency. Linear regression in the range between 1 and 200 ppm for caffeine was conducted, where internal standard theobromine was used. Some real samples were also detected with the instrument. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
675.
部分润湿液滴是适宜纳米结构表面上滴状冷凝传热的主要载体,研究纳米结构参数与部分润湿液滴合并弹跳之间的关系有重要意义,本文依据冷凝液滴生长过程中能量增加最小的原理来判断其是否为部分润湿状态,并根据液滴合并前后的体积和界面自由能守恒,确定了合并液滴的初始形状,进而对合并液滴变形过程的动力学方程进行了求解,结果表明:部分润湿冷凝液滴仅在纳米柱具有一定高度、直径间距比较大的表面上形成,而当纳米柱高度过低、直径间距比小于0.1时则形成完全润湿的冷凝液滴;液滴合并后能否弹跳与纳米结构参数紧密相关,仅在纳米柱较高、直径间距比适宜的表面上,部分润湿液滴合并后才能诱发弹跳;液滴尺度及待合并液滴间的尺度比对合并弹跳也有重要影响;多个部分润湿液滴合并后由于具有更多的过剩界面自由能而比两个液滴合并更容易诱发弹跳,本模型对纳米结构表面上冷凝液滴是否合并诱发弹跳的计算结果与绝大部分实测结果相一致,准确率达到95%。 相似文献
676.
677.
678.
《Journal of Electrostatics》2014,72(6):470-476
Electrically driven coalescence is one of the important methods to separate water from crude oils. In this paper, the coalescence behaviour of two water drops was studied experimentally using a high-speed imaging. The results show that the electric force induces the drops migrating towards each other before their contact. However the electric force drags the drops to separate after contact. There is a critical electric field strength above which the two drops would be separated again after they have been coalesced together. The understanding of the electric coalescence could be helpful to advance the design of the electrocoalescencers. 相似文献
679.
《Journal of Electrostatics》2014,72(5):402-411
A single-stage, single-wire vertical wet electrostatic precipitator was designed and operated in air–water droplets flow to investigate its performance. The efficiency was compared with a glass micro fiber filter and proposed semi-empirical efficiency model, which was in good accuracy while considering the vapor content. Effects of geometric parameters on efficiency under different charge conditions were discussed. Due to evaporation mechanism, the corona current decreases for high flow rates at the same applied voltage. Findings indicated while developing flow is created inside the ESP, there exists an optimum wire-to-flow inlet spacing that provides maximum droplet collection efficiency. 相似文献
680.
根据Mie散射理论,基于一次实测资料拟合得出雾滴谱分布,计算了雾滴粒子群的散射相函数矩阵,揭示了不同波长的雾滴粒子群对入射激光的散射偏振特征。结果表明:激光散射强度随散射角的增加呈现先减小后增大的趋势,且波长越小散射光强分布越集中;波长越大,偏振度随散射角分布越平滑,反之分布震动则越剧烈;各波段偏振度随散射角增大的分布趋势大致相同,关键散射角随波长的减小向增大的方向偏移。 相似文献