离子液体改性燃料的电流体动力学效应研究

Research on the Electrohydrodynamic Effects of Ionic Liquid-Modified Fuels

摘要

为明确离子液体改性燃料在静电场中的运动机制，实现静电场对微尺度流场运动行为的高效调控，采用粒子图像测速技术对针-板电极结构附近介电燃料液体中产生的电流体动力学效应进行表征，研究了不同电场施加条件及离子液体改性对流体运动特性的影响。研究结果表明，高压静电场作用下，外加电压幅值及电极间隙可显著影响介电液体流动特性，流场扰动速度随电压和间隙的增加而增大。通过添加离子液体对燃料液体进行改性，发现混合溶液黏度随离子液体的体积分数增加呈非线性增长特征，电导率呈现先上升后下降的非单调变化趋势。与传统添加高电导率液体增强电流体动力学效应不同，离子液体的引入会在电极附近形成由阴、阳离子定向运动产生的反向屏蔽电场，形成局部电场屏蔽作用，抑制溶液的电流体运动特性，添加体积分数为1%的离子液体后，在电场作用下，溶液流速降低91.9%。该研究揭示了离子液体改性对燃料电流体动力学行为的调控机制，为发展新型电控燃料喷射或微流体驱动技术提供了理论依据与实验支撑。

Abstract

To clarify the motion mechanism of ionic liquid-modified fuels in electrostatic fields and to efficiently regulate the fluid motion behavior of the micro-scale flow field under electrostatic fields, the electrohydrodynamic (EHD) effects generated in dielectric fuel liquids near a needle-plate electrode structure were characterized using particle image velocimetry (PIV). The effects of varying electric field conditions and ionic liquid modification on fluid motion characteristics were systematically investigated. The results show that under high-voltage electrostatic fields, the flow characteristics of the dielectric fluid are significantly influenced by the applied voltage magnitude and electrode gap. Furthermore, the flow disturbance velocity rises as the voltage and electrode gap increase. Through the modification of fuel liquids with ionic liquids, it was observed that the viscosity of the blended solution increases nonlinearly with the volume fraction of the ionic liquid, while the electrical conductivity varies non-monotonically with ionic liquid fraction, first increasing and then decreasing. Contrary to the conventional enhancement of EHD effects via highly conductive additives, the addition of ionic liquids was found to generate a reverse shielding electric field near the electrodes due to the directed migration of anions and cations. This results in a local electric field shielding effect that suppresses the EHD motion characteristics of the solution. Specifically, with the addition of 1.0% volume of ionic liquid, the flow velocity of the solution under the electric field was reduced by 91.9%. This research elucidates the regulatory mechanism of ionic liquid modification on the EHD behavior of fuels, providing a theoretical basis and experimental support for the development of novel electronically-controlled fuel injection and microfluidic drive technologies.

关键词

电流体动力学 / 针-板电极结构 / 介电液体 / 离子液体改性 / 电场屏蔽 / 粒子图像测速技术

Key words

electrohydrodynamics / needle-plate electrode structure / dielectric fluids / ionic liquid modification / electric field shielding / particle image velocimetry

参考文献

[1] Onses M S, Sutanto E, Ferreira P M, et al. Mechanisms, capabilities, and applications of high—resolution electrohydrodynamic jet printing[J].Small, 2015, 11(34): 4237-4266.

[2] Abdul Halim B, Dehghanghadikolaei A, Amili O, et al. Understanding electrohydrodynamic (EHD) performance of corona discharge via particle image velocimetry (PIV)[J].SN Applied Sciences, 2022, 5(1): 33.

[3] Peng Yanhong, Li Dongze, Yang Xiaoyan, et al. A review on electrohydrodynamic (EHD) pump[J].Micromachines, 2023, 14(2): 321.

[4] Wang Pohao, Wen T Y . Effects of inlet blockage and electrical driving mode on static pressure and flow rate of wire—rod electrohydrodynamic pumps[J].Journal of Electrostatics, 2020, 103: 103409.

[5] Cui Yan, Yu Hao, Abbas Z, et al. PZT composite film preparation and characterization using a method of sol—gel and electrohydrodynamic jet printing[J].Micromachines, 2023, 14(5): 918.

[6] Han Yiwei, Dong Jingyan . Electrohydrodynamic (EHD) printing of molten metal ink for flexible and stretchable conductor with self—healing capability[J].Advanced Materials Technologies, 2018, 3(3): 1700268.

[7] Seyed—Yagoobi J. Augmentation of two—phase and single—phase heat transfer and mass transport with electrohydrodynamics in thermal equipment[C]//Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL’99). Piscataway, NJ, USA: IEEE, 1999: 378-383.

[8] Paul N, Suresh L, Seo J, et al. Electrohydrodynamically printed solid—state Photo—electro protein micro—capacitors[J].Energy Storage Materials, 2023, 61: 102839.

[9] 许光可，房新振，刘勇，等 . 用于电流体动力气流控制的等离子体发生器[J].高压电器，2011，47(1): 95-99.

[10] Xu Guangke, Fang Xinzhen, Liu Yong, et al. Plasma actuator used for electrohydrodynamic (EHD) flow control[J].High Voltage Apparatus, 2011, 47(1): 95-99.

[11] Pham T T, Tu H P, Dao T D, et al. Fabrication of an anode functional layer for an electrolyte—supported solid oxide fuel cell using electrohydrodynamic jet printing[J].Advances in Natural Sciences: Nanoscience and Nanotechnology, 2019, 10(1): 015004.

[12] Chen Xiaopeng, Cheng Jiusheng, Yin Xiezhen . Advances and applications of electrohydrodynamics[J].Chinese Science Bulletin, 2003, 48(11): 1055-1063.

[13] Jiang Zhengwei, Gan Yunhua, Juu Yiguang, et al. Experimental study on the electrospray and combustion characteristics of biodiesel—ethanol blends in a meso—scale combustor[J].Energy, 2019, 179: 843-849.

[14] Wang Z, Tian Y, Zhang C, et al. Massively multiplexed electrohydrodynamic tip streaming from a thin disc[J].Physical Review Letters, 2021, 126(6): 064502.

[15] Duby M H, Deng Weiwei, Kim K, et al. Stabilization of monodisperse electrosprays in the multi—jet mode via electric field enhancement[J].Journal of Aerosol Science, 2006, 37(3): 306-322.

[16] Zhu Yong, Gao Mengxiang, Chen Mingxia, et al. Numerical simulation of capture process of fine particles in electrostatic precipitators under consideration of electrohydrodynamics flow[J].Powder Technology, 2019, 354: 653-675.

[17] Shrimpton J S, Yule A J . Atomization, combustion, and control of charged hydrocarbon sprays[J].Atomization and Sprays, 2001, 11(4): 365-396.

[18] Elegant D S, Kang T, Kyritsis D C . Experimental investigation of electrostatic effects on ethanol and ethanol—diesel blend sprays in atmospheric ambiance[J].International Journal of Vehicle Design, 2009, 50: 1-4.

[19] Xu Haojie, Wang Junfeng, Tian Jiameng, et al. Electrohydrodynamic disintegration of dielectric fluid blended with ethanol[J].Physics of Fluids, 2021, 33(6): 062107.

[20] 邓友全 . 离子液体：性质、制备与应用[M].北京：中国石化出版社，2006.

[21] Guerrero I, Bocanegra R, Higuera F J, et al. Ion evaporation from Taylor cones of propylene carbonate mixed with ionic liquids[J].Journal of Fluid Mechanics, 2007, 591: 437-459.

[22] Lee J W, Heo H, Sohn D K, et al. Control of electrohydrodynamic (EHD) flow by secondary electric potential[J].International Journal of Heat and Mass Transfer, 2022, 186: 122490.

[23] Perri A E, Sankaran A, Kashir B, et al. Electrically driven toroidal Moffatt vortices: experimental observations[J].Journal of Fluid Mechanics, 2020, 900: A12.

[24] Wilson B M, Smith B L . Uncertainty on PIV mean and fluctuating velocity due to bias and random errors[J].Measurement Science and Technology, 2013, 24(3): 035302.

[25] Daaboul M, Louste C, Romat H . PIV measurements of the influence of seeding particles concentration on the velocity of an EHD flow[C]//ESA/IEEE—IAS/IEJ/SFE Joint Conference on Electrostatic. Piscataway, NJ, USA: IEEE, 2009: 1-6.

[26] Chirkov V A, Stishkov Y K . Current—time characteristic of the transient regime of electrohydrodynamic flow formation[J].Journal of Electrostatics, 2013, 71(3): 484-488.

[27] Kendall J, Monroe K P . The viscosity of liquids: II the viscosity—composition curve for ideal liquid mixtures[J].Journal of the American Chemical Society, 1917, 39(9): 1787-1802.

[28] 王方惠，李春喜，孟洪，等 . 离子液体在水、乙醇及其混合物中的电导率测定[J].北京化工大学学报(自然科学版)，2006，33(6): 17-21.

[29] Wang Fanghui, Li Chunxi, Meng Hong, et al. Determination of conductivity of ionic liquids in water or ethanol and their mixtures[J].Journal of Beijing University of Chemical Technology (Natural Science Edition), 2006, 33(6): 17-21.

[30] Debye P, Hückel E . The theory of electrolytes: I Freezing point depression and related phenomenon[J].Physikalische Zeitschrift, 1923, 24: 185-206.

基金资助

国家自然科学基金资助项目(U2241255)

国家自然科学基金资助项目(52236001)