为深入理解液态金属射流的磁流体力学特性，基于自行搭建的液态金属射流实验平台，对流向磁场条件下液态金属镓铟锡射流破碎过程开展实验研究。从射流形态、破碎长度、表面扰动和液滴分布4个方面分析射流破碎特性。无磁场时破碎长度随We增大而增大，射流表面波长在表面张力的作用下趋近于临界波长，射流破碎液滴体积直径呈现双峰结构。施加流向磁场后，射流破碎形成的液滴发生振动衰减，在破碎位置下游呈现等大球形液滴，表面波长随磁场的增强而变短，射流破碎长度随磁场的增强而变长。最后归纳了流向磁场对射流破碎长度的3种影响方式。
To gain a deeper understanding of the magnetohydrodynamic characteristics of liquid metal jets, this study conducted experimental research on the breakup process of a liquid metal GaInSn jet under a flow-aligned magnetic field condition. Based on a self-built liquid metal jet experimental platform, the jet breakup characteristics were experimentally analyzed from four aspects: jet morphology, breakup length, surface disturbance, and droplet distribution. In the absence of a magnetic field, the breakup length increased with the increasing We number. The surface wavelength of the jet approached the critical wavelength under the action of surface tension, and the volume diameter of the jet breakup droplets showed a bimodal structure. When a flow-aligned magnetic field was applied, the droplets formed after jet breakup were subject to vibration attenuation under the action of the flow-aligned magnetic field and exhibited equally sized spherical droplets downstream of the breakup position. The surface wavelength decreased with increasing magnetic field, while the breakup length increased. Three types of influences of the flow-aligned magnetic field on the breakup length of the jet were summarized.
[1] Eggers J, Villermaux E. Physics of liquid jets[J]. Reports on Progress in Physics, 2008, 71(3): 036601. DOI: 10.1088/0034-4885/71/3/036601.
[2] Sarkar A, Nitin N, Karwe M V, et al. Fluid flow and heat transfer in air jet impingement in food processing[J]. Journal of Food Science, 2004, 69(4): CRH113-CRH122. DOI: 10.1111/j.1365-2621.2004.tb06315.x.
[3] Khlyustova A, Labay C, Machala Z, et al. Important parameters in plasma jets for the production of RONS in liquids for plasma medicine: a brief review[J]. Frontiers of Chemical Science and Engineering, 2019, 13(2): 238-252. DOI: 10.1007/s11705-019-1801-8.
[4] Reneker D H, Yarin A L. Electrospinning jets and polymer nanofibers[J]. Polymer, 2008, 49(10): 2387-2425. DOI: 10.1016/j.polymer.2008.02.002.
[5] Abdou M A. Exploring novel high power density concepts for attractive fusion systems[J]. Fusion Engineering and Design, 1999, 45(2): 145-167. DOI: 10.1016/S0920-3796(99)00018-6.
[6] Kuteev B V, Sergeev V Y, Krylov S V, et al. Conceptual analysis of a tokamak reactor with lithium dust jet[J]. Nuclear Fusion, 2010, 50(7): 075001. DOI: 10.1088/0029-5515/50/7/075001.
[7] Halfon S, Arenshtam A, Kijel D, et al. High-power liquid-lithium jet target for neutron production[J]. The Review of Scientific Instruments, 2013, 84(12): 123507. DOI: 10.1063/1.4847158.
[8] Savart. Auszug aus einer abhandlung über den stoss eines flüssigen strahls Gegen eine kreisrunde scheibe[J]. Annalen Der Physik Und Chemie, 1833, 105(10): 356-362. DOI: 10.1002/andp.18331051015.
[9] Rayleigh L. On the instability of jets[J]. Proceedings of the London Mathematical Society, 1878 (1): 4-13. DOI: 10.1112/plms/s1-10.1.4.
[10] Weber C O. The aesthetics of rectangles and theories of affection[J]. Journal of Applied Psychology, 1931, 15(3): 310-318. DOI: 10.1037/h0074279.
[11] Reitz R D, Bracco F V. Mechanism of atomization of a liquid jet[J]. The Physics of Fluids, 1982, 25(10): 1730. DOI: 10.1063/1.863650.
[12] Wu K J, Reitz R D, Bracco F V. Measurements of drop size at the spray edge near the nozzle in atomizing liquid jets[J]. Physics of Fluids, 1986, 29(4): 941. DOI: 10.1063/1.865689.
[13] Oshima S, Yamane R, Mochimaru Y, et al. The shape of a liquid metal jet under a non-uniform magnetic field[J]. JSME International Journal, 1987, 30(261): 437-448. DOI: 10.1299/jsme1987.30.437.
[14] Bucenieks I, Lielausis O, Platacis E, et al. An experimental study of liquid metal film and jet flows in a strong magnetic field[J]. Magnetohydrodynamics (New York), 1994, 30(2)：219-230. DOI:10.22364/mhd.58.1-2.1.
[15] 许增裕. 自由表面射流磁流体不稳定性分析(Ⅰ)[J]. 核聚变与等离子体物理, 2003, 23(2): 96-100. DOI: 10.16568/j.0254-6086.2003.02.006.
[16] 许增裕, 薛世华, 康伟山, 等. 自由表面磁流体射流不稳定性分析(Ⅱ)[J]. 核聚变与等离子体物理, 2004, 24(1): 19-23. DOI: 10.16568/j.0254-6086.2004.01.005.
[17] 于星星, 张杰, 倪明玖. 水平磁场中液态金属射流的三维数值研究[J]. 中国科学院大学学报, 2019, 36(4): 481-486. DOI: 10.7523/j.issn.2095-6134.2019.04.006.
[18] 董泉润, 阳倦成, 倪明玖. 水平磁场作用下液态金属自由射流破碎特性的实验研究[J]. 中国科学院大学学报, 2022, 39(5): 577-585. DOI: 10.7523/j.ucas.2022.029.
[19] Shugai G A, Yakubenko P A. Convective and absolute instability of a liquid jet in a longitudinal magnetic field[J]. Physics of Fluids, 1997, 9(7): 1928-1932. DOI: 10.1063/1.869308.
[20] Molokov S, Reed C B. Review of free-surface MHD experiments and modeling[R]. ANL/TD/TM99-08, Argonne National Lab., IL (US), 2000. DOI:10.2172/757509.
[21] Morley N B, Burris J, Cadwallader L C, et al. GaInSn usage in the research laboratory[J]. The Review of Scientific Instruments, 2008, 79(5): 056107. DOI: 10.1063/1.2930813.
[22] Liu T Y, Sen P, Kim C J. Characterization of nontoxic liquid-metal alloy galinstan for applications in microdevices[J]. Journal of Microelectromechanical Systems, 2012, 21(2): 443-450. DOI: 10.1109/JMEMS.2011.2174421.
[23] Yang J C, Qi T Y, Han T Y, et al. Elliptical spreading characteristics of a liquid metal droplet impact on a glass surface under a horizontal magnetic field[J]. Physics of Fluids, 2018, 30(1): 012101. DOI: 10.1063/1.5000054.
[24] Birouk M, Lekic N. Liquid jet breakup in quiescent atmosphere: a review[J]. Atomization and Sprays, 2009, 19(6): 501-528. DOI: 10.1615/atomizspr.v19.i6.20.
[25] Sallam K A, Dai Z, Faeth G M. Liquid breakup at the surface of turbulent round liquid jets in still gases[J]. International Journal of Multiphase Flow, 2002, 28(3): 427-449. DOI: 10.1016/S0301-9322(01)00067-2.
