Associate Professor Juancheng Yang
State Key Laboratory for Strength and Vibration of Mechanical Structures
School of Aerospace
Xi'an Jiaotong University
yangjc@xjtu.edu.cn
Juancheng Yang received his PhD degree in Harbin Institute of Technology in 2013. After working as a postdoctoral fellow at University of Chinese Academy of Sciences (UCAS), he joined the Xi'an Jiaotong University as an associate professor in July 2015. His research interests are the magnetohydrodynamics (MHD) of liquid metal flows related to nuclear fusion and electromagnetic metallurgy, including the measurement methods of liquid metal flow, liquid metal free surface flow, liquid metal droplet dynamics, liquid metal thermal convection, et al. He has published more than 40 refereed journal papers. The citation of his paper is more than 700.
Title: Influence of magnetic field on the dynamics of liquid metal droplets impacting on solid or liquid surface
Abstract: The impingement of droplets on the solid surface or liquid film is a very common phenomenon in both daily life and industrial applications. Regarding the conventional liquid drop, a considerable amount of theoretical, simulation and experimental work is done. However, when the impingement of droplet which is formed by liquid metal with larger surface tension, density and conductivity than common liquid, happens in an environment with a magnetic field, the dynamic of droplet motion naturally been changed due to the action on flow by extra body force, Lorentz force. Due to limited data, the corresponding magnetohydrodynamic (MHD) effects on drop impingement are far from fully understood. Here, the present study investigates the liquid metal drops impacting a solid or liquid surface with the external magnetic field. The eutectic alloy of gallium, indium, and tin (GaInSn) which is in the liquid state at room temperature is adopted. The magnetic field is aligned with the horizontal direction with its strength can be adjusted continuously from 0 to 20000 Gs. When the liquid metal drop impacts the solid surface, the elliptical spreading pattern of a liquid metal droplet induced by the horizontal magnetic field is discovered. A non-dimensional parameter is introduced to get scaling laws for the averaged maximum spreading factor and the aspect ratio of the elliptical shape at the moment of maximum spreading. When the liquid metal drop impacts on the liquid metal free surface, we observe three typical outcomes after drop impacts on the film, namely, symmetric crown, asymmetric crown, and prompt splashing, among which the asymmetric crown is first discovered by the present experiments. Finally, to fully understand the phenomena observed, by selecting typical cases, numerical simulations are carried out.