Influence of eddy effect of coils on convection and deformation of electromagnetically levitated droplet. (January 2022)

• Record Type: Journal Article
• Authors: Feng, Lin; Shi, Wan-Yuan
• Is Part Of: International communications in heat and mass transfer. Volume 130(2022)
• Publication Date: 2022-01
• Subjects: Melt convection -- Temperature field -- Free surface deformation -- Eddy effect -- Electromagnetic levitation; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Heat -- Transmission; Mass transfer; Periodicals; 621.4022
• DOI: 10.1016/j.icheatmasstransfer.2021.105766
• Languages: English
• ISSNs: 0735-1933

Abstract

Abstract: This paper presents a comparative modeling of free surface deformation, fluid flow, and temperature distribution in electromagnetically levitated molten droplets with and without the eddy effect of coils in both normal and microgravity environments. The results show that in the TEMPUS device (Tiegelfreies ElektroMagnetisches Prozessieren Unter Schwerelosigkeit), a dual-frequency electromagnetic levitation system in microgravity, the alternating currents in the positioning and heating coils function as a reciprocal load owing to the mutual inductance, which leads to a visible decline in the induced current in the droplet. Consequently, the temperature level and deformation of the droplet were dramatically overestimated after the eddy effect was omitted. Under terrestrial conditions, the alternating currents in the lower and upper coils have the same frequency and magnitude but run in opposite directions. The major influence of the omitted eddy effect is the enhanced equilibrium position of the droplet, whereas the influence on convection and the temperature field is minimal. With this work, it is expected that the behaviors of electromagnetically levitated droplets can be predicted more precisely by considering the eddy effect of coils for a better understanding of the convection, temperature distribution, and deformation of the droplet. Highlights: Eddy effect of coils has significant influence on the behaviors of an electromagnetically levitated droplet. The convection, temperature and deformation of droplet are overestimated when eddy effect is ignored in TEMPUS device. On terrestrial condition, the predicted equilibrium position of droplet is much higher when eddy effect is ignored.