Off-campus UMass Amherst users: To download campus access dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Dissertations that have an embargo placed on them will not be available to anyone until the embargo expires.
ORCID
N/A
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Mechanical Engineering
Degree Type
Master of Science in Mechanical Engineering (M.S.M.E.)
Year Degree Awarded
2014
Month Degree Awarded
May
Abstract
The condition of fluid flow has been proven to have a significant influence on a wide variety of material processes. In electromagnetic levitation (EML) experiments, the internal flow is driven primarily by electromagnetic forces. In 1-g, the positioning forces are very strong and the internal flows are turbulent. To reduce the flows driven by the levitation field, experiments may be performed in reduced gravity and parabolic flights experiments have been adopted as the support in advance. Tracer particles on the surface of levitated droplets in EML experiment performed by SUPOS have been used to investigate the transition from laminar to turbulent flow. A sample of NiAl3 was electromagnetically levitated in parabolic flight and the laminar-turbulent transition observed from the case was studied in this work. For the sample with clearly visible tracer patterns, the fluid flow has been numerical evaluated with magnetohydrodynamic models and the laminar-turbulent transition happened during the acceleration of the flow, instead of steady state. The Reynolds number at transition was estimated approximately as 860 by the experiment record. The predicted time to transition obtained from the results of simulation showed significant difference (~ up to 300 times) compared with the time obtained from the experiment—0.37s.
The discrepancy between numerical and experimental results could not be explained by the proposed hypotheses: geometry, boundary conditions or solid core. The simulations predict that the flow would become turbulent almost instantaneously after the droplet was fully molten. There are important physics shown by the simulation which were not captured.
DOI
https://doi.org/10.7275/5586284
First Advisor
Robert W Hyers
Recommended Citation
Zhao, Jie, "TURBULENT TRANSITION IN ELECTROMAGNETICALLY LEVITATED LIQUID METAL DROPLETS" (2014). Masters Theses. 57.
https://doi.org/10.7275/5586284
https://scholarworks.umass.edu/masters_theses_2/57
Included in
Aerodynamics and Fluid Mechanics Commons, Metallurgy Commons, Thermodynamics Commons, Transport Phenomena Commons