M.S. Thesis Presentation by Brian Shellabarger
Thursday, November 13, 2003

(Drs. Minami Yoda and Said Abdel-Khalik, co-advisors)

"Experimental Studies of High-Speed Liquid Films on Downward-Facing Curved and Flat Surfaces for IFE Applications"

Abstract

Inertial fusion energy (IFE) may help solve our growing energy needs. IFE also poses many technical challenges that need to be overcome before it can become a viable alternative energy source, however. One of these challenges is designing an IFE reactor chamber first wall that can endure more than a billion fusion events. It has been proposed to protect the upper end cap of the reactor chamber from the damaging photons and charged particles from the fusion event by a thin film of molten lead injected tangentially to the first wall. Implementation of this “forced film” thin liquid protection scheme requires a basic understanding of the behavior of turbulent liquid films over a downward-facing surface.

Experimental investigations of high-speed water films on downward facing surfaces will therefore be conducted for Reynolds numbers of 3,500 to 20,000 and Weber numbers ranging from 100 to 2,800. Both a flat and a curved surface with a radius of 5 m will be investigated at different angles of inclination up to 30 degrees below the horizontal. Films flowing over surfaces with contact angles varying from 25° to 90° will be studied to determine the effect of surface wettability. Mean detachment distances will be determined for liquid films of varying thickness and initial velocity. The flow of the liquid films around cylindrical obstructions on curved surfaces will also be examined and compared to previous results for similar obstruction on flat surfaces. Ejected droplet mass flux from the free surface due to turbulent primary breakup at varied downstream distances will be estimated for liquid films of varying initial velocity. The experimental data will be presented as generalized nondimensional charts to provide design guidelines for this type of thin liquid protection scheme in IFE power plant designs.