(Drs. Yoda and Abdel-Khalik, co-advisors)
"Experimental Studies of High-Speed Liquid Films on Downward-Facing Surfaces for IFE Applications"
The fusion event in inertial fusion energy (IFE) reactors creates neutrons, photons and charged particles that can damage the chamber first walls. The Promotheus conceptual design study considered using a high-speed film of molten lead injected tangential to the wall to protect the upper end cap of the reactor chamber from damaging X-rays and charged particles. The film must remain attached to assure complete chamber coverage for robust protection and efficient heat conduction to the coolant. Film detachment under the influence of gravity is most likely to occur on the downward facing surfaces of the reactor chamber upper end cap.
Experimental investigations of high-speed water films injected onto downward-facing surfaces at angles of inclination up to 45o below the horizontal were therefore carried out to investigate the growth and detachment of these flows. Films with initial thickness up to 2 mm and injection speeds up to 11 m/s, corresponding to Reynolds numbers up to 21000 and Froude numbers up to 121 were studied. The effect of varying contact angle on the growth and detachment of the films as well as the effect of flow blockage was examined. The results of these studies, which are to our knowledge the first experimental studies of such high-speed liquid films on downward-facing surfaces, will provide design windows for wet wall, or thin liquid protection, schemes in IFE power plants.