Ph.D. Proposal Presentation by Samuel Durbin
Wednesday, October 29, 2003

(Dr. Charles Ume, advisor)

"Dynamics and Free-Surface Geometry of Turbulent Liquid Sheets"

Abstract

Turbulent liquid sheets have been proposed to protect solid structures in fusion power plants by attenuating damaging radiation. For the High-Yield Lithium-Injection Fusion Energy (HYLIFE-II) inertial fusion energy (IFE) power plant concept, arrays of liquid sheets form a sacrificial barrier between the fusion event and the chamber first wall while permitting target injection and ignition. Thick liquid protection can help make fusion energy commercially attractive by reducing chamber size and prolonging chamber lifetime. Establishing an experimental design database for this basic “building block” flow will provide valuable information about various thick liquid protection schemes and allow reactor designers to establish acceptable tolerances between chamber components.

This doctoral thesis proposes an experimental study of turbulent liquid sheets at Reynolds numbers of 50,000 – 130,000 and Weber numbers ranging from 2900 – 19,000 based on average velocity and the short dimension of the nozzle exit (?). Characterization of the fluctuations in free-surface position, or surface ripple, and estimation of the amount of mass ejected as droplets from the free surface will be studied in the near-field (within 25d of the nozzle exit). Surface ripple will be determined directly from planar laser-induced fluorescence visualization at the free surface. The droplets due to the turbulent breakup of the jet, termed here the hydrodynamic source term, will be measured using a simple collection technique to within 1? of the nominal free surface of the jet. The influence of various passive flow control techniques such as removing low-momentum fluid at the free surface (“boundary layer cutting”) on surface ripple and turbulent breakup will also be quantified. The data to be obtained in this research will allow designers of inertial fusion energy systems to identify the parameter ranges necessary for successful implementation of the thick liquid wall protection system.