Effect of initial turbulence intensity and velocity profile on liquid jets for IFE beamline protection

Current designs for thick liquid protection of heavy ion inertial fusion reactors utilize banks of liquid jets and vortex flow tubes to protect sensitive beam line components from neutrons and debris following target explosions. These hydraulic protection systems have issues regarding their formation and flow characteristics that need to be further understood as part of the ongoing chamber technology program for IFE. In this paper, modeling and experimental observations and quantitative data for rectangular and circular jets are compared in an effort to illuminate the critical phenomena involved. For rectangular jets a variety of wave patterns have been observed owing to competing effects of turbulence, surface tension and boundary layer formation in nozzles. Modeling of these jet flows using a Large Eddy Simulation technique is a useful tool for understanding the various origin of these waves, and experimenting with techniques to control their behavior. Recommendations for nozzle designs within IFE constraints are presented based on the numerical simulations.