Study On Turbulent Heat Transfer Mechanism Inside High-Speed Lithium Jet Irradiated By Ion Beam For Fusion Neutron Sources

Liquid lithium (Li) jet is planned as a beam target in fusion neutron sources developed in Japan and EU. We have been studying the hydrodynamic characteristics of the Li jet experimentally and numerically. For the safety and the efficiency of fusion neutron sources, it is necessary to understand the heat transfer inside the Li target irradiated by ion beams. In this paper, in order to evaluate the heat transfer under the turbulent flow with complex vortex structure inside the Li jet, 3-dimensional simulation of it with beam irradiation is conducted using LES. As the first step of this study, the Li jet is modeled as single-phase for reducing the computational load, in which the Li surface is treated as the free-slip boundary condition. Simulation model is large-scale with over thirty million meshes for resolving the detailed vortex structure. In this simulation, it was found that the temperature peak was disturbed by wall turbulence near the bottom wall of the flow channel.