Thermofluid modeling and experiments for free surface flows of low-conductivity fluid in fusion systems

The paper summarizes results of experimental and theoretical studies related to the flow of liquids with a free surface and poor electrical and thermal conductivity, such as molten salts, under conditions relevant to fusion energy systems. These results have been obtained over last several years when developing the liquid wall concept as a part of the APEX project [M.A. Abdou, The APEX TEAM, On the exploration of innovative concepts for fusion chamber technology, Fusion Eng. Des. 54 (2001) 181-247]. As a theoretical tool a modified K-ε model of turbulence coupled with the Navier-Stokes equations written in the thin-shear-layer approximation is used for studying wavy, turbulent flows in a spanwise magnetic field. The experimental part covers current results for supercritical flows in regimes transitional from "weak" to "strong" turbulence, which are expected to occur in the reference liquid wall flows. The paper also describes on-going work on novel schemes of heat transfer promotion and current directions for direct numerical simulation.