The MTOR LM-MHD flow facility, and preliminary experimental investigation of thin layer, liquid metal flow in a 1/R toroidal magnetic field

Fairly recently, a new experimental free surface liquid metal MHD facility, the so-called MTOR facility, has come on-line, and new data has been taken concerning flows of gallium alloy across a moderately strong toroidal field with characteristic I/R field gradient. The purpose of these experiments has been two-fold: to gather data for benchmarking currently existing one and two dimensional free surface computational flow models (as well as 3D models currently under development), and to investigate phenomena not predicted by models, especially effects of nozzles, drains, waves and turbulence. Data is presented concerning MHD effects on the mean flow height and wave structure, both with and without the so-called Zakharov magnetic propulsion current added to help control and stabilize the flow. The test section is wide enough so that the characteristic factor (Hartmann Number * Aspect Ratio) is less than unity. In this case the Hartmann layer drag effects are small, allowing comparison of experimental data to two-dimensional axisymmetric models. Preliminary conclusions suggest that the field gradient in these experiments does not adversely affect the stability of the surface, and that magnetic propulsion current is effective in flattening and accelerating the liquid metal flow.