Abstract

Recent developments in Liquid Metal Magnetohydrodynamic systems show that the self-evaporating magnetohydrodynamic system is a promising power generator that converts heat directly into electricity dispensing with a mixer and separator found in conventional systems. The vaporized fraction generated by heating the working liquid metal, drives the remaining liquid by a vapor ejector action. Aiming at higher power density, and higher conversion effectiveness for Liquid Metal Magnetohydrodynamic, we investigate the utilization of a circumferential annular ejector instead of the commonly used central axial ejector. For that purpose, we use Computational Fluid Dynamics to carry out a parametric study that includes the variations in annular ejector geometry, input heating power, and the mass fraction of the ejector flow. In addition, spatial distributions of the velocity, pressure, temperature, and liquid and vapor fractions are presented and analyzed. For an optimized study case, the circumferential annular ejector increased the output power by 8.7 % more than the central axial ejector.