Improvement of Plasma-flow Behavior and Performance of a Disk MHD Generator under High Magnetic Flux Densities

Abstract

A two dimensional large eddy simulation has been carried out to study and compare the performance of two disk MHD generators with different wall profiles under high magnetic flux densities. One disk MHD generator has the commonly used straight disk walls and the other has newly proposed contoured disk walls. The numerical results clearly show that the generator with contoured disk walls achieves higher performance than the generator with straight disk walls, because of the improvements in the flow behavior and plasma conditions in the generator channel. For high magnetic flux densities, the flow becomes subsonic in the generator with straight disk walls and its performance tends to saturate with increasing in magnetic flux density. In the generator with contoured disk walls, on the other hand, the supersonic flow is maintained in the entire generator region and its performance increases with increasing in magnetic flux density even under the same working conditions.