Analysis of MHD effects in entrance regions of self-cooled liquid metal blankets

A key problem in self-cooled liquid metal blankets for magnetic fusion reactors is the high pressure drop due to MHD effects. This work is concerned with analysis of the contribution to the pressure drop from longitudinal eddy currents for flow in a transverse magnetic field which varies in the direction of the flow. The order of magnitude of these currents is, in some cases, comparable to eddy currents generated in the plane perpendicular to the flow. In magnetic fusion reactor blankets the liquid metal must flow from regions with low or no magnetic fields to regions of higher magnetic fields. A two-dimensional finite difference computer code was developed to determine longitudinal eddy current distributions. Pressure drops are calculated using these distributions. Results are compared with the presently limited experimental data available and with theoretical predictions. Estimates of uncertainties in calculating pressure drops are obtained. These uncertainties are found to be large and indicate a need for further study