End effects in Faraday type MHD generators with nonequilibrium plasmas

The influence of the end losses on a linear nonequilibrium Faraday type MHD generator with finite segmented electrodes is studied theoretically. Numerical two-dimensional calculations are performed for constant, parabolically increasing and parabolically decreasing magnetic induction near the generator exit. The plasma considered consists of argon at 5 atm and 2000 K and seeded with 0.2 % cesium. The influence of the described magnetic induction configurations on the current distribution in the MHD-generator exit is studied. The effect of several configurations on the existence of a region near the generator exit with higher electrical conductivity than in the generator itself is discussed. It is preferable to extend the magnetic induction over a distance equal to the generator height, keeping the value of the magnetic induction constant; then the electrical conductivity is not increased near the generator exit and the homogeneous current pattern is hardly disturbed. From the given analysis information is obtained for the design of an appropriate magnetic induction configuration.