Attenuating the Transverse Edge Effect in MHD Generators

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HE longitudinal edge effect associated with a sharp drop in the magnetic field when entering and leaving the channel of an MHD generator results in the formation of closed current loops (Fig. la), which reduce the net generator output, increase Joule losses, and reduce the generator efficiency. It was suggested by Sutton 1 that the longitudinal edge effect be attenuated by placing nonconducting partitions at the inlet and exit of the electrode zone. A specific inhomogeneity of the electric current, the socalled * 'transverse edge effect, also arises in the channel cross section when, as a result of nonuniformity of the velocity in the direction of the magnetic field, a part of the current forms a closed loop over the boundary layers near nonconducting walls (Fig. Ib). We suggest in this study that nonconducting baffles, parallel to the magnetic field and adjoining the insulated walls, be placed in the electrode region of the generator. By analogy with the partitions employed by Sutton, 1 such a placement of baffles just will attenuate the shunting currents flowing along boundary layers at the insulated walls of the channel (Fig. Ib).