Effects of cathode slag polarization on MHD generator performance

Conference · Mon Aug 01 04:00:00 EDT 1983 · Proc., Intersoc. Energy Convers. Eng. Conf.; (United States)

OSTI ID:5515985

Petty, S W

A series of experiments was conducted on a slagging MHD generator to investigate the loss in channel performance brought about by slag polarization phenomena in which large reductions in slag resistivity are observed on the cathode wall. However, tests in which the seed was discontinued resulted in relatively no change in generated Hall voltage (about 500 volts) while power levels dropped to less than 1 kW, demonstrating minimal leakage in the slag layer. It is concluded that the cathode slag layer is not continuous but is periodically ''broken''. Shorting of Faraday currents in the presence of a Hall field results in increasing current concentrations at the downstream edge of the shorted group until sufficient joule heating is produced to locally remove or thin the slag layer and create an open insulator gap capable of sustaining the Hall voltage. The net effect was a resegmentation of the cathode wall from a design pitch of 1.5 cm to a pitch of between 4 and 10 cm depending on the iron oxide concentration in the ash.

• Research Organization: Avco Everett Research Laboratory, Inc., Everett, Massachusetts 02149
• DOE Contract Number: AC22-80ET15614
• OSTI ID: 5515985
• Report Number(s): CONF-830812-
• Conference Information: Journal Name: Proc., Intersoc. Energy Convers. Eng. Conf.; (United States) Journal Volume: 1
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300102* -- MHD Generators-- Performance & Testing
ASHES
CATHODES
CHALCOGENIDES
COAL-FIRED MHD GENERATORS
CURRENTS
DESIGN
DIRECT ENERGY CONVERTERS
ELECTRIC CURRENTS
ELECTRIC HEATING
ELECTRIC POTENTIAL
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTRODES
EQUIPMENT
FARADAY CURRENT
HALL EFFECT
HEATING
IRON COMPOUNDS
IRON OXIDES
JOULE HEATING
LAYERS
LEAKAGE CURRENT
MHD GENERATORS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
PLASMA HEATING
POLARIZATION
RESIDUES
RESISTANCE HEATING
SEED-SLAG INTERACTIONS
SLAGS
TESTING
TRANSITION ELEMENT COMPOUNDS
WALLS