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Replenishment of electrodes for MHD power generation
H. F. FELDMANN, W. H. SIMONS and D. BIENSTOCK, Pittsburgh Coal Research Center, Pittsburgh, Pa., U.S.A.
U.S. Bureau of Mines,
The effect of air/fuel level in the MI-ID generator on the operation of an open-cycle MHDtopped power plant: Energy Conversion 10, 89-91 (1970). Summary-Operation of an MHD generator at below stoichiometric air,‘fuel ratios is compared with that at a 5 per cent excess air level. At the below stoichiometric air levels combustion is completed by injecting additional air downstream of the MI-ID generator. Major advantages pointed out for operating the MHD generator below the stoichiometric air levels are increased power densities and reduced air pre-heat temperatures without loss of overall plant thermal efficiency. Key words:
air/fuel level
combustion
MHD generator
A. C. WARREN and P. G. MEIER, Central Electricity Research Avenue, Leatherhead, Surrey, England.
thermal efficiency
Laboratories,
Kelvin
Replenishment of electrodes for MI-ID power generation: Energy Conversion 10,93-97 (1970). Summary-The replenishment of zirconia MHD electrodes directly from a plasma has been investigated both in open flame and duct configurations. The zirconia deposited only on the electrodes and the rate of deposition was a function of injected zirconia particle size and distance along the duct. The results may be adequately explained if it is assumed that the deposition occurs by molecules subliming from the injected particles and condensing on the electrodes but is inconsistent with the view that the particles are deposited directly. Key words: MHD flame deposition
electrode sublimation
zirconia turbulence
electrode boundary
replenishment layer
D. M. FRANCE and G. J. TREZEK, Department of Mechanical Engineering, Systems Division, University of California, Berkeley, California, U.S.A.
Thermal
E.G.D. energy converter geometry studies: Energy Conversion 10, 99-104 (1970). Summary-Comparison of the performance characteristics, current ratio voltage amplification ratio, and electric power efficiency, of an electrogasdynamic energy converter are presented for three conversion channel geometries: abrupt expansion, divergent, and free jet. Of the three channels investigated, a higher power efficiency was obtained for the jet type flows where solid boundaries in the vicinity of the flow had been removed. Best results were obtained from the abrupt expansion channel due to the further under-expansion of the jet from the free jet case. Experimental results are presented over a range of load resistance up to 10” ohms using air as the working fluid. Maximum voltage amplification ratio of 10 is reported at a peak electrical efficiency of 2.5 for the abrupt expansion channel. Optimum channel length studies on the abrupt expansion and free jet channels suggest that a relation between channel length and resistance at which peak efficiency occurs can be given by L/d’ (R/lOg)-B = K where the constants B and K vary with channel geometry. The existing theory for prediction of load current was modified to include a field coefficient. The magnitude of this coefficient was observed to vary with channel geometry. Key words: performance free jet-E.G.D. converters
characteristics abrupt expansion divergent geometry optimization for peak efficiency
V
channel
U.S. Bureau of Mines,
The effect of air/fuel level in the MI-ID generator on the operation of an open-cycle MHDtopped power plant: Energy Conversion 10, 89-91 (1970). Summary-Operation of an MHD generator at below stoichiometric air,‘fuel ratios is compared with that at a 5 per cent excess air level. At the below stoichiometric air levels combustion is completed by injecting additional air downstream of the MI-ID generator. Major advantages pointed out for operating the MHD generator below the stoichiometric air levels are increased power densities and reduced air pre-heat temperatures without loss of overall plant thermal efficiency. Key words:
air/fuel level
combustion
MHD generator
A. C. WARREN and P. G. MEIER, Central Electricity Research Avenue, Leatherhead, Surrey, England.
thermal efficiency
Laboratories,
Kelvin
Replenishment of electrodes for MI-ID power generation: Energy Conversion 10,93-97 (1970). Summary-The replenishment of zirconia MHD electrodes directly from a plasma has been investigated both in open flame and duct configurations. The zirconia deposited only on the electrodes and the rate of deposition was a function of injected zirconia particle size and distance along the duct. The results may be adequately explained if it is assumed that the deposition occurs by molecules subliming from the injected particles and condensing on the electrodes but is inconsistent with the view that the particles are deposited directly. Key words: MHD flame deposition
electrode sublimation
zirconia turbulence
electrode boundary
replenishment layer
D. M. FRANCE and G. J. TREZEK, Department of Mechanical Engineering, Systems Division, University of California, Berkeley, California, U.S.A.
Thermal
E.G.D. energy converter geometry studies: Energy Conversion 10, 99-104 (1970). Summary-Comparison of the performance characteristics, current ratio voltage amplification ratio, and electric power efficiency, of an electrogasdynamic energy converter are presented for three conversion channel geometries: abrupt expansion, divergent, and free jet. Of the three channels investigated, a higher power efficiency was obtained for the jet type flows where solid boundaries in the vicinity of the flow had been removed. Best results were obtained from the abrupt expansion channel due to the further under-expansion of the jet from the free jet case. Experimental results are presented over a range of load resistance up to 10” ohms using air as the working fluid. Maximum voltage amplification ratio of 10 is reported at a peak electrical efficiency of 2.5 for the abrupt expansion channel. Optimum channel length studies on the abrupt expansion and free jet channels suggest that a relation between channel length and resistance at which peak efficiency occurs can be given by L/d’ (R/lOg)-B = K where the constants B and K vary with channel geometry. The existing theory for prediction of load current was modified to include a field coefficient. The magnitude of this coefficient was observed to vary with channel geometry. Key words: performance free jet-E.G.D. converters
characteristics abrupt expansion divergent geometry optimization for peak efficiency
V
channel