Wall surface leakage effects on magnetohydrodynamic power generator performance

Abstract

Internal surface-leakage effects on magnetohydrodynamic power generator performance were studied using a combined experimental and analytical approach. A method to determine the wall resistance and slag layer conductivity distributions from seed shutoff test data is introduced. These measured resistance values were then utilized in generator performance analyses. Calculated generator variables were compared with measured data to verify the modeling approach. Finally, these calculated results were used to investigate the distribution of internal leakage currents as a function of generator size, generator operating conditions, and iron oxide injection rates. An advantage of this analysis methodology is the ability to differentiate wall leakage from apparent leakage effects in the measured test data. NomenclatureA = channel cross-sectional area, m 2 H = channel height, m H' = height of iron oxide wake, m / = current, A L = streamwise distance over which voltage differences were measured, m P = channel cross-sectional perimeter, m p = electrode pitch, m R = electrical resistance, ft/gap s = slag layer thickness, m W = channel width, m X, X a = streamwise distance, m AV = measured voltage differential, V cr = electrical conductivity, mho/m <f > = combustion equivalence ratio Subscripts asg csg gap i plasma ps sg, slag = mean slag layer value swsg = sidewall slag layer = anode wall slag layer = cathode wall slag layer = insulator gap = iron-rich slag layer = plasma value = power supply value