Dv. Paramonov et Ms. Elgenk, EFFECT OF OXYGEN ON THE OPERATION OF A PLANAR THERMIONIC CONVERTER FOR ISOTHERMAL AND ISOFLUX HEATING CONDITIONS, Energy conversion and management, 39(5-6), 1998, pp. 375-390
In this paper, the effects of oxygen on the performance of and the emi
tter material transport in a planar thermionic converter were investig
ated. The oxygen and cesium partial pressures in the interelectrode ga
p were varied parametrically, and their effects on the operational cha
racteristics of the converter were quantified for both isothermal and
isoflux emitter heating conditions. With isothermal heating, a signifi
cant increase in the electric power density in the presence of oxygen
(by a factor of 3-10, depending on the emitter temperature and the ini
tial composition of the collector surface) was predicted. The load vol
tages corresponding to the maximum output power were similar to 0.3-0.
5 V lower than those corresponding to the optimum efficiency. With an
isoflux emitter heating of 20 W/cm(2), the introduction of oxygen into
the interelectrode gap of a converter with an initially pure tungsten
collector increased the electric power density by only similar to 19%
; however, no improvement occurred for-an initially oxidized tungsten
collector. (C) 1997 Elsevier Science Ltd.