PERFORMANCE AND ENERGY-TRANSFER MEASUREMENTS ON CYLINDRICAL CESIUM THERMIONIC CONVERTERS
Detailed measurements of performance and energy transfer were made on two highly instrumented cylindrical cesium thermionic converters with electrically heated tungsten emitters. The first converter, OC-4, which had a niobium collector, operated with an initial electrical output of 6.9 watts/cm/sup 2/. This output gradually degraded to a value of 4.6 watts/cm/sup 2/ after 1351 hr. These power values were measured at the electrodes for an average emitter temperature of 1 750 deg C, Converter OC-5, which had a molybdenum collector, has operated 260 hr to date, with a power output and efficiency of 11.1 watts/cm/sup 2/ and 16%, respectively, at an average emitter temperature of 1800 deg C. These operating data are compared with those for lower emitter temperatures below. Temperature Density Efficiency Energy values of the emitter electron cooling, collector electron heating, thermal radiation, and cesium conduction were calorimetrically determined as a function of emitter temperature, collector temperature, cesium pressure, and current. For all the data obtained, the emitter temperature profile was measured by thermocouples. From the calorimeter measurements, correlations were found for the prediction of emitter electron cooling DELTA Q/sub E/ and collector electron heating DELTA Q/sub C/: DELTA Q/sub E/ = I (2.6 + V), and DELTA Q/sub C/ = I (2. The correlation is valid within 4% accuracy over the operating variable range: emitter temperature of 1200 to 1800 deg C; cesium reservoir temperature of 300 to 400 deg C;, collector temperature of 600 to 700 deg C; and current of zero to 15 amp/cm/sup 2/ . Through measurements of emitterstructure heat losses, of the cesium-vapor thermal conduction, and of the electrode radiation heat transfer, it was found that all the zero-current energy-transfer quantities can be accurately predicted with RAT, a two-dimensional digital-computer heat-transfer code. The electron cooling correlation, together with the ability to calculate all of the power-loss values in a thermionic converter, makes it possible to compute the efficiency of a converter when the I-V characteristics and materials properties are known This is of special interest to thermionic reactor analysis, since the input to the reactor problem is the amount of fission produced in each of a very large number of cells within the reactor. Apart from the utility of the correlation discovered, the determination of the value of 2.6 volts in the current-heating terms is of fundamental interest and invites further study. (auth)
- Research Organization:
- General Atomic Div., General Dynamics Corp., San Diego, Calif.
- DOE Contract Number:
- AT(04-3)-167
- NSA Number:
- NSA-18-014779
- OSTI ID:
- 4070752
- Report Number(s):
- GA-4729
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CESIUM
COMPUTERS
CONFIGURATION
CONVERSION
COOLING
CURRENTS
CYLINDERS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRICITY
ELECTRODES
ELECTRONS
EMISSION
ENERGY
ERRORS
FISSION
HEAT TRANSFER
HEATING
LOSSES
MEASURED VALUES
MOLYBDENUM
NESDPS Office of Nuclear Energy Space and Defense Power Systems
NIOBIUM
OPERATION
PERFORMANCE
PHYSICS
POWER
PRESSURE
PROGRAMMING
QUANTITATIVE ANALYSIS
REACTORS
TEMPERATURE
THERMAL CONDUCTIVITY
THERMAL RADIATION
THERMIONICS
THERMOCOUPLES
TUNGSTEN