Bench-scale screening tests for a boiling sodium-potassium alloy solar receiver
Bench-scale tests were carried out in support of the design of a second-generation 75-kW{sub t} reflux pool-boiler solar receiver. The receiver will be made from Haynes Alloy 230 and will contain the sodium-potassium alloy NaK-78. The bench-scale tests used quartz-lamp-heated boilers to screen candidate boiling-stabilization materials and methods at temperatures up to 750{degree}C. Candidates that provided stable boiling were tested for hot-restart behavior. Poor stability was obtained with single 1/4-inch diameter patches of powdered metal hot-press-sintered onto the wetted side of the heat-input area. Laser-drilled and electric-discharge-machined cavities in the heated surface also performed poorly. Small additions of xenon, and heated-surface tilt out of the vertical dramatically improved poor boiling stability; additions of helium or oxygen did not. The most stable boiling was obtained when the entire heat-input area was covered by a powdered-metal coating. The effect of heated-area size was assessed for one coating: at low incident fluxes, when even this coating performed poorly, increasing the heated-area size markedly improved boiling stability. Good hot-restart behavior was not observed with any candidate, although results were significantly better with added xenon in a boiler shortened from 3 to 2 feet. In addition to the screening tests, flash-radiography imaging of metal-vapor bubbles during boiling was attempted. Contrary to the Cole-Rohsenow correlation, these bubble-size estimates did not vary with pressure; instead they were constant, consistent with the only other alkali metal measurements, but about 1/2 their size.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10175668
- Report Number(s):
- SAND-92-2253; ON: DE93018512; TRN: AHC29307%%10
- Resource Relation:
- Other Information: PBD: Jun 1993
- Country of Publication:
- United States
- Language:
- English
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Boiling behavior of sodium-potassium alloy in a bench-scale solar receiver
Boiling behavior of sodium-potassium alloy in a bench-scale solar receiver
Related Subjects
36 MATERIALS SCIENCE
CAVITY RECEIVERS
DESIGN
SODIUM ALLOYS
BOILING
STABILITY
POTASSIUM ALLOYS
MATERIALS TESTING
BENCH-SCALE EXPERIMENTS
START-UP
XENON
HELIUM
OXYGEN
ADDITIVES
COATINGS
BUBBLES
SIZE
OPERATION
LIQUID METALS
COST
SERVICE LIFE
HEAT TRANSFER
TEST FACILITIES
PRESSURE MEASUREMENT
INDUSTRIAL RADIOGRAPHY
EXPERIMENTAL DATA
CSP
Concentrating Solar Power
141000
360104
SOLAR COLLECTORS AND CONCENTRATORS
PHYSICAL PROPERTIES