High temperature loop heat pipes

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:163404

Anderson, W G; Bland, J J ^[1]; Fershtater, Y; Goncharov, K A; Nikitkin, M ^[2]; Juhasz, A ^[3]

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1. Thermacore, Inc., Lancaster, PA (United States)
2. TAIS, Inc., Moscow (Russian Federation)
3. NASA Lewis Research Center, Cleveland, OH (United States)

Advantages of loop heat pipes over conventional heat pipes include self-priming during start-up, improved tolerance for noncondensible gas, and ability for ground testing in any orientation. The applications for high temperature, alkali-metal working fluid loop heat pipes include space radiators, and bimodal systems. A high temperature loop heat pipe was fabricated and tested at 850 K, using cesium as the working fluid. Previous loop heat pipes were tested with ambient temperature working fluids at temperatures below about 450 K. The loop heat pipe had a titanium envelope, and a titanium aluminide wick. The maximum cesium loop heat pipe power was only about 600 watts, which was lower the predicted 1,000 W power. The power limitation may be due to a wettability problem with the cesium not completely wetting the titanium aluminide wick. This would reduce the pumping capability of the wick, and the maximum power that the heat pipe could carry. This problem could be solved by using a refractory metal powder wick, since the alkali metals are known to wet refractory metal wicks.

• OSTI ID: 163404
• Report Number(s): CONF-950729--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DESIGN
HEAT PIPE WICKS
HEAT PIPES
POWER RANGE 100-1000 W
PRESSURE DROP
TEMPERATURE RANGE 0400-1000 K
USES
WORKING FLUIDS