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Title: Cool-down and frozen start-up behavior of a grooved water heat pipe

Technical Report ·
DOI:https://doi.org/10.2172/10181001· OSTI ID:10181001

A grooved water heat pipe was tested to study its characteristics during the cool-down and start-up periods. The water heat pipe was cooled down from the ambient temperature to below the freezing temperature of water. During the cool-down, isothermal conditions were maintained at the evaporator and adiabatic sections until the working fluid was frozen. When water was frozen along the entire heat pipe, the heat pipe was rendered inactive. The start-up of the heat pipe from this state was investigated under several different operating conditions. The results show the existence of large temperature gradients between the evaporator and the condenser, and the moving of the melting front of the working fluid along the heat pipe. Successful start-up was achieved for some test cases using partial gravity assist. The start-up behavior depended largely on the operating conditions.

Research Organization:
NASA Lewis Research Center, Cleveland, OH (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States)
DOE Contract Number:
AI03-86SF16310
OSTI ID:
10181001
Report Number(s):
NASA-CR-187053; CONF-910318-17; ON: DE94051193; TRN: 94:008266
Resource Relation:
Other Information: PBD: Dec 1990
Country of Publication:
United States
Language:
English