Theoretical Studies of Hard Filling in Loop Heat Pipes

• Published in: Journal of thermophysics and heat transfer 2010-01, Vol.24 (1), p.173-183
• Main Authors: Adoni, Abhijit A, Ambirajan, Amrit, Jasvanth, V. S, Kumar, D, Dutta, Pradip
• Format: Article
• Language: English
• Subjects: Applied sciences; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Heat pipes; Integrated circuits; Loop heat pipes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0887-8722; 1533-6808
• DOI: 10.2514/1.44382

Loop heat pipe is a passive two-phase heat transport device that is gaining importance as a part of spacecraft thermal control systems and also in applications (such as in avionic cooling and submarines). Hard fill of a loop heat pipe occurs when the compensation chamber is full of liquid. A theoretical study is undertaken to investigate the issues underlying the loop heat pipe hard-fill phenomenon. The results of the study suggest that the mass of charge and the presence of a bayonet have significant impact on the loop heat pipe operation. With a larger mass of charge, a loop heat pipe hard fills at a lower heat load. As the heat load increases, there is a steep rise in the loop heat pipe operating temperature. In a loop heat pipe with a saturated compensation chamber, and also in a hard-filled loop heat pipe without a bayonet, the temperature of the compensation chamber and that of the liquid core are nearly equal. When a loop heat pipe with a bayonet hard fills, the compensation chamber and the evaporator core temperatures are different.