Development of Multi-Loop Heat Pipes for Superconducting Magnet Applications
In an early work, we reported that we have lowered the operation temperature level of a multi-loop heat pipe from the previously lowest 77 K level to 4 K level. The limiting heat transport of the heat pipe at 4 K using helium as the working fluid was however only about 0.2 W at the best. For the helium heat pipe to be able to transport 1 W, it is required to increase the heat transfer area at the heater section of the heat pipe. The area can be increased either by increasing the number of turns of the heat pipe or by increasing the heated length per turn of the heat pipe. Another factor that could have caused a low heat transport capacity in the heat pipe is the insufficiency of liquid charge. Therefore, we increased the number of turns from 10 to 52, the heated length per turn from 30 to 100 mm, and the liquid charge from 1/3 to 0.75. We have achieved nearly 1 W of heat transport for the following conditions: 52 turns, 100 mm heated length per turn, 45° heat pipe orientation and 0.45 liquid helium charge.
KeywordsHeat Transport Heat Pipe Heater Power Critical Heat Flux Heat Transfer Area
Unable to display preview. Download preview PDF.
- 1.G. R. Chandratilleke, Y. Ohtani, H. Hatakeyama, and H. Nakagome, Development of loop heat pipes for cryogenic applications, in: “Proceedings of 16th ICEC,” T. Haruyama, ed., Elsevier Science, Kitakyushu (1996) p. 501.Google Scholar
- 2.G. R. Chandratilleke, H. Hatakeyama, and H. Nakagome, Development of Cryogenic Loop Heat Pipes, Cryogenics (1997) (in print).Google Scholar
- 3.S. Lehongre, J. C. Bossin, C. Johannes, and A. De La Harpe, Critical nucleate boiling of liquid helium in narrow tubes and annuli, in: “Proceedings of 2nd ICEC,” Heywood-Temple Industrial Publications, London (1968) p. 274.Google Scholar
- 4.S. Sato, and H. Ogata, Boiling heat transfer to liquid helium in inclined channels, in:“Cryophysics and Cryoengineering: Topical Problems,” International. Inst, of Ref. Commission I, Tokyo (1970), p. 119.Google Scholar
- 6.M. Hosoda, S. Nishio, and R. Shirakashi, Bubble-driven heat transport tube: Flow pattern and heat transport model, in:”Proceedings 34th National Heat Trans. Symposium of Japan,” JSME, Sendai (1997) p. 267. (in Japanese)Google Scholar