Forced Flow, Single-Phase Helium Cooling Systems
The advantages of using forced flow of single-phase helium for cooling of superconducting devices were first pointed out by Kolm . Briefly, they are: (1) with reasonable flow rates, heat transfer rates comparable with or better than pool boiling can be obtained (Fig. 1), (2) the decrease of heat transfer at high heat flux is less severe and less sudden than that which occurs when the peak nucleate boiling heat flux is exceeded, (3) flow instabilities due to vapor lock, choking flow, or density differences of the phases are absent, or at least minimized, (4) the operating temperatures can be optimized over a wider range than with pool boiling helium, (5) for larger systems, construction costs might be reduced, since the device would be built into a vacuum tank rather than a vacuum-insulated dewar, and (6) the required quantity of helium would be much less than with pool-boiling systems. The problems, however, with this approach are (1) vacuum-tight flow channels must be manifolded into the system, and (2) a pump must be used for maintaining the helium circulation.
KeywordsHeat Transfer Heat Transfer Coefficient Nusselt Number Pump Power Friction Factor
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- 1.H. H. Kolm, in: Proceedings of the International Symposium on Magnet Technology (1965), p. 611. (Available from Clearinghouse for Federal and Scientific Information, US Dept. of Commerce, Springfield, Va.)Google Scholar
- 2.C. Johannes, in: Advances in Cryogenic Engineering, Vol. 17, Springer Science+Business Media New York (1972), p. 352.Google Scholar
- 5.F. W. Dittus and L. M. Boelter, University of California Publications Eng., 2: 443 (1930).Google Scholar
- 6.A. J. Cornelius, Argonne National Laboratory, Rept. No. ANL-7032 (1965).Google Scholar
- 7.R. S. Thurston, in: Advances in Cryogenic Engineering, Vol. 10, Springer Science+Business Media New York (1965), p. 305.Google Scholar
- 8.K. Goldman, in: International Developments in Heat Transfer, Part III, ASME, New York (1961), p. 561.Google Scholar
- 9.J. R. McCarthy and H. Wolf, Rocketdyne Research Rept. RR-60–12 (1960).Google Scholar
- 10.K. K. Knapp and R. H. Sabersky, Int. J. Heat and Mass Transfer, 9: 51 (1966).Google Scholar