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Tatsumoto, Hideki; Aso, Tomokazu; Kato, Takashi; Otsu, Kiichi; Hasegawa, Shoichi; Maekawa, Fujio; Futakawa, Masatoshi
Proceedings of International Cryogenic Engineering Conference 22 (ICEC-22) and International Cryogenic Materials Conference 20 (ICMC 2008), p.711 - 716, 2009/00
In J-PARC, a cryogenic hydrogen system, which plays a role in providing supercritical hydrogen with a pressure of 1.5 MPa and a temperature of 20 K to three moderators, has been designed. The performance test of the helium refrigeration system was conducted independently. The helium refrigeration system was cooled down to 18 K within 4.5 hours, and the refrigerator power of 6.45 kW at 15.6 K was confirmed. The performance test results proved that the helium refrigerator met the performance requirements.
Tatsumoto, Hideki; Aso, Tomokazu; Kato, Takashi; Otsu, Kiichi; Hasegawa, Shoichi; Maekawa, Fujio; Futakawa, Masatoshi
Proceedings of International Cryogenic Engineering Conference 22 (ICEC-22) and International Cryogenic Materials Conference 20 (ICMC 2008), p.717 - 722, 2009/00
In J-PARC, an intense spallation neutron source (JSNS) driven by a 1-MW proton beam has been constructed. A cryogenic hydrogen system, which provides supercritical hydrogen at the temperature of around 20 K and the pressure of 1.5 MPa to the moderators and absorbs nuclear heating in the moderators, has been completed in November 2007 and the commissioning has been started. As a first step, the primary cryogenic operations were conducted by using helium, instead of hydrogen. We confirmed the system soundness at operation temperature, and established operation method of the cool-down process. The cryogenic tests have been successfully completed without problems.
Tatsumoto, Hideki; Shirai, Yasuyuki*; Hata, Koichi*; Kato, Takashi; Shiotsu, Masahiro*
Proceedings of International Cryogenic Engineering Conference 22 (ICEC-22) and International Cryogenic Materials Conference 20 (ICMC 2008), p.383 - 388, 2009/00
Forced flow heat transfers of supercritical nitrogen in a horizontal tube was measured for wide range of inlet temperature and flow velocity conditions. The heat transfer coefficients agreed well with those predicted by Dittus-Boelter correlation for the surface temperature lower than pseudo-critical temperature, Tc'. When the surface temperature exceeds Tc', they become lower than those by the correlation. The heat transfer coefficients at a certain wall temperature became lower with decrease in Reynolds number (Re) down to about 8000. Further decrease in Re did not affect the heat transfer coefficients. The lowest limits agreed with those obtained for natural convection.
Aso, Tomokazu; Tatsumoto, Hideki; Hasegawa, Shoichi; Otsu, Kiichi; Uehara, Toshiaki; Kawakami, Yoshihiko; Sakurayama, Hisashi; Maekawa, Fujio; Futakawa, Masatoshi; Ushijima, Isamu*
Proceedings of International Cryogenic Engineering Conference 22 (ICEC-22) and International Cryogenic Materials Conference 20 (ICMC 2008), p.741 - 746, 2009/00
no abstracts in English
Shiotsu, Masahiro*; Tatsumoto, Hideki; Shirai, Yasuyuki*
Proceedings of International Cryogenic Engineering Conference 22 (ICEC-22) and International Cryogenic Materials Conference 20 (ICMC 2008), p.359 - 364, 2008/07
In designing a superconducting coil wound with Cable in Conduit Conductor cooled by supercritical helium, accurate knowledge of heat transfer in forced flow of He I under supercritical pressure is necessary. The authors performed experiments on heat transfer from a test plate in a horizontal duct cooled by supercritical helium. On the other hand, there have been many experimental data and correlations for non-cryogenic fluids such as water and CO
at supercritical pressures. Most of these data are on far longer tubes compared with our data for helium, and ratios of wall temperature increase to the critical temperature are far lower than that for helium. In this work, our data for supercritical helium above mentioned are compared with the correlations for the non-cryogenic fluids. The data are not predicted well by the correlations. The reasons of the discrepancies are considered and a new generalized correlation is presented.