DNB heat flux on inner side of a vertical pipe in forced flow of liquid hydrogen and liquid nitrogen. (June 2018)

• Record Type: Journal Article
• Authors: Shirai, Yasuyuki; Tatsumoto, Hideki; Shiotsu, Masahiro; Hata, Koichi; Kobayashi, Hiroaki; Naruo, Yoshihiro; Inatani, Yoshifumi
• Is Part Of: Cryogenics. Volume 92(2018)
• Page Start: 105
• Page End: 117
• Publication Date: 2018-06
• Subjects: Hydrogen -- Nitrogen -- Heat transfer -- Forced flow -- DNB heat flux; Low temperature engineering -- Periodicals; Low temperature research -- Periodicals; 536.56
• DOI: 10.1016/j.cryogenics.2018.02.002
• Languages: English
• ISSNs: 0011-2275

Abstract

Highlights: Liquid hydrogen as a coolant of HTS magnets. Forced flow heat transfer in liquid hydrogen. DNB heat fluxes on a vertical heater pipes. Effects of pressure, liquid subcooling and flow rate. New correlation of DNB heat flux. Abstract: Heat transfer from inner side of a heated vertical pipe to liquid hydrogen flowing upward was measured at the pressures of 0.4, 0.7 and 1.1 MPa for wide ranges of flow rate and liquid temperature. Nine test heaters with different inner diameters of 3, 4, 6 and 9 mm and the lengths of 50, 100, 150, 200, 250 and 300 mm were used. The DNB (departure from nucleate boiling) heat fluxes in forced flow of liquid hydrogen were measured for various subcoolings and flow velocities at pressures of 0.4, 0.7 and 1.1 MPa. Effect of L / d (ratio of heater length to diameter) was clarified for the range of L / d ⩽ 50 . A new correlation of DNB heat flux was presented based on a simple model and the experimental data. Similar experiments were performed for liquid nitrogen at pressures of 0.5 MPa and 1.0 MPa by using the same experimental system and some of the test heaters. It was confirmed that the new correlation can describe not only the hydrogen data, but also the data of liquid nitrogen.