Investigation of boiling hydrogen flow characteristics under low-pressure conditions - Flow regime transition characteristics

Yuki Sakamoto*, Hiroaki Kobayashi, Yoshihiro Naruo, Yuichiro Takesaki, Yo Nakajima, Koki Kabayama, Tetsuya Sato

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Understanding the thermal-fluid characteristics of boiling hydrogen is of great significance for applications of liquid hydrogen, such as alternative clean energy and space vehicles. The boiling temperature of liquid hydrogen under atmospheric pressure is 20.3 K; thus, it is easy to boil to form a gas–liquid two-phase flow. Fuel transfer under the boiling state has been avoided in the space industry because of its unstable flow characteristics; precise control of the fuel, including the boiling flow, is necessary to improve the space-vehicle performance. This study aims to understand the flow-regime transition characteristics of boiling hydrogen through experimental investigation. The experimental conditions were as follows: the flow direction was horizontal, the inner diameter of the heating pipe was 15 mm, the mass flux ranged from 50 to 110 kg/m2s, and the pressure ranged from 250 to 300 kPa A. The flow-regime transition characteristics were obtained by a high-speed camera. Fully liquid phase (LP), dispersed bubbly flow (DB), intermittent flow (IN), and annular flow (AN) were observed during the experiment. Each flow-regime boundary model is constructed using two dominant forces from the experimental result based on a Taitel–Dukler model. For the DB/IN boundary, a large-bubble sustainable condition is derived by the balance between the shear and buoyancy forces acting upon the bubble; for the IN/AN boundary, a droplet-sustainable condition is derived in terms of the force balance between the drag and gravity acting on the droplet. The semi-theoretical model predicts the experimental data with 96.7% accuracy.

Original languageEnglish
Pages (from-to)8239-8252
Number of pages14
JournalInternational Journal of Hydrogen Energy
Issue number11
Publication statusPublished - 2021 Feb 11


  • Boiling
  • Flow regime
  • Liquid hydrogen
  • Void fraction

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology


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