Experimental study on onset of nucleate boiling in wide-ranged parameters for narrow rectangular channels

• Published in: Annals of nuclear energy Vol. 211; p. 110935
• Main Authors: Kuang, Bo, Zhao, Yu, Wang, Gang, Cao, Chengque, Liu, Pengfei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2025
• Subjects: ONB; Rectangular narrow channels; Wall superheating; Wide-ranged parameters; ONB; Rectangular narrow channels; Wall superheating; Wide-ranged parameters
• ISSN: 0306-4549
• DOI: 10.1016/j.anucene.2024.110935

•Onset of nucleate boiling tests are conducted in a relatively wide parameter range.•The effect of thermal hydraulics parameters and dimensions on ONB is analyzed.•The force and phase equilibrium equations have been established for bubbles.•A new correlation is proposed for ONB in narrow rectangular channels. The onset of nucleate boiling (ONB), which marks the emergence of nucleate boiling, is an important transition point in the boiling curve. For exploring the influence of geometric and thermodynamic parameters on ONB in rectangular narrow channels, a detailed experimental study is conducted to investigate ONB under wide range of parameters. The experimental parameters range is pressure of 0.1–5.5 MPa, mass flux of 200–2000 kg/m2s, inlet subcooling of 10–150 K. According to the experimental results, the location of ONB is identified based on the axial distribution of wall temperature, and the influence of various parameters on ONB in narrow rectangular channels is analyzed. It is found that heat flux, pressure, mass flux, and the gap size of the channel have a significant impact on ONB. By comparing the computed results of existing correlations, it is evident that there is a deviation, which can be attributed to the narrow range of experimental parameters in previous studies. Finally, a new ONB model is developed based on basic equations proposed by Hsu and the distribution of liquid temperature, taking into account the influence of mass flux and the enhanced heat transfer results from surrounding bubbles to correct the liquid temperature. The new correlation accurately describes the impact of each parameter and is in good agreement with the current experimental results.