Numerical investigation of hydrogen bubble growth enhancement using variable-frequency ultrasonic waves

초록

The enhancement of hydrogen bubble growth induced by ultrasonic waves is investigated using a numerical model that incorporates both vapor phase change and dissolved hydrogen mass transfer. The model couples the Keller–Miksis equation with energy and hydrogen mass fraction equations, directly computing vapor phase change rates and hydrogen mass flux based on temperature and mass fraction fields. A bubble growing under ultrasonic excitation experiences a sudden increase in hydrogen mass under resonance conditions. The timing and magnitude of this rapid bubble growth are highly sensitive to ultrasonic frequency, emphasizing the need for precise frequency modulation to effectively induce bubble resonance and enhance hydrogen mass growth. The resonance frequency-bubble radius correlation for hydrogen bubbles in a supersaturated solution is provided, incorporating both vapor phase change and hydrogen mass transfer effects. Ultrasonic waves with a variable resonance frequency, adapting to the continuously growing bubble, significantly enhance hydrogen accumulation within the bubble compared to both silent conditions and conventional single-frequency excitation. The influence of operating parameters, including the initial bubble radius, electrolyte concentration, and temperature, on the hydrogen mass enhancement achieved by variable-frequency excitation is also examined. © 2026 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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