Experimental study on the boiling behavior and film evolution of e-liquid on the surface of porous ceramic in e-cigarette

• Published in: Applied thermal engineering 2024-01, Vol.236, p.121694, Article 121694
• Main Authors: Zhu, Dong-Qing, Yang, Ran, Chen, Shu-Yan, He, Zhi-Zhong, Lin, Xiang-Wei, Zhou, Zhi-Fu, Chen, Bin
• Format: Article
• Language: English
• Subjects: Bubble boiling; E-aerosols; Electronic cigarette; Frequency characteristic; Porous flow
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2023.121694

•Experiment is conducted to study boil behavior and film evolution in e-cigarette.•Three boiling modes of e-liquid film on porous ceramic surface are identified.•Higher heating power enhances oscillation of boiling and rise e-liquid consuming.•Higher puff pressure provides more e-liquid supply for bubble boiling.•Heating power higher than 9.5 W cause non-bubble boiling and heat deterioration. Electronic nicotine delivery systems (ENDS) have gained popularity worldwide. Research on the boiling behavior of e-liquid in ENDS helps to better understand heat transfer and e-aerosols generation mechanism. This paper designed an experimental system to investigate boiling behavior and liquid film evolution on the porous ceramic surface of ENDS. The effects of puffing duration, heating power and puffing pressure on the variations of temperature on ceramic surface and chamber pressure, boiling behavior of e-liquid were systematically explored. The boiling/vaporization of e-liquid mainly occurred on the e-liquid thin film formed on the ceramic bottom surface, which took ∼3 s to become relatively stable. Three boiling modes, i.e., incipient boiling, bubble boiling and non-bubble boiling have been identified based on the analysis of boiling images, which greatly relied on the heating power and puffing pressure. Increasing puffing pressure mainly caused greater liquid supply to the liquid film with larger thickness accompanied by bubbling mode, while higher heating power intensified liquid–vapor interface instability with higher oscillation frequency and consuming rate of e-liquid, more easily to induce non-bubbling boiling. The results provided insight into the boiling phenomenon and associated mechanisms, being of important significance in optimizing puffing parameters and avoiding failure of ENDS.