Formation, coalescence and behaviour of bulk nanobubbles in dodecane and isooctane and their thermophysical properties: A comprehensive molecular study
Formation, coalescence and behaviour of bulk nanobubbles in dodecane and isooctane and their thermophysical properties: A comprehensive molecular study
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DOI：
10.1016/j.fuel.2023.130254
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发表时间：
2024-02
期刊：
影响因子：
7.4
通讯作者：
Hamidreza Hassanloo;Xinyan Wang
中科院分区：
文献类型：
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作者：
Hamidreza Hassanloo;Xinyan Wang
近几十年来，纳米气泡在水产养殖、水处理、生物医学工程和能源/动力工程等领域引起了研究者的极大关注。然而，通过实验技术对这些微小气泡的基本理解是非常具有挑战性的。高沸点的相变材料十二烷和高辛烷值、低挥发性的代用燃料异辛烷在能源领域得到了广泛的研究和应用。本文采用分子动力学模拟方法，研究了二氧化碳（CO2）、氧气（O2）、氮气（N2）和氢气（H2）在十二烷和异辛烷中的成核、聚结过程及其对样品热物理性质的影响。还研究了添加气体的重量分数和温度，以了解它们对气泡动力学和固有性质的影响。结果表明，CO2气体的加入使十二烷的粘度下降最大，降幅达20.47%，而氧气在十二烷中的分散使十二烷的粘度增加。研究还发现，含有铌的样品比不含铌的样品具有更高的比热容，并且通过溶解氢铌可以获得最高的比热容改善。异辛烷样品的比热容随分散气质量分数的增加而增加。然而，十二烷显示出相反的趋势。随着体系温度的升高，十二烷样品的比热容增大，而异辛烷样品的比热容又呈现相反的趋势。
In recent decades, nanobubbles (NBs) have attracted great attentions of researchers in a number of fields, including aquaculture, water treatment, biomedical engineering and energy/power engineering. However, the fundamental understanding of these tiny bubbles through experimental techniques is very challenging. Dodecane, as a phase change material with a high boiling point, and isooctane, as an alternative fuel with high octane number and low volatility, have been researched and used in energy applications. In this work, the nucleation, coalescence and behaviour of formed NBs of carbon dioxide (CO2), oxygen (O2), nitrogen (N2), and hydrogen (H2) gases in dodecane and isooctane samples as well as their effects on the thermo-physical properties of the samples were investigated by means of molecular dynamics (MD) simulations. The weight fraction of the added gas and temperature were also investigated to understand their effects on the bubble dynamics and inherent properties. The results reveal that the addition of CO2gas leads to the biggest drop in the viscosity of the dodecane by 20.47%, while the dispersion of oxygen gas in dodecane increases the viscosity. It is also found that samples containing NBs have higher specific heat capacity than samples without NBs and the highest specific heat capacity improvement can be obtained by dissolving hydrogen NBs. Furthermore, it is found that specific heat capacity of isooctane sample increases by increasing the weight fraction of dispersed gas. However, dodecane shows the opposite trend. By increasing the system temperature, the specific heat capacity of dodecane sample increases while isooctane sample again shows the opposite trend.