Sasikumar Kiran, Keblinski Pawel
Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
J Chem Phys. 2014 Dec 21;141(23):234508. doi: 10.1063/1.4903783.
We use molecular dynamics simulations to investigate the cavitation dynamics around intensely heated solid nanoparticles immersed in a model Lennard-Jones fluid. Specifically, we study the temporal evolution of vapor nanobubbles that form around the solid nanoparticles heated over ps time scale and provide a detail description of the following vapor formation and collapse. For 8 nm diameter nanoparticles we observe the formation of vapor bubbles when the liquid temperature 0.5-1 nm away from the nanoparticle surface reaches ∼90% of the critical temperature, which is consistent with the onset of spinodal decomposition. The peak heat flux from the hot solid to the surrounding liquid at the bubble formation threshold is ∼20 times higher than the corresponding steady state critical heat flux. Detailed analysis of the bubble dynamics indicates adiabatic formation followed by an isothermal final stage of growth and isothermal collapse.
我们使用分子动力学模拟来研究浸没在模型 Lennard-Jones 流体中的强烈加热固体纳米颗粒周围的空化动力学。具体而言,我们研究了在皮秒时间尺度上加热的固体纳米颗粒周围形成的蒸汽纳米气泡的时间演化,并详细描述了随后的蒸汽形成和坍塌过程。对于直径为 8 纳米的纳米颗粒,当距离纳米颗粒表面 0.5 - 1 纳米处的液体温度达到临界温度的约 90%时,我们观察到蒸汽气泡的形成,这与旋节线分解的开始一致。在气泡形成阈值处,从热固体到周围液体的峰值热通量比相应的稳态临界热通量高约 20 倍。对气泡动力学的详细分析表明,气泡先是绝热形成,随后是等温生长的最后阶段以及等温坍塌。