Baidakov V G, Bobrov K S
Institute of Thermophysics of the Ural Branch of the Russian Academy of Sciences, Amundsen Street 107a, 620016 Ekaterinburg, Russia.
J Chem Phys. 2014 May 14;140(18):184506. doi: 10.1063/1.4874644.
We report a molecular dynamics (MD) study of homogeneous bubble nucleation in a Lennard-Jones liquid under a negative pressure (cavitation). The rate of bubble nucleation has been determined in the range 2 x 10(-9) < J() = Jσ(4)(m/ε)(1/2) < 6 x 10(-6) by the mean lifetime method at temperatures T() = kBT/ε = 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.4, 0.5, 0.6, 0.7, 0.8. In molecular dynamics simulation calculations have also been made of the coefficient of bubble size diffusion, the Zeldovich nonequilibrium factor, and the radius of a critical nucleus R*. Different approaches to the determination of the nucleation rate in a stretched liquid have been considered in the framework of classical nucleation theory (CNT). The values of J obtained in MD simulation are by 8-20 orders higher than those predicted by CNT. The work of formation of a critical bubble and the dependence of surface tension γ(R*) at the critical bubble-liquid interface have been determined by data of MD simulation from CNT. The values of γ obtained have been approximated by an extended Tolman formula that takes into account, besides a linear correction, also the quadratic in curvature terms. The Tolman length δ∞ is negative and equals -(0.1-0.2)σ. The coefficient at 1/R*(2) is positive and does not exceed σ(2).
我们报告了在负压（空化）下对 Lennard-Jones 液体中均匀气泡成核的分子动力学（MD）研究。通过平均寿命法，在温度 T* = kBT/ε = 0.35、0.4、0.5、0.6、0.7、0.8 下，确定了气泡成核速率在 2×10⁻⁹ < J() = Jσ⁴(m/ε)¹/² < 6×10⁻⁶ 的范围内。在分子动力学模拟中，还计算了气泡尺寸扩散系数、泽尔多维奇非平衡因子以及临界核半径 R。在经典成核理论（CNT）的框架内，考虑了确定拉伸液体中成核速率的不同方法。MD 模拟中获得的 J 值比 CNT 预测的值高 8 - 20 个数量级。通过 MD 模拟数据从 CNT 确定了临界气泡的形成功以及临界气泡 - 液体界面处表面张力γ(R*)的依赖性。获得的γ值已通过扩展的托尔曼公式进行近似，该公式除了线性校正外，还考虑了曲率的二次项。托尔曼长度δ∞为负，等于 - (0.1 - 0.2)σ。1/R*(2)的系数为正，且不超过σ²。
