Phase change characteristics of thin film liquid argon subjected to ultrafast boundary heating for different liquid film thicknesses (3 nm $~$ 6 nm), boundary heating rates (8 × 10⁹ K/s $~$ 320 × 10⁹ K/s) for different surface wetting conditions are main objectives of the present study. Molecular dynamics (MD) simulation has been conducted involving a three-phase domain where liquid and vapor argon (Ar) atoms are placed over the solid platinum-like (Pt) surface. Depending on the combination of boundary heating rate and liquid film thickness, two types of phase change phenomena have been observed namely-diffusive evaporation and explosive boiling. The variations in the system temperature, net evaporation number and wall heat flux normal to the surface over time are closely investigated to explicate the evolution of thin film phase change characteristics. Besides, to get a better understanding of phase change phenomena of thin film liquid, the time-averaged wall heat flux (q_avg) obtained from the MD simulation has been compared with classical thermodynamics prediction. The thermodynamic heat flux (q_therm) values are in excellent agreement with the time-averaged wall heat flux (q_avg) for diffusive evaporation cases while they differ significantly for explosive boiling cases. A comparative study has been performed on the estimation of cumulative energy density in the liquid film prior to the explosive boiling both from macroscopic as well as MD viewpoints based on simplified control volume approach. The cumulative energy density within the liquid film as obtained from macroscopic viewpoint reasonably matches with that obtained in MD approach for hydrophilic and super-hydrophilic surfaces. Interestingly, for all explosive boiling cases, accumulated energy density at the boiling explosion assumes a mean value with 95% confidence level within 5.6% of the mean, which refers to a critical condition in context to energy content of the liquid film in atomistic approach which is in agreement with other macroscopic model prediction.

不同液膜厚度(3 nm)超快边界加热下薄膜液氩的相变特性 $~$6 nm)，边界加热速率 (8 × 10 ⁹  K/s$~$320 × 10 ⁹  K/s) 对于不同的表面润湿条件是本研究的主要目标。已进行分子动力学 (MD) 模拟，涉及三相域，其中液态和气态氩 ( Ar ) 原子放置在固体铂类 ( Pt） 表面。根据边界加热速率和液膜厚度的组合，已经观察到两种类型的相变现象，即扩散蒸发和爆炸沸腾。密切研究系统温度、净蒸发数和垂直于表面的壁热通量随时间的变化，以解释薄膜相变特性的演变。此外，为了更好地理解薄膜液体的相变现象，将MD模拟得到的时均壁面热通量（q _avg）与经典热力学预测进行了比较。热力学热通量 ( q _therm ) 值与时间平均壁面热通量 ( q _avg ) 非常吻合) 对于扩散蒸发情况，而对于爆炸沸腾情况则有显着差异。基于简化的控制体积方法，从宏观和 MD 的角度对爆炸沸腾之前液膜中累积能量密度的估计进行了比较研究。从宏观角度获得的液膜内累积能量密度与在亲水和超亲水表面的 MD 方法中获得的能量密度合理匹配。有趣的是，对于所有爆炸性沸腾情况，沸腾爆炸时的累积能量密度假定平均值为 95%，置信水平在平均值的 5.6% 以内，这是指原子方法中液膜能量含量的临界条件，即与其他宏观模型预测一致。