微尺度沸腾的团聚过程分析与压力扰动模型

本文从团聚(clustering)的分子动力学过程出发,研究微尺度沸腾相变的物理机制。通过分析沸腾系统势能变化趋势,指出核化阶段必然伴随团聚体积的增加,从而导致压力扰动的产生。在微尺度条件下,这种压力扰动将可能主导沸腾系统的相变行为。由此模型导出相变发生的临界尺度判据,在量级上与实验取得很好的一致

Clustering Process Analysis and Pressure Disturbance Model for Microscale Boiling

The formation process of molecular clusters was considered in order to understand the boiling and nucleation of superheated liquid in microchannels and/or microstructure.The nucleation is inevitably accompanied with the volume increase of the clusters for the clusters to reach more stable state.This volume change causes pressure disturbance in the surrounding environment.Under microscale conditions,the pressure disturbance may play a leading role in phase change.The interaction of clusters with the pressure disturbance could cause the association and dissociation of clusters.The comparison between the propagation time of the pressure disturbance and the time of clusters growing to the critical radius in superheated liquid can determine whether the clusters are able to grow into boiling nuclei or vanish.Thus a critical microchannel size scale is obtained for "fictitious boiling" .The estimated value is in a satisfactory agreement with experimental data for water.