Abstract:

Based on the classical nucleation theory, nanofluid is considered to be a nanoparticle-uniform-distribution system. Clustering and deposition of particles are ignored. A nanoparticle is analogous to a molecule, base fluid is analogous to solvent, and nanofluid is analogous to a dilute solution. Nanoparticles absorbed at the vapor-liquid interface were assumed to be embedded at the interface, partially in the vapor and partially in the liquid. The distribution of nanoparticles at the interface was assumed to be uniform. Using the thermodynamic theory of solution, homogeneous and heterogeneous nucleation models of nanofluids were then developed to discuss nanoparticles effect on nucleation. The results showed that nanoparticles accumulation at the vapor-liquid interface decreased embryo bubble radius and the potential barrier of nucleation, facilitating liquid nucleation.

摘要：

基于经典的核化理论，将纳米流体看成是一个均匀的体系，不考虑颗粒的团聚及其在壁面处的富集和沉积，仅考虑体相纳米颗粒的影响。将纳米颗粒类比为大分子溶质，基液类比为溶剂，则纳米流体便可看作是浓度极稀的溶液，借用溶液热力学的相关理论，并假设气液界面处的颗粒是单层嵌入的方式且排布均匀，分别建立了纳米流体的均相和非均相核化模型，分析探讨颗粒对核化的影响。结果表明，纳米颗粒在界面处的吸附可减小核化的平衡胚泡半径，降低沸腾核化势垒，有利于核化的发生。