含油纳米制冷剂沸腾中纳米颗粒相间迁移特性预测模型

Model for Predicting the Migration Characteristics of Nanoparticles During the Boiling of Nanorefrigerant Containing Lubricating Oil

为了评估纳米颗粒对沸腾传热的影响效果和采用纳米制冷剂的制冷系统长期运行稳定性,提出了含油纳米制冷剂沸腾中纳米颗粒相间迁移特性预测模型,通过模拟气泡的脱离和上升过程、纳米颗粒的运动、纳米颗粒与气泡的黏附、气液交界面上纳米颗粒的脱离,最终得到纳米颗粒的迁移量。该模型能够反映热流密度和加热容器几何结构等因素对纳米颗粒迁移特性的影响,模型预测值与95%的实验值的偏差在20%以内。

In order to evaluate the effect of nanoparticles on the boiling heat transfer and the long-term stability of the refrigeration system using nanorefrigerant,a model for predicting the migration characteristics of nanoparticles during the boiling of nanorefrigerant containing lubricating oil is proposed.In the present model,the migrated mass of nanoparticles is obtained by the simulation of the departure and rising processes of bubble,the movement of nanoparticles in the liquid-phase,the adhesion of nanoparticles and bubble,and the escape of nanopaticles from the liquid-vapor interface.The proposed model can predict the influences of the heat flux and the geometry of boiling vessel on the migration of nanoparticles.The migrated mass of nanoparticles predicted by the model can agree with 95%of the experimental data within a deviation of±20%.