Prediction model of the average size of aggregate in nano-refrigerant.

Nanoparticles form aggregates in nano-refrigerant. The average size of aggregate has significant effect on the heat transfer performance of nano-refrigerant. The objective of this study is to propose a model for predicting the average size of aggregate in nano-refrigerant. The average size of aggregate in nano-refrigerant depends on the coupled aggregation-sedimentation process. This process was simulated by two sub-models, i.e., the single particle motion sub-model and the particle-particle interaction sub-model. In the computing procedure, the cell-linked list (CLL) method was introduced to speed up scanning particle pairs in order to save computation time, and the constant-number method was adopted to eliminate the negative effect of aggregation on the computation accuracy. The prediction values were compared with the experimental data, and good agreement was obtained.