▎ 摘　　要

Graphene oxide nanosheet is considered as an excellent additive owing to desirable thermal conductivity and hydrophilicity. Graphene oxide nanofluids were prepared by adding graphene oxide nanosheets into deionized water under ultrasonic oscillation. Particle size distributions were measured by Laser Size and Zeta Potential Analyzer. Nucleation rates and supercooling degrees of deionized water and graphene oxide nanofluids are investigated using classical nucleation theory. Deionized water nucleates homogeneously, but graphene oxide nanofluids involve homogeneous nucleation of inside deionized water and heterogeneous nucleation arising from graphene oxide nanosheets. Our theoretical analysis shows that two types of nucleation in graphene oxide nanofluids can differ by 23.08 orders of magnitude at 241.65 K. Therefore, nucleation rate mainly refers to the heterogeneous part. The heterogeneous nucleation rates are obtained by integrating the particle size based on the probability density functions and particle size distributions fitted via MATLAB. The supercooling degree of deionized water is approximately 31.5 K, whereas the supercooling degrees of four different concentrations of graphene oxide nanofluids are 7.98, 7.93, 3.05, and 3.03 K. The supercooling degrees were reduced by more than 74% with the corresponding increase in volume concentration. Therefore, graphene oxide nanofluids can be used as alternative phase change materials in cold storage application because of their low supercooling degrees. (C) 2016 Elsevier Ltd. All rights reserved.