The micro-interaction and diffusion characteristics of R1132a with lubricating oil PVE68

Most HFC refrigerants suffer from the drawback of high global warming potential （GWP）, whereas the novel refrigerant R1132a exhibits an extremely low GWP value. In this study, molecular dynamics simulations were employed to construct molecular models of a single-component R1132a system, a single-component PVE68 system, and a mixture of the two, within an operating range of 233.15–293.15 K and 5–65 MPa. The conclusions indicate: The solubility parameters of both substances exhibit an increasing trend with decreasing temperature and increasing pressure, with R1132a showing a more pronounced trend. Within the mixed system, intramolecular interactions between carbon and oxygen atoms are strongest, while intermolecular interactions between fluorine and oxygen atoms are the most significant. In terms of diffusion characteristics, the root-mean-square displacement and self-diffusion coefficient of R1132a are significantly higher than those of PVE68. The diffusion behaviour of the former is sensitive to changes in temperature and pressure, with temperature exerting a stronger driving force than pressure; the latter, due to its strong dipole interaction, exhibits high molecular motion resistance, and its diffusion process is minimally affected by temperature and pressure fluctuations. This study reveals the interaction mechanisms of the R1132a-PVE68 system at the microscopic level, providing theoretical support for the engineering applications of this refrigerant combination.