Taylor dispersion of mixture gas-oil miscible flow in silica nanochannels under different temperatures

Miscible flow in nanochannels constitutes a central topic in multiphase flow research. Nevertheless, the microscopic mechanisms governing Taylor dispersion in mixed gas–oil systems and its temperature dependence under nanoconfinement remain insufficiently understood. In this work, molecular dynamics (MD) simulations are conducted to systematically explore the flow properties, miscibility, dispersion behavior, and underlying molecular mechanisms of mixed gas–oil miscible flow over a range of gas compositions and temperatures. Relative to single-component gases, all binary gas mixtures achieve moderately higher oil-phase velocities and exhibit strong composition-dependent miscibility: CH₄-containing mixtures show favorable intermediate miscibility, while the CO₂ + N₂ mixture presents inferior miscibility due to unfavorable intermolecular interactions. The Taylor dispersion coefficient (D _TA) increases monotonically with temperature for all gas and gas-mixture systems. The enhanced dispersion originates from promoted molecular self-diffusion and decreased fluid viscosity, which collectively reinforce the diffusion–convection coupling effect. This work extends the applicability of Taylor dispersion theory to multicomponent gas systems and delivers a fundamental molecular interpretation for nanoconfined multi-component two-phase miscible flow and dispersion.