Thermal conductivity of diatomic liquid in a narrow channel including a nanobubble

The thermal conductivity of a diatomic liquid in a narrow channel including a nanobubble is analyzed using a nonequilibrium molecular dynamics method. Oxygen is assumed as the liquid and the two-center Lennard-Jones model is used to express the intermolecular potential acting on liquid molecules. Heat conduction of the liquid at various states (single phase, two-phase including a nanobubble and separated two-phase) at T = 0.7 T_cr is simulated and the thermal conductivity is estimated, where T is temperature and T_cr is the critical temperature. These values are shown to be consistent with experimental data within 10% accuracy. The thermal conductivity decreases with the decrease in the pressure in a single phase, whereas they are almost independent of the bubble size in two-phase including a nanobubble. Detailed analysis of the molecular contribution to the thermal conductivity reveals that the contribution of the heat flux caused by translational energy transfer to the thermal conductivity is dominant and the heat flux passing through the liquid phase increases with the decrease in the effective cross-section of liquid.