A numerical investigation of flow boiling of non-azeotropic and near-azeotropic binary mixtures

• The single-phase and two-phase flows for binary refrigerant mixtures are studied by steady-state 1D models.
• The model is validated with the experimental data from Takamatsu et al. (1993).
• The effect of fluid physical properties on pressure drop is studied.
• The effect of fluid properties and mass transfer resistance on heat transfer is studied.

The flow and heat transfer characteristics of binary refrigerant mixtures in a heated horizontal tube were investigated numerically. The pressure drop, temperature profile, and heat transfer coefficient for non-azeotropic and near-azeotropic mixtures of different bulk compositions were obtained. It is found that the non-linear physical properties of the mixtures strongly affect the pressure drop characteristics. Both the fluid properties and mass transfer resistance are responsible for the heat transfer characteristics. The mass transfer resistance has a more significant influence on the nucleate boiling than the convective evaporation for non-azeotropic mixtures, while the resistance can be neglected for near-azeotropic mixtures.