Distribution pattern of void fraction in subcooled boiling of liquid nitrogen

To understand two-phase flow distribution patterns in subcooled boiling of cryogenic fluid, the subcooled boiling process of liquid nitrogen in an upward vertical tube was simulated by using CFD. The distribution of void fraction in the wall-heated tube was systematically analyzed through the revision of bubble models and the variation of different operating parameters. The results show that the heat and mass transfer of gas-liquid phase is the main reason influencing the distribution of void fraction. The average void fraction nonlinearly increases along the axial direction and it is U-shaped distributed along the radial direction. The average void fraction in the axial direction increases with increasing wall heat flux and decreases with increasing inlet mass flow rate and subcooled temperature.