Numerical investigation on wall heat transfer characteristics of subcooled boiling of liquid nitrogen

The subcooled boiling of liquid nitrogen was numerically simulated by means of computational fluid dynamics (CFD). The different heat transfer modes of surface heat transfer during subcooled boiling were systematically analyzed and the distribution of the three components of wall heat flux along the tube was obtained. The results show that the heat flux transferred by evaporation is the leading mode of surface heat transfer at the final region of subcooled boiling. Meanwhile, the effect of wall heat flux on the partition of the three components was also studied. It indicates that at the outlet of subcooled boiling, the surface quenching heat flux and the turbulent convective heat flux decrease with the increasing of wall heat flux, but only evaporation heat flux increases and its percentage is absolutely dominant. The increase of wall heat flux can effectively promote the boiling heat transfer.