Investigation on heat transfer and flow of a sonic steam jet condensation in crossflow of water in pipes

Direct contact condensation is widely used in nuclear reactor thermal-hydraulic systems, underwater propulsion systems, liquid propellant rocket engines and other industrial fields due to its highly efficient heat and mass transfer. Understanding the distribution of the thermal-hydraulic parameters of steam jet condensation systems has become an urgent need for optimal design and safe operation of industrial processes. In this paper, the flow characteristics and heat transfer for the condensation of sonic steam jet in crossflow in a subcooled water pipe are numerically simulated based on experimental results. A two-resistance model under the framework of two-fluid model is employed to consider the mass and heat transfer across the steam-water interface. The steam plume transforms from contraction-cone into expansion-cone when steam mass flux rises from 500 to 900 kg/m²s, and the plume length gradually increases approximately linearly from 2.43d_e to 4.17d_e. When the steam mass flux is 900 kg/m²s, the expanding channel of the steam plume allows the jet to accelerate from sonic to supersonic with Ma = 1.43. At the transition of expansion to contraction, the steam dynamic pressure reaches a maximum and the steam total pressure decreases to a minimum. Because the water dynamic pressure is significantly higher than the steam dynamic pressure, the total pressure is maximum at the end of the two-phase region. Mass transfer is much higher in two-phase region than in other regions. The heat transfer coefficient calculated from the interface area decreases from 1.98 to 1.56 MW/m²K, and that calculated from the two-phase region volume increases from 3.37 × 10³ to 4.05 × 10³ MW/m²K.