Simulation of direct contact condensation of steam jets submerged in subcooled water by means of a one-dimensional two-fluid model

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A one-dimensional simulation model for the direct contact condensation of steam in subcooled water is presented. The model allows to determine major parameters of the process such as the jet penetration length and the axial development of the temperature. Entrainment of water by the steam jet is modelled according to the turbulent entrainment assumption, which can be derived from the Kelvin-Helmholtz instability theory. The steamwater two-phase flow obtained during the mixing process is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations which is discretized by means of an explicit Runge-Kutta method. The model shows good agreement with published data of pool direct contact condensation experiments at low steam mass flux.