CFD simulation of steam–air jet condensation

Abstract

A three dimensional model was established based on Euler–Euler two-fluid model to simulate the steam jet direct contact condensation with air involved. Condensation of steam in the gas mixture was realized using thermal phase change model. Species transport equation for the gas phase was employed to account for composition variation of the steam air mixture. The investigated gas mass flux at nozzle exit was within 300kg/m2/s, with non-condensable air of less than 10%. Numerical results show the steam in gas plume condenses rapidly after leaving the nozzle, until only air and a little uncondensed steam remain in the gas plume. The addition of air in the jet deteriorates the condensation heat transfer, leading temperature and void fraction around the nozzle to decrease more slowly in both axial and radial directions. Five cases of experimental results were demonstrated with three of them validating the temperature distribution and two of them validating the void fraction. The comparison between numerical and experimental results demonstrates the CFD model can predict the steam–air jet condensation process quite reasonably.Classification: K. Thermal hydraulics