Abstract
In nuclear power system, the phenomenon of condensation is familiar especially in the progress of accident like containment spray. In present work, a CFD method is proposed to simulate the condensation of steam, and the negative quality source and energy source were considered by user-defined function (UDF). After that, the simulation method was validated by the relevant experimental results. Thus, the transient condensation of steam in a large space is numerically investigated with the consideration of non-condensable gas and different working conditions including inlet velocity, initial pressure, wall temperature, and inlet the mass fraction of non-condensable gas. The distributions of species and the field information of velocity, temperature, condensation rate, mass fraction and wall heat flux are acquired by simulation. The results indicate that the inlet velocity and gravity have significant influence on the distribution of steam with the consideration of convective and diffusion. Furthermore, the condensation occurs earlier in the area of the superior gradient of the concentration of steam. In addition, the condensation rate increases with greater the inlet velocity and the initial pressure and decreases with greater the wall temperature and mass fraction of non-condensable gas.
