Predictive Modeling of Steam Condensation onto Finned Tubes in the Presence of Noncondensable Gases for Passive Safety Reactor Containment Heat Exchangers

A mechanistic model is presented to predict the steam condensation on containment finned tubes in the presence of noncondensables (NCs). The total thermal resistance from bulk gas to coolant is formulated as a parallel combination of the convective and condensation gas resistances coupled in series to those of the condensate layer, the wall, and the coolant. The condensate layer thermal resistance is calculated by means of an Adamek-based model, while the gas mixture thermal resistance is formulated based on diffusion layer modeling. The model results are compared with the available experimental data of Wanniarachi and Rose for pure steam condensation on finned tubes and with the data of Mazzochi for condensation in the presence of NC gases