Improvement of wall condensation modeling with suction wall functions for containment application

• Assessment of wall functions for single phase condensation models for large scale application.
• Identification of modeling errors related to standard log-law due to buoyancy and wall normal mass transfer (suction).
• Modeling of wall normal mass transfer by literature formulation (Sucec, 1999) and in-house approach (FIBULA).
• Validation against isothermal Favre experimental data.
• Comparison against reference fine grid solution for condensing conditions.

To simulate wall condensation on containment scale with CFD methods at reasonable computational cost, a single phase approach has to be applied and wall functions have to be used. However, standard wall functions were derived for flows without heat and mass transfer and their fundamental simplifications are not appropriate to deal with condensation. This paper discusses the limitations of standard wall functions and proposes two wall functions for the momentum equation dealing with mass transfer normal to the sheared wall (suction). The first proposed suction wall function is an algebraic modification based on the standard wall function concept. The second proposed wall function is an in-house developed suction wall function with the potential to cover also heat and mass transfer effects by storing the complex solutions of the RANS-Equations in a lookup table. The wall function approaches are compared to experimental results for boundary layer flows with suction and to the reference results obtained using a refined grid in order to resolve the condensing boundary layer.