Subgrid-based analytical wall function for steam condensation in the presence of air

相馬 秀 ; 石垣 将宏* ; 安部 諭  ; 柴本 泰照 

Soma, Shu; Ishigaki, Masahiro*; Abe, Satoshi; Shibamoto, Yasuteru

This paper presents a study on an advanced wall function model applicable to steam condensation in the presence of air. Since condensation flows encountered in a nuclear reactor containment vessel experience suction and buoyancy forces near the wall, more general and cost-efficient wall treatments are needed to overcome the limitations of conventional wall functions relying on the log-law of the wall. In this study, we propose a subgrid-based analytical wall function, extending an original model developed for single-species flows to address suction effects and buoyancy induced by temperature variations and accumulation of non-condensable gas near the condensing wall. Validation against separate-effect test data for channel flows (WINCS, CONAN, and SETCOM) demonstrates that the proposed model generally provides reasonable agreement and low mesh sensitivity in the predicted boundary layer profiles and condensation heat flux under various conditions for suction and buoyancy effects.