Atomic Energy Society of Japan

In a CFD computation where definition of the bulk is difficult, the boundary condition should be given from the physical properties in a computational cell contacting with the structural wall. Therefore, it was confirmed that the condensation heat transfer coefficient was approximately evaluated from the physical properties at an optional location far from the condensation surface by using condensation heat transfer data with downward flows of steam-air mixture in a vertical pipe with the diameter of 49.5 mm.