Numerical study of void drift in rod bundle with subchannel and CFD codes (KIT Scientific Reports ; 7669)

In the present study, a new phenomenological two-phase interchannel mixing model was proposed for subchannel analysis in bubbly flow regime under PWR pressure level. The key constitutive relation is the modeling of void drift, for which the concept of a two-phase flow approaching an equilibrium state was adopted. Based on systematic CFD simulations, correlations were proposed to describe both the void fraction distribution at equilibrium state and the effective mixing velocity due to void drift.