Sensitivity analysis for subcooled flow boiling using Eulerian CFD approach

Abstract

This paper presents capability of Eulerian CFD (Computational Fluid Dynamics) approach using sensitivity-analysis-based model to predict subcooled boiling flows in the DEBORA experiment, the conditions corresponding to those in PWRs (Pressurized Water Reactors). The main feature of the developed model is a good estimation of the void fraction distribution in a cross section of a heated pipe, not only in the lower void regime but also in the high void regime (>0.5), which is achieved by modifying the lift force coefficients in the model developed by Baglietto’s group. In addition, the Sauter diameter profile is well predicted by employing the MUSIG population balance model, in which the coalescence and breakage factors are tuned to the experiments. A nucleation site density model recently proposed by Li is employed together with the Tolubinsky and Kostanchuk bubble departure diameter model, whose coefficient is again obtained via a sensitivity analysis. The model developed in this work, CTU-PSI model, is expected to be applied to boiling flow simulations in PWRs.