Theory and implementation of nuclear safety system codes - Part II: System code closure relations, validation, and limitations

摘要

This is Part II of two articles describing the details of thermal-hydraulic system codes. In this second part of the article series, the system code closure relationships (used to model thermal and mechanical non-equilibrium and the coupling of the phases) for the governing equations are discussed and evaluated. These include several thermal and hydraulic models, such as heat transfer coefficients for various flow regimes, two phase pressure correlations, two phase friction correlations, drag coefficients and interfacial models between the fields. These models are often developed from experimental data. The experiment conditions should be understood to evaluate the efficacy of the closure models.