An analytical model for the determination of stability boundaries in a natural circulation single-phase thermosyphon loop

In this paper, an extension of previous analyses of natural circulation in a simple single-phase loop is presented. Assuming more general correlations for the friction factor and the heat transfer coefficient, an analytical model describing the system is obtained and a parametric representation of its dynamic behaviour is achieved. On this basis, stability maps can be drawn. A preliminary validation of the analytical model has been carried out by using an independent program developed for the analysis of stability in natural circulation loops. The aim of the present work is to provide a simple analytical tool devoted to the stability analysis of a reference single-phase loop. This model can be applied in a relatively wide range of conditions and regimes to provide benchmark solutions for thermal-hydraulic codes and related nodalisations.