A numerical and three-dimensional analysis of steady state rectangular natural circulation loop

Free convection circuits or natural circulation systems are employed in several engineering fields. In nuclear reactors, natural circulation can be used as a passive safety system or as a main heat transfer mechanism.This work presents the results of a three-dimensional numerical analysis of a steady state rectangular natural circulation loop located at the Instituto de Pesquisas Energéticas e Nucleares/Comissão Nacional de Energia Nuclear (IPEN/CNEN-SP). Numerical results and experimental data present in this paper are discussed and compared.The model is good enough to capture 3-D effects, such as the formation of vortex structures and swirl effects.

► We developed a thermal fluid dynamics numerical model for a natural circulation rectangular loop. ► We compared the numerical model to the experimental ones and showed up a good agreement. ► The three-dimensional effects, such as the formation of vortex structures and swirl e effects, were captured.