CFD simulation of the pre-heater of a nuclear facility steam generator using a thermal coupled model

A thermal-hydraulic study of the pre-heater belonging to the steam generator of the nuclear experimental facility RD-14M was carried out. The thermal coupling between the primary and secondary flows was solved through three-dimensional Computational Fluid Dynamics (CFD) and the conjugated heat transfer model. The net heat transfer coefficient was calculated and compared with well-known literature correlations from Bell-Delaware and Kern, as well as with RELAP simulation. Acceptable agreement among the different methodologies was found, even though literature correlations underestimated heat transfer. The occurrence of flow stagnation, high turbulence, and recirculation zones in the secondary circuit was also analyzed. It was concluded that the Bell-Delaware correlation is suitable for preliminary calculus, and CFD is useful and reliable for designing as well as assessing heat transfer devices, giving a large understanding of the thermal hydraulic phenomena. Finally, the RELAP code showed to be fast and accurate to get the heat transfer and pressure loss with minimal input data requirements.