Flow visualization in a simplified helically coiled steam generator geometry

Helically coiled steam generators (HCSG) have been considered for new nuclear power plant designs including high temperature gas cooled reactors and small modular reactors. In this study a simplified HCSG design with single flow channel was proposed to generate experimental benchmarking data. The experiment was conducted at Re ≈ 9,000 considering the currently reasonable computing power. The mean velocity and the second order statistics profiles were obtained from multiple locations. Also, the vortex structure was analyzed using Q-criterion. The results showed interactions between rods and flow oscillations. The oscillating rotational flow in cavity regions seemed to be related to the tangential vortical flow structure along the rods. This phenomenon requires additional simultaneous flow visualization from a different angle in further works. (author)