Experience in Gas Dynamic Tests of Model Bundles of Self-Separating Helical Fuel Elements Made Using Additive Technologies

This article considers the experience in arranging and conducting gas dynamic tests of model self-separating fuel element bundles made using additive technologies. The models consist of helical rectangular-sectioned rods of 4.8 mm in specified diameter and 2.5 mm in width and differ by the coiling pitch and rod production technology, including 3D printing modes and surface treatment. The models are tested at the aerodynamic test bench of the Department of Nuclear Reactors and Facilities of Bauman Moscow State Technical University. The data about the static pressure distribution along and around the perimeter of the model jacket are used to calculate the hydraulic characteristics of bundles in the Reynolds number range from 2.8 × 10³ to 6.8 × 10³. It is shown that the rod production technology determining the quality and roughness of the surface has a significant effect on these characteristics.