New studies of the natural convection around the fuel rod model of the BME training reactor with PIV/LIF technique
21st Symposium of AER on VVER Reactor Physics and Reactor Safety (2011, Dresden, Germany)
Nuclear applications of three dimensional thermal hydraulics
Abstract
In this paper the model of a fuel pin of the Training Reactor of Budapest University of
Technology and Economics was investigated with Particle Image Velocimetry and Laser Induced
Fluorescence measurement methods. An experimental setup was designed, built and optimized to
investigate the natural convection around a model of a fuel pin of the Training Reactor. The
processes were analysed using an electrically heated rod, which models the geometry of the fuel
rods in the Training Reactor. The heated length of the model is the same as the active length of
the real fuel rods. The rod is placed in a glass tank with a shape of a square-based prism. An
additional cooling system ensures constant flow conditions around the rod. The setup consists of
an additional flow channel box, the equivalent diameter of which is equal to the equivalent
diameter of the real fuel assembly. Simultaneous measurements of velocity and temperature
fields were performed in different vertical positions for both cases of natural convection with and
without the flow channel box. The effect of the presence of the channel was analyzed, and a
laminarizating influence was observed. The local heat transfer coefficient was calculated for
every measurement. The two dimensional measurement techniques gave extensive results, the
structure of the hydraulic and thermal boundary layer were fully analyzed.