NACIE-UP post-test simulations by CFD codes

The paper concerns about CFD calculations of LBE flowing in the wire-wrapped hexagonal array electrical pin bundle of NACIE-UP facility. Pressure drop and friction factor analyses are performed in order to find possible matching between CFD results and available correlations to be used in the frame of forthcoming applications involving CFD/System Codes (STH) coupling calculations. The Fuel Pin Simulator of the NACIE-UP facility is presently considered for calculations; post-test analyses are performed as well in order to understand capabilities and uncertainties of available CFD codes and techniques in the liquid metal thermal hydraulics field. Calculations were performed using the commercial codes STAR-CCM+ and ANSYS FLUENT and promising results were provided. In particular, good matching between CFD results and predictions from the Cheng and Todreas (1986) correlation is observed in the frame of the pressure drop analysis. Post-test analyses aiming at comparing the measured and calculated temperature values for three selected operating conditions were performed; the adopted CFD tool reported good capabilities in reproducing the experimental results. Sensitivity analyses considering anomalous power distributions were also performed. The lesson drawn provided further comprehension of the involved phenomena and interesting information for future applications involving CFD/STH codes in coupling calculations.