Turbulent mixing model applicable to supercritical condition

In the design of a nuclear reactor, it is very important to predict the detailed flow and temperature distributions in the reactor core. The turbulent velocity fluctuation across the gap is an important parameter determining the inter-channel exchange, but the existing correlations show a rather large discrepancy with each other under supercritical conditions. Two types of subchannel lattices, triangular and square arrays are selected to be investigated using the CFD tools. The thermal-hydraulic behavior was investigated between the subchannels. A turbulent mixing correlation developed applicable under the supercritical condition was conducted under the adiabatic condition, a modifying factor was given for heating. Finally, the model was compiled into the subchannel code to analyze the CANFLEX bundle. (author)