INVESTIGATION OF TURBULENT PRT MODEL AND THE SEGMENTATION RULE FOR LBE TURBULENT HEAT TRANSFER

With liquid metal like lead-bismuth alloy(LBE) acting as a coolant for nuclear reactors, it is necessary to use a more accurate heat transfer relationship and a more reliable Pr-t model for the low Pr fluid. Because of the low Pr of liquid metal, the thermal conductivity is more dominant than the momentum transfer, which is quite different from ordinary fluids. In this case, the turbulent Pr-t can better reflect the heat transfer process. In this study, the Pr-t = A(1) +A(2)/Pr form is selected, and the corresponding coefficients are obtained by the renormalization group analysis method, then corrected by Pr. Furthermore, the applicable range and segmentation rule of the turbulent Pr-t model are discussed, and the obtained Pr-t segmentation theoretical model is written into CFD. The result shows that, compared with the previously unmodified model, the radial temperature distribution and Nusselt number (Nu) of the annular and bundle channel obtained by RANS method with the improved Pr-t model is in good agreement with experimental results, and the deviations are within 5%. It is proved that the turbulent Pr-t segmentation theoretical model proposed in this study is effective and can represent the heat transfer characteristics of liquid metal from the mechanism.