Validation and Verification Analyses of Turbulent Forced Convection of Na and NaK in Miniature Heat Sinks

The aim of this work is to evaluate the accuracy of two computational models applied to the turbulent forced convection of alkali liquid metals of Na and NaK. The results of local Nusselt numbers for two turbulent models of realizable k-ε and SST k-ω are evaluated in this analysis. A solution verification process is carried out to determine epistemic uncertainty in computational results of convective heat transfer rates of Na in stainless steel (SS-316) miniature heat sinks. Besides solutions verification, the Numerical results were validated against the experimental data for local Nusselt numbers of NaK turbulent flow within a uniformly heated tube at a Reynolds number of 30,260. The results from the SST k-ω model follow the trend of the experimental data better than the realizable k-ε turbulent model. The realizable k-ε turbulent model overestimates the NaK local Nusselt numbers by almost 5%. In both turbulent models, the maximum epistemic uncertainty of the local convective heat transfer rate is 4% within the investigated miniature heat sink at a Reynolds number of 9,000.