Heat Transfer in Sodium-Potassium Alloy

To provide heat transfer data of high precision for NaK heat exchange systems, a NaK heat transfer loop was designed to minimize experimental errors and yield results with a high degree of reproducibility. Average heat transfer coefficients were determined for both tube and annulus in a horizontal concentric tube, NaK (56% K) to NaK exchanger. The results after correction for entrance effects are described by the following empirical relations: No distinction was found between the Nusselt moduli measured at uniform heat flux and those measured at variable heat flux. No change in the experimental Nusselt moduli was observed when the oxide content was varied between 0.0025 and 0.006 wt. % oxygen.