Heat transfer to a $\rm Na$–$\rm K$ alloy in a close-packed rod array with mixed convections

Results of combined natural and induced convection in bundles of heat-generating rods surrounded by liquid metals are given. The apparatus and methods are described and results are given for the temperature distribution and heat transfer under various flow conditions and flow directions for a $\rm Na$–$\rm K$ alloy. A considerable increase in $\rm Nu$ is obtained for $\rm Pe$ less than equivalent to $100$ and parallel mixed convection, this being relative to purely forced motion. A formula is given to evaluate the magnitude of the effect.