A Note on Turbulent-Laminar Transition for Flow in Triangular Rod Bundles

The Ramm-Johannsen correlation of eddy diffusivity for momentum is used to compute the onset and growth of flow laminarization in triangular rod bundles. The laminarization is indicated by Reynolds numbers based on the bulk flow condition in the coolant channel. Simple correlations that qualitatively estimate the transition Reynolds numbers are developed for applications in the safety analysis of liquid-metal fast breeder reactors.