Model for turbulent momentum and heat transport in large rod bundles. [LMFBR]

A quasi-continuum model for turbulent momentum and heat transport in large rod bundles has been developed. This model has been derived from a subchannel analysis and adapted to a quasi-continuum form by introducing concepts of porosity and distributed resistance. The effects of turbulent kinetic energy generation due to shear, viscosity, diffusion, geometric effects, buoyancy, and Reynolds number are explicitly included. The proposed model of turbulence is relatively simple, yet it is believed to provide a framework for taking account of important turbulent mechanisms in rod bundles.