Analytical prediction of subchannel friction factor for infinite bare rod square and triangular arrays of low pitch to diameter ratio in turbulent flow Original Research Article

A theoretically based prediction method for the determination of the subchannel friction factor at low pitch to rod diameter ratio (PD < 1.2) in turbulent flow of the infinite bare rods array has been developed. The present model assumes the validity of the ‘law of the wall’ over the entire flow area. The algebraic form of the law of the wall is integrated over the entire flow area and the local friction velocity variation along the rod periphery is considered in this study. The present method is applied to the infinite bare rod square and triangular arrays with PD < 1.2, and the prediction results show good agreement with the available experimental data.