Effects of buoyancy on laminar vertical upward flow friction factors in cylindrical tubes

The coupled energy and momentum equations were solved for fully developed vertical upward laminar flow in a cylindrical tube. A simple engineering correlation which agreed well with the analytical solution was obtained. In addition, an effect was obtained and incorporated into a general engineering correlation. Comparison of the general correlation with the existing data was adequate. If the results for a cylindrical tube can be applied to typical wire-wrapped rod bundles in a LMFBR the use of an increased friction factor to account for buoyancy effects in laminar flow is not justified because the maximum value of the Grashof—Reynolds number ratio is small.